北秦岭地质新知及一些有关问题

根据北秦岭地层新知,讨论它的地质演化史。元古亩到古生代,它是陆内裂陷环境,经加里东期特别是海西期的转折,至中、新生代结束了陆内造山阶段。迄今未在北秦岭找到洋壳存在的确凿证据,板块构造机制应用于北秦岭,必须解释己知的地质事实。

RECENT TIDING OF GEOLOGY AND SOME PROBLEMS OF THE NORTHERN QINLING

Recent studies show that not only the early paleoyoic strata but also the late Proterozoic and the late Palaeozoic strata exist in the northern Qinling orogenic belt located between the Kuanping Group and the Qinling Groyp. Moreover, all the newly discovered late Ordovician and late Devonian strata unconformably overlie older strata. The formation of the northern Qinling can be divided into the early (the early -middle Proterozoic ), the intermediate (the late proterozoic - the midle Ordovician) and the late (the late Palaeozoic) stages of inner continental (no tintercontinental) rift sedimentation. The inner continental orogeny of the northern Qinling accomplished in the Meso-Cenozoic after the polydeformation and polymetamorphism of the Jinning, Caledonian and Hercynian. The existence of oceanic crust in the northern Qinling still lacks reliable evidence , and the explanation in the light of plate tectonics for the northern Qinling orogenic belt is doubtful.