Latest Triassic bivalves and gastropods from South Germany - implications for the end-Triassic mass extinction and the early evolution of veneroid bivalves

A suite of Early Mesozoic (Late Triassic, Norian to Early Jurassic) calcareous beds was studied from the Hochfelln Mountain in the Northern Calcareous Alps (NCA, South Germany). The Hauptdolomit Group consists of thick peritidal deposits and is overlain by basin deposits of the Rhaetian Kossen Formation and Rhaetian reefoidal limestone with corals. Unlike many other sections in the Tethys realm, coral growth seems to continue into the Jurassic or starts again relatively early within the Early Jurassic. Silicified corals and other marine invertebrates are present in the calcareous, micritic Hochfelln Beds. A re-examination of previously collected ammonite material indicates the presence of Coroniceras sp. which suggests an Early Sinemurian age for the Hochfelln Beds. Abundant sponge spicules (spiculites) suggest that sponges were the source for the silicification. The site produced one of the most diverse Early Jurassic (Sinemurian) gastropod faunas of the NCA (25–30 species, some undescribed). The relatively diverse Early Sinemurian gastropod fauna and coral growth indicate rapid recovery from the end-Triassic biotic crisis.

Nine monoplacophoran taxa and one bivalve are described from a late Middle Cambrian limestone lens in New Zealand. Two new genera, Eurekapegma and Enigmaconus, and five new species, Obtusoconus foliaceus, Anabarella simesi, Eurekapegma cooperi, Enigmaconus parvus, and Protowenella cobbensis are named. Enigmaconus, a pegma-bearing monoplacophoran, is assigned to the new family Enigmaconidae within the order Cyrtonellida. Eurekapegma is assigned to the Stenothecidae Runnegar & Jell 1980. Pelagiellid monoplacophorans are assigned to a new order Pelagiellida. Aspects of the Pojeta-Runnegar model for the early evolution of the Mollusca are critically appraised. It is argued that Heraultipegma was not a rostroconch and that riberioid rostroconchs may have evolved from an Enigmaconus-like monoplacophoran as late as late Middle Cambrian. Evolution of bivalves from rostroconchs is rejected and replaced by the suggestion that bivalves are descended directly from monoplacophorans.

Astronomical tuning of the end-Permian extinction and the Early Triassic Epoch of South China and Germany

The end-Triassic (also Triassic-Jurassic) mass extinction severely affected life on planet Earth 200 million years ago. Paleoclimate change triggered by the volcanic eruptions of the Central Atlantic Magmatic Province (CAMP) caused a great loss of marine biodiversity, among which 96% coral genera were get lost. However, there is precious little detail on the paleoecology and growth forms lost between the latest Triassic extinction and the Early Jurassic recovery. Here a new pilot study was conducted by analyzing corallite integration levels among corals from the latest Triassic and Early Jurassic times. Integration levels in corals from the Late Triassic and Early Jurassic were determined through both the Paleobiology Database as well as from a comprehensive museum collection of fossil corals. Results suggest that in addition to a major loss of diversity following the end-Triassic mass extinction, there also was a significant loss of highly integrated corals as clearly evidenced by the coral data from the Early Jurassic. This confirms our hypothesis of paleoecological selectivity for corals following the end-Triassic mass extinction. This study highlights the importance of assigning simple to advanced paleoecological characters with integration levels, which opens a useful approach to understanding of mass extinction and the dynamics of the recovery.

Beef and cone-in-cone calcite fibrous cements associated with the end-Permian and end-Triassic mass extinctions: Reassessment of processes of formation

SUMMARY Anomalies of the Earth's total magnetic field reveal important information about crustal structures. For the first time, a homogenous map of anomalies of the Earth's total magnetic field for the whole of Germany is available. The map is based on 50 shipborne, airborne and ground surveys, which were conducted between 1960 and 1990 and complemented by 17 new surveys after German reunification. The map, with a grid spacing of 100 m, consistently images the entire anomaly pattern in Germany at an altitude of 1000 m a.s.l. related to the DGRF 1980, epoch 1980.0. Because of these reference parameters and consideration of new data, the resolution of this map is higher than any previously published map. The homogenized and complete data set enables the distinction of different magnetic anomalies and – by observing their vector character – the identification of magnetic sources from different stages of the geological history. Since the map images the superposition of magnetic source anomalies from different depths and therefore combines long- and short-wavelength spectrums within one data set, it offers new insights into crustal structures. Not only regional tectonic units, such as the Variscan terranes in south and central Germany, or the extent of old Scandinavian crust under North Germany, as a relict of the collision between Baltica and Avalonia are imaged, but also details of local structures such as the volcanic areas of the Vogelsberg and the Eifel region. Therefore, the new data set can be used for work on modern topics in geosciences that cover both fundamental and applied research – for example, the structural and petrophysical characterization of the crust, its rheology and geodynamic evolution, or even hydrocarbon exploration. The gridded data is available as an electronic supplement to this paper.

