广东深圳断裂带活动性的第四纪地质和地貌研究

AN INVESTIGATION ON GEOMORPHOLOGY AND QUATERNARY DEPOSITIONS FOR ACTIVITY OF THE SHENZHEN FAULT ZONE, GUANGDONG PROVINCE

深圳断裂带分布着一系列第四纪盆地,发育了以晚更新世河流相为主的沉积物,其厚度一般小于10—15米。它们的出现与断裂破碎带、岩溶地层分布及断裂早期活动有关。但是,未见错动了第四纪沉积物的断层。从约180万年以来,断裂带内发育了四级夷平面和三级河流阶地。不同时期地壳相对升降平均速率估计为约0.04毫米/年至0.2毫米/年。 在第四纪地质时期,深圳断裂带总体处于区域性的间歇性抬升过程,断裂活动不明显。

Activity and neotectonics of the Shenzhen fault zone in the Shenzhen Special Economic Zone, Guangdong Province, has been discussed on the basis of geomorphic features and Quaternary sediments, as follows:1. There is a series of the smaller intermontane basins and valleys, with axis orientation of NE-SW or ENE-WSW same as trending of the major faults within the fault zone. Most of these basins and valleys, in which the colluvium, alluvium and swamp deposits, with a total thickness of less than 10-15m, were accumulated during the period from the middle of the Late Pleistocene to the middle of the Holocene, are located in the older fracture and or the limistone strata undergoing karstification strongly. Their distribution, hence, might be related to the faulting processes before the Late Pleistocene. However, any fault and marked deformation in the sediments of the Late Pleistocene and Holocene has not been observed. It may be suggested that no remarkably faulting has occurred in the fault zone at least since the middle of the Late Pleistocene.2. Four paleo-denudation surfaces and three alluvium tarraces have been developed in the fault zone since about 1.8 Ma. The vertical deformation rates of crust uplift relative to the regional erosion basis could be estimated as 0.04-0.2mm/a for different ages, based upon the elevations and duration estimates of the geomorphic surfaces formed in different stage. The Quaternary tectonic movement would be characcterized by pulse uplift and depression of the crust for the Shenzhen fault zone.