| 1. |
- Pienkowski, Grzegorz, et al.
(författare)
-
Climatic reversals related to the Central Atlantic magmatic province caused the end-Triassic biotic crisis : evidence from continental strata in Poland
- 2014
-
Ingår i: Geological Society of America, Special Paper. - : Geological Society of America. - 0072-1077. ; 505, s. 263-286
-
Tidskriftsartikel (refereegranskat)abstract
- Eight climatic events can be distinguished in the Triassic–Jurassic (ca. 201 Ma) continental strata of Poland. These events are distinguished by kaolinite/illite ratio, chemical index of alteration (CIA), color of sediments, and palynomorphs. The first transition to wetter climate, evidenced by a shift from smectite- to kaolinite dominated mudrocks, coincides with the earlier (“precursor”) Rhaetian negative δ13Corg excursion, which means that the beginning of climate perturbations predates the oldest known Central Atlantic magmatic province fl ood basalts by some 100–200 k.y. The later global, late Rhaetian “initial” negative δ13Corg excursion is divided into two subpeaks, each corresponding to hot and humid events, separated by a cooler and drier event. The upper subpeak is also associated with perturbation of the osmium isotope system (attributed to volcanic fallout), and darkened miospores, pointing to acid rains. Between the “initial” excursion and the Triassic-Jurassic boundary interval, five climatic fluctuations are inferred from the changing kaolinite/illite ratio, the last two of which are also associated with an Os isotope perturbation, polycyclic aromatic hydrocarbon (PAH) occurrences, a “spore peak,” and darkened miospores. A series of periodic atmospheric loading events by CO2, CH4, or alternatively by SO2, sulfate aerosols, and toxic compounds, is inferred to have caused this series of rapid climatic reversals and resulting extinction of many less-adapted forms. Just above thepalynofloral extinction level, appearance of new forms commenced Jurassic palynofloral recovery. Tetrapod evolution events in the end-Triassic–earliest Jurassic were related to the extinction of the Pseudosuchia, Dicynodontia, Capitosauroidea, Plagiosaroidea, and Rhynchosauria, while appearance of highly diversifi ed tetrapod ichnofauna in the earliest Jurassic strata indicates a rapid recovery and refi ll of ecological niches by dinosaurs.
|
|
| 2. |
- Bajdek, Piotr, et al.
(författare)
-
Putative dicynodont coprolites from the Upper Triassic of Poland
- 2014
-
Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 411, s. 1-17
-
Tidskriftsartikel (refereegranskat)abstract
- A significant number (more than 100) of brownto dark and silty, carbonate or pyrite-mineralized, in part organic carbon-rich, spherical or oval-shaped structures have been collected fromthe Upper Triassic (uppermost NorianlowerRhaetian) sediments of the Lipie Śląskie clay-pit at Lisowice near Lubliniec town, Poland. Their geological context, morphology, content, geochemistry and association with skeletal remains suggest they are fecal masses of a sizable herbivorous tetrapod. The only large herbivore known from the site is a giant 5 meter-long dicynodont (Synapsida: Anomodontia), represented by numerous bones and also by large, oval-shaped footprints. The putative dicynodont coprolites were collected from mudstone and siltstone with numerous organic remains that were deposited in anoxic conditions. In addition, REEs and other trace element concentrations suggest that the burial environment and diagenesis of these coprolites were under anoxic conditions. SEM and thin section images of the coprolite matrix show numerous nests with pyrite (probably bacterial in origin) and large amount of mineral particles. The putative dicynodont coprolites contain also amorphous, dark organic matter, poorly preserved palynomorphs, small fragments of plant cuticle. Detailed characteristic of these coprolites reveals possible implications for the ecology and physiology of the source animal species. The δ 13C values of the gymnospermcuticle and dark organic matter measured in three coprolites are −23.4‰, −21.2‰and −20.3‰, all average. The evidence from these coprolites suggests that dicynodonts processed plant soft elements into very small pieces, but wood fragments were found also in a mass accumulation in two coprolites.
|
|
| 3. |
- Niedzwiedzki, Grzegorz, 1980-, et al.