Incidence of the early Toarcian global change on Dasycladales (Chlorophyta) and the subsequent recovery: Comparison with end-Triassic Mass Extinction

Abstract. ​​​​​​​We held the MagellanPlus workshop SVALCLIME “Deep-time Arctic climate archives: high-resolution coring of Svalbard's sedimentary record”, from 18 to 21 October​​​​​​​ 2022 in Longyearbyen, to discuss scientific drilling of the unique high-resolution climate archives of Neoproterozoic to Paleogene age present in the sedimentary record of Svalbard. Svalbard is globally unique in that it facilitates scientific coring across multiple stratigraphic intervals within a relatively small area. The polar location of Svalbard for some of the Mesozoic and the entire Cenozoic makes sites in Svalbard highly complementary to the more easily accessible mid-latitude sites, allowing for investigation of the polar amplification effect over geological time. The workshop focused on how understanding the geological history of Svalbard can improve our ability to predict future environmental changes, especially at higher latitudes. This topic is highly relevant for the ICDP 2020–2030 Science Plan Theme 4 “Environmental Change” and Theme 1 “Geodynamic Processes”. We concluded that systematic coring of selected Paleozoic, Mesozoic, and Paleogene age sediments in the Arctic should provide important new constraints on deep-time climate change events and the evolution of Earth's hydrosphere–atmosphere–biosphere system. We developed a scientific plan to address three main objectives through scientific onshore drilling on Svalbard: a. Investigate the coevolution of life and repeated icehouse–greenhouse climate transitions, likely forced by orbital variations, by coring Neoproterozoic and Paleozoic glacial and interglacial intervals in the Cryogenian (“Snowball/Slushball Earth”) and late Carboniferous to early Permian time periods.b. Assess the impact of Mesozoic Large Igneous Province emplacement on rapid climate change and mass extinctions, including the end-Permian mass extinction, the end-Triassic mass extinction, the Jenkyns Event (Toarcian Oceanic Anoxic Event), the Jurassic Volgian Carbon Isotopic Excursion and the Cretaceous Weissert Event and Oceanic Anoxic Event 1a.c. Examine the early Eocene hothouse and subsequent transition to a coolhouse world in the Oligocene by coring Paleogene sediments, including records of the Paleocene–Eocene Thermal Maximum, the Eocene Thermal Maximum 2, and the Eocene–Oligocene transition. The SVALCLIME science team created plans for a 3-year drilling programme using two platforms: (1) a lightweight coring system for holes of ∼ 100 m length (4–6 sites) and (2) a larger platform that can drill deep holes of up to ∼ 2 km (1–2 sites). In situ wireline log data and fluid samples will be collected in the holes, and core description and sampling will take place at The University Centre in Svalbard (UNIS) in Longyearbyen. The results from the proposed scientific drilling will be integrated with existing industry and scientific boreholes to establish an almost continuous succession of geological environmental data spanning the Phanerozoic. The results will significantly advance our understanding of how the interplay of internal and external Earth processes are linked with global climate change dynamics, the evolution of life, and mass extinctions.

