What caused Earths largest mass extinction event? New evidence from the Permian-Triassic boundary in northeastern Utah

Abstract. The Permian–Triassic boundary sections in north-western Iran belong to the most complete successions, in which the largest mass extinction event in the history of the Earth can be studied. We investigated the Changhsingian stage in six sections in the area of Julfa (Aras Valley) for their lithology, conodonts and ammonoids. Revision of the biostratigraphy led to the separation of 10 conodont zones (from bottom to top Clarkina orientalis–C. subcarinata interval zone, C. subcarinata, C. changxingensis, C. bachmanni, C. nodosa, C. yini, C. abadehensis, C. hauschkei, Hindeodus praeparvus–H. changxingensis and Merrilina ultima–Stepanovites ?mostleri zones) and 8 ammonoid zones (from bottom to top Iranites transcaucasius–Phisonites triangulus, Dzhulfites nodosus, Shevyrevites shevyrevi, Paratirolites trapezoidalis, P. waageni, Stoyanowites dieneri, Abichites stoyanowi and Arasella minuta zones). The new ammonoid genera Stoyanowites and Arasella are described.

Download Full-text

Marine Early Triassic Actinopterygii from the Candelaria Hills (Esmeralda County, Nevada, USA)

Journal of Paleontology ◽

10.1017/jpa.2019.18 ◽

2019 ◽

Vol 93 (5) ◽

pp. 971-1000

Author(s):

Carlo Romano ◽

Adriana López-Arbarello ◽

David Ware ◽

James F. Jenks ◽

Winand Brinkmann

Keyword(s):

New Species ◽

Mass Extinction ◽

New Genus ◽

Current Data ◽

Early Triassic ◽

Triassic Boundary ◽

Bony Fishes ◽

Mass Extinction Event ◽

In The Beginning ◽

Permian Triassic Boundary

AbstractA new locality for low-latitudinal, Early Triassic fishes was discovered in the Candelaria Hills, southwestern Nevada (USA). The fossils are derived from the lower Candelaria Formation, which was deposited during the middle–late Dienerian (late Induan), ca. 500 ka after the Permian-Triassic boundary mass extinction event. The articulated and disarticulated Osteichthyes (bony fishes), encompassing both Actinistia (coelacanths) and Actinopterygii (ray-fins), are preserved in large, silicified concretions that also contain rare coprolites. We describe the first actinopterygians from the Candelaria Hills. The specimens are referred toPteronisculus nevadanusnew species (Turseoidae?),Ardoreosomus occidentalisnew genus new species (Ptycholepidae), the stem neopterygianCandelarialepis argentusnew genus new species (Parasemionotidae), and Actinopterygii indet. representing additional taxa.Ardoreosomusn. gen. resembles other ptycholepids, but differs in its more angulate hyomandibula and lack of an elongate opercular process.Candelarialepisn. gen. is one of the largest parasemionotids, distinguished by its bipartite preopercle and scale ornamentation. Presented new species belong to genera (Pteronisculus) or families (Ptycholepidae, Parasemionotidae) that radiated globally after the mass extinction, thus underlining the striking similarities between Early Triassic (pre-Spathian) osteichthyan assemblages. The current data suggest that the diversity of low-latitudinal, Early Triassic bony fishes may have been greater than indicated thus far by the fossil record, probably due to sampling or taphonomic failure. All 24 fossils from the Candelaria Hills represent mid-sized or large osteichthyans, confirming the obvious absence of very small species (≤ 10 cm adult body length) in the beginning of the Mesozoic Era—even in low latitudes.UUID:http://zoobank.org/6a66ac96-d6b7-4617-94db-5a93cdb14215

Download Full-text

Magnetostratigraphy across the end-Permian mass extinction event from the Meishan sections, southeastern China

Geology ◽

10.1130/g49072.1 ◽

2021 ◽

Author(s):

Min Zhang ◽

Hua-Feng Qin ◽

Kuang He ◽

Yi-Fei Hou ◽

Quan-Feng Zheng ◽

...

Keyword(s):

Mass Extinction ◽

Southeastern China ◽

Triassic Boundary ◽

Biodiversity Crisis ◽

Normal Polarity ◽

Mass Extinction Event ◽

Geomagnetic Polarity ◽

Permian Mass Extinction ◽

Permian Triassic Boundary ◽

Geomagnetic Polarity Time Scale

The end-Permian mass extinction (EPME) has been recorded as the most severe biodiversity crisis in Earth’s history, although the timing of the marine and terrestrial extinctions remains debatable. We present a new high-resolution magnetostratigraphic succession across the EPME and the Permian-Triassic boundary (PTB) from the Meishan sections in southeastern China, which contain the global boundary stratotype section and point (GSSP) for the base of the Triassic (also the Induan Stage) and the base of the Changhsingian Stage. We identified five normal and five reverse magnetozones, including MS1n to MS5n and MS1r to MS5r, from oldest to youngest, in the Changhsingian and Induan Stages. The Induan Stage was determined to consist of two polarity intervals, where the upper one is reverse (MS5r), and the lower one is normal (MS5n). The Changhsingian Stage is dominated by normal polarity, intercalated with four short-term reverse magnetozones (MS1r to MS4r). Consequently, the PTB and the Wuchiapingian-Changhsingian boundary are clearly located in MS5n and MS1n, respectively. These new magnetostratigraphic results provide a potential reference geomagnetic polarity pattern with which to refine the geomagnetic polarity time scale for the EPME and the Permian-Triassic transition.

