北淮阳东段变质构造地层的古构造环境  

Paleotectonic Settings of the Metamorphic Tectonostratigraphy in the Eastern Beihuaiyang Belt

作　　者：王果胜[1] 马文璞[1] 徐毅[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083

出　　处：《现代地质》2005年第2期217-223,共7页Geoscience

基　　金：国家自然科学基金资助项目 (49902017)。

摘　　要：关于大别山北麓北淮阳东段原佛子岭岩群的古构造环境问题, 存在着认识分歧, 其主要原因是将形成构造背景与地质演化历史本不相同的不同构造地层单元混在了一起, 不加区分地进行古构造环境分析。根据构造变形、岩相学、岩石地球化学等的综合研究, 将原佛子岭岩群解体为被一重要的构造滑脱带所分隔的下部卢镇关构造混杂岩带和上部诸佛庵岩群。通过对新厘定的构造岩石地层单元分别进行沉积建造和岩石化学、地球化学特征的研究发现, 下部卢镇关构造混杂岩带形成于被动大陆边缘环境, 而上部诸佛庵岩群形成于华北板块南部活动大陆边缘环境。这意味着华北、扬子板块的古生代板块碰撞缝合带的位置应该位于诸佛庵岩群分布区域的南侧, 而且板块俯冲—碰撞的极性表现为扬子板块向华北板块之下俯冲。There are different opinions on regarding to the paleotectonic settings of the previous so called Foziling Lithogroup in the eastern Beihuaiyang belt, north foothills of the Dabie Mountains. This difference is derived from the mixing of tectonostratigraphic units with different tectonic settings and geologic history under the name of Foziling Lithogroup and the study of paleotectonic settings based on the Foziling Lithogroup as a whole. Recent work in structural and tectonic deformation, petrography and geochemistry on the so called Foziling Lithogroup indicates that it is composed of two distinct tectonostratigraphic units separated by a nearly horizontal ductile shear detachment system. The newly defined tectonostratigraphic units above and below the detachment zone are named as Zhufoan Lithogroup and Luzhenguan Melange respectively. Sedimentary characteristics together with the petrographic and geochemical analysis results revealed from the newly defined units in this study imply that the Luzhenguan Melange was formed in a passive continental margin, the Zhufoan Lithogroup, however, was formed in the southern active continental margin of the North China Plate. These research results indicate that the collision between the North China and Yangtze plates in the Palaeozoic is supposed to be located in the north of Zhufoan Lithogroup, and the Yangtze Plate served as a subducted plate beneath the North China Plate

关 键 词：古构造环境 变质构造地层 北淮阳构造带 

分 类 号：P588.3[天文地球—岩石学]