The Campanian and Paleogene ("Greenhouse") Arctic Ocean paleoenvironment: Implications from organic-carbon and biomarker records (ACEX-IODP Leg 302)

洛蒙诺索夫海脊IODP 302(北极取心探险-ACEX)期间发现的寒武纪、古新世晚期和始新世中早段200m厚的层序，具有有机碳含量高达1~6%的特点。我们对这些独特沉积物的有机地球化学研究集中在有机-碳循环及其与这一时期的长期和短期古环境/古海洋演化的关系上。正如我们正在进行的研究所表明的，在这里，正己烷条件和陆源输入是控制有机碳沉积的最重要的过程。在本项目的剩余时间内，利用烯烃重建始新世中期(50-44 Ma)的海表面温度变化，以及它与北极冰筏历史和全球温度曲线的相关性，将是特别有意义的。此外，ACEX记录中确定的主要极端气候事件，如古新世/始新世最高温度(PETM)事件、Elmo事件和Azolla事件，在缺氧、淡水排放、生产力和陆源输入方面的变化将是我们详细生物标志物研究的主要焦点。应用的方法集中在利用GC和GC/MS技术进行生物标志物分析，以及特定生物标志物的稳定碳(和氢)同位素。

The 200m thick sequence of Campanian, late Paleocene and middle-early Eocene age, recovered during IODP Expedition 302 (Arctic Coring Expedition - ACEX) on Lomonosov Ridge, are characterized by high organic-carbon contents of about 1 to 6%. Our organicgeochemical study of these unique sediments focuses on the organic-carbon cycle and its relationship to the long- and short-term paleoenvironmental/paleoceanographic evolution during this time interval. Here, euxinic conditions and terrigenous input are the most important processes controlling organic-carbon deposition, as shown in our ongoing study. In the remaining time of our project, the reconstruction of sea-surface temperature changes during middle Eocene times (50 to 44 Ma) using alkenones, and its correlation with the history of Arctic ice-rafting as well as the global temperature curve, will be of special interest. Furthermore, changes in anoxia, freshwater discharge, productivity, and terrigenous input across major extreme climate events identified in the ACEX record, such as the Paleocene/Eocene Temperature Maximum (PETM) Event, the Elmo Event, and the Azolla Event, will be a major focus of our detailed biomarker studies. Applied methods concentrate on biomarker analyses using GC and GC/MS techniques, and stable carbon (and hydrogen) isotopes of specific biomarkers.