A High Resolution Stable Isotope Record of the lower Danian from the Caravaca Section (SE Spain)

Abstract:

Early Eocene hyperthermals represent large perturbations of the global carbon cycle characterized by significant global temperature increases. The best known and largest episode is represented by the Paleocene Eocene Thermal Maximum (PETM) also known as the Eocene Thermal Maximum 1 (ETM1), which occurs at ~55.7 Ma. Two other major episodes include the ETM2 (~55.7 Ma) and the ETM3 (~54.3 Ma). Available geochemical and sedimentary records indicates that other hyperthermal events might have occurred during the Paleocene, including the DanC2 event at ~ 65.4 Ma (Quillévéré et al., 2008), Top C27N event at ~61.6 Ma (Westerhold et al., 2008) and the Lower C29N event (Coccioni et al., 2012). A key feature of hyperthermals is the abrupt negative shift in δ¹³C values, which is interpreted to reflect the release of a large mass of ¹³C-depleted carbon in the form of CH₄ and/or CO₂ into the atmosphere-ocean system, causing dramatic warming and ocean acidification (Zachos et al., 2005). Here we present a high resolution biostratigraphic, magnetic susceptibility, and geochemical record of the lower Danian from the Caravaca section (SE Spain). By combining inorganic and organic geochimistry proxies we were able to identify the Dan-C2 event in our section and the Lower C29N event. A sampling spacing of 5 cm corresponding to ~3 kyr in the time domain based on the average sedimentation rate of 1.5 cm/kyr (Smit, 2004) provides a well resolved record of the two events. This resolution can be used to detect short-term periodicity and, therefore, accurately determine the timing of the two events and their duration.