Variation of seawater chemical composition by fluid inclusions of evaporites

2015 Fiscal Year Final Research Report

• Project/Area Number: 25400505
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: Kuroda Junichiro 国立研究開発法人海洋研究開発機構, 生物地球化学研究分野, 主任研究員 (10435836)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 蒸発岩 / 流体包有物

Outline of Final Research Achievements

In this study we 1) developed a method to date evaporite with various isotope records (e.g., sulfur and strontium of sulfate evaporites), 2) measured the major element compositions of fluid inclusions of halite with a cryo-FIB-EDS, and then investigated water exchange history of the source brine based on Os isotopic records. The Os isotopic records of the drilled cores in the Mediterranean basins show that an offset with the coeval Atlantic ocean water, which is attributed to limited exchange with the North Atlantic during the Messinian salinity crisis. The source of unradiogenic Os is likely to be weathering of ultramafic rocks (ophiolites) cropping out in the editerranean drainage basins. Based on a boxmodel we estimated the amount of unradiogenic Os and the Atlantic-Mediterranean exchange rate to explain this offset.

Free Research Field

古海洋学，海洋地質学