一种假说:湛江港(湾)成因问题之思考

A Hypothesis to Explain the Origin and Formation of the Zhanjiang Bay

对湛江港(湾)的成因提出如下假说:1)第四纪晚更新世时期,湛江地区可能发生过一次天体撞击地球的突变事件,撞击地点在麻斜海;2)从撞击坑中升起的大量尘烟被风向北吹送,在湛江港(湾)以北地区沉落下来,形成了面积颇广、厚约50 cm的风成黄土层;3)受此撞击事件影响,南三岛分裂成3个小岛,还诱发了周边的火山活动;4)湛江港(湾)上端伸入陆地的溺谷湾区域,出现"X"形裂痕,该裂痕在其后的低海面时期,遭受地表流水的侵蚀作用而加深、拓宽,再于冰后期海侵时成为溺谷湾。以上猜想,主要依据对以下3方面的现象及问题的观察与思考得出:一是湛江以北大面积、铺天盖地而来的风成黄土源于何处;二是麻斜海象是一个"坑",坑中物质及其周边环境有一些异常;三是湛江溺谷湾发育的基础像一条裂谷。

In this paper,a hypothesis about the origination and formation of the Zhanjiang bay is proposed on the basis of following arguments： 1） an event of meteorite impact might occur on Zhanjiang area during the late Pleistocene epoch,and today’s Maxie Sea would be the impact crater;2） a large number of dust raised by the impact event flowed northward and deposited around the northern Zhanjiang,which formed a large area of eolian loess with about 50cm in thickness;3） as a consequence of the impact effect,the Nansan.Island was separated into three islands,causing a number of volcanic activity in the area around the impact crater;4） in the northern area of the Maxie impact crater,there was ‘X’ crack,which was eroded deeper and wider during the lower sea level period after the impact event and then became a drowned valley during the post glacial period of Holocene.This hypothesis is derived from observation on the following three aspects： First,what did the materials of the large area of eolian loess come from？ Second,the Maxie Sea likes an impact crater with some unusual signs both in the impact crater and its surroundings.And third,the drowned valley of the Zhanjiang Bay looks like a rift valley.