Provenance discrimination of eolian dust in sediments from IODP Site U1425 base on mineral composition in relation to the lead isotopes

Abstract

The Japan Sea sediments are a mixture of detrital materials of various origins, such as eolian dust from Asian continent and Japanese riverine suspensions. Understanding the sources of eolian dust in the sediments can help reconstruct past wind systems and monsoon variability. The sediments from the Integrated Ocean Drilling Program (IODP) Site U1425 were separtated into silt and clay fractions and semi-quantification of the minerals by powder X-ray diffraction (XRD) was conducted. The XRD profiles were statistically unmixed to the endmembers by Parallel Factor Analysis (PARAFAC). As a result, the Taklimakan, Gobi, and Ordos desert regions were identified as sources of eolian dust endmembers, and an endmember originated from riverine suspension from the Japanese Islands was also identified. Relative contribution of each detrital endmember was also determined. A part of the sample set analyzed for XRD was also subjected to Pb isotopes measurement for both silt and clay fractions. In this report, the interrelationship between the mineralogically estimated contribution of each clastic subcomponent and Pb isotopes will be presented, and the more precise interpretation for provenance discrimination will be discussed.