【摘要】 太康隆起与周口坳陷位于华北板块南缘,中生代以前同属南华北盆地,中生代的燕山运动使隆起与坳陷格局初具雏形,古近纪是隆起与坳陷形成的关键时期,新生界沉积厚度是判别太康隆起与周口坳陷的关键点之一.太康隆起与周口坳陷边界位置争议较多,缺乏深部地球物理数据支撑.本文通过对许昌东部太康隆起与周口坳陷边界处一条长约55 km的南西—北东向大地电磁测深剖面数据的定性分析及反演解释,获得了太康隆起与周口坳陷两构造单元4 km以浅电性结构图.阻抗张量分解结果表明研究区主构造走向为EW向,研究区电性结构纵向上具有典型的分层特征,从上到下可分为三层:低阻层-中高阻层-高阻层.从南往北剖面经过区域发育四条断裂:商水断裂、固相断裂、张桥断裂和柏梁断裂.柏梁断裂两侧新生界沉积厚度差别大,据此判断太康隆起与周口坳陷的边界断裂为柏梁断裂,在L1-73测点位置处.太康隆起与周口坳陷边界断裂带划分对于该区地热资源勘探开发具有指导意义.更多还原

【Abstract】 Taikang uplift and Zhoukou depression are located in the southern margin of north China plate, and belong to south north China basin before Mesozoic. Yanshan movement made uplift and depression pattern take shape initially. Paleogene is the key period of uplift and depression formation, and Cenozoic sedimentary thickness is one of the key points to distinguish Taikang uplift and Zhoukou depression. The boundary position between Taikang uplift and Zhoukou depression is controversial and lacks the support of deep geophysical data. Through the interpretation of a length of about 55 km SW to NE magnetotelluric sounding profiles between Taikang uplift and the Zhoukou depression in eastern Xuchang, the shallow electrical structure map of the two tectonic unit 4 km of the Taikang uplift and the Zhoukou depression has been obtained. The results of impedance tensor decomposition show that the main structure of the study area is heading for EW direction, and the electrical structure of the study area has typical stratification characteristics vertically. From top to bottom, it can be divided into three layers: low resistivity layer, relatively high resistivity layer and high resistance layer. Four faults developed from the south to the north through the regional development:Shangshui fault,Guxiang fault,Zhang qiao fault and Bailiang fault. The thickness of Cenozoic deposits is quite different on both sides of Bailiang fault. Based on this, it is judged that the boundary fault between Taikang uplift and Zhoukou depression is Bailiang fault, located at the location of L1-73.Taikang uplift and Zhoukou depression has guiding significance for geothermal resources exploration and development in this area.更多还原