宁夏中南部新生界沉积特征及其与青藏高原演化的关系  

The Sedimentary Characteristics of Cenozoic Strata in Central and Southern Ningxia and Their Relationships with the Development of the Qinghai-Tibetan Plateau

作　　者：张进[1] 马宗晋[1] 任文军 

机构地区：[1]中国地震局地质研究所,北京100029 [2]东方物探公司长庆物探处,银川750006

出　　处：《地质学报》2005年第6期757-773,共17页Acta Geologica Sinica

基　　金：国家重点自然科学基金项目(编号4983402)的部分成果。

摘　　要：通过对宁夏中南部十余条新生界剖面沉积相特征的分析与观察,我们认为该地区新生界的发育与青藏高原的发展有密切的联系,能够反映一个山前挠曲盆地从诞生到解体的全过程,它们是印欧板块持续碰撞的结果。当印欧板块碰撞后一段时间(距今30～40Ma),碰撞效应在走廊南山就已体现,出现了一期比较强烈的逆冲推覆构造,形成最早一期山前挠曲盆地,在该盆地前隆位置上产生了正断层,正是这些断层控制了寺口子组的分布。清水营组的沉积处在走廊南山逆冲活动减弱的阶段,整个盆地逐渐由非补偿型盆地转变为过补偿型盆地,沉积体系也产生相应的转变。红柳沟沉积时构造运动开始加剧,这期运动使得盆地内香山等地区开始隆起,早期盆地解体,形成比较复杂的背驮盆地。而上新世末—更新世构造运动是本区受到最强烈的一次构造运动,该运动在早先的基础上进一步使盆地变形分解,盆地内发生规模较大的逆冲运动,并成为青藏高原东北缘逆冲构造楔体的一部分。By observing and analyzing of the sedimentary facies of about ten Cenozoic profiles in the central and southern Ningxia region, we suggest that the distribution of these strata had close relationship with the development of the Qinghai -- Tibetan Plateau, which showed the whole process of a flexural basin from its birth to death resulting from the continuous compression of the Indian Plate. During some periods after the collision between the Indian Plate and Eurasian Plate （30-40 Ma）, the collisional effect had shown in the Nanshan Corridor, a thrust belt and its flexural basin took form, and on the forebulge of this basin many normal faults developed. It is these normal faults that controlled the distribution of the Sikouzi Formation. The deposition of the Qingshuiying Formation occurred during the weakening stage of thrusting along the Nanshan Corridor. The whole basin changed from an underfilled basin to an overfilled one, and the deposition system also changed accordingly. During the deposition of the Hongliugou Formation, tectonism became more active, which resulted in the uplift of the Xiangshan area and other in the basin, earlier basins were disassembled, and some piggy-back basins took form. Tectonism from the end of the Pliocene to Pleistocene was the strongest one affecting this region, which led to the further disassembly of earlier basins, large-scale thrusting occurred in the basin and earlier basins were included into the thrust wedge of the northeastern margin of the Qinghai--Tibetan Plateau.

关 键 词：宁夏 新生界 沉积相 青藏高原 前陆盆地 

分 类 号：P512.2[天文地球—地质学]