一、前言 深海底部的沉积物没有被搅乱而保存下来,可以用它来追溯过去的地球环境。但其沉积速度极慢,千年内仅沉积几毫米(Golb Berg和Kolde, 1972),因此用它来了解几千年内的地球环境变化是不可能的。对此,用沉积速度在一年内就有几毫米—几厘米的 I. INTRODUCTION Sediments at the bottom of the deep sea are preserved without being disturbed and can be used to trace the past earth environment. However, its deposition rate is very slow and deposits only a few millimeters in a few years (Golb Berg and Kolde, 1972), so it is impossible to use it to understand the changes in the Earth’s environment for thousands of years. In this regard, with the deposition rate in a year there are a few millimeters - a few centimeters