Unravelling the sources of carbon emissions at the onset of Oceanic Anoxic Event (OAE) 1a

High‐Resolution C‐Isotope, TOC and Biostratigraphic Records of OAE 1a (Aptian) From an Expanded Hemipelagic Cored Succession, Western Tethys: A New Stratigraphic Reference for Global Correlation and Paleoenvironmental Reconstruction

“…These variations in the C‐isotope profile could be related to changes in the intensity of the volcanic activity in the Ontong‐Java Plateau. However, recent studies on high‐resolution records have led to the differentiation of successive phases within the onset of OAE 1a, with both volcanic CO 2 and methane emissions (Adloff et al., 2020; Bottini et al., 2012, 2015; Erba et al., 2010; Méhay et al., 2009). The largest negative spike in the Cau core has an amplitude of −1.8‰ and an estimated duration of <10 kyr.…”

“…(2016); Os‐isotope data from Adloff et al. (2020). (c) C‐ and Os‐isotope data from Cismon core (Bottini et al., 2012, 2015), with Os‐isotope segments A to E Gorgo a Cerbara data from Tejada et al.…”

“…Carbon cycle modelling from the Cau outcrop section (Adloff et al, 2020) proposed a dominance of methane sources for the carbon emissions during the onset of OAE 1a, which contrasts with the biomarker-based interpretation of the carbon source by Méhay et al (2009). Kemp et al (2005) reported a very similar C-isotope pattern from the Toarcian OAE, with a succession of abrupt negative peaks in δ 13 C, which were interpreted as the result of pulses of methane emissions controlled by astronomically forced changes in climate, superimposed upon longer-term global warming.…”

“…Demise of carbonate platforms and carbonate ramps along the northern Tethys coincided with OAE 1a and a widespread nannoconid crisis (Erba et al, 2004). These changes have been considered to be related to surface ocean acidification due to 2016; Os-isotope data from Adloff et al (2020). (c) C-and Os-isotope data from Cismon core (Bottini et al, , 2015, with Os-isotope segments A to E Gorgo a Cerbara data from Tejada et al (2009).…”

“…. A rapid rise of atmospheric CO 2 has been invoked as a trigger for OAE 1a, which has been linked to submarine volcanic activity and possibly to methane emissions (Adloff et al, 2020;Bottini et al, , 2015Erba et al, 2010Erba et al, , 2015Kuhnt et al, 2011;Leckie et al, 2002;Méhay et al, 2009;Weissert & Erba, 2004). In addition to a direct volcanic source of CO 2 , Polteau et al (2016) have proposed that injection of magma into organic-rich sediments in the High Arctic Large Igneous Province (HALIP) may have forced a massive emission of methane.…”