豫西内乡文龙庙地区秦岭群卵形褶皱构造解析

秦岭地轴东段核心部位有规律地分布着一系列卵形褶皱,本文对其中之一的文龙庙卵形褶皱进行了构造解析,该卵形褶皱是由三期褶皱叠加而成。该区变形十分复杂,总的变形体制为塑性流变、韧性剪切、似弯滑、似弯流等;叠加褶皱的形成是在东秦岭开合构造背景下长期发展之结果,既有前寒武纪的塑造作用,也有后寒武纪的再造作用。

STRUCTURAL ANALYSIS OF THE OVAL FOLDS IN QINLING GROUP AT THE WENLONGMIAO AREA, NEIXIANG COUNTY, HENAN PROVINCE

A series of oval folds in Qinling Group are regularly distributed at the central part of theeastcrn Qinling Geoaxis. Detailed mapping and structural analysis have been made for the Wenlongmiao area. It is revealed that these oval folds are formed by three generations of folding.The first generation folds (f_1) are isoclinal and recumbent with their hinges oriented to NW.The second generation folds (f_2). superimposing on f_1 by coaxial deformation, are relatively tightwith vertical axis planes. The third generation folds (f_3), superimposing on f_1 and f_2 by crossfolding. are of open and wave-shaped flexures. Therefore, Qinling Group has undergone complexdeformation. resulting in structural domes and basins. The first generation folds are related tohigh temperature and nigh pressure deformation which is characterized in plastic flowing andductile shearing. The second and third generation folds have a deformation mechanism of similarflexuring and gliding. The development of these superimposed folds must have happened in a longterm evolution of the opening-and-closing tectonic environment in eastern Qinling. includingboth Precambrian plastic deformation and post-Cambrian reconstruction.