“…The TFB is of exceptional value for the age determination of late Variscan Carboniferous-Permian basins because it is well investigated concerning lithostratigraphy and biostratigraphy (e.g., Schneider and Werneburg 2012;Schneider et al 2020). The TFB also shows recurrent strong intra-basinal volcanism that produced piles of lava flows and tuffs hundreds of meters thick.…”
Section: Geological Overviewmentioning
confidence: 99%
“…Paleontological projects were performed by T. Martens in cooperation with experts from the USA (Martens 2001;Eberth et al 2000 and others). The state of biostratigraphic correlation was summarized by Schneider et al (2020). They consider for the Bromacker Horizon an Artinskian age, which is not proven by radioisotopic studies.…”
Mainly acidic Stephanian to early Permian volcanic rocks and intercalated sediments accumulated in the Thuringian Forest Basin (TFB) in central Germany to a total thickness of ca. 2000 m. This basin offers a wide range of biostratigraphic information. New high-precision U–Pb CA–ID–TIMS (chemical abrasion–isotope dilution–thermal ionization mass spectrometry) zircon data are obtained from volcanic rocks for the first time in the TFB. Pre-treatment of the zircons by chemical abrasion was important to get rid of severe Pb loss. The zircon ages of the investigated formations indicate that the total duration of the volcanic activity in the TFB was considerably shorter [ca. 4 Myr: from 300 Ma for the oldest formation (Möhrenbach) until ca. 296 Ma for the youngest volcanic-rock-bearing formation (Rotterode)] than suggested in previous studies (ca. 20 Myr; 295 Ma to 275 Ma). Consequently, the well-documented gap of the sedimentary record from the early Permian volcanic rocks up to the Illawarra geomagnetic reversal has to be extended to ca. 25 Myr from the previously proposed 5 Myr. The zircon ages of the investigated volcanic rocks allow the constraining of some intercalated fossiliferous horizons crucial for biostratigraphic correlation of latest Carboniferous–early Permian (Rotliegend) sections. The high-precision age data require a new interpretation of the evolution of the TFB but also offer the chance to obtain a more reliable comparison of the timing of the main magmatic activity across intramontane basins as well as to obtain links to the Standard Global Stratigraphic Scale.
“…The TFB is of exceptional value for the age determination of late Variscan Carboniferous-Permian basins because it is well investigated concerning lithostratigraphy and biostratigraphy (e.g., Schneider and Werneburg 2012;Schneider et al 2020). The TFB also shows recurrent strong intra-basinal volcanism that produced piles of lava flows and tuffs hundreds of meters thick.…”
Section: Geological Overviewmentioning
confidence: 99%
“…Paleontological projects were performed by T. Martens in cooperation with experts from the USA (Martens 2001;Eberth et al 2000 and others). The state of biostratigraphic correlation was summarized by Schneider et al (2020). They consider for the Bromacker Horizon an Artinskian age, which is not proven by radioisotopic studies.…”
Mainly acidic Stephanian to early Permian volcanic rocks and intercalated sediments accumulated in the Thuringian Forest Basin (TFB) in central Germany to a total thickness of ca. 2000 m. This basin offers a wide range of biostratigraphic information. New high-precision U–Pb CA–ID–TIMS (chemical abrasion–isotope dilution–thermal ionization mass spectrometry) zircon data are obtained from volcanic rocks for the first time in the TFB. Pre-treatment of the zircons by chemical abrasion was important to get rid of severe Pb loss. The zircon ages of the investigated formations indicate that the total duration of the volcanic activity in the TFB was considerably shorter [ca. 4 Myr: from 300 Ma for the oldest formation (Möhrenbach) until ca. 296 Ma for the youngest volcanic-rock-bearing formation (Rotterode)] than suggested in previous studies (ca. 20 Myr; 295 Ma to 275 Ma). Consequently, the well-documented gap of the sedimentary record from the early Permian volcanic rocks up to the Illawarra geomagnetic reversal has to be extended to ca. 25 Myr from the previously proposed 5 Myr. The zircon ages of the investigated volcanic rocks allow the constraining of some intercalated fossiliferous horizons crucial for biostratigraphic correlation of latest Carboniferous–early Permian (Rotliegend) sections. The high-precision age data require a new interpretation of the evolution of the TFB but also offer the chance to obtain a more reliable comparison of the timing of the main magmatic activity across intramontane basins as well as to obtain links to the Standard Global Stratigraphic Scale.
