Abstract We investigated the origin of marine sediments and their transfer by water currents using the spatial distribution patterns of multi-elements in terrestrial and marine areas of Kyushu, western Japan. Quaternary volcanic material covers Cretaceous granitic rock and Jurassic–Paleogene sedimentary rock of an accretionary complex in this region. Cluster analysis based on chemical compositions identified the origin of marine sediments from stream sediments originating from the above lithologies. Pyroclastic-flow deposits associated with caldera formation, particularly that of the Kikai Caldera (7.3 ka), were characterized by low Cr/Ti and La/Yb ratios. In contrast, the La/Yb ratio was very high in sediments derived from granitic rock and sedimentary rock of the accretionary complex. The spatial distributions of low Cr/Ti and La/Yb ratios suggest that marine sediments containing pyroclastic materials, which are found within an 80 km radius of the Kikai Caldera, were distributed on the shelf and transported northeastwards by a branch of the Kuroshio Current. The continuous distribution of the medium Cr/Ti and high La/Yb ratios from the land to the coast, slope and deep basin on the Pacific Ocean side suggests that sediments supplied from the terrestrial area were transferred by gravitational transport from the shelf to the deep basin.

Abstract In the West Kunlun Mountains, four volcanic fields (Kangxiwa, Dahongliutan, Qitaidaban and Quanshuigou) are distributed along the Dahongliutan fault, which is c. 180 km long. Based on field investigations, chronological measurements and geochemical analysis of some volcanic fields, the results of geological, geochemical and geophysical research in previous studies in the corresponding study areas are summarized. The volcanic activities in these areas were mainly effusive eruptions, explosive eruptions and phreatomagmatic eruptions. In this study, we discovered the Qitaiyanhu volcanic field for the first time and determined that the 14 C age of the lacustrine strata underlying the Qitaiyanhu lava flows is 13.110 ± 0.04 ka BP, indicating that there may still have been volcanic activities in the late Pleistocene and even the Holocene in the Dahongliutan fault area. Base surge deposits, which are the products of the interaction between magma and water, were found in the Kangxiwa volcanic field. The four shoshonitic rock fields of Kangxiwa, Dahongliutan, Qitaidaban and Quanshuigou are likely to be products of different evolution stages from the same magma source area. The magmatic origin of these volcanic fields may be related to the upwelling of the asthenosphere, triggered by the collision between the Indian and Tarim plates.