Mineral provinces and matter provenance of the surficial sediments in the western Philippine Sea: implication for modern sedimentation in West Pacific marginal basin

The characteristics and distribution patterns of detrital minerals (0.063~0.125 mm) in marine sediments provide a significant indicator for the identification of the origin of sediment.The detrital mineral composition of 219 surface sediment samples was analysed to identify the distribution of sediments within the western Philippine Sea.The area can be divided into three mineral provinces:(Ⅰ) province east of the Philippine Trench,the detrital minerals in this province are mainly composed of calcareous or siliceous organisms,with the addition of volcanogenic minerals from an adjacent island arc; (Ⅱ) middle mineral province,clastic minerals including feldspar,quartz and colorless volcanic glass,sourced from seamounts with intermediate-acid volcanic rock,or erupting intermediate-acid volcano; (Ⅲ) province west of the Palau-Kyūshū Ridge,the matter provenance within this province is complex; the small quantity of feldspar and quartz may be sourced from seamounts or erupting volcano with intermediate-acid composition,with a component of volcanic scoria sourced from a volcano erupting on the Palau-Kyūshū Ridge.it is suggested that,(1) Biogenic debris of the study area is closely related to water depth,with the amount of biogenic debris controlled by carbonate lysocline.(2) Volcaniclastic matter derived from the adjacent island arc can be entrained by oceanic currents and transported towards the abyssal basin over a short distance.The weathering products of volcanic rocks of the submarine plateau (e.g.,Benham Plateau) and adjacent ridges provide an important source of detrital sedimentation,and the influence scope of them is constrained by the intensity of submarine weathering.(3) Terrigenous sediments from the continent of Asia and the adjacent Philippine island arc have little influence on the sedimentation of this study area,and the felsic mineral component is probably sourced from volcanic seamounts of intermediate-acid composition.