Major and minor element signatures of OC-rich Paleogene sediments from Lomonosov-Ridge (IODP Leg 302)

点击翻译按钮获取中文摘要

The focus of the proposed project lies on medium- and high-resolution geochemical records of major and minor elements in specific Paleogene OC-rich sediments recovered during IODP Leg 302 on Lomonosov-Ridge, particularly the zebra-layer and the PETM. The Arctic Ocean represents an important archive of changing oceanic circulation and therefore global climate and to date has not been accessible for geochemical proxy-investigations. Now material from Lomonosov-Ridge has been made available through the successful ACEX drilling campaign. The aim of this proposal is to provide a general geochemical characterization of the Paleogene sedimentary record, and collaborative investigation of distinct intervals, i.e. the zebra-layer , by means of major elements and to test several paleoenvironmental hypotheses using diagnostic trace metals (TM), such as Ag, Cd, Re, Mo, V, and Zn. Modern analogues of organic carbonrich sedimentation typically are enriched in TM. The enrichment patterns provide useful information deciphering the paleoenvironment of deposition and paleoceanographic setting. Furthermore major elements contain important information on the provenance of terrigenous detrital material and the weathering regime in the hinterland. The following questions will be addressed by this proposal: To what degree are specific TM found enriched in Paleogene OC-rich sediments and how do they vary with time in relation to correlative micropaleontological and organic geochemical proxies? What are the paleoenvironmental and paleoceanographic consequences that may be deduced from major and minor element patterns, particularly with respect to the zebra-layer , Azolla freshening and the P/E boundary events? What are the most likely sources for TM enrichments and are there any indications for a freshwater contribution? How do trace metal enrichments in Paleogene OC-rich sediments compare with those from Cretaceous settings and modern analogues of OC-rich sedimentation? What is the significance of TM enrichments in Arctic Paleogene OC-rich sediments in relation to global TM cycles and basin-wide TM budgets?