Download Full-text

A Hiatus Obscures the Early Evolution of Modern Lineages of Bony Fishes

Frontiers in Earth Science ◽

10.3389/feart.2020.618853 ◽

2021 ◽

Vol 8 ◽

Author(s):

Carlo Romano

Keyword(s):

Mass Extinction ◽

Fossil Record ◽

Middle Triassic ◽

Early Evolution ◽

Early Triassic ◽

Triassic Boundary ◽

Bony Fishes ◽

Extinction Event ◽

Mass Extinction Event ◽

The Impact

About half of all vertebrate species today are ray-finned fishes (Actinopterygii), and nearly all of them belong to the Neopterygii (modern ray-fins). The oldest unequivocal neopterygian fossils are known from the Early Triassic. They appear during a time when global fish faunas consisted of mostly cosmopolitan taxa, and contemporary bony fishes belonged mainly to non-neopterygian (“paleopterygian”) lineages. In the Middle Triassic (Pelsonian substage and later), less than 10 myrs (million years) after the Permian-Triassic boundary mass extinction event (PTBME), neopterygians were already species-rich and trophically diverse, and bony fish faunas were more regionally differentiated compared to the Early Triassic. Still little is known about the early evolution of neopterygians leading up to this first diversity peak. A major factor limiting our understanding of this “Triassic revolution” is an interval marked by a very poor fossil record, overlapping with the Spathian (late Olenekian, Early Triassic), Aegean (Early Anisian, Middle Triassic), and Bithynian (early Middle Anisian) substages. Here, I review the fossil record of Early and Middle Triassic marine bony fishes (Actinistia and Actinopterygii) at the substage-level in order to evaluate the impact of this hiatus–named herein the Spathian–Bithynian gap (SBG)–on our understanding of their diversification after the largest mass extinction event of the past. I propose three hypotheses: 1) the SSBE hypothesis, suggesting that most of the Middle Triassic diversity appeared in the aftermath of the Smithian-Spathian boundary extinction (SSBE; ∼2 myrs after the PTBME), 2) the Pelsonian explosion hypothesis, which states that most of the Middle Triassic ichthyodiversity is the result of a radiation event in the Pelsonian, and 3) the gradual replacement hypothesis, i.e. that the faunal turnover during the SBG was steady and bony fishes were not affected by extinction events subsequent to the PTBME. Based on current knowledge, hypothesis three is favored herein, but further studies are necessary to test alternative hypotheses. In light of the SBG, claims of a protracted diversification of bony fishes after the PTBME should be treated with caution.

Download Full-text

Heterogeneous volcanism across the Permian–Triassic Boundary in South China and implications for the Latest Permian Mass Extinction: New evidence from volcanic ash layers in the Lower Yangtze Region

Journal of Asian Earth Sciences ◽

10.1016/j.jseaes.2016.06.003 ◽

2016 ◽

Vol 127 ◽

pp. 197-210 ◽

Cited By ~ 24

Author(s):

Zhiwei Liao ◽

Wenxuan Hu ◽

Jian Cao ◽

Xiaolin Wang ◽

Suping Yao ◽

...

Keyword(s):

South China ◽

Mass Extinction ◽

Volcanic Ash ◽

Triassic Boundary ◽

Lower Yangtze Region ◽

Lower Yangtze ◽

Permian Mass Extinction ◽

Permian Triassic Boundary ◽

New Evidence

Download Full-text

High-resolution Sampling and Photogrammetry of the Permian-Triassic Boundary Within the Festningen Profile, Svalbard

10.5194/egusphere-egu21-15598 ◽

2021 ◽

Author(s):

Lars Eivind Augland ◽

Sverre Planke ◽

Valentin Zuchuat ◽

Morgan Jones ◽

Kim Senger ◽

...

Keyword(s):

Mass Extinction ◽

Outer Part ◽

Easy Access ◽

Tectonic Deformation ◽

Pixel Resolution ◽

Triassic Boundary ◽

Ash Layer ◽

Mass Extinction Event ◽

Permian Triassic Boundary ◽

Digital Outcrop

<p>The Permian period ended with a mass extinction event about 252 million years ago. A likely trigger of the mass extinction was the eruption of large volumes of magma which had moved through the Tunguska Basin in Siberia. The renowned Festningen section in the outer part of Isfjorden, western Spitsbergen, offers a c. 7 km long nearly continuous stratigraphic section of Lower Carboniferous to Cenozoic strata, where the end-Permian extinction interval is well-exposed. Tectonic deformation associated with the Paleogene West Spitsbergen fold-and-thrust-belt tilted the strata to near-vertical, allowing easy access along the shoreline. The section is a regionally important stratigraphic reference profile and is a key locality for geologists visiting Svalbard. The main objective of our fieldwork in September 2020 was to collect closely spaced mudstone (0.25 to 1 m interval) and ash layer (6 layers of 0.5 to 1.5 cm thickness) samples across the Festningen Permian-Triassic boundary for chemostratigraphic and geochronological assessments. Carbon isotope data reveal a well-defined negative deltaC13 excursion in the lower part of the Vardebukta Fm. Zircons are present in most of the ash layer samples and these will be dated at the University of Oslo TIMS U-Pb Isotope Geology Laboratory. In this contribution, we will also present a new digital outcrop model of the P-Tr boundary section acquired using a UAV (Mavic 2 Pro, 20MP Hasselblad camera). During acquisition, the maximum drone speed was set to 1 meter/second (i.e., &#8220;tripod mode&#8221;), and photographs were taken automatically at set time intervals (e.g., 1 photo every 5 seconds &#8776; meters). The digital outcrop model offers a pixel resolution of 7.27 mm/pixel. The Festningen model will be available online through the Svalbox.no geoscience data platform.</p>

Download Full-text