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1.
  • 2019
  • Tidskriftsartikel (refereegranskat)
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2.
  • Elsik, Christine G., et al. (författare)
  • The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
  • 2009
  • Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
  • Tidskriftsartikel (refereegranskat)abstract
    • To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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3.
  • Sampson, Joshua N., et al. (författare)
  • Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
  • 2015
  • Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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4.
  • Sawcer, Stephen, et al. (författare)
  • Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis
  • 2011
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 476:7359, s. 214-219
  • Tidskriftsartikel (refereegranskat)abstract
    • Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis.
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5.
  • Teslovich, Tanya M., et al. (författare)
  • Biological, clinical and population relevance of 95 loci for blood lipids
  • 2010
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 466:7307, s. 707-713
  • Tidskriftsartikel (refereegranskat)abstract
    • Plasma concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides are among the most important risk factors for coronary artery disease (CAD) and are targets for therapeutic intervention. We screened the genome for common variants associated with plasma lipids in >100,000 individuals of European ancestry. Here we report 95 significantly associated loci (P<5 x 10(-8)), with 59 showing genome-wide significant association with lipid traits for the first time. The newly reported associations include single nucleotide polymorphisms (SNPs) near known lipid regulators (for example, CYP7A1, NPC1L1 and SCARB1) as well as in scores of loci not previously implicated in lipoprotein metabolism. The 95 loci contribute not only to normal variation in lipid traits but also to extreme lipid phenotypes and have an impact on lipid traits in three non-European populations (East Asians, South Asians and African Americans). Our results identify several novel loci associated with plasma lipids that are also associated with CAD. Finally, we validated three of the novel genes-GALNT2, PPP1R3B and TTC39B-with experiments in mouse models. Taken together, our findings provide the foundation to develop a broader biological understanding of lipoprotein metabolism and to identify new therapeutic opportunities for the prevention of CAD.
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6.
  • Machiela, Mitchell J., et al. (författare)
  • Characterization of Large Structural Genetic Mosaicism in Human Autosomes
  • 2015
  • Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 96:3, s. 487-497
  • Tidskriftsartikel (refereegranskat)abstract
    • Analyses of genome-wide association study (GWAS) data have revealed that detectable genetic mosaicism involving large (>2 Mb) structural autosomal alterations occurs in a fraction of individuals. We present results for a set of 24,849 genotyped individuals (total GWAS set II [TGSII]) in whom 341 large autosomal abnormalities were observed in 168 (0.68%) individuals. Merging data from the new TGSII set with data from two prior reports (the Gene-Environment Association Studies and the total GWAS set I) generated a large dataset of 127,179 individuals; we then conducted a meta-analysis to investigate the patterns of detectable autosomal mosaicism (n = 1,315 events in 925 [0.73%] individuals). Restricting to events >2 Mb in size, we observed an increase in event frequency as event size decreased. The combined results underscore that the rate of detectable mosaicism increases with age (p value = 5.5 x 3 10(-31)) and is higher in men (p value = 0.002) but lower in participants of African ancestry (p value = 0.003). In a subset of 47 individuals from whom serial samples were collected up to 6 years apart, complex changes were noted over time and showed an overall increase in the proportion of mosaic cells as age increased. Our large combined sample allowed for a unique ability to characterize detectable genetic mosaicism involving large structural events and strengthens the emerging evidence of non-random erosion of the genome in the aging population.
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7.
  • Sodergren, Erica, et al. (författare)
  • The genome of the sea urchin Strongylocentrotus purpuratus.
  • 2006
  • Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 314:5801, s. 941-52
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.
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8.
  • Asselbergs, Folkert W., et al. (författare)
  • Large-Scale Gene-Centric Meta-analysis across 32 Studies Identifies Multiple Lipid Loci
  • 2012
  • Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297. ; 91:5, s. 823-838
  • Tidskriftsartikel (refereegranskat)abstract
    • Genome-wide association studies (GWASs) have identified many SNPs underlying variations in plasma-lipid levels. We explore whether additional loci associated with plasma-lipid phenotypes, such as high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglycerides (TGs), can be identified by a dense gene-centric approach. Our meta-analysis of 32 studies in 66,240 individuals of European ancestry was based on the custom similar to 50,000 SNP genotyping array (the ITMAT-Broad-CARe array) covering similar to 2,000 candidate genes. SNP-lipid associations were replicated either in a cohort comprising an additional 24,736 samples or within the Global Lipid Genetic Consortium. We identified four, six, ten, and four unreported SNPs in established lipid genes for HDL-C, LDL-C, TC, and TGs, respectively. We also identified several lipid-related SNPs in previously unreported genes: DGAT2, HCAR2, GPIHBP1, PPARG, and FTO for HDL-C; SOCS3, APOH, SPTY2D1, BRCA2, and VLDLR for LDL-C; SOCS3, UGT1A1, BRCA2, UBE3B, FCGR2A, CHUK, and INSIG2 for TC; and SERPINF2, C4B, GCK, GATA4, INSR, and LPAL2 for TGs. The proportion of explained phenotypic variance in the subset of studies providing individual-level data was 9.9% for HDL-C, 9.5% for LDL-C, 10.3% for TC, and 8.0% for TGs. This large meta-analysis of lipid phenotypes with the use of a dense gene-centric approach identified multiple SNPs not previously described in established lipid genes and several previously unknown loci. The explained phenotypic variance from this approach was comparable to that from a meta-analysis of GWAS data, suggesting that a focused genotyping approach can further increase the understanding of heritability of plasma lipids.
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9.
  • Lange, Leslie A, et al. (författare)
  • Whole-Exome Sequencing Identifies Rare and Low-Frequency Coding Variants Associated with LDL Cholesterol.
  • 2014
  • Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297. ; 94:2, s. 233-245
  • Tidskriftsartikel (refereegranskat)abstract
    • Elevated low-density lipoprotein cholesterol (LDL-C) is a treatable, heritable risk factor for cardiovascular disease. Genome-wide association studies (GWASs) have identified 157 variants associated with lipid levels but are not well suited to assess the impact of rare and low-frequency variants. To determine whether rare or low-frequency coding variants are associated with LDL-C, we exome sequenced 2,005 individuals, including 554 individuals selected for extreme LDL-C (>98(th) or <2(nd) percentile). Follow-up analyses included sequencing of 1,302 additional individuals and genotype-based analysis of 52,221 individuals. We observed significant evidence of association between LDL-C and the burden of rare or low-frequency variants in PNPLA5, encoding a phospholipase-domain-containing protein, and both known and previously unidentified variants in PCSK9, LDLR and APOB, three known lipid-related genes. The effect sizes for the burden of rare variants for each associated gene were substantially higher than those observed for individual SNPs identified from GWASs. We replicated the PNPLA5 signal in an independent large-scale sequencing study of 2,084 individuals. In conclusion, this large whole-exome-sequencing study for LDL-C identified a gene not known to be implicated in LDL-C and provides unique insight into the design and analysis of similar experiments.
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10.
  • Postmus, Iris, et al. (författare)
  • Pharmacogenetic meta-analysis of genome-wide association studies of LDL cholesterol response to statins.
  • 2014
  • Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5
  • Tidskriftsartikel (refereegranskat)abstract
    • Statins effectively lower LDL cholesterol levels in large studies and the observed interindividual response variability may be partially explained by genetic variation. Here we perform a pharmacogenetic meta-analysis of genome-wide association studies (GWAS) in studies addressing the LDL cholesterol response to statins, including up to 18,596 statin-treated subjects. We validate the most promising signals in a further 22,318 statin recipients and identify two loci, SORT1/CELSR2/PSRC1 and SLCO1B1, not previously identified in GWAS. Moreover, we confirm the previously described associations with APOE and LPA. Our findings advance the understanding of the pharmacogenetic architecture of statin response.
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11.
  • Ademuyiwa, Adesoji O., et al. (författare)
  • Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
  • 2016
  • Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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12.
  • de Vries, Paul S., et al. (författare)
  • Comparison of HapMap and 1000 Genomes Reference Panels in a Large-Scale Genome-Wide Association Study
  • 2017
  • Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:1
  • Tidskriftsartikel (refereegranskat)abstract
    • An increasing number of genome-wide association (GWA) studies are now using the higher resolution 1000 Genomes Project reference panel (1000G) for imputation, with the expectation that 1000G imputation will lead to the discovery of additional associated loci when compared to HapMap imputation. In order to assess the improvement of 1000G over HapMap imputation in identifying associated loci, we compared the results of GWA studies of circulating fibrinogen based on the two reference panels. Using both HapMap and 1000G imputation we performed a meta-analysis of 22 studies comprising the same 91,953 individuals. We identified six additional signals using 1000G imputation, while 29 loci were associated using both HapMap and 1000G imputation. One locus identified using HapMap imputation was not significant using 1000G imputation. The genome-wide significance threshold of 5x10(-8) is based on the number of independent statistical tests using HapMap imputation, and 1000G imputation may lead to further independent tests that should be corrected for. When using a stricter Bonferroni correction for the 1000G GWA study (P-value < 2.5x10(-8)), the number of loci significant only using HapMap imputation increased to 4 while the number of loci significant only using 1000G decreased to 5. In conclusion, 1000G imputation enabled the identification of 20% more loci than HapMap imputation, although the advantage of 1000G imputation became less clear when a stricter Bonferroni correction was used. More generally, our results provide insights that are applicable to the implementation of other dense reference panels that are under development.
