Field of Science

New Triassic Papers

Thanks to Ben Creisler for originally compiling these...

Chen, Z. Q-., and M. J. Benton. 2012. The timing and pattern of biotic recovery following the end-Permian mass extinction. Nature Geoscience 5: 375–383doi:10.1038/ngeo1475
Abstract - The aftermath of the great end-Permian period mass extinction 252 Myr ago shows how life can recover from the loss of >90% species globally. The crisis was triggered by a number of physical environmental shocks (global warming, acid rain, ocean acidification and ocean anoxia), and some of these were repeated over the next 5–6 Myr. Ammonoids and some other groups diversified rapidly, within 1–3 Myr, but extinctions continued through the Early Triassic period. Triassic ecosystems were rebuilt stepwise from low to high trophic levels through the Early to Middle Triassic, and a stable, complex ecosystem did not re-emerge until the beginning of the Middle Triassic, 8–9 Myr after the crisis. A positive aspect of the recovery was the emergence of entirely new groups, such as marine reptiles and decapod crustaceans, as well as new tetrapods on land, including — eventually — dinosaurs. The stepwise recovery of life in the Triassic could have been delayed either by biotic drivers (complex multispecies interactions) or physical perturbations, or a combination of both. This is an example of the wider debate about the relative roles of intrinsic and extrinsic drivers of large-scale evolution.


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Lindström, S., van de Schootbrugge, B., Dybkjær, K., Pedersen, G. K.,  Fiebig, J., Nielsen, L. H.,  and S. Richoz. 2012.  No causal link between terrestrial ecosystem change and methane release during the end-Triassic mass extinction.
Geology 40(6): 531-534
doi: 10.1130/G32928.1

Abstract - Profound changes in both marine and terrestrial biota during the end-Triassic mass extinction event and associated successive carbon cycle perturbations across the Triassic-Jurassic boundary (T-J, 201.3 Ma) have primarily been attributed to volcanic emissions from the Central Atlantic Magmatic Province and/or injection of methane. Here we present a new extended organic carbon isotope record from a cored T-J boundary succession in the Danish Basin, dated by high-resolution palynostratigraphy and supplemented by a marine faunal record. Correlated with reference C-isotope and biotic records from the UK, it provides new evidence that the major biotic changes, both on land and in the oceans, commenced prior to the most prominent negative C-isotope excursion. If massive methane release was involved, it did not trigger the end-Triassic mass extinction. Instead, this negative C-isotope excursion is contemporaneous with the onset of floral recovery on land, whereas marine ecosystems remained perturbed. The decoupling between ecosystem recovery on land and in the sea is more likely explained by long-term flood basalt volcanism releasing both SO2 and CO2 with short- and long-term effects, respectively.

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Hamad, A. M. B. A. Jasper, A., and D. Uhl. 2012. The record of Triassic charcoal and other evidence for palaeo-wildfires: Signal for atmospheric oxygen levels, taphonomic biases or lack of fuel? International Journal of Coal Geology  96–97: 60–71 http://dx.doi.org/10.1016/j.coal.2012.03.006
Abstract - As wildfires are today important sources of disturbance in many terrestrial ecosystems, it is of great interest to understand how different environmental parameters and fire-activity interacted during past periods of the Earth history. Fossil charcoal, inertinites, and pyrogenic polycyclic aromatic hydrocarbons (PAHs) represent the only direct evidence for the occurrence of such palaeo-wildfires. In the present study, a review of published data, together with new data on the occurrence of fossil charcoal for the Permian and the Triassic is presented. For a long time, it has been speculated, that an assumed lack of evidence for palaeo-wildfires during the Triassic should be explained by a large drop in atmospheric oxygen concentration following or during the end-Permian mass extinction event, preventing the occurrence of wildfires. However, evidence for palaeo-wildfires is relatively common in many middle and late Triassic strata, whereas such evidence is almost totally lacking from early Triassic sediments. The interpretation of this “charcoal gap” or depression is difficult, as many factors (e.g. atmospheric oxygen concentration, taphonomical biases, lack of sediments suitable for the preservation of macroscopic charcoal, lack of fuel, and “ignorance” of scientists) may have influenced not only the production, but also the preservation and recovery of evidence for palaeo-wildfires during this period. Thus, it is not clear whether this Early Triassic “charcoal gap” can also be seen as evidence for an assumed “wildfire gap” or not. Without any doubt further investigations on the early Triassic record of charcoal and other evidence for palaeo-wildfires will be necessary before this problem can be solved. In fact, it can be expected that the number of published records of (early) Triassic evidence for palaeo-wildfires will increase in the future as more and more scientist working on
sediments of this age may become aware of the interest in fires from this time. This will certainly make it possible to give a much better picture of the temporal and regional distribution of wildfires during this period in the future.


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Bodzioch, A., and M. Kowal-Linka. 2012. Unraveling the origin of the Late Triassic multitaxic bone accumulation at Krasiejów (S Poland) by diagenetic analysis. Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication) http://dx.doi.org/10.1016/j.palaeo.2012.05.015

Abstract - A study of aquatic and terrestrial vertebrate remains from a bonebed in the Late Triassic continental succession near Krasiejów (S Poland) shows it was deposited by a single catastrophic event, perhaps a flood. Hardparts of Metoposaurus, Paleorhinus, and Stagonolepis show sedimentary infill and geochemical evidence for early diagenesis at different times and in different microenvironments. The infills in the aquatic animal bones (sediment, pyrite, calcite) show deposition in a freshwater environment, while those in the terrestrial Stagonolepis remains (mainly barite) point to an arid terrestial environment. The trace element content of the remains, together with the absence of a distinct pattern of element distribution, supports the conclusion that individual hardparts underwent diagenesis in various microenvironments and at different times. The accumulation of multitaxic vertebrate remains in a single bed clearly indicates event deposition. The hardparts must originally have been deposited at various locations during different times, but were later transported and deposited together in a pond by a short-lived, high-energy event, probably a flood after catastrophic rainfall.

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