Complex Interactions Between Large Igneous Province Emplacement and Global‐Temperature Changes During the Cenomanian‐Turonian Oceanic Anoxic Event (OAE 2)

Abstract

Super greenhouse temperatures at the onset of the Cenomanian-Turonian oceanic anoxic event (OAE 2) have been widely linked with large igneous province (LIP) volcanic activity. However, the extent to which volcanism influenced subsequent climate changes throughout OAE 2, such as global cooling during the Plenus Cold Event (PCE) early in the OAE, and the subsequent return to very warm conditions through the second part of the crisis remain less clear. Here, new osmium-isotope (187 Os/ 188 Os) data are presented from the northeastern margin of the proto-North Atlantic Ocean (ODP Leg 174AX Bass River, NJ, USA). The results are consistent with previously published OAE 2 records and are similarly interpreted as documenting LIP activity while further demonstrating the ability to use osmium-isotope stratigraphy as a global chemostratigraphic marker in open-ocean records. Correlations of 187 Os/ 188 Os and sea-surface temperature trends at Bass River and other sites show that the earliest PCE cooling coincided with intense volcanism, but that LIP activity began to decline during or soon after the cold pulse. These temporal relationships support previous hypotheses that the PCE was regionally diachronous and likely caused by enhanced carbon sequestration via organic-matter burial and silicate weathering, rather than a period of volcanic quiescence, while the persistently warm conditions later in OAE 2 were linked to reduced silicate weathering rather than sustained volcanism. These findings highlight the complex interactions between LIP emplacement and climate responses during OAE 2, reemphasizing the need for similar correlations between volcanism and paleotemperature proxy data for other major events in Earth's history.

Upper Devonian mercury record from North America and its implications for the Frasnian–Famennian mass extinction

“…The osmium-isotope ratio of a sedimentary rock is another widely used proxy to study ancient volcanic events (e.g., Dickson et al, 2015;Du Vivier et al, 2014;Georgiev et al, 2015;Liu et al, 2020b;Liu et al, 2019b;Percival et al, 2020;Peucker-Ehrenbrink and Ravizza, 2012;Turgeon and Creaser, 2008). The modern seawater osmium-isotope ( 187 Os/ 188 Os) composition is controlled by the mass balance of unradiogenic Os input from mantle and extraterrestrial sources (~0.126) and riverine input of radiogenic material following weathering of ancient continent crust (~1.4 today) (Peucker-Ehrenbrink and Ravizza, 2000).…”

“…Thus, if volcanism indeed occurred at this time, it is likely to be a small/transient event that differs from other LIPs claimed to be responsible for major environmental/biotic perturbations. For example, LIP activity associated with the Late Cretaceous Cenomanian-Turonian Oceanic Anoxic Event lasted ~200 kyr and is marked by a global-scale shift to very unradiogenic values in the sedimentary Os isotope record (e.g., Du Vivier et al, 2014Percival et al, 2020;Jones et al, 2020). Prolonged unradiogenic Os isotope shifts are also documented in response to widespread igneous activity related to the Central Atlantic magmatic province during the Triassic-Jurassic boundary interval (Cohen and Coe, 2002;Kuroda et al, 2010).…”

A new giant sauropod,Australotitan cooperensisgen. et sp. nov., from the mid-Cretaceous of Australia

“…The basin rapidly filled with volcanoclastic input from the east and transitioned from low terrestrial vegetation productivity (e.g., shallow/coastal marine habitats) to highly productive habitats (e.g., paralic to fluvial and lacustrine environments). Such labile and frequently disturbed environments were likely further disturbed by the sauropods themselves, and this was set within a backdrop of variable or seasonal local climate ( Fletcher, Moss & Salisbury, 2018 ) and major mid-Cretaceous global climatic fluctuations ( Hay, 2011 ) associated with volcanism ( Percival et al, 2020 ). Of note, a combination of frequent disturbance with climatic variability and instability has been proposed as a mechanism that maintained megaherbivore diversity of Quaternary megafauna ( Mann et al, 2018 ).…”

Evidence for changes in sea-surface circulation patterns and ~20° equatorward expansion of the Boreal bioprovince during a cold snap of Oceanic Anoxic Event 2 (Late Cretaceous)

“…Different geochemical proxies obtained from the European epicontinental basins, the Western Interior Seaway (WIS) and the North and equatorial Atlantic Ocean suggest a 5 to 11°C drop in seasurface temperatures, increased equator-to-pole temperature gradients, and a 400 to 600 ppmv decrease of the atmospheric pCO 2 levels, which has been generally related to the burial of organic matter during the initial phase of OAE 2 (e.g., Arthur et al, 1988;Kump and Arthur, 1999;Paul et al, 1999;Tsikos et al, 2004;Voigt et al, 2006;Forster et al, 2007;Sinninghe Damsté et al, 2010;Jarvis et al, 2011;Jenkyns et al, 2017;Kuhnt et al, 2017;Gale et al, 2019). However, the timing and magnitude of cooling might have been modulated by local factors (O'Connor et al, 2020;Percival et al, 2020) and evidence for cooling are doubtful (Gangl et al, 2019;Petrizzo et al, 2021) or missing from the Southern Hemisphere and from the Pacific Ocean, where the OAE 2 interval is often incomplete (e.g., Ando et al, 2009;Jiménez Berrocoso et al, 2015;Falzoni et al, 2016a;Robinson et al, 2019) or shows a noisy  13 C record (Takashima et al, 2011) that complicates the chemostratigraphic correlations.…”

“…The typical OAE 2 hot greenhouse climate conditions re-established soon after the PCE likely as a response to a reduced rate of silicate weathering (Robinson et al, 2019;Percival et al, 2020) and/or to the LIP(s) reactivation after brief quiescence (Sullivan et al, 2020).…”