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13.
  • Machiela, Mitchell J, et al. (författare)
  • Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome
  • 2016
  • Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases.
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14.
  • Mueller, Stefanie H., et al. (författare)
  • Aggregation tests identify new gene associations with breast cancer in populations with diverse ancestry
  • 2023
  • Ingår i: Genome Medicine. - : BioMed Central (BMC). - 1756-994X. ; 15
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Low-frequency variants play an important role in breast cancer (BC) susceptibility. Gene-based methods can increase power by combining multiple variants in the same gene and help identify target genes.Methods: We evaluated the potential of gene-based aggregation in the Breast Cancer Association Consortium cohorts including 83,471 cases and 59,199 controls. Low-frequency variants were aggregated for individual genes' coding and regulatory regions. Association results in European ancestry samples were compared to single-marker association results in the same cohort. Gene-based associations were also combined in meta-analysis across individuals with European, Asian, African, and Latin American and Hispanic ancestry.Results: In European ancestry samples, 14 genes were significantly associated (q < 0.05) with BC. Of those, two genes, FMNL3 (P = 6.11 x 10(-6)) and AC058822.1 (P = 1.47 x 10(-4)), represent new associations. High FMNL3 expression has previously been linked to poor prognosis in several other cancers. Meta-analysis of samples with diverse ancestry discovered further associations including established candidate genes ESR1 and CBLB. Furthermore, literature review and database query found further support for a biologically plausible link with cancer for genes CBLB, FMNL3, FGFR2, LSP1, MAP3K1, and SRGAP2C.Conclusions: Using extended gene-based aggregation tests including coding and regulatory variation, we report identification of plausible target genes for previously identified single-marker associations with BC as well as the discovery of novel genes implicated in BC development. Including multi ancestral cohorts in this study enabled the identification of otherwise missed disease associations as ESR1 (P = 1.31 x 10(-5)), demonstrating the importance of diversifying study cohorts.
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15.
  • Alimena, Juliette, et al. (författare)
  • Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider
  • 2020
  • Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 47:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton-proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments-as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER-to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity 'dark showers', highlighting opportunities for expanding the LHC reach for these signals.
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16.
  • Benedict, G. Fritz, et al. (författare)
  • Distance scale zero points from galactic RR Lyrae star parallaxes
  • 2011
  • Ingår i: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 142:6, s. 187-
  • Tidskriftsartikel (refereegranskat)abstract
    • We present new absolute trigonometric parallaxes and proper motions for seven Population II variable stars-five RR Lyr variables: RZ Cep, XZ Cyg, SU Dra, RR Lyr, and UV Oct; and two type 2 Cepheids: VY Pyx and kappa Pav. We obtained these results with astrometric data from Fine Guidance Sensors, white-light interferometers on Hubble Space Telescope. We find absolute parallaxes in milliseconds of arc: RZ Cep, 2.12 +/- 0.16 mas; XZ Cyg, 1.67 +/- 0.17 mas; SU Dra, 1.42 +/- 0.16 mas; RR Lyr, 3.77 +/- 0.13 mas; UV Oct, 1.71 +/- 0.10 mas; VY Pyx, 6.44 +/- 0.23 mas; and. Pav, 5.57 +/- 0.28 mas; an average sigma(pi)/pi = 5.4%. With these parallaxes, we compute absolute magnitudes in V and K bandpasses corrected for interstellar extinction and Lutz-Kelker-Hanson bias. Using these RR Lyrae variable star absolute magnitudes, we then derive zero points for M(V)-[Fe/H] and M(K)-[Fe/H]-log P relations. The technique of reduced parallaxes corroborates these results. We employ our new results to determine distances and ages of several Galactic globular clusters and the distance of the Large Magellanic Cloud. The latter is close to that previously derived from Classical Cepheids uncorrected for any metallicity effect, indicating that any such effect is small. We also discuss the somewhat puzzling results obtained for our two type 2 Cepheids.
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17.
  • Smith, Gustav, et al. (författare)
  • The Impact of Ancestry and Common Genetic Variants on QT Interval in African Americans.
  • 2012
  • Ingår i: Circulation: Cardiovascular Genetics. - 1942-325X. ; 5:6, s. 647-655
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: -Ethnic differences in cardiac arrhythmia incidence have been reported, with a particularly high incidence of sudden cardiac death (SCD) and low incidence of atrial fibrillation in individuals of African ancestry. We tested the hypotheses that African ancestry and common genetic variants are associated with prolonged duration of cardiac repolarization, a central pathophysiological determinant of arrhythmia, as measured by the electrocardiographic QT interval. METHODS AND RESULTS: -First, individual estimates of African and European ancestry were inferred from genome-wide single nucleotide polymorphism (SNP) data in seven population-based cohorts of African Americans (n=12 097) and regressed on measured QT interval from electrocardiograms. Second, imputation was performed for 2.8 million SNPs and a genome-wide association (GWA) study of QT interval performed in ten cohorts (n=13 105). There was no evidence of association between genetic ancestry and QT interval (p=0.94). Genome-wide significant associations (p<2.5x10(-8)) were identified with SNPs at two loci, upstream of the genes NOS1AP (rs12143842, p=2x10(-15)) and ATP1B1 (rs1320976, p=2x10(-10)). The most significant SNP in NOS1AP was the same as the strongest SNP previously associated with QT interval in individuals of European ancestry. Low p-values (p<10(-5)) were observed for SNPs at several other loci previously identified in GWA studies in individuals of European ancestry, including KCNQ1, KCNH2, LITAF and PLN. CONCLUSIONS: -We observed no difference in duration of cardiac repolarization with global genetic indices of African ancestry. In addition, our GWA study extends the association of polymorphisms at several loci associated with repolarization in individuals of European ancestry to include African Americans.
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18.
  • Agic, Heda, et al. (författare)
  • Late Ediacaran occurrences of the organic-walled microfossils Granomarginata and flask-shaped Lagoenaforma collaris gen. et sp. nov.
  • 2022
  • Ingår i: Geological Magazine. - : Cambridge University Press. - 0016-7568 .- 1469-5081. ; 159:7, s. 1071-1092
  • Tidskriftsartikel (refereegranskat)abstract
    • New occurrences of flask-shaped and envelope-bearing microfossils, including the predominantly Cambrian taxon Granomarginata, are reported from new localities, as well as from earlier in time (Ediacaran) than previously known. The stratigraphic range of Granomarginata extends into the Cambrian System, where it had a cosmopolitan distribution. This newly reported Ediacaran record includes areas from Norway (Baltica), Newfoundland (Avalonia) and Namibia (adjacent to the Kalahari Craton), and puts the oldest global occurrence of Granomarginata in the Indreelva Member (< 563 Ma) of the Stahpogieddi Formation on the Digermulen Peninsula, Arctic Norway. Although Granomarginata is rare within the assemblage, these new occurrences together with previously reported occurrences from India and Poland, suggest a potentially widespread palaeogeographic distribution of Granomarginata through the middle-late Ediacaran interval. A new flask-shaped microfossil Lagoenaforma collaris gen. et sp. nov. is also reported in horizons containing Granomarginata from the Stahpogieddi Formation in Norway and the Dabis Formation in Namibia, and flask-shaped fossils are also found in the Gibbett Hill Formation in Newfoundland. The Granomarginata-Lagoenaforma association, in addition to a low-diversity organic-walled microfossil assemblage, occurs in the strata postdating the Shuram carbon isotope excursion, and may eventually be of use in terminal Ediacaran biostratigraphy. These older occurrences of Granomarginata add to a growing record of body fossil taxa spanning the Ediacaran-Cambrian boundary.
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19.
