摘要
丹凤—信阳蛇绿混杂带作为秦岭—大别碰撞造山带主缝合带，其南部属于扬子板块北部大陆边缘。研究区域位于东秦岭南翼，是扬子板块北部大陆边缘的一部分。①晚元古—中震旦世，扬子板块北缘（东秦岭段）为活动型大陆边缘，发育有陡岭岛弧和武当弧后盆地；②晚震旦—早古生代，扬子板块北缘转为被动型大陆边缘，陡岭古岛弧构成边缘地块，武当古弧后盆地演化为边缘盆地；③早古生代晚期，华北板块南缘的秦岭岛弧首先与扬子板块北缘的陡岭边缘地块（古岛弧）碰撞，造成武当边缘（古弧后）盆地的闭合，并形成刘岭前渊和二峪沟前陆盆地；④由于岛弧—边缘地块碰撞加之弧后和边缘盆地的存在，因此在早古生代末期，秦岭—大别山并未大规模隆起，造山带只具雏形。直至中生代早期，华北与扬子两个板块间进一步的陆内俯冲作用才使秦岭—大别山大规模隆起。陡岭古岛弧和武当古弧后盆地的确认合理地解释了秦岭—大别碰撞造山带“加里东碰撞不造山，印支造山不碰撞”的“矛盾”现象。
The Danfeng-Xinyang ophiolitic melange zone is the principal suture zone of the Qinling Dabie collisional orogenic belt and its southern part is the continental margin in the northernpart of the Yangtze plate. The study area,located on the southern side of the East QinlingMountains,is a part of the northern continental margin of the Yangtze plate. (1)In the LateProterozoic-Middle Sinian the northern margin of the Yangtze plate (the East Qinlingsector) was an active continental margin,where the Douling arc and Wudang backarc basindeveloped. (2)During the Late Sinian-Early Paleozoic the northern margin transformed into apassive margin:the Douling arc became a marginal massif and the Wudang backarc basin evolved into a marginal basin. (3)In the late Early Paleozoic the Qinling arc on the southernmargin of the North China plate collided with the Douling massif (paleo-arc),resulting in theclosing of the Wudang basin (paleo-backarc) and the formation of the Linting foredeep andEryugou foreland basin. (4)The collision did not bring about large-scale uplift in the QinlingDabie area at the end of the Early Paleozoic because of the existence of the Erlangpingbackarc basin and Wudang marginal basin,and the Qinling-Dabie orogenic belt only took itsembryonic form. A large-scale uplift of the Qinling-Dabie area took place in the Early Mesozoic and it was attributed to the intracontinental subduction. The recognition of the Doulingpaleo-arc and Wudang paleo-backarc basin is a key to explain the contradictory phenomenonthat the collision in the Qinling-Dabie area in the Caledonian Stage did not make mountainswhile mountains were created without collision in the indosinian.
出处
《中国区域地质》
CSCD
1996年第1期44-50,共7页
Regional Geology of China