Although a majority of biologists are convinced that a mass extinction is underway on earth today, the human history with direct observatory data is too short to predict its future trends. At least five mass extinctions occurred during the Phanerozoic Eon, causing the rapid extinction of at least 75% of existing marine species; they also seriously affected species diversity on land once the terrestrial ecosystem developed. The causes and consequences of these mass extinctions have become the most useful analogs for understanding whether the current global ecosystem is experiencing an extinction event. Previous multidisciplinary studies of the extinction patterns of fossil groups and concurrent environmental changes of the five mass extinctions during the past 500 million years (occurring in the end-Ordovician, Late Devonian Frasnian-Famennian, end-Permian, end-Triassic, and end-Cretaceous) suggested that no catastrophic event wiped out all organisms on earth. However, all five mass extinctions were associated with serious environmental deterioration and major paleoclimatic changes. The end-Ordovician mass extinction, occurring 445.2–443.8 million years ago, consists of two phases separated by an interval dominated by the cold Hirnantia fauna. The wax and wane of glaciation and associated widespread anoxia were the major causes of the two phases of the end-Ordovician mass extinctions. The Late Devonian mass extinction consists of a few different events from the Givetian to the Devonian-Carboniferous boundary, of which the most important is the Kellwasser event around the Frasnian-Famennian boundary. This extinction most seriously affected the coral and stromatoporoid reefs, and caused the extinction of two brachiopod orders (Pentamerida and Atrypida). As of yet, there is no consensus on the cause of this extinction event. Global cooling related to the widespread development of the terrestrial vegetation ecosystem and marine anoxia are the two most plausible scenarios. Although impact events were reported from a few horizons in the Late Devonian, they cannot account for the multiple phases of the Late Devonian mass extinctions. The end-Permian mass extinction about 252 million years ago has been universally documented as the most serious, which caused the disappearances of about 95% of all marine and 75% of all terrestrial species. Based on the latest high-precision geochronology data from South China, this extinction happened within an interval of less than 61 thousand years. This extinction was associated with a sharp negative excursion of δ 13Ccarb. A rapid temperature rise of 6–8 °C also occurred within the extinction interval. The Siberian Traps eruption and volcanism in South China, triggered by the dispersal of the supercontinent Pangea, is the most plausible explanation for the end-Permian mass extinction. The end-Triassic mass extinction at 201.564±0.015 Ma also seriously affected both marine and terrestrial ecosystems. Amphibians and reptiles both suffered a great loss during this extinction, and they were subsequently replaced by highly diverse dinosaurs. Marine conodonts and Ceratitida became extinct, and the sponge Demospongea and the brachiopod order Spiriferinida were also greatly affected. Recent studies suggest that the extinction stage may have extended over 10–20 million years, and the volcanism of the Central Atlantic Magmatic Province may be the cause. The end-Cretaceous mass extinction has been the best-known event among the general public because it caused the extinction of various dinosaurs that prevailed during the Mesozoic Era. The cause of this extinction has been documented as the extraterrestrial Chicxulub impact event. However, detailed paleontological studies suggested that the extinction is more likely to have been caused by another major volcanism event, the massive eruption of the Deccan Traps. In summary, global changes in atmospheric CO2 and paleotemperature (both icehouse and greenhouse), oceanic acidification, sea-level changes, and anoxia triggered by massive volcanic eruptions are the most plausible causes of the past extinctions. Massive volcanism not only ejected a huge amount of CO2 and volcanic sulfates, but also caused a massive release of thermogenic CO2 and methane stored in the deposits of inland basins and continental shelves. Extraterrestrial impact, supernova explosion, and solar flares could instantaneously wipe out all organisms on earth, but they are not the main causes of the five mass extinctions experienced in the history of the earth.

The role of LIPs in Phanerozoic mass extinctions: An Hg perspective

The end-Triassic Mass Extinction (ETME) is generally regarded as a consequence of the environmental changes associated with the emplacement of the Central Atlantic Magmatic Province (CAMP) and ranks among the ‘big five’ mass extinctions in Earth history. A notable feature of the ETME is a halt in marine carbonate deposition followed by the formation of unusual facies such as carbonate cement fans and oolites in the early aftermath of the event. The ETME time interval has been well studied over the last few decades, in contrast to a few minor extinction events that preceded it, among them the extinctions associated with the Norian-Rhaetian boundary (NRB). This study provides new insights into these extinction events with complete mid-Norian to Hettangian δ18Ocarb and δ13Ccarb record from a key section at Wadi Milaha (Ras Al Khaimah Emirate, United Arab Emirates). Ooids are important proxies for palaeoenvironmental reconstruction. The post ETME oolite horizon is documented providing morphological classification as well as a detailed modal analysis of rock components and different types of coated grains. Through a multi-technique approach, we argue for the stability of the carbon cycle across the NRB extinction event and the existence of a hiatus at the TJB (Triassic-Jurassic Boundary) in Wadi Milaha. Our new morphological classification of post-extinction ooids is compatible with a major role for seawater geochemistry with respect to sedimentological processes, by example in the peculiar way ooids diversify and alternate with other kinds of coated grains.