  • Agic, Heda, et al. (författare)
  • Life through an Ediacaran glaciation : Shale- and diamictite-hosted organic-walled microfossil assemblages from the late Neoproterozoic of the Tanafjorden area, northern Norway
  • 2024
  • Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier. - 0031-0182 .- 1872-616X. ; 635
  • Tidskriftsartikel (refereegranskat)abstract
    • New organic-walled microfossil (OWM) assemblages are reported from upper Neoproterozoic glacial and interglacial siliciclastic deposits in Finnmark, northern Norway. A nearly continuous sedimentary succession of the Vestertana Group contains two glaciogenic units, the Smalfjorden and Mortensnes formations, interpreted as end-Cryogenian Marinoan and Ediacaran glaciations, respectively. We investigated the OWM record in the Nyborg, Mortensnes, and St ' ahpogieddi formations to assess the impact of a glacial interval on the diversity of microscopic eukaryotes. A modified acid-extraction technique was applied to recover OWM from the diamictite matrix. The upper Nyborg Formation contains morphologically complex Doushantuo-Pertatataka acritarchs (DPA), restricting the age of the Nyborg Formation to early-mid Ediacaran. DPA occur below the dolostones that record a negative carbon isotope excursion correlated with the Shuram anomaly and below a glacial diamictite. A decline in species richness and compositional change is observed in the Mortensnes glacial assemblage. DPA are replaced by bacterial filaments and cell aggregates. The overlying Indreelva Member, St ' ahpogieddi Formation contains Ediacara-type biota and palaeopascichnids, but only a depauperate OWM assemblage of leiosphaerids and flask-shaped microfossils characteristic of the late Ediacaran.The succession of assemblages in the Vestertana Group demonstrates a turnover from large eukaryotic OWM to a microbial community in the glacial interval, to a low diversity post-glacial assemblage during the rise of macroscopic life. We compared the Vestertana record to global DPA occurrences. Although one DPA assemblage zone postdates the Shuram excursion, no DPA occur above Ediacaran glacial diamictites in successions where those deposits are present. Considering this, and the community changes in the Vestertana succession, we suggest that DPA were affected by the onset of an Ediacaran glaciation. Lastly, we combined the biostratigraphic markers in the Vestertana Group to constrain the age of the Mortensnes diamictite.
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20.
  • Agic, Heda, et al. (författare)
  • Life through the 'Varanger ice ages' : microfossil record of late Neoproterozoic glacial-interglacial units from arctic Norway
  • 2018
  • Ingår i: Geological Society of America <em>Abstracts with Programs</em>. - : Geological Society of America.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The late Neoproterozoic strata in Finnmark (Arctic Norway) provide a good sedimentary record of Neoproterozoic glaciations on the Baltica paleocontinent. The lower Vestertana Group exposed on the Digermulen Peninsula contains two glaciogenic units, the Smalfjord and Mortensnes formations. Chemostratigraphic correlation dated the Smalfjord diamictite to the Marinoan glaciation (650-635 Ma), yet its age was also proposed to be older, per correlation to glacial units in central and southern Scandinavia. The diamictites are bracketing shales and siltstones of the interglacial Nyborg Formation. Stratigraphic, paleontological, and sedimentological data are presented from the interglacial-glacial succession, investigated by the Digermulen Early Life Research Group. Palynological analysis yielded well-preserved organic-walled microfossils (OWM) from the Nyborg Fm., and from fine-grained diamictite matrix in the Mortensnes Fm. via a modified extraction method.The interglacial Nyborg Fm. hosts a moderate diversity assemblage of prokaryotic and eukaryotic OWM, as well as acanthomorphic acritarchs such as Ceratosphaeridium, ?Cavaspina, and a novel process-bearing form. Organically preserved, enigmatic multicellular eukaryotic fossils occur in the upper Nyborg Fm. The Mortensens glacial assemblage is less diverse and contains bacterial filaments, leiosphaerids, toroidal forms, and Micrhystridium-type minute acanthomorphs.The presence of Doushantuo-Pertatataka type acritarchs in the Nyborg Fm., and small acanthomorphs in the Mortensnes diamictite corroborate an early Ediacaran age for the interglacial-glacial succession on Digermulen. In addition to the trace fossil and body-fossil record of Ediacara-biota in the overlying Stáhpogieddi Formation, the microfossil biostratigraphy suggests Marinoan and Gaskiers glaciation equivalent ages of the Varanger glaciations in Finnmark. Protistan diversity in the succession declined through and following the glaciation, until late Ediacaran.
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21.
  • Agić, Heda, 1989-, et al. (författare)
  • Organically-preserved multicellular eukaryote from the early Ediacaran Nyborg Formation, Arctic Norway
  • 2019
  • Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • Eukaryotic multicellularity originated in the Mesoproterozoic Era and evolved multiple times since, yet early multicellular fossils are scarce until the terminal Neoproterozoic and often restricted to cases of exceptional preservation. Here we describe unusual organically-preserved fossils from mudrocks, that provide support for the presence of organisms with differentiated cells (potentially an epithelial layer) in the late Neoproterozoic. Cyathinema digermulense gen. et sp. nov. from the Nyborg Formation, Vestertana Group, Digermulen Peninsula in Arctic Norway, is a new carbonaceous organ-taxon which consists of stacked tubes with cup-shaped ends. It represents parts of a larger organism (multicellular eukaryote or a colony), likely with greater preservation potential than its other elements. Arrangement of open-ended tubes invites comparison with cells of an epithelial layer present in a variety of eukaryotic clades. This tissue may have benefitted the organism in: avoiding overgrowth, limiting fouling, reproduction, or water filtration. C. digermulense shares characteristics with extant and fossil groups including red algae and their fossils, demosponge larvae and putative sponge fossils, colonial protists, and nematophytes. Regardless of its precise affinity, C. digermulense was a complex and likely benthic marine eukaryote exhibiting cellular differentiation, and a rare occurrence of early multicellularity outside of Konservat-Lagerstatten.
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22.
  • Agic, Heda, et al. (författare)
  • Unusual organic-walled microfossil from the late Neoproterozoic Nyborg Formation, Digermulen Peninsula, Arctic Norway
  • 2017
  • Ingår i: ISECT 2017.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The late Neoproterozoic Nyborg Formation is exposed in the Tanafjord area, Finnmark, Arctic Norway, on Digermulen and Varanger Peninsulas. The succession is composed of ~400 m of interbedded shales, siltstone and purple to grey sandstone, deposited between Neoproterozoic low latitude glacial deposits. The Nyborg Fm. lies on top of the Smalfjord diamictite, and is overlain by the Mortensnes diamictite (the latter was attributed to both Marinoan (650-635 Ma) and Gaskiers (579 Ma) glaciations) and the Ediacaran-Cambrian Stáhpogieddi Formation. Thus, the Nyborg Fm. represents late Neoproterozoic, probably the last Cryogenian interglacial interval. Presented material was collected in 2014 by members of Digermulen Early Life Research Group, from organic-rich, grey-green shales and siltstones of the Nyborg Mbr. D, uppermost Nyborg Fm. between Árasulluokta and Guvssájohka valleys. Organic-walled microfossils were extracted from shale via standard palynological acetolysis in hydrofluoric acid, and studied via light and scanning electron microscopy. Microfossils from the Nyborg Fm. include Synsphaeridium-type aggregated cells, unbranched bacterial filaments (Polythrichoides and Siphonophycus), sphaeromorph and envelope-bearing acritarchs (leiosphaerids, Stictosphaeridium, Simia), and previously unrecognized aggregated tubular microfossils. These taxa are long-ranging, but common in glacial-interglacial units worldwide, and thus broadly corroborate the Cryogenian age of the Nyborg sediments. The novel fossil, up to 300 μm in size, is a parenchymatous meshwork of interconnected organic-walled tubes that terminate in cup-shaped apices 4-11 µm in diameter. Irregular tube clusters are truncated both in macerates and in thin sections, suggesting post mortem transport. Elemental EDXS analysis indicates that extracted meshwork microfossils are predominantly composed of carbonaceous material and also associated with small amounts of titanium and vanadium. Considering the branching and adjoined body plan of carbonaceous fossil, it was likely multicellular and of eukaryotic affinity. As such, it may represent an important step in the evolution of complex multicellularity and morphological complexity several million years before the appearance of Ediacaran organisms.
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23.
  • Araujo, Nathalia, et al. (författare)
  • Tumor Suppressor Par-4 Regulates Complement Factor C3 and Obesity
  • 2022
  • Ingår i: Frontiers in Oncology. - : Frontiers Media SA. - 2234-943X. ; 12
  • Tidskriftsartikel (refereegranskat)abstract
    • Prostate apoptosis response-4 (Par-4) is a tumor suppressor that induces apoptosis in cancer cells. However, the physiological function of Par-4 remains unknown. Here we show that conventional Par-4 knockout (Par-4-/-) mice and adipocyte-specific Par-4 knockout (AKO) mice, but not hepatocyte-specific Par-4 knockout mice, are obese with standard chow diet. Par-4-/- and AKO mice exhibit increased absorption and storage of fat in adipocytes. Mechanistically, Par-4 loss is associated with mdm2 downregulation and activation of p53. We identified complement factor c3 as a p53-regulated gene linked to fat storage in adipocytes. Par-4 re-expression in adipocytes or c3 deletion reversed the obese mouse phenotype. Moreover, obese human subjects showed lower expression of Par-4 relative to lean subjects, and in longitudinal studies, low baseline Par-4 levels denoted an increased risk of developing obesity later in life. These findings indicate that Par-4 suppresses p53 and its target c3 to regulate obesity.
