The relationship between global warming/cooling and shallow marine environments in the Sea of Japan during the Pliocene

利用介形虫、浮游有孔虫化石区系分析和介形虫阀的微量元素分析，重建了上新世日本海暖流流入时间、相对海平面变化和古温度等古环境。结果，流入日本海的暖流开始于3.66-ca。3.4 Ma，之后频繁发生。发现MIS M2的全球变冷可能导致海平面下降，水深估计最多减少50 m。根据介形虫阀的Mg/Ca比值，推测新潟海中间水体的古温度可能比现在高5℃左右。

Fossil ostracode and planktonic foraminiferal faunal analyses and trace element analysis of ostracode valves were conducted to reconstruct paleoenvironments such as timing of inflow of warm-water current, relative sea-level changes, and paleotemperature, in the Sea of Japan during the Pliocene. As a result, the inflow of the warm-water current to the Sea of Japan started at 3.66-ca. 3.4 Ma and it occurred frequently afterwards. Sea-level lowering possibly caused by the global cooling at MIS M2 was found and the decrease in water depth was estimated at 50 m at most. On the basis of Mg/Ca ratio of ostracode valves, paleotemperature in the intermediate water mass off Niigata was probably ca. 5 °C higher than now.