STUDY ON FORAMINIFERA AND CaCO₃ IN SEDIMENTS OF THE WESTERN MID-PACIFIC

Two cores and ten surface sediment samples were taken in the western area of Mid-Pacific during the investigation from December 1978 to July 1979.According to the analysis of planktonic foraminifera and CaCO₃ in the surface samples, the investigated area is divided into three different sediment regions.The initial depth of lysocline of this area is estimated at about 3500 m and the CaCO₃ compensation depth (CCD) is 5000 m.The water depth of the sediment core at L2016 is 2705 m and it is located above the lysocline.The sediments belong to white planktonic foraminiferal ooze.The evolution of paleoclimate is studied according to the variation of the following three parameters:the abundance value of the species indicating warm of planktonic foriminifera, the solution index and the determination of the paleotemperature carve of δ¹⁸O.The age of 4.2 m-long core is estimated at about 300, 000 years BP according to the extinct time of the pink shell G.rubra, and the comparison between cores.