江汉平原长湖近代沉积物磁性测量及其气候意义

MAGNETIC MEASUREMENTS OF RECENT SEDIMENTS IN LAKE CHANGHU OF THE JIANGHAN PLAIN AND THEIR CLIMATIC IMPLICATIONS

根据１９９２年长湖所取代表性９２－５剖面沉积物磁性测量结果并结合化学分析和孢粉分析，研究了长湖近代沉积物磁性参数变化与气候变化的关系，指出该地区最近４００ａ来气候变化总趋势是一个由冷变暖的过程。

A research on magnetic measurements has been done on the sediments of core 92-5, which was taken in 1992 and was representative of environment changes in Lake Changhu in the Jianghan Plain, the core can be divided into 4 sediments on the parameters of the magnetic measurements: 1. Zone A (144-140cm in depth, before 1581 A.D.), each magnetic parameter is obviously small, the concentrations of magnetic minerals are low. 2. Zone B (140-74cm in depth, 1581 A.D.-1774 A.D.), each magnetic parameter changes slowly under the fundamental steady prerequisite. 3. Zone C (74-10cm in depth, 1774 A.D.-1964 A.D.), the magnetic parameters are relatively high, the undulations of the magnetic parameters are slightly more. 4. Zone D (10-0cm in depth, 1964 A.D.-1992 A.D.), owing to the growth of aquatic plants and human activities, changes of magneticparameters are complex. The concentration of component of the magnetic minerals in the sediment is high, if the temperature is high and/or the precipitation is large. The magnetic parameters corresponds to hot or cold climate. The magnetic parameters of core 92-5 show that the tendecy of the climatic changes is from cold to warm in the Jianghan Plain in recent 400 years. This is consistent with the historic records and sporo pollen analysis.