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24.
  • Barretina, Jordi, et al. (författare)
  • Subtype-specific genomic alterations define new targets for soft-tissue sarcoma therapy.
  • 2010
  • Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 42:8, s. 715-21
  • Tidskriftsartikel (refereegranskat)abstract
    • Soft-tissue sarcomas, which result in approximately 10,700 diagnoses and 3,800 deaths per year in the United States, show remarkable histologic diversity, with more than 50 recognized subtypes. However, knowledge of their genomic alterations is limited. We describe an integrative analysis of DNA sequence, copy number and mRNA expression in 207 samples encompassing seven major subtypes. Frequently mutated genes included TP53 (17% of pleomorphic liposarcomas), NF1 (10.5% of myxofibrosarcomas and 8% of pleomorphic liposarcomas) and PIK3CA (18% of myxoid/round-cell liposarcomas, or MRCs). PIK3CA mutations in MRCs were associated with Akt activation and poor clinical outcomes. In myxofibrosarcomas and pleomorphic liposarcomas, we found both point mutations and genomic deletions affecting the tumor suppressor NF1. Finally, we found that short hairpin RNA (shRNA)-based knockdown of several genes amplified in dedifferentiated liposarcoma, including CDK4 and YEATS4, decreased cell proliferation. Our study yields a detailed map of molecular alterations across diverse sarcoma subtypes and suggests potential subtype-specific targets for therapy.
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25.
  • Ebbestad, Jan Ove R., 1967-, et al. (författare)
  • Biostratigraphy and palaeontology of the lower Cambrian Duolbagáisá Formation on the Digermulen Peninsula, Arctic Norway
  • 2018
  • Ingår i: International Conference on Arctic Margins.
  • Konferensbidrag (refereegranskat)abstract
    • The lower Cambrian sequence on the Digermulen Peninsula (Finnmark, Arctic Norway) is the northernmost extension of the Cambrian deposits along the Caledonian front. It is exceedingly thick compared to cratonal successions typical of most of Baltica. The Duolbagáisá Formation represents the youngest lower Cambrian unit on the peninsula with the first trilobite-bearing strata, a plethora of trace fossils including diverse arthropod traces and Plagiogmus arcuatus, and abundant and wellpreserved organic walled microfossils (OWM). Extensive field work by the Digermulen Early Life Research Group allows for the first time a detailed appreciation of the age and faunal composition of the unit. The lower member is ~250 m thick with thin-bedded siltstone, sandstone and mudstone. A single unidentifiable holmiid thorax region occurs alongside arthropod trace fossils. OWM indicate the S. ornata-F. membranacea Zone. The upper member is ~390 m thick and consist of several upward shallowing parasequences with fine-grained sandstone, siltstone and mudstone followed by thick mature quartzite. The trace fossil Syringomorpha occurs throughout the upper member and Cruziana and Rusophycus are especially abundant in the upper parts. The first identifiable olenellid trilobites occur in a thick mudstone/siltstone interval at the middle of the member, along with an elliptocephalid trilobite and other arthropods. Abundant OWM indicate the H. dissimilare-S. ciliosa Zone with the higher levels belonging to the Volkovia-Liepaina Zone. The entire sequence thus span the Cambrian Series 2, stages 3–5.
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26.
  • Ebbestad, Jan Ove R., 1967-, et al. (författare)
  • Distribution and correlation of Sabellidites cambriensis (Annelida?) in the basal Cambrian on Baltica
  • 2022
  • Ingår i: Geological Magazine. - : Cambridge University Press. - 0016-7568 .- 1469-5081. ; 159:7, s. 1262-1283
  • Tidskriftsartikel (refereegranskat)abstract
    • Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-shaped imprints with transverse wrinkling, thick walls and an even tube diameter of up to 3 mm. The distribution of Sabellidites is investigated in three Ediacaran-Cambrian sections on the Digermulen Peninsula in Arctic Norway, spanning the Manndrapselva Member of the Stahpogieddi Formation and the lower member of the Breidvika Formation. Here, the Ediacaran-Cambrian boundary is located in the lower part of the upper parasequence (third cycle) of the Manndrapselva Member. Specimens of Sabellidites are rare but consistently present close to the lowest level of Treptichnus pedum and upsection, whereas the taxon is common and abundant in the lower part of the lower member of the Breidvika Formation, with an upper record at c. 55 m above the base. The range is comparable with that of the GSSP section in Newfoundland, Canada, establishing Sabellidites as an index fossil for the lowermost Cambrian. In the Manndrapselva Member, Sabellidites co-occurs with the acritarch Granomarginata, indicative of the lowermost Cambrian Granomarginata Zone, whereas in the Breidvika Formation it co-occurs with Asteridium. Sabellidites is widely distributed in Baltica, through the Rovnian and Lontovan regional stages but confined to the Fortunian global stage. In its lower range, Sabellidites is associated with a Treptichnus pedum trace fossil association and a depauperate leiosphaerid acritarch assemblage, followed by a Granomarginata assemblage. In its upper range, Sabellidites co-occurs with acritarchs of the Asteridium-Comasphaeridium Zone and the tubular foraminiferan Platysolenites. In Baltica, Sabellidites is a useful index fossil.
  •  
27.
  • Ebbestad, Jan Ove R., et al. (författare)
  • Distribution and correlation of Sabellidites cambriensis (Annelida?) in the basal Cambrian on Baltica
  • 2021
  • Ingår i: Geological Magazine. - Cambridge : Cambridge University Press (CUP). - 0016-7568 .- 1469-5081. ; 159:7, s. 1262-1283
  • Tidskriftsartikel (refereegranskat)abstract
    • Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-shaped imprints with transverse wrinkling, thick walls and an even tube diameter of up to 3 mm. The distribution of Sabellidites is investigated in three Ediacaran–Cambrian sections on the Digermulen Peninsula in Arctic Norway, spanning the Manndrapselva Member of the Stáhpogieddi Formation and the lower member of the Breidvika Formation. Here, the Ediacaran–Cambrian boundary is located in the lower part of the upper parasequence (third cycle) of the Manndrapselva Member. Specimens of Sabellidites are rare but consistently present close to the lowest level of Treptichnus pedum and upsection, whereas the taxon is common and abundant in the lower part of the lower member of the Breidvika Formation, with an upper record at c. 55 m above the base. The range is comparable with that of the GSSP section in Newfoundland, Canada, establishing Sabellidites as an index fossil for the lowermost Cambrian. In the Manndrapselva Member, Sabellidites co-occurs with the acritarch Granomarginata, indicative of the lowermost Cambrian Granomarginata Zone, whereas in the Breidvika Formation it co-occurs with Asteridium. Sabellidites is widely distributed in Baltica, through the Rovnian and Lontovan regional stages but confined to the Fortunian global stage. In its lower range, Sabellidites is associated with a Treptichnus pedum trace fossil association and a depauperate leiosphaerid acritarch assemblage, followed by a Granomarginata assemblage. In its upper range, Sabellidites co-occurs with acritarchs of the Asteridium–Comasphaeridium Zone and the tubular foraminiferan Platysolenites. In Baltica, Sabellidites is a useful index fossil.
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28.
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29.
  • Ebbestad, Jan Ove R., 1967-, et al. (författare)
  • Holmiid trilobites from the lower Cambrian of the Digermulen Peninsula, Arctic Norway
  • 2017
  • Ingår i: 6th International Conference on Trilobites and their Relatives. Tallinn, Estonia, 7-10 July 2017. - Tallinn : Libris Est OU. - 9789949818617
  • Konferensbidrag (refereegranskat)abstract
    • Lower Cambrian holmiid olenelloids are used for biozonation of lower Cambrian (Series 2) strata in Baltoscandia. About a dozen species have been named since the description of Holmia kjerulfi (Linnarsson, 1868), but except for the classical area in Mjøsa, Norway, the species traditionally occur in small numbers, are variably preserved, occur at one or a few localities only and usually with only one taxon present. Definitions of the biozones are therefore still problematic. One level in the lower Cambrian Duolbasgáissá Formation of the Digermulen Peninsula, Arctic Norway, has yielded more than 50 new specimens of holmiids, preliminarily assigned to Elliptocephala n. sp. and Kjerulfia n. sp. Acritarchs indicate the Heliosphaeridium dissimilare–Skagia ciliosa acritarch Zone which corresponds to the traditional Holmia kjerulfi Assemblage Zone. Elliptocephala n. sp. is known from about a dozen specimens. It is characterized by very long palpebral lobes, a parallel-sided glabella, a short anterior glabellar lobe and short genal spines. A node is developed on the occipital ring. Semi-complete specimens show up to 10 thoracic segments, but the full number of thoracic segments and the pygidium is unknown. The slightly older E. lundgreni (Moberg, 1892), known from the Schmidtiellus mickwitzi Zone of southern Sweden, differs in the proportions of the glabella, the length of the palpebral lobes and definition of the cephalic border. Both H. mobergi and H. sulcata from Sweden show similarities to Elliptocephala n. sp. in the weakly developed lateral border with an effaced anterior border furrow. Nikolaisen & Henningsmoen (1987) described Kjerulfia lata Kiær, 1917 from two fragmentary specimens from this locality in Digermulen. More than 20 new specimens from this site shows that the species differs from Kjerulfia lata from the type area in southern Norway in proportions and features of the glabella, the width of the genal field and the possession of a stout and high spine on the occipital ring, and it is tentatively assigned to Kjerulfia n. sp. The material from the Digermulen Peninsula adds to the diversity of the Baltoscandian holmiids and is tightly constrained stratigraphically.