“…Further evidence is that Subzone B is placed stratigraphically between subzones that have been independently assigned to the late Olenekian (Subzone A) and the late Anisian (Subzone C), again using vertebrate biostratigraphy [ 56 ]. There has been some recent suggestion of a Carnian age based on SHRIMP U-Pb dating of the Quebrada de los Fósiles Formation (Argentina) to 235.8 ± 2 Ma, and biostratigraphic correlation of the Cynognathus Assemblage Zone (in particular Subzone B) with the overlying Río Seco de La Quebrada Formation (based on the presence of Cynognathus , Diademodon and Kannemeyeria ) [ 58 ], but this is not yet broadly accepted, given the major discordance with previous understanding and the well-constrained Anisian age of the overlying Perovkian Land Vertebrate Faunochron [ 59 ]. Figure 2.…”
Archosauria (birds, crocodilians and their extinct relatives) form a major part of terrestrial ecosystems today, with over 10 000 living species, and came to dominate the land for most of the Mesozoic (over 150 Myr) after radiating following the Permian–Triassic extinction. The archosaur skull has been essential to this diversification, itself diversified into myriad forms. The archosauriform
Euparkeria capensis
from the Middle Triassic (Anisian) of South Africa has been of great interest since its initial description in 1913, because its anatomy shed light on the origins and early evolution of crown Archosauria and potentially approached that of the archosaur common ancestor.
Euparkeria
has been widely used as an outgroup in phylogenetic analyses and when investigating patterns of trait evolution among archosaurs. Although described monographically in 1965, subsequent years have seen great advances in the understanding of early archosaurs and in imaging techniques. Here, the cranium and mandible of
Euparkeria
are fully redescribed and documented using all fossil material and computed tomographic data. Details previously unclear are fully described, including vomerine dentition, the epiptergoid, number of premaxillary teeth and palatal arrangement. A new diagnosis and cranial and braincase reconstruction is provided, and an anatomical network analysis is performed on the skull of
Euparkeria
and compared with other amniotes. The modular composition of the cranium suggests a flexible skull well adapted to feeding on agile food, but with a clear tendency towards more carnivorous behaviour, placing the taxon at the interface between ancestral diapsid and crown archosaur ecomorphology, corresponding to increases in brain size, visual sensitivity, upright locomotion and metabolism around this point in archosauriform evolution. The skull of
Euparkeria
epitomizes a major evolutionary transition, and places crown archosaur morphology in an evolutionary context.
“…he end-Permian extinction event represents the most catastrophic demise of the Phanerozoic biosphere, with an estimated "instantaneous" biodiversity loss exceeding 90% of marine invertebrate species 1,2 and a reportedly coeval turnover of up to 70% of terrestrial vertebrates 3,4 but see 5 . It is a deep-time model for ecosystem response to increasingly warmer climates, and considered a potential scenario comparable to changes now documented in today's Earth Systems 2,6 .…”
The current model for the end-Permian terrestrial ecosystem crisis holds that systematic loss exhibited by an abrupt turnover from the Daptocephalus to the Lystrosaurus Assemblage Zone (AZ; Karoo Basin, South Africa) is time equivalent with the marine Permian-Triassic boundary (PTB). The marine event began at 251.941 ± 0.037 Ma, with the PTB placed at 251.902 ± 0.024 Ma (2σ). Radio-isotopic dates over this interval in the Karoo Basin were limited to one high resolution ash-fall deposit in the upper Daptocephalus AZ (253.48 ± 0.15 (2σ) Ma) with no similar age constraints for the overlying biozone. Here, we present the first U-Pb CA-ID-TIMS zircon age (252.24 ± 0.11 (2σ) Ma) from a pristine ash-fall deposit in the Karoo Lystrosaurus AZ. This date confirms that the lower exposures of the Lystrosaurus AZ are of latest Permian age and that the purported turnover in the basin preceded the end-Permian marine event by over 300 ka, thus refuting the previously used stratigraphic marker for terrestrial end-Permian extinction.
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