| 1. |
- Darbandi, Mahboobeh Parvaresh, et al.
(författare)
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The gabbro-diorite magmatism from the Narm area, western Kuh-e-Sarhangi (Central Iran): Evolution from Eocene magmatic flare up to Miocene asthenosphere upwelling
- 2022
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Ingår i: Journal of African Earth Sciences. - : Elsevier. - 1464-343X .- 1879-1956. ; 196
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Tidskriftsartikel (refereegranskat)abstract
- Geodynamically, the Kashmar-Kerman Tectonic Zone (KKTZ) is one of the most perplexing tectonomagmatic belts of the Central Iran Microcontinent (CIM), comprising two important districts, Bafq and Kuh-e-Sarhangi. The Late Neoproterozoic-Early Cambrian granitoids, metamorphic rocks, and mildly metamorphosed volcansedimentary sequences are the oldest geologic outcrops in the Narm area, which is located in the western part of Kuh-e-Sarhangi. Alkaline gabbro-diorites with relatively high contents of K2O (1.99–3.03 wt%) and Na2O (2.7–5.99 wt%) are among the youngest intrusive rocks in the area, representing a within-plate provenience. These rocks were emplaced into Paleozoic sedimentary units as mafic-intermediate stocks, sills and dykes. Geochemically, these rocks could have resulted directly from partial melting (e.g., FeOT/MgO>1, Nb/La>0.5) with no considerable indication of assimilation with crustal materials (e.g., Ti/Zr > 30, Ti/Y > 200). Assimilation and fractional crystallization cannot account for magma evolution of gabbro-diorite rocks in the Narm area, using rare earth element ratios and geochemical models. There are also some geochemical signatures of an asthenospheric origin for the Narm gabbro-diorite rocks, such as the low ratios of La/Nb (1.5) and La/Ta (22). U–Pb zircon ages show that the Narm gabbro-diorites formed during two major episodes of magmatism in Central Iran: 40.3 ± 0.1 Ma in the Late Eocene (Bartonian) for gabbroic units and 8.04 ± 0.05 and 7.86 ± 0.05 in the late Miocene (Tartonian) for diorite stocks and diorite sills, respectively. Despite a time difference of more than thirty million years, geochemical similarities between the Eocene gabbro rocks and the Miocene diorite from the Narm area are striking. It is proposed that the best scenarios for the west of Kuh-e-Sarhangi mafic-intermediate magmatic pulses along with the deep faults of the Central Iran, are an Eocene magmatic flare up and a Miocene asthenosphere upwelling. Temporally and spatially, these rocks are comparable to the Cenozoic alkaline intrusive rocks of the Bafq region.
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| 2. |
- Jaranowski, Maciej, et al.
(författare)
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U-Pb and trace element zircon and apatite petrochronology of eclogites from the Scandinavian Caledonides
- 2023
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Ingår i: Contributions to Mineralogy and Petrology. - : Springer. - 0010-7999 .- 1432-0967. ; 178
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Tidskriftsartikel (refereegranskat)abstract
- The petrochronological records of eclogites in the Scandinavian Caledonides are investigated using EPMA and LA-ICPMS of zircon and apatite for U-Pb geochronology, combined with major and trace element characteristics. Metamorphic zircon from two eclogites from the Lofoten-Vesteralen Complex (Lofoten Archipelago region) collectively yielded a Concordia age 427.8 & PLUSMN; 5.7 Ma and an upper intercept U-Pb age 425 & PLUSMN; 30 Ma. Apatites from the same eclogites provided U-Pb lower intercepts at 322 & PLUSMN; 28 Ma and 354 & PLUSMN; 33 Ma, with the latter also yielding a younger age of 227 & PLUSMN; 24 Ma. Two eclogites from the Lower Seve Nappe (Northern Jamtland) demonstrate different zircon and apatite age records. Metamorphic zircon provided Concordia ages of 467.2 & PLUSMN; 5.9 Ma and 444.5 & PLUSMN; 5.5 Ma, which resolve the age of prograde metamorphism and zircon growth during retrogression, respectively. The lower intercept U-Pb ages of apatites from the same eclogites are 436 & PLUSMN; 18 and 415 & PLUSMN; 25 Ma, respectively. In combination with their geochemical characteristics, they suggest two separate stages of exhumation of eclogite bodies in the Lower Seve Nappe. Zircons from an eclogite from the Blaho Nappe (Nordoyane Archipelago) yielded a continuum of concordant U-Pb dates from ca. 435 to 395 Ma, which suggests several cycles of HT metamorphism within short intervals. Distinctive trace element characteristics of apatites from the Blaho Nappe eclogite suggest formation coeval with zircon and garnet during HT metamorphism, but Pb diffusion behaved as an open system until cooling during exhumation of the nappe at 390 & PLUSMN; 12 Ma (lower intercept U-Pb age of apatite). To summarize, this study presents the high potential of coupled zircon and apatite petrochronology of eclogites in resolving their metamorphic evolution, particularly with respect to using trace element characteristics of apatites to constrain the records of their growth, alterations and the meaning of their U-Pb age record.
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| 3. |
- Pinto, Patrícia, et al.
(författare)
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Patient satisfaction with ultrasound, whole-body CT and whole-body diffusion-weighted MRI for pre-operative ovarian cancer staging : a multicenter prospective cross-sectional survey
- 2024
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Ingår i: International Journal of Gynecological Cancer. - 1048-891X.
