上海地区新构造隐伏活动断裂的标志──石灰华

上海地区沿基岩断裂带表面,有零星分布的石灰华,成因与泉水(温泉)活动有关,形成时代下限为新第三纪晚期,上限为第四纪更新世早期。本文初步确定,区内自新第三纪晚期以来,具有活动性的隐伏断裂,除北北东向及近东西向的两组断裂外,还新发现一组北西西向活动性显著的断裂,它们均与石灰华分布有着密切的关系,这种现象与山区新构造活动断裂带的特征相似。区内分布的石灰华,可以作为识别隐伏活动断裂的标志。

A CRITERION OF THE NEOTECTONIC HIDDEN ACTIVE FAULT IN SHANGHAI AREA-CALCAREOUS SINTER

There are some fragmentary calcareous sinters distributed along the surface of the fault zone of the bedrock in Shanghai area. Their origin relates to the spring(or thermal spring) activity, and they were formed between the late Neocene and the early pleistocene. This paper preliminarily determines that are active hidden faults in this area since the late Neocene. Besides faults in the NNE and near EW directions, recently a group of obviously active main fault in the NW-direction has been found. They are closely related to the distrinution of calcareous sinters and this phenomenon is similar to the character of the Neotectonic active fault zone in some mountain areas. There calcareous sinters can be regarded as the criterion to distinguish the hidden active fault.