  •  
30.
  • Ebbestad, Jan Ove R., 1967-, et al. (författare)
  • Stratigraphy of the Ediacaran and basal Cambrian of the Digermulen Peninsula, Northern Norway
  • 2015
  • Ingår i: Geological Society of America Abstracts with Programs, vol 47.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The succession of the Digermulen Peninsula in Finnmark, northern Norway, is the only fossiliferous site inScandinavia with sedimentation across the Ediacaran–Cambrian transition without a significant hiatus. Geologicalinvestigations started in the 1930’s, but the Peninsula was first mapped in the 60’s. Ediacara-type fossils werefirst discovered in the late 80’s but recent discoveries will establish the Digermulen Peninsula as one of the mostsignificant Ediacaran sites in northern Europe. The parautochthonous strata are exposed in the Tanafjord areaalong the coast and in valleys on the east side of the Peninsula. The beds dip slightly to the west with the strikefollowing the coastline (ca. 045°). The Ediacaran succession is close to 1000 m thick and dominantly siliciclastic.It starts with interglacial sediments of the Nyborg Formation (tentatively the earliest Ediacaran), overlying astacked succession of diamictites of the Cryogenian Smalfjord Formation. After a hiatus follows the glaciogenicdiamictites of the Mortensnes Formation (~60 m thick), which is commonly seen to represent the ~582 Ma-oldGaskiers glaciation. Upwards, the contact to the overlying Stáhpogiedde Formation is not exposed locally, but hasbeen shown to represent a hiatus followed by transitional fluvial to marine sediments of the Lillevannet Member.Ediacaran-type fossils appear in the succeeding Innerelva Member. This is a two-cycle deepening upwardssuccession of laminated mudstone with intercalated sand bodies showing load structures. Preliminary microfossilssamples of the Member have so far proven almost barren, making dating more challenging. The basal part of thesucceeding Manndraperelva Member consists of three cycles; first a succession of reddish sandstone followed bytwo coarsening-upward cycles. Each starts with mudstone and fine sandstone and terminates in cross-beddedsandstone. The Ediacaran–Cambrian boundary is located within the third cycle, identified by the trace fossilTreptichnus pedum and associated trilobed trace fossils.The Digermulen Early Life Research Group has since2011 made significant new finds, and focused fieldwork aims to resolve tighter age constraints, provenance of thesediments and the range and diversity of the extended Ediacaran biota.
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31.
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32.
  • Ebbestad, Jan Ove R., 1967-, et al. (författare)
  • Trilobites from the North: lower Cambrian olenelloids fromthe Digermulen Peninsula, Arctic Norway
  • 2016
  • Ingår i: 3. Trilobiten-Tagung [Berlin, 8. und 9. Oktober 2016] - Kurzfassungen der Vortrage. - Halle, Saale : Ampyx-Verlag. - 9783932795398
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Scandinavian lower Cambrian stratigraphy is largely trilobite based, defined by the occurrence of distincttrilobite assemblages with classic olenelloid trilobites like Holmia and Kjerulfia. Except for a few localities in Scandinavia where these taxa are fairly common, most occurrences are represented by a single or a fewincomplete specimens at the best. Since 2011 a collecting effort in the lower Cambrian strata on the Digermulen Peninsula, Arctic Norway has yielded close to 100 specimens of at least three different olenelloid trilobite taxa, including Kjerulfia lata, Kjerulfia sp. and Elliptocephalus sp., as well as an ellipsocephalid. These specimens are found in a narrow stratigraphical interval in the silty mudstone of the Duolbagaisa Formation,and are accompanied by rich material of organic walled microfossils and trace fossils. The age constraints onthe occurrence are therefore well established, placing the trilobites in the Holmia kjerulfi assemblage Zone.Compared to the classical T0mten locality in the Mjösa area, southern Norway, the Digermulen Peninsula assemblage lacks Holmia kjerulfi. Ellipsocephalids are found with the new material and also slightly higher in the succession. Although the occurrence of trilobites in the Duolbagaisa Formation have been known for along time, the new extensive trilobite material is both better preserved and more abundant, even compared tomost other places in Scandinavia. This ensures that this succession will be a major reference for lower Cambrian trilobite zonation in this part of the world.
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33.
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34.
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35.
  • Högström, Anette, et al. (författare)
  • Exploring the Ediacaran Biota of the Digermulen Peninsula, Northern Norway
  • 2015
  • Ingår i: Geological Society of America Abstracts with Programs, vol 47, no 7..
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The Digermulen Peninsula in northern Norway is the only locality that has yielded Ediacara-type fossils inScandinavia. The Peninsula exhibits an Ediacaran to Lower Ordovician succession consisting of roughly 3000 mof siliciclastic deposits formed in a foreland basin marginal to Baltica. In 2011 a restudy of the Ediacaran deposits(1000 m thick) was launched resulting in new finds that promise to establish the Digermulen Peninsula as asignificant new Ediacaran biota locality. First described in the 1990´s the assemblage is dominated by medusoidtypefossils, such as Cyclomedusa, Ediacaria?, Beltanella and Nimbia? now possibly reinterpreted astaphomorphs of the broadly defined Aspidella as exemplified by the Fermeuse assemblage in Newfoundland.Previous field seasons have produced abundant new material of discoidal forms (tentatively Aspidella), the lowestin stratigraphic proximity to the glacial Mortensnes diamictite (tentatively c. 580 Ma). Recent fieldwork during thesummer of 2015 yielded the first specimen of a multi-vaned Ediacara-type fossil from the Innerelva Member of theStáhpogiedde Formation not far from where the first discoidal fossils were found in the 90´s. Reconstructed toreach approximately 7.5 – 8 cm above the sediment surface this organism appears to have a roughly sphericalshape with three or more vanes, but more detailed study is needed. We know little of the holdfast structure but itappears to possess a generalized Aspidella-like morphology, emphasizing the variety of organisms that may havehad very similar holdfasts. In addition to Aspidella sp., well-preserved Hiemalora are present in these beds.Another important find are several specimens of Palaeopascichnus from near the base of the Innerelva Membermaking them the oldest non-stromatolite macroscopic fossils in Scandinavia. Future work for the DigermulenEarly Life Research Group will focus on extensive excavation and sampling of this important interval to increasethe understanding of the Ediacaran record on the Peninsula.
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36.
  • Högström, Anette, et al. (författare)
  • New occurrences and extension of the stratigraphical range of discoidal Ediacara‑type fossils on the Digermul Peninsula, northern Norway
  • 2014
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • In Scandinavia the evolutionary events across the Ediacaran–Cambrian transition can only be studied in continuous section on the Digermul Peninsula, northern Norway, in the siliciclastic Stáhpogiedde Formation. This roughly 500 m-thick unit comprises, in ascending order, the Lillevannet, Innerelva and Manndraperelva members. Trace fossils, including Treptichnus pedum, and organic-walled microfossils, including Granomarginata prima, position the base of the Cambrian in the upper part of the Manndraperelva Member. Some 20 years ago discoidal Ediacara-type fossils were found in the middle part of Innerelva Member. Recent field seasons have provided abundant new material of Aspidella-type fossils and extended their stratigraphical range to within about 15 m above the Lillevannet Member. The exclusive presence of discoidal forms may reflect a taphonomic bias and/or be evidence of a greater age than that of the more diverse Ediacaran assemblages. That the latter may be the case is indicated by the stratigraphic proximity of the lowest occurrences of Aspidella to the Mortensnes diamictite, recently tentatively considered a Gaskiers glaciation equivalent (c.580 Ma). This raises the question of hitherto unrecognised breaks in sedimentation in the Stáhpogiedde Formation. In order to explore this question we have sampled the succession for organic-walled microfossils, detrital mineral geochronology and sediment geochemistry.
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37.
