First Record of Oceanic Anoxic Event 1d at Southern High Latitudes: Sedimentary and Geochemical Evidence From International Ocean Discovery Program Expedition 369

Oceanic anoxic event 1d (OAE 1d) has been well studied at northern low latitudes (i.e., in Tethys and the North Atlantic); however, the paleoenvironmental response to this event at high latitudes has not been documented and the triggering mechanism remains unknown. Here, we address both of these shortcomings by presenting the first detailed sedimentary and multi-proxy geochemical record of the OAE 1d at southern high latitudes (60-62 degrees S), obtained from sediments using Site U1513, IODP Expedition 369. Biostratigraphic and chemostratigraphic data support correlation of the interval studied with OAE 1d, and the sedimentary mercury proxy reveals that at least at Site U1513, OAE 1d is associated with the Central Kerguelen large igneous province volcanism. Furthermore, the significant increase in continental runoff and consequent terrigenous input from southwestern Australia in the southeastern proto-India Ocean might have resulted in regionally weakened bottom-water oxygenation and strengthened organic matter burial during OAE 1d.