赣杭构造带红层盆地原型及其沉积作用  

Prototype and Sedimentation of Red Basins along the Ganhang Tectonic Belt

作　　者：余心起[1] 舒良树[1] 颜铁增 祖辅平[1] 

机构地区：[1]南京大学地球科学系,南京210093 [2]浙江省地质调查院,浙江萧山311203

出　　处：《沉积学报》2005年第1期12-20,共9页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(批准号: 40172067);国家自然科学重点基金项目(批准号: 40132010)联合资助

摘　　要：盆地原型是指盆地沉积时的构造属性类型,盆地原型分析就是按阶段的盆地结构分析法.文章暂不讨论赣杭带晚侏罗世-早白垩世早期的火山杂色断陷盆地,而以实地观察资料和前期研究成果,对早白垩世晚期以后形成的一系列NEE方向分布的红色断陷盆地及其沉积作用进行综合分析.盆地红层下部夹有玄武岩层,已有的K-Ar年龄值为105～98Ma,由此判断赣杭带红色断陷盆地演化从早白垩世晚期开始.早期属典型的断陷盆地,呈现半地堑式形态,北界为向南倾斜的正断层,南界为超覆不整合.晚白垩世中后期演变为拗陷盆地,沉积盆地扩大,南北两侧均见到超覆不整合,北侧部分地段保留早期断裂边界.河流沉积作用为最主要沉积作用方式,盆地中心部位可见少量内生沉积的白云岩、泥灰岩及炭质泥岩.沉积组合大致为湖泊相、冲积扇相、三角洲相及河流相,代表了拉张型盆地的基本沉积类型,也反映了断陷湖盆由初始拉张断陷、中后期扩张为拗陷、到最后萎缩的完整过程.Basin-prototype belongs to the tectonic property when sedimentation occurs. The method of prototype analysis is just used to distinguish one stage basin types from the other stages. Other than working on the volcanical-fault basins of the first circle produced in the late Jurassic-early period of early Cretaceous, this paper discussed on the prototype and sedimentation of red fault basins along the Ganhang Tectonic Belt of the second circle, they produced after late period of early Cretaceous. There is a series of red fault basins at the center of the Ganhang Tectonic Belt, such as the Fuzhou-Chongren Basin, Xinjiang Basin, Jinhua-Quzhou Basin and Zhuji Basin, distributing northeastward and mostly contacting each other in there two ends. Combiningwith the regional extension background manifested by the basalts at the bottom of red beds, these basins started at the late period of early Cretaceous, and almost every basin displayed an one-tendency fault basin in geometry, which are all restricted within the normal fault in the north and unconformable boundary in the south. By the middle-late period of late Cretaceous, all basins turned into depressive basins, thus the sediments overlay on the basement of the two sides, and there are some self-generating dolomite, marlite and claystone deposit in the centre. In the evolutional process of the red fault basin, the fluvial sedimentation plays a much important role than any other ways of deposition. The sedimentary facies vary from lake facies to fan facies, delta facies and fluvial facies, etc. This assembly is the basic sedimentation type of an extensional fault basin, and the changing model reflects the evolutional process of the fault basin from initial extension (deep lake) to final wither (ground river).

关 键 词：沉积作用 盆地原型 断陷盆地 拉张 构造带 不整合 红层 河流相 超覆 三角洲相 

分 类 号：P618.13[天文地球—矿床学] P542[天文地球—地质学]