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 associated with this event at high latitudes has not been documented and the trigger mechanism remains unknown. Here, we address both of these shortcomings by presenting the first detailed sedimentary and geochemical multi-proxy records of the OAE 1d at southern high latitudes (60-62°S), obtained from sediments at Site U1513, IODP Expedition 369. In particular, the record of sedimentary mercury proxy reveals that OAE 1d is associated with the Central Kerguelen large igneous province volcanism. Furthermore, the significant increase in continental runoff and consequent terrigenous input for southwestern Australia in the southeastern proto-India Ocean might have resulted regionally in weakened bottom-water oxygenation and strengthened organic matter burial during OAE 1d. 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 associated with this event at high latitudes has not been documented and the trigger mechanism remains unknown. Here, we address both of these shortcomings by presenting the first detailed sedimentary and geochemical multi-proxy records of the OAE 1d at southern high latitudes (60-62°S), obtained from sediments at Site U1513, IODP Expedition 369. In particular, the record of sedimentary mercury proxy reveals that OAE 1d is associated with the Central Kerguelen large igneous province volcanism. Furthermore, the significant increase in continental runoff and consequent terrigenous input for southwestern Australia in the southeastern proto-India Ocean might have resulted regionally in weakened bottom-water oxygenation and strengthened organic matter burial during OAE 1d.大洋缺氧事件1d（Oceanic anoxic event 1d, OAE 1d）已在北低纬度地区（即特提斯洋与北大西洋海域）得到充分研究；然而，该事件在高纬度地区对应的古环境响应尚未被记录，其触发机制仍未明确。本文依托综合大洋钻探计划（Integrated Ocean Drilling Program, IODP）第369次航次U1513站位的沉积物样品，首次报道了南极高纬度（60°S~62°S）区域OAE 1d的详细沉积与地球化学多代用指标记录，以此填补上述两项研究空白。特别地，沉积汞代用指标记录显示，OAE 1d与凯尔盖朗中央大火成岩省（Central Kerguelen large igneous province）的火山活动存在关联。此外，古东印度洋东南部的澳大利亚西南部区域出现的大陆径流显著增强及伴随的陆源输入增加，可能在区域上导致了OAE 1d期间底层水氧化作用减弱、有机质埋藏作用增强。大洋缺氧事件1d（Oceanic anoxic event 1d, OAE 1d）已在北低纬度地区（即特提斯洋与北大西洋海域）得到充分研究；然而，该事件在高纬度地区对应的古环境响应尚未被记录，其触发机制仍未明确。本文依托综合大洋钻探计划（Integrated Ocean Drilling Program, IODP）第369次航次U1513站位的沉积物样品，首次报道了南极高纬度（60°S~62°S）区域OAE 1d的详细沉积与地球化学多代用指标记录，以此填补上述两项研究空白。特别地，沉积汞代用指标记录显示，OAE 1d与凯尔盖朗中央大火成岩省（Central Kerguelen large igneous province）的火山活动存在关联。此外，古东印度洋东南部的澳大利亚西南部区域出现的大陆径流显著增强及伴随的陆源输入增加，可能在区域上导致了OAE 1d期间底层水氧化作用减弱、有机质埋藏作用增强。