A new correlation of Triassic–Jurassic boundary successions in NW Europe, Nevada and Peru, and the Central Atlantic Magmatic Province: A time-line for the end-Triassic mass extinction

Abstract

Understanding the end-Triassic mass extinction event (201.36 Ma) requires a clear insight into the stratigraphy of boundary sections, which allows for long-distance correlations and correct distinction of the sequence of events. However, even after the ratification of a Global Stratotype Section and Point, global correlations of TJB successions are hampered by the fact that many of the traditionally used fossil groups were severely affected by the crisis. Here, a new correlation of key TJB successions in Europe, U.S.A. and Peru, based on a combination of biotic (palynology and ammonites), geochemical (δ 13 C org ) and radiometric (U/Pb ages) constraints, is presented. This new correlation has an impact on the causality and temporal development during the end-Triassic event. It challenges the hitherto used standard correlation, which has formed the basis for a hypothesis that the extinction was caused by more or less instantaneous release of large quantities of light carbon (methane) to the atmosphere, with catastrophic global warming as a consequence. The new correlation instead advocates a more prolonged scenario with a series of feedback mechanisms, as it indicates that the bulk of the hitherto dated, high-titanium, quartz normalized volcanism of the Central Atlantic Magmatic Province (CAMP) preceded or was contemporaneous to the onset of the mass extinction. In addition, the maximum phase of the mass extinction, which affected both the terrestrial and marine ecosystems, was associated with a major regression and repeated, enhanced earthquake activity in Europe. A subsequent transgression resulted in the formation of hiati or condensed successions in many areas in Europe. Later phases of volcanic activity of the CAMP, producing low titanium, quartz normalized and high-iron, quartz normalized basaltic rocks, continued close to the first occurrence of Jurassic ammonites and the defined TJB. During this time the terrestrial ecosystem had begun to recover, but the marine ecosystem remained disturbed.

Deep CO2 in the end-Triassic Central Atlantic Magmatic Province

“…Such short and powerful eruptions may have had a severe impact on global climate by limiting the time in which negative feedback processes, such as the weathering of Ca-Mg silicates, can abate warming and acidification. CAMP magmatism coincided in time with three marked negative carbon isotope excursions bracketing the main extinction period 20,24,25 , and with an inferred strong rise of atmospheric CO 2 8,9 . In general, the pulsed magmatic and degassing activities of LIPs 6,7 can cause a rapid rise of atmospheric CO 2 and greenhouse conditions, which are reflected by rapid δ 13 C negative excursions recorded in both organic matter and carbonates 10 , testifying to a global perturbation of the exogenic (i.e., superficial) carbon cycle.…”

Platinum-group elements link the end-Triassic mass extinction and the Central Atlantic Magmatic Province

“…The stratigraphic framework for discussing the PGE data is based on Lindström et al 44 and is shown in Fig. 2.…”

The temporal and spatial distribution of Triassic dinoflagellate cysts

“…Warrington, 1983;Mettraux and Mohr, 1989;Embry and Suneby, 1994;Warrington et al, 1995;Kürschner et al, 2007;Bonis et al, 2009;Ruckwied and Götz, 2009) and papers on sequence stratigraphy (e.g. Paterson et al, 2016;Lindström et al, 2017b) Table 1). The composition of these Late Triassic assemblages varies, and is often poorly known in part due to a lack of quantitative data.…”

“…Lindström 2002 Lindström (2006); these two forms may reflect different salinity levels. Only one occurrence of Lunnomidinium scaniense from Schandelach, Germany has been reported outside Sweden (Lindström et al, 2017b). Lindström and Erlström (2006b) Several studies recorded Rhaetian dinoflagellate cysts from south-eastern France (Doubinger and Adloff, 1977;Adloff and Doubinger, 1982;Fauconnier et al, 1996;Courtinat et al, 1998;2002;Courtinat and Piriou, 2002).…”