One of the five greatest mass extinction events in Earth's history occurred at the end of the Triassic,c.200 million years ago. This event ultimately eliminated conodonts and nearly annihilated corals, sphinctozoan sponges and ammonoids. Other strongly affected marine taxa include brachiopods, bivalves, gastropods and foraminifers. On the land, there is evidence for a temporal disturbance of plant communities but only few plant taxa finally disappeared. Terrestrial vertebrates also suffered but timing and extent of this extinction remains equivocal. The cause of the end‐Triassic mass extinction was probably linked to the contemporary activity of the Central Atlantic Magmatic Province, which heralded the breakup of the supercontinent Pangaea. Possible kill mechanisms associated with magmatic activity include sea‐level changes, marina anoxia, climatic changes, release of toxic compounds and acidification of seawater. Remarkably, long‐term effects on marine biota were rather different between ecological groups: a nearly instantaneous recovery of level‐bottom communities is contrasted by the virtual absence of reef systems for nearly 10 million years after the extinction event.Key Concepts:Nearly half of all marine genera and a smaller but still significant proportion of terrestrial taxa went extinct at the end of the Triassic period,c.200 million years ago.The end‐Triassic mass extinction took place during a geologically short time interval, which coincided with the onset of massive magmatic extrusions along fracture zones of the disassembling supercontinent Pangaea.A cause‐and‐effect relationship between magmatic activity and mass extinction is indicated by the accordance of predicted extinction patterns and observed data from the fossil record.Ocean acidification as a kill mechanism in marine ecosystems is confirmed by preferential extinction of taxa with thick aragonitic skeletons.The end‐Triassic mass extinction event provides a test‐case for studying evolutionary responses to major environmental disturbances on the global scale and over geological time.Although there are differences in emission rates, the massive magmatic CO2release at the end of the Triassic is quantitatively similar to a potential release by complete combustion of the global fossil fuel reserves.A provisional prediction from the data of the fossil record is that in the marine realm level‐bottom communities are able to recover much more quickly from the effects of excess CO2than reef systems.

The Triassic–Jurassic transition – A review of environmental change at the dawn of modern life

Dating the end-Triassic and Early Jurassic mass extinctions, correlative large igneous provinces, and isotopic events

One of the five greatest mass extinction events in Earth's history occurred at the end of the Triassic, c . 200 million years ago. This event ultimately eliminated conodonts and nearly annihilated corals, sphinctozoan sponges and ammonoids. Other strongly affected marine taxa include brachiopods, bivalves, gastropods and foraminifers. On land, there is evidence for a temporal disturbance of plant communities but only few plant taxa finally disappeared. Terrestrial vertebrates also suffered but timing and extent of this extinction remain equivocal. The cause of the end‐Triassic mass extinction was probably linked to the contemporary activity of the Central Atlantic Magmatic Province, which heralded the breakup of the supercontinent Pangaea. Possible kill mechanisms associated with magmatic activity include sea‐level changes, marina anoxia, climatic changes, release of toxic elements and compounds and ocean acidification. Recovery from the extinction event was remarkably fast for marine level‐bottom faunas but delayed for reef communities, possibly because reef organisms were more co‐evolved and suffered higher losses during the extinction. Key Concepts Nearly half of all marine genera and a smaller but still significant proportion of terrestrial taxa went extinct at the end of the Triassic period, c . 200 million years ago. The end‐Triassic mass extinction took place during a geologically short time interval, which coincided with the onset of massive magmatic extrusions along fracture zones of the disassembling supercontinent Pangaea. A cause‐and‐effect relationship between magmatic activity and mass extinction is indicated by the accordance of predicted extinction patterns and observed data from the fossil record. Ocean acidification as a kill mechanism in marine ecosystems is confirmed by preferential extinction of taxa with thick aragonitic skeletons. The end‐Triassic mass extinction event provides a test case for studying evolutionary responses to major environmental disturbances on the global scale and over geological time. Although there are differences in emission rates, the massive magmatic CO 2 release at the end of the Triassic is quantitatively similar to a potential release by complete combustion of the global fossil fuel reserves. A prediction from data of the fossil record for marine ecosystems is that level‐bottom communities are able to recover much more quickly from the effects of excess CO 2 than reefs.