  • Högström, Anette, et al. (författare)
  • Palaeopascichnus from the Ediacaran of the Digermulen Peninsula, Arctic Norway and the age of the Varanger Ice Age
  • 2018
  • Ingår i: 5th International Palaeontological Conference. ; , s. 292-
  • Konferensbidrag (refereegranskat)abstract
    • Palaeopascichnids are possibly the longest-ranging macroscopic Ediacaran fossils (ca. 565-542 Ma).They are bedding plane-parallel modular fossils composed of series of closely spaced millimeter sizedcircular, sausage- or kidney- shaped units. Earlier regarded as trace fossils, they are now seen as bodyfossils: possible xenophyophoran protists or protists of uncertain affinities. The Cryogenian to lower Cambrian succession (Vestertana group) exposed on the Digermulen Peninsula starts with the glacial Smalfjorden, interglacial Nyborg and glacial Mortensnes fms, collectively known as the Varanger Ice Age.Together with the succeeding Stáhpogieddi Fm. they reflect changes from global icehouse to greenhouse conditions. The Stáhpogieddi Fm. starts with the Lillevannet Mbr. followed by the Indreelva Mbr., yielding Ediacara-type fossils. The highest member in the Stáhpogieddi Fm, the Manndrapselva Mbr, contains the Ediacaran- Cambrian boundary. Palaeopascichnus is found at three horizons within the Stáhpogieddi Fm. The youngest, within the Manndrapselva Mbr., is latest Ediacaran, based on associated trace fossils, as well as occurring below trace fossils from the Treptichnus pedum ichnozone. Palaeopascichnus is also present near the base of the Manndrapselva Mbr. The oldest occurrence is from a horizon transitional between the Lillevannet and Indreelva Mbrs. Age constraints on the Varangerian glacial deposits are poor and their relationship to Neoproterozoic glacial events is equivocal. Studies over the last several decades have placed the Smalfjorden Fm. within the globally developed Marinoan glaciation (ca. 645–635 Ma) based on the presence of cap dolostones. The Mortensnes Fm. has been aligned within the Ediacaran Gaskiers glaciation(ca. 580 Ma) on the basis of carbon isotope stratigraphy. However, alternative interpretations exist,including that of a Marinoan affinity for all of the Varanger ice age. Palaeopascichnus at the Lillevannet Mbr. to Indreelva Mbr. transition indicates that this part of the succession is younger than 565 Ma. Because the transition between the Mortensnes Fm. and the succeeding Stáhpogieddi Fm. is seemingly without major breaks in sedimentation, this is consistent with a Gaskiers, or younger age for the Mortensnes Fm. An older age (Marinoan) requires the discovery of major breaks in the sedimentary record.
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38.
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39.
  • Jensen, Soren, et al. (författare)
  • New occurrences of Palaeopascichnus from the Stahpogieddi Formation, Arctic Norway, and their bearing on the age of the Varanger Ice Age
  • 2018
  • Ingår i: Canadian journal of earth sciences (Print). - : CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS. - 0008-4077 .- 1480-3313. ; 55:11, s. 1253-1261
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on new occurrences of the late Ediacaran problematicum Palaeopascichnus (Protista?) from the Stahpogieddi Formation, Arctic Norway. The stratigraphically lowest occurrences are in beds transitional between the Lillevannet and Indreelva members: the highest in the second cycle of the Manndrapselva Member, stratigraphically close to the lowest occurrences of Cambrian-type trace fossils. This establishes a long stratigraphical range of Palaeopascichnus on the Digermulen Peninsula, as has been previously documented from Newfoundland, South Australia, and elsewhere in Baltica. The age range of Palaeopascichnus in Avalonia and Baltica is from similar to 565 to 541 Ma. Since the transition from the Mortensnes Formation to the Stahpogieddi Formation is without a major break in sedimentation, this supports the inference that the underlying glacigenic Mortensnes Formation is ca. 580 Ma, and therefore Gaskiers-equivalent, or younger.
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40.
  • Jensen, Soren, et al. (författare)
  • Scratch circles from the Ediacaran and Cambrian of Arctic Norway and southern Africa, with a review of scratch circle occurrences
  • 2018
  • Ingår i: Bulletin of Geosciences. - : CZECH GEOLOGICAL SURVEY. - 1214-1119 .- 1802-8225. ; 93:3, s. 287-304
  • Forskningsöversikt (refereegranskat)abstract
    • Scratch circles - bedding plane parallel sedimentary structures formed by the passive rotation of a tethered organism into the surrounding sediment - are relatively rare in the geological record. Here new occurrences of scratch circles are described from the Ediacaran-Cambrian Stahpogieddi Formation, Digermulen Peninsula, Arctic Norway, and from the Ediacaran Nudaus and Urusis formations, Nama Group, of southern Africa. A literature survey confirms a previously noted concentration of scratch circles reported from shallow marine upper Ediacaran-lower Cambrian and paralic Carboniferous rocks. Scratch circle identification and nomenclature are discussed. The stratigraphical range of the trace fossils Treptichnus pedum and Gyrolithes isp. in the Stahpogieddi Formation are extended downward. Combined with earlier reports of Harlaniella podolica this adds new precision to the placement of the Ediacaran-Cambrian boundary on the Digermulen Peninsula.
  •  
41.
  • Jensen, Sören, et al. (författare)
  • Trace fossils across the Ediacaran–Cambrian boundary on the Digermulen Peninsula, Arctic Norway
  • 2017
  • Ingår i: ISECT 2017. - : Memorial University, St. Johns.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The Digermulen Peninsula, Arctic Norway, contains one of the most complete Ediacaran–Cambrian sedimentary rock successions on Baltica. The boundary interval spans the Manndrapselva Mbr of the Stáhpogieddi Fm. and the Lower Mbr of the Breidvika Fm., consisting of several coarsening upward cycles, each less than 100 meters thick, dominated by mudstone and sandstone, and terminated by shallow-marine sandstone. Nigel Banks established the general succession of trace fossils in the 1970's, with additional information added more recently by Duncan McIlroy and members of the Digermulen Early Life Research Group.                      The second cycle of the Manndrapselva Mbr is late Ediacaran on the presence of the problematicum Harlaniella podolica. Trace fossils in this cycle include Planolites, Torrowangea rosei and, uniquely for the Digermulen succession, the horizontal cork-screw shaped Helicolithus. A report of treptichnids is here revised as vertically meandering trace fossils. The greatest trace fossil width in this sequence is 8 mm, although most are a few mm wide; recorded depth less than 10 mm. Close to the base of the third cycle of the Manndrapselva Mbr Treptichnus pedum and Gyrolithes appear. Harlaniella and the lowest occurrences of T. pedum and Gyrolithes are separated by some 30 metres of a sandstone-dominated interval from which trace fossils have not been recovered to date. Higher in the third cycle three-lobed trace fossils of the “Bure ichnocomplex” are found. Treptichnus pedum, Gyrolithes and trace fossils of the Bure ichnocomplex continue into the Lower Mbr of the Breidvika Fm., with T. pedum and Gyrolithes of larger size than found in the Manndrapselva Mbr. In addition there are Rusophycus and rare Teichichnus. The Treptichnus pedum Zone on the Digermulen Peninsula spans about 100 metres of section.                      The general validity of global Ediacaran–Cambrian trace fossil-based correlation has stood the test of time. The succession of trace fossils and problematica on the Digermulen Peninsula allows for particularly close comparison with that of the GSSP section on the Burin Peninsula, Newfoundland, as well as Podolia, Ukraine. Important future challenges include better control on the age of the base of the T. pedum Zone, as well as that of the base of the Rusophycus avalonensis Zone, and the identification of possible diachroneities of these zones, where this is not obviously the result of facies unsuited for trace fossil preservation.
  •  
42.
  • Meinhold, Guido, et al. (författare)
  • A late Caledonian tectono-thermal event in the Gaissa Nappe Complex, Arctic Norway : evidence from fine-fraction K‒Ar dating and illite crystallinity from the Digermulen Peninsula
  • 2019
  • Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 141:4, s. 289-294
  • Tidskriftsartikel (refereegranskat)abstract
    • Fine-fraction K‒Ar dating and illite crystallinity determination were applied on a peculiar pale olive green shale sample from the upper Ediacaran Indreelva Member (Stáhpogieddi Formation, Vestertana Group, Gaissa Nappe Complex) of the Digermulen Peninsula in Finnmark, Arctic Norway, to constrain the age and metamorphic conditions of tectono-thermal overprint. The <2 and <0.2 μm grain-size fractions are almost purely illite and yielded an illite crystallinity (expressed as the Kübler index) of 0.215 Δ° 2θ and 0.228 Δ° 2θ and K‒Ar ages of 403.9 ± 4.2 and 391.5 ± 4.0 Ma, respectively. The K‒Ar ages are interpreted to present late-stage thermal overprint under low epizonal conditions along a localised shear zone, likely post-dating the peak of metamorphism and cleavage generation on the Digermulen Peninsula. Thus, a later tectono-metamorphic event related to the late stage of the Scandian orogeny is locally recorded in the Gaissa Nappe Complex of the Caledonides of Finnmark. This late Scandian event was probably caused by orogenic extensional collapse and appears to have extended at least into Mid-Devonian time.