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Tidskriftsartikel (refereegranskat)abstract
- Background In addition to the diagnostic accuracy of imaging methods, patient-reported satisfaction with imaging methods is important. Objective To report a secondary outcome of the prospective international multicenter Imaging Study in Advanced ovArian Cancer (ISAAC Study), detailing patients’ experience with abdomino-pelvic ultrasound, whole-body contrast-enhanced computed tomography (CT), and whole-body diffusion-weighted magnetic resonance imaging (WB-DWI/MRI) for pre-operative ovarian cancer work-up. Methods In total, 144 patients with suspected ovarian cancer at four institutions in two countries (Italy, Czech Republic) underwent ultrasound, CT, and WB-DWI/ MRI for pre-operative work-up between January 2020 and November 2022. After having undergone all three examinations, the patients filled in a questionnaire evaluating their overall experience and experience in five domains: preparation before the examination, duration of examination, noise during the procedure, radiation load of CT, and surrounding space. Pain perception, examination-related patient-perceived unexpected, unpleasant, or dangerous events (‘adverse events’), and preferred method were also noted. Results Ultrasound was the preferred method by 49% (70/144) of responders, followed by CT (38%, 55/144), and WB-DWI/MRI (13%, 19/144) (p<0.001). The poorest experience in all domains was reported for WB-DWI/ MRI, which was also associated with the largest number of patients who reported adverse events (eg, dyspnea). Patients reported higher levels of pain during the ultrasound examination than during CT and WB-DWI/MRI (p<0.001): 78% (112/144) reported no pain or mild pain, 19% (27/144) moderate pain, and 3% (5/144) reported severe pain (pain score >7 of 10) during the ultrasound examination. We did not identify any factors related to patients' preferred method.for diagnosing malignant ovarian tumors3 but has rarely been used for pre-operative ovarian cancer work-up.4–7 In 2022, the results of a prospective single-unit study indicated that ultrasound might be an alternative to CT and whole-body diffusion-weighted (WB-DWI)/ MRI for ovarian cancer work-up and prediction of tumor resectability.8 In the recently published European Society of Gynecological Oncology/European Society of Medical Oncology/European Society of Pathology (ESGO/ESMO/ESP) consensus conference recommendations on ovarian cancer, ultrasound is suggested to be an effective alternative to CT, MRI and PET-CT to assess tumor extent and tumor resectability in the pelvis and abdomen.2 In addition to diagnostic accuracy and costs of an imaging method, patient acceptance and preference are important before an imaging test is implemented in clinical practice.9 10 Although there is evidence regarding patients’ experience of and satisfaction with ultrasound,11 12 CT,13–17 and WB-DWI/MRI,16 18–20 little is known about how these three imaging modalities compare when applied in the same patient. Many factors can influence a patient’s experience with an imaging examination—for example, preparation for, and duration of, the examination; use of contrast agent (especially iodinated contrast agent); radiation dose (which depends on the duration of radiation exposure, distance from the radiation source, and physical shielding); noise, feeling of claustrophobia, and occurrence of unexpected unpleasant or dangerous events (adverse events).21–25 The aim of this study is to report a secondary outcome of the prospective, multicentric Imaging Study in Advanced ovArian Cancer (ISAAC Study)—namely, patients’ experience with ultrasound, CT, and WB-DWI/MRI for pre-operative estimation of the extent of ovarian cancer.
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| 4. |
- Slama, Jiri, et al.
(författare)
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Plesovice zircon : A new natural reference material for U-Pb and Hf isotopic microanalysis
- 2008
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Ingår i: Chemical Geology. - : Elsevier BV. - 0009-2541 .- 1872-6836. ; 249:02-jan, s. 1-35
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Tidskriftsartikel (refereegranskat)abstract
- Matrix-matched calibration by natural zircon standards and analysis of natural materials as a reference are the principle methods for achieving accurate results in inicrobeam U-Pb dating and Hf isotopic analysis. We describe a new potential zircon reference material for laser ablation ICP-MS that was extracted from a potassic granulite facies rock collected in the southern part of the Bohemian Massif (Plesovice, Czech Republic). Data from different techniques (ID-TIMS, SIMS and LA ICP-MS) and several laboratories suggest that this zircon has a concordant U-Pb age with a weighted mean Pb-206/U-238 date of 337.13 +/- 0.37 Ma (ID-TIMS, 95% confidence limits, including tracer calibration uncertainty) and U-Pb age homogeneity on the scale used in LA ICP-MS dating. Inhomogeneities in trace element composition due to primary growth zoning prevent its use as a calibration standard for trace element analysis. The content of U varies from 465 ppm in pristine parts of the grains to similar to 3000 ppm in actinide-rich sectors that correspond to pyramidal faces with a high degree of metamictization (present in ca. 30% of the grains). These domains are easily recognized from high intensities on BSE images and should be avoided during the analysis. Hf isotopic composition of the Plesovice zircon (>0.9 wt.% Hf) is homogenous within and between the grains with a mean Hf-176/Hf-177 value of 0.282492 +/- 0.000013 (2SD). The age and Hf isotopic homogeneity of the Plesovice zircon together with its relatively high U and Pb contents make it an ideal calibration and reference material for laser ablation ICP-MS measurements, especially when using low laser energies and/or small diameters of laser beam required for improved spatial resolution.
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