(författare)
-
Basal dinosauriform and theropod dinosaurs from the middle-late Norian (Late Triassic) of Poland : implications for Triassic dinosaur evolution and distribution
- 2014
-
Ingår i: Palaeontology. - : Wiley. - 0031-0239 .- 1475-4983. ; 57:6, s. 1121-1142
-
Tidskriftsartikel (refereegranskat)abstract
- The rise of dinosaurs during the Triassic is a widely studied evolutionary radiation, but there are still many unanswered questions about early dinosaur evolution and biogeography that are hampered by an unevenly sampled Late Triassic fossil record. Although very common in western North America and parts of South America, dinosaur (and more basal dinosauriform) remains are relatively rare in the Upper Triassic deposits of Europe, making any new discoveries critically important. One of the most diverse dinosauriform assemblages from Europe comes from the Poreba site in Poland, a recently described locality with exposures of the Zbazszynek Beds, which have a palynomorph assemblage characteristic for the mid–late Norian in the biostratigraphic schemes of the Germanic Basin. Using a synapomorphy-based approach, we evaluate several isolated dinosauriform specimens from Porezba. This assemblage includes a silesaurid, a herrerasaurid and remains of another type of theropod (potentially a neotheropod). The Poreba herrerasaurid is the first record of this rare group of primitive dinosaurs from Europe and one of the youngest records worldwide, whereas the silesaurid is the youngest record of a silesaurid from Europe. These findings indicate that silesaurids persisted alongside true dinosaurs into the mid–late Norian of Europe and that silesaurid–herrerasaurid–neotheropod assemblages (which are also known from the Norian of North America, at low latitudes) were more widespread geographically and latitudinally than previously thought. Silesaurid–herrerasaurid–neotheropod assemblages may have been a common ecological structuring of dinosaurs during their early evolution, and their widespread distribution may indicate weak palaeolatitudinal controls on early dinosaur biogeography during the latest Triassic.
|
|
| 4. |
- Niedzwiedzki, Grzegorz, 1980-, et al.
(författare)
-
Middle Devonian invertebrate trace fossils from the marginal marine carbonates of the Zachełmie tetrapod tracksite, Holy Cross Mountains, Poland
- 2014
-
Ingår i: Bulletin of Geosciences. - : Czech Geological Survey. - 1214-1119 .- 1802-8225. ; 89:3, s. 593-606
-
Tidskriftsartikel (refereegranskat)abstract
- The dolomitic deposits of the Middle Devonian Wojciechowice Formation exposed at the tetrapod tracksite in the Zachełmie Quarry in the Holy Cross Mountains (Poland) are characterised by a low diversity of invertebrate trace fossilassociation. Four ichnoassemblages can be identified in the track-bearing, lower part of the succession. The most conspicuous are trace fossils produced by arthropods (probably crustaceans), which can form distinctive and large horizontal burrows. The described ichnotaxa (cf. Skolithos isp., cf. Balanoglossites isp., Alcyonidiopsis isp., Spongeliomorpha isp., Gordia isp., and Rhizocorallium isp.) are well known from typical marginal-marine and shallow-marine deposits. Nevertheless, the studied assemblages were found in sparsely distributed horizons and are dominated by a single or a few ichnotaxa with locally high trace-densities. Distribution and composition of the trace fossil assemblages probably reflects occurrence of the impoverished, stressed Cruziana ichnofacies. It was affected by changes in water depth with intermittent periods of subaerial exposure connected with salinity fluctuations. The invertebrate trace fossil assemblage, tetrapod tracks and associated sedimentological features point to deposition in a marginal-marine, mostly peritidal and lagoonal environment with minor terrestrial influences.
|
|
| 5. |
- Sulej, Tomasz, et al.
(författare)
-
New perspectives on the Late Triassic vertebrates of East Greenland : preliminary results of a Polish−Danish palaeontological expedition
- 2014
-
Ingår i: Polish Polar Research. - : Polish Academy of Sciences Chancellery. - 0138-0338 .- 2081-8262. ; 35:4, s. 541-552
-
Tidskriftsartikel (refereegranskat)abstract
- The Fleming Fjord Formation (Jameson Land, East Greenland) documents a diverse assemblage of terrestrial vertebrates of Late Triassic age. Expeditions from the turn of the 21st century have discovered many important fossils that form the basis of our current knowledge of Late Triassic Greenlandic faunas. However, due to the scarcity and incompleteness of the fossils and their insufficient study, our understanding of the taxonomic diversity of the Fleming Fjord Formation is hindered. Here, we report the preliminary findings of a Polish−Danish expedition to the Fleming Fjord Formation that took place in 2014. Three areas were visited – the fairly well known MacKnight Bjerg and Wood Bjerg and the virtually unexplored Liasryggen. MacKnigth Bjerg and Liasryggen yielded fossils which promise to significantly broaden our knowledge of vertebrate evolution in the Late Triassic. Stem−mammal remains were discovered at Liasryggen. Other fossils found at both sites include remains of actinopterygians, sarcopterygians, temnospondyl amphibians and various archosaurs (including early dinosaurs). Numerous vertebrate trace fossils, including coprolites, pseudosuchian footprints, theropod and sauropodomorph dinosaur tracks, were also discovered. Newly discovered skeletal remains as well as abundant trace fossils indicate higher tetrapod diversity in the Late Triassic of Greenland than previously thought. Trace fossils also allow inferences of early theropod and sauropodomorph dinosaur behaviour.
|
|
| 6. |
- Swilo, Marlena, et al.
