Anoxia and high primary production in the Paleogene central Arctic Ocean: First detailed records from Lomonosov Ridge
Anoxia and high primary production in the Paleogene central Arctic Ocean: First detailed records from Lomonosov Ridge
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DOI：
10.1029/2006gl026776
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发表时间：
2006-09
影响因子：
5.2
通讯作者：
R. Stein;Bettina Boucsein;H. Meyer
中科院分区：
文献类型：
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作者：
R. Stein;Bettina Boucsein;H. Meyer
除了少数不连续的晚白垩世/早新生代气候史和沉积环境碎片外，在2004年在Lomonosov海脊进行IODP Expedition 302(北冰洋取心考察-ACEX)钻探活动之前，新近纪之前的北冰洋中部的古环境演化几乎是未知的。在这里，我们提供了ACEX钻探现场整个约200米厚的古近纪富含有机碳的部分的详细有机碳(OC)记录。这些记录表明，有利于保存不稳定的水生(海藻类)有机碳的“黑海型”条件存在于早始新世上部和中始新世，这是由于淡水排放造成的盐度分层所致。有机碳在数量和组成上的叠加短期(“米兰科维奇类型”)变化与初级生产力和陆源投入的变化有关。始新世早期突出的藻类有机碳保存事件与全球δ13C事件相吻合，如PETm事件和ELMO事件。ELMOδ13C事件首次在北冰洋被发现。
Except for a few discontinuous fragments of the Late Cretaceous/Early Cenozoic climate history and depositional environment, the paleoenvironmental evolution of the pre‐Neogene central Arctic Ocean was virtually unknown prior to the IODP Expedition 302 (Arctic Ocean Coring Expedition–ACEX) drilling campaign on Lomonosov Ridge in 2004. Here we present detailed organic carbon (OC) records from the entire ca. 200 m thick Paleogene OC‐rich section of the ACEX drill sites. These records indicate euxinic “Black Sea‐type” conditions favorable for the preservation of labile aquatic (marine algae‐type) OC occur throughout the upper part of the early Eocene and the middle Eocene, explained by salinity stratification due to freshwater discharge. The superimposed short‐term (“Milankovitch‐type”) variability in amount and composition of OC is related to changes in primary production and terrigenous input. Prominent early Eocene events of algae‐type OC preservation coincide with global δ13C events such as the PETM and Elmo events. The Elmo δ13C Event has been identified in the Arctic Ocean for the first time.