  •  
43.
  • Meinhold, Guido, et al. (författare)
  • Changes of sediment composition at the dawn of animal life: Insights from the Ediacaran‒Cambrian boundary section of the Digermulen Peninsula (Finnmark, Arctic Norway)
  • 2016
  • Ingår i: Abstract Volume of GeoTirol2016 - Annual Meeting of DGGV and PANGEO Austria, 25-28. September 2016, Innsbruck.. ; , s. 205-
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The Digermulen Peninsula in northern Norway is the only fossiliferous site in Scandinavia with sedimentationacross the Ediacaran–Cambrian transition without a significant hiatus. Furthermore, it is the only locality inScandinavia where Ediacara-type fossils have been found. The site is located at the edge of Baltica during theEdiacaran–Cambrian transition, where potentially the dramatic climatic turnover from icehouse to greenhouseconditions can be deduced and tied to large-scale plate tectonics. Since 2011, studies by the Digermulen EarlyLife Research Group have recorded significant new finds, promising to establish the site as a significant Ediacaranbiota locality. The Ediacaran succession is about 1000 m thick. Ediacara-type fossils occur in the InnerelvaMember of the Stáhpogiedde Formation. Discoidal fossils dominate the Ediacaran assemblage, although apotentially much greater diversity is suggested because of the recent discovery of a frond-shaped fossil. TheEdiacaran–Cambrian boundary is located within the Manndraperelva Member of the Stáhpogiedde Formation,based on biostratigraphic age control, followed by the Lower Cambrian Breidvika Formation. The successionconsists mainly of quartz-rich sandstones and mudrocks. Deposition took place in various environments, includingfluvial, shallow marine and deeper marine settings. As shown by previous studies using palaeocurrent data,sediment supply was from the Baltic Shield toward the passive margin of Baltica in pre-Ediacaran time. At onepoint within the Ediacaran succession, it shifted by 180 degrees due to the newly formed Timanian orogen. Thisorogen formed in north-eastern Baltica during the late Neoproterozoic and caused a shift in sediment transportdirection and change in source area due to the formation of the Timanian foreland basin to the east of DigermulenPeninsula. In order to track sediment supply and to test current palaeotectonic models a multi-disciplinaryapproach on late Neoproterozoic and Cambrian sediments of the Digermulen Peninsula has been applied. Themethods include, amongst other things, thin section petrography, bulk rock geochemistry (XRF, ICP-MS, ICPOES),bulk rock mineralogy (XRD), heavy mineral analysis, single grain chemistry (EMP, LA-ICP-MS) and zirconU-Pb geochronology.
  •  
44.
  • Meinhold, Guido, et al. (författare)
  • Composition and provenance of upper Neoproterozoic and Cambrian sediments from Finnmark, Arctic Norway : Insights from a multi-method approach on the Digermulen Peninsula
  • 2018
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The remote Digermulen Peninsula by the Tanafjorden of north-eastern Finnmark, Arctic Norway, contains an almost complete sedimentary record across the Ediacaran–Cambrian transition as well as microfossils, macrofossils and trace fossils for studying the Ediacaran biota and the Cambrian radiation. It is one of the few localities worldwide and the only locality in Scandinavia where Ediacara-type fossils have been found. The site was located at the edge of Baltica during the Ediacaran–Cambrian transition, where potentially the dramatic climatic turnover from icehouse to greenhouse conditions can be deduced and tied to large-scale plate tectonics. The Digermulen Peninsula was first studied in the 1930s by Sven Føyn, who also published a geological map in 1937, emended by Harold G. Reading in 1959. In the following years, more detailed mapping was carried out by students from Oxford University. The exposed rocks on the Digermulen Peninsula belong to the Vestertana and Digermulen groups of the Lower Allochthon overlying the Baltic Shield. The succession consists mainly of quartz-rich sandstones and mudrocks. Deposition took place in various environments including fluvial, shallow marine and deeper marine settings. As shown by previous studies using palaeocurrent data, sediment supply was from the Baltic Shield toward the passive margin of Baltica in pre-Ediacaran time. At one point within the Ediacaran succession, it shifted by 180 degrees due to the newly formed Timanian orogen. This orogen formed in north-eastern Baltica during the late Neoproterozoic. It caused a change in source area due to the formation of the Timanian foreland basin to the east of Digermulen Peninsula. Extensive field and laboratory work by the Digermulen Early Life Research Group, with funding from the Research Council of Norway, allows for the first time a detailed analysis of sediment supply and to test current palaeotectonic models based on a multi-method provenance approach on Neoproterozoic and Cambrian mudrocks and sandstones of the Digermulen Peninsula. The methods include, amongst others, thin-section petrography, bulk-rock geochemistry (XRF, ICP-MS), bulk-rock mineralogy (XRD), conventional heavy mineral analysis, single-grain geochemistry (EMP) and zircon U-Pb geochronology. We present and discuss the first results to decipher the sediment sources and to track changes of sediment supply through this critical time interval of Earth’s history.
  •  
45.
  • Meinhold, Guido, et al. (författare)
  • First record of carbonates with spherulites and cone-in-cone structures from the Precambrian of Arctic Norway, and their palaeoenvironmental significance
  • 2019
  • Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268 .- 1872-7433. ; 328, s. 99-110
  • Tidskriftsartikel (refereegranskat)abstract
    • We report for the first time carbonates from the upper Ediacaran sedimentary succession of Finnmark, Arctic Norway. Carbonates occur as calcareous siliciclastic beds, lenses, and concretions, some with calcite spherulites and cone-in-cone (CIC) calcite, in a mudrock to fine-grained sandstone succession from approximately 3 m to 26 m above the base of the 2nd cycle of the Manndrapselva Member of the Stahpogieddi Formation (Vestertana Group). They occur c. 40 m below the Ediacaran-Cambrian boundary, which is well defined by trace fossils. Thin-section petrography and scanning micro X-ray fluorescence elemental mapping reveal a layered composition of the calcareous sedimentary rocks. In some of those, well-developed nested cones of CIC calcite form the outer layer. Thin clay coatings outline individual cones. The inner layers are composed of (1) carbonate with calcite spherulites (grainstone) and (2) thinly laminated fine-grained calcareous siliciclastics (mudstone and wackestone) indicated by elevated concentrations of Al, Si, Fe, and Ti. The inner siliciclastic layers contain framboidal pyrite and probably organic matter. Formation of calcite spherulites took place probably at the sediment-water interface either in a coastal littoral environment or in situ in the sublittoral zone under high alkaline conditions whereas CIC calcite formed during burial diagenesis and clearly in pre-Caledonian time before metamorphism and cleavage formation. This new record of carbonates with calcite spherulites and CIC structures from the Ediacaran of Arctic Norway adds to their rare occurrences in the geological record.
  •  
46.
  • Meinhold, Guido, et al. (författare)
  • Rare earth elements and neodymium and strontium isotopic constraints on provenance switch and post-depositional alteration of fossiliferous Ediacaran and lowermost Cambrian strata from Arctic Norway
  • 2022
  • Ingår i: Precambrian Research. - : Elsevier. - 0301-9268 .- 1872-7433. ; 381
  • Tidskriftsartikel (refereegranskat)abstract
    • The Digermulen Peninsula in northeastern Finnmark, Arctic Norway, comprises one of the most complete Ediacaran-Cambrian transitions worldwide with a nearly continuous record of micro-and macrofossils from the interval of the diversification of complex life. Here, we report on the provenance and post-depositional alteration of argillaceous mudstones from the Digermulen Peninsula using rare earth elements and Sm-Nd and Rb-Sr isotopic systematics to provide an environmental context and better understand this important transition in Earth's history. The studied sections comprise a mid-Ediacaran glacial-interglacial cycle, including the Nyborg Formation (ca. 590 Ma) and Mortensnes Formation (related to the ca. 580 Ma-old Gaskiers glaciation), and the St & PRIME;ahpogieddi Formation (ca. 560-537 Ma), which yields Ediacara-type fossils in the Indreelva Member and contains the Ediacaran-Cambrian boundary interval in the Manndrapselva Member and basal part of the informal Lower Breidvika member (ca. 537-530 Ma). Three sample groups, (1) Nyborg and Mortensnes for-mations, (2) the lowermost five samples from the Indreelva Member and (3) the remaining samples from the Indreelva as well as from the Manndrapselva and Lower Breidvika members, can be distinguished, belonging to distinct depositional units. All samples have negative epsilon(Nd)(T) values (-6.00 to -21.04) indicating a dominant input of terrigenous detritus with an old continental crust affinity. Significant shifts in Sm-Nd isotope values are related to changes in the sediment source, i.e. Svecofennian province vs Karelian province vs Svecofennian province plus in addition likely some juvenile (late Neoproterozoic volcanic) material, and probably reflect palaeotectonic reorganisation along the Iapetus-facing margin of Baltica. The combined Rb-Sr isotopic data of all samples yield an errorchron age of about 430 Ma reflecting the resetting of the Rb-Sr whole-rock isotope systems of the mudstones during the Scandian tectono-metamorphic event in the Gaissa Nappe Complex of Finnmark. Preservation of palaeopascichnids coincides with the sedimentation regimes of sample groups 2 and 3 while other Ediacara-type fossils, e.g. Aspidella-type and frondose forms, are limited to the sample group 3. Our results are similar to those of earlier studies from the East European Platform in suggesting oxic seafloor conditions during the late Ediacaran.
