南阳凹陷边界断层三维几何学及运动学特征

新野断层位于南襄盆地南阳凹陷南部的控凹边界断裂，研究其三维几何学和运动学特征对分析南阳凹陷的形成演化至关重要。以2/3D地震、钻井及测井资料为基础，以正断层相关褶皱理论和构造复原理论为指导，深入剖析新野断层的三维几何学和运动学特征及其对凹陷形成的控制作用。根据断层平面走向，结合倾角和断距变化，将新野断层分为西、中、东3段；空间上认为，新野断层是由多个等倾角面构成的复杂曲面，通过两个垂向轴面和4个横向轴面，将新野断层断面分为11个等倾角区。根据平衡地质剖面复原结果对比，认为新野断层西段、东段形成于晚白垩世，中段形成于始新世大仓房期并逐渐与西段、东段硬连接形成一条断层；断层及其上盘地层旋转程度自西向东逐渐增强；断层反转强度自西向东亦逐渐变大。新野断层西段为"座椅式"正断层，中段由"转折式"正断层转"犁式"正断层，东段为"犁式"正断层。沿断层走向的差异沉降和断面形态差异是南阳凹陷构造特征及形成演化的重要控制因素。

3D Geometrical and Kinematic Characteristics of the Boundary Fault in Nanyang Depression

Xinye Fault is a boundary fault in the south of Nanyang Depression, Nanxiang Basin. It is very important to study its 3D geometrical and kinematic characteristics in analyzing the formation and evolution of Nanyang Depression. Based on 2/3D seismic, drilling and logging data, guided by normal fault related fold theory and structural restoration theory, the 3D geometrical and kinematic characteristics of Xinye Fault are analyzed in this paper. According to plane strike, combined with dip angle and fault distance changes, Xinye Fault is divided into three segments, i.e. west, central and east. The fault plane, which could be subdivided into 11 subzones by 2 vertical axial planes and 4 transversal axial planes, is a curved surface consisting of several dip domains. Based on the balanced geologic cross-sections, we established that the west and east segments of this fault developed in the late Cretaceous; the central segment formed in the sedimentary period of Dacangfang Formation in the Eocene, then the three segments linked into one fault. The rotation degree of the fault weakens from east to west. The largest reverse degree appears on the east segment, followed by the central segment and the west segment. The seat-type normal fault form developed in the west segment; the central segment is a turning normal fault instead of listric form and listric in the east segment. The differential subsidence along fault strike and the difference of section shape are important controlling factors for the formation and evolution of Nanyang Depression.