(författare)
-
Mammal-like tooth from the Upper Triassic of Poland
- 2014
-
Ingår i: Acta Palaeontologica Polonica. - : Polska Akademia Nauk Instytut Paleobiologii (Institute of Paleobiology, Polish Academy of Sciences). - 0567-7920 .- 1732-2421. ; 59:4, s. 815-820
-
Tidskriftsartikel (refereegranskat)abstract
- Recent Triassic discoveries have extended the record of near-mammals (Mammaliaformes) back to the Norian, about 215 Ma, and reveal a significant diversity of Late Triassic (Norian-Rhaetian) forms. We now add to this Late Triassic diversity a nearly complete double-rooted right lower molariform tooth (ZPAL V.33/734) from the Polish Upper Triassic that is significant because it comes from uppermost Norian–lower Rhaetian rocks and is the first discovery of a mammal-like tooth in the Mesozoic of Poland. The described tooth shows transitional dental morphology between advanced cynodonts and mammaliaforms and it appears to represent a basal mammaliaform (genus Hallautherium), probably belonging to Morganucodonta.
|
|
| 7. |
- Szrek, Piotr, et al.
(författare)
-
Storm origin of bone-bearing beds in the Lower Devonian placoderm sandstone from Podlazie Hill (Holy Cross Mountains, central Poland)
- 2014
-
Ingår i: Geological Quarterly. - : Polish Geological Institute - National Research Institute (PGI-NRI). - 1641-7291 .- 2082-5099. ; 58:4, s. 795-806
-
Tidskriftsartikel (refereegranskat)abstract
- The placoderm sandstone (Emsian, Holy Cross Mountains) exposed in the abandoned quarry at Podlazie Hill was revisited and excavated during fieldwork conducted in 2011–2013. Bone-bearing breccias were studied in details for the first time at this site and subjected to taphonomic analysis. Vertebrate remains are dominated by heterostracans, while true placoderm compose less than 20% of the total vertebrate assemblage. The high degree of fragmentation of the bones and low degree of abrasion indicate that the remains were reworked and transported be fore final burial. This is consistent with the mixed character of the bone accumulations, which comprise both open-shelf forms (acanthodians, chondrichthyans) as well as those related to marginal-marine environments (placoderms and sarcopterygians). The bone-bearing succession has been subdivided into five depositional facies attributed to a coastal lagoon influenced by stormy, possibly tidal conditions. The occurrence of the invertebrate trace fossil Ilmenichnus sp. accompanied by Lockeia and Monomorphichnus supports this interpretation.
|
|
| 8. |
- Xing, Li-Da, et al.
(författare)
-
Asianopodus-type footprints from the Hekou Group of Honggu District, Lanzhou City, Gansu, China and the “heel” of large theropod tracks
- 2014
-
Ingår i: Palaeoworld. - : Elsevier BV. - 1871-174X .- 1875-5887. ; 23:3-4, s. 304-313
-
Tidskriftsartikel (refereegranskat)abstract
- An increasing number of dinosaur tracksites have been reported from the Cretaceous Hekou Group deposits of the Lanzhou-Minhe Basin in theGansu Province region. These include small sites such as the Huazhuang tracksite, from the Honggu District reported here, the Zhongpu tracksitewith multiple track levels but few well-preserved tracks, other small tracksites currently under investigation, and the large and diverse LiujixiaNational Dinosaur Geopark site at Yanguoxia, where intensive study is ongoing. Collectively these sites reveal that ichnofaunas in the HekouGroup are widespread and diverse. The Huazhuang tracksite yields a small assemblage of moderately well-preserved theropod tracks assigned toAsianopodus. This is the first report of Asianopodus from the Hekou Group. Huazhuang Asianopodus belongs to the Eubrontes morphotype. Thelarge theropod tracks from Lanzhou-Minhe Basin were left by large theropod trackmakers with the same general foot morphology. The specimensare described in detail and compared with other theropod track morphotypes from the Lower Cretaceous of China and elsewhere. In general,although the metatarsophalangeal pads of some Jurassic Eubrontes-type tracks are aligned with the axis of digit III, this feature appears mostcommon in the Early Cretaceous theropod (Eubrontes-type) tracks.
|
|