  •  
47.
  • Meinhold, Guido, et al. (författare)
  • Sediment provenance at the edge of Baltica during the late Neoproterozoicand Cambrian : Insights from a multi‐method approach on the Digermulen Peninsula (Finnmark, Arctic Norway)
  • 2018
  • Ingår i: International Conference on Arctic Margins.
  • Konferensbidrag (refereegranskat)abstract
    • The Digermulen Peninsula contains an almost complete sedimentary record across the Ediacaran–Cambrian transition as well as microfossils, macrofossils and trace fossils for studying the Ediacaranbiota and the Cambrian radiation. The site was located at the edge of Baltica during the Ediacaran–Cambrian transition, where potentially the dramatic climatic turnover from icehouse to greenhouse conditions can be deduced and tied to large‐scale plate tectonics. The succession consists mainly of quartz‐rich sandstones and mudrocks. Deposition took place in various environments including fluvial, shallow marine and deeper marine settings. As shown by previous studies using palaeocurrent data, sediment supply was from the Baltic Shield toward the passive margin of Balticain pre‐Ediacaran time. At one point within the Ediacaran succession, it shifted by 180 degrees due tothe newly formed Timanian orogen. This orogen formed in north‐eastern Baltica during the late Neoproterozoic. It caused a change in source area due to the formation of the Timanian foreland basin to the east of Digermulen Peninsula. Extensive field and laboratory work by the Digermulen Early Life Research Group allows for the first time a detailed analysis of sediment supply and to test current palaeotectonic models based on a multi‐method provenance approach on Neoproterozoicand Cambrian sedimentary rocks of the Digermulen Peninsula. We present and discuss the first results to decipher the sediment sources and to track changes of sediment supply through thiscritical time interval of Earth history.
  •  
48.
  • Meinhold, Guido, et al. (författare)
  • U-Pb dating of calcite in ancient carbonates for age estimates of syn- to post-depositional processes : a case study from the upper Ediacaran strata of Finnmark, Arctic Norway
  • 2020
  • Ingår i: Geological Magazine. - : CAMBRIDGE UNIV PRESS. - 0016-7568 .- 1469-5081. ; 157:8, s. 1367-1372
  • Tidskriftsartikel (refereegranskat)abstract
    • Results of in situ U-Pb dating of calcite spherulites, cone-in-cone (CIC) calcite and calcite fibres from a calcareous concretion of the upper Ediacaran of Finnmark, Arctic Norway, are reported. Calcite spherulites from the innermost layers of the concretion yielded a lower intercept age of 563 +/- 70 Ma, which, although imprecise, is within uncertainty of the age of sedimentation based on fossil assemblages. Non-deformed CIC calcite from the bottom part of the concretion yielded an age of 475 +/- 25 Ma, which is interpreted as the age of CIC calcite formation during a period of fluid overpressure induced during burial of the sediments. Deformed CIC calcite from the top part of the concretion yielded an age of 418 +/- 23 Ma, which overlaps with a known Caledonian tectono-metamorphic event, and indicates a potential post-depositional overprint at this time. Calcite fibres that grew in small fissures along spherulite rims, which are interpreted as a recrystallization feature during deformation and formation of a cleavage, gave an imprecise age of 486 +/- 161 Ma. Our results show that U-Pb dating of calcite can provide age constraints for ancient carbonates and syn- to post-depositional processes that operated during burial and metamorphic overprinting.
  •  
49.
  • Palacios, Teodoro, et al. (författare)
  • Acritarchs from the Duolbagaisa Formation (Cambrian Series 2, Miaolingian) on the Digermulen Peninsula, Finnmark, Arctic Norway : towards a high-resolution Cambrian chronostratigraphy
  • 2020
  • Ingår i: Geological Magazine. - : CAMBRIDGE UNIV PRESS. - 0016-7568 .- 1469-5081. ; 157:12, s. 2051-2066
  • Tidskriftsartikel (refereegranskat)abstract
    • New information on acritarchs from the Duolbagaisa Formation, Digermulen Peninsula, Arctic Norway, enable recognition of the three Cambrian Series 2 acritarch-based zones: the Skiagia ornata-Fimbriaglomerella membranacea, Heliosphaeridium dissimilare-Skiagia ciliosa and Volkovia dentifera-Liepaina plana Assemblage zones. Acritarchs of the Skiagia ornata-Fimbriaglomerella membranacea Zone (Cambrian Stage 3) appear near the base of the unit, close to an undetermined trilobite. In the Upper Member of the Duolbagaisa Formation, in levels with Kjerulfia n. sp. and Elliptocephala n. sp., appears an assemblage with abundant Skiagia ciliosa, indicative of the Heliosphaeridium dissimilare-Skiagia ciliosa Zone. A few metres higher appear Liepaina plana, Heliosphaeridium notatum and Retisphaeridium dichamerum, which indicate the Volkovia dentifera-Liepaina plana Zone (Cambrian Stage 4). The transition between the Duolbagaisa Formation and the overlying Kistedalen Formation is marked by the appearance of Comasphaeridium longispinosum, Multiplicisphaeridium llynense and Eliasum llaniscum, diagnostic of the Miaolingian Series. This coincides with the disappearance of Skiagia; occurrences of Skiagia in Miaolingian strata consist of reworked material related to the Hawke Bay regression at the Cambrian Stage 4-Wuliuan transition. The absence of Skiagia in higher levels of the Duolbagaisa Formation and Kistedalen Formation suggests that no unconformity formed during the Hawke Bay regression in this area. The chronostratigraphical significance of the Skiagia ornata-Fimbriaglomerella membranacea, Heliosphaeridium dissimilare-Skiagia ciliosa and Volkovia dentifera-Liepaina plana zones is critically analysed. Correlation of the Duolbagaisa Formation with peri-Gondwanan terrains of Avalonia and Iberia is established. The Digermulen Peninsula has great potential as a reference section for establishing a Cambrian chronostratigraphy based on acritarchs.
  •  
50.
  • Palacios, Teodor, et al. (författare)
  • Organic-walled microfossils and organic fossils across the Ediacaran–Cambrian boundary on the Digermulen Peninsula, Arctic Norway
  • 2017
  • Ingår i: ISECT 2017. - : Memorial University, St. Johns.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The Digermulen Peninsula, Arctic Norway, contains one of the most complete Ediacaran–Cambrian sedimentary rock successions on Baltica. The boundary interval spans the Manndrapselva Mbr of the Stáhpogieddi Fm. and the Lower Mbr of the Breidvika Fm.Abundant organic-walled microfossils (OWM) and organic fossils (OF) in the second and third cycles of Manndrapselva Mbr and the lower part of the Breidvika Fm., coupled with a rich record of trace fossils reinforces the potential of the area for detailed biostratigraphic studies of the Ediacaran–Cambrian transition.The second cycle of the Mandrapselva Mbr, with simple trace fossils and the Ediacaran- confined problematicum Harlaniella podolica, contains a low diversity of OWM represented by abundant filamentous cyanobacterial sheaths, thick-walled sphaeromorphs, Pterospermopsimorpha sp. and Leiosphaeridia spp. Organic fossils include abundant tussled masses of nano-scale filament interpreted as degraded sabelliditid tubular fossils. The third cycle, which yields the first occurrence of the trace fossil Treptichnus pedum, include a similar assemblage of OWM, and the first appearance of Granomarginata prima, a cosmopolitan acritarch with a first appearance in the Cambrian. Close to the base of the third cycle there is an increased diversity of OF, including the appearance of Ceratophyton at a level approximating the first T. pedum. In the upper part of the third cycle Cochleatina is found.The Lower Mbr of the Breidvika Fm. yields productive samples in levels below the lowest occurrence of the arthropod-type trace fossil Rusophycus. The association remains one of low diversity, with the continued presence of Ceratophyton and nano-scale filaments, the latter abundant in levels with rich occurrences of Sabellidites cambriensis but absent at levels close to the appearance of Rusophycus. Basal levels of the Breidvika Fm. yield the first process-bearing acritarchs, represented by rare specimens of the small and weakly ornamented Asteridium tornatum. There are also abundant clusters of Symplassosphaeridium sp. Compared to Manndrapselva Mbr there is a decrease in thick-walled sphaeromorphs.
  •  
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