Association of phosphates with tuffites in a core of sediments from the Sea of Japan

One of the hypotheses on the origin of phosphorites suggests that products of volcanic and hydrothermal activity are phosphorus sources [1]. The cases when phosphorites are associated with volcanic rocks [2, 3] were adduced as evidence in support of this hypothesis. However, some opponents do not consider these facts as indications of the cognation of phosphorites and volcanic rocks [46]. In this regard, a finding of phosphatized rocks in the core of tufte from the southern Sea of Japan attracts interest. The core was taken in Cruise 25 of R/V Professor Bogorov in 1987 from a depth of 1380 m on the northeastern slope of Krishtofovich Seamount at Station 2676 with coordinates 3834.1 N and 13116.5 E. The core, 2.25 m long, was obtained with a hydrostatic corer having an inner diameter of 90 mm.