摘要
一、“康滇地軸”在哪里?在四川西部东經102度左右,呈北微偏东及南微偏西方向自泸定、雅安一带向南一直延伸到云南中部,有一条断断續續的出露着前震旦紀岩层的地区,或地层发育不全的地带。从大地构造观点上看,黄汲清称之为“康滇地軸”;中国科学院地貭研究所所編《中国大地构造綱要》称之为“康滇台背斜”;常隆庆、楊鴻达說它是“康滇地盾”;张云湘等称它为“康滇古台隆”;米士(Misch,P.)則就云南部分說它是“中部云南隆起”(Central Yünnan Swell)。
Approximately along the meridian of 102°E in western Szechuan and central Yünnan there was an uplifted zone in different geological ages.From the geotectonic point of view it is called the"Kang-Dian axis",the"Kang-Dian platform anticlinorium"or by some bodies the"Kang-Dian shield".The outline of this geotectonic unit,however,has not been definitely ascertained.In order to clarify the character and extension of this zone it is advisable to study the palacogeography of this region first.The writer has made the palaeogeographical maps of every period since Sinian time.He finds the following facts therefrom:(1)The Pre-Sinian metamorphic rocks do not form a shield on account of the scattering of their outcrops and the cover of the younger sediments overlying them in a considerable thickness.(2)In Sinian and Cambrian time the sea was in the east and the old land in the west.There was no"axis"existed.(3)In the periods of Ordovician,Silurian,Devonian,Carboniferous,Permian and Triassic the central zone was really uplifted.But the extension of this zone varied from time to time.(4)From Jurassic to Cretaceous age the central zone was no longer uplifted but depressed to receive the scattered coal bearing formations and successively the red-beds in tremendous thickness.From these facts,it is obvious that the uplifted zone,which had happened in different past ages,can hardly be delimited in the geographical map of present time.The uplift of the"Kang-Dian axis"was chiefly due to warping of oscillatory movement accompanied with faulting.It is neither the result of any certain folding nor an uplifted block to be delimited by certain deep faults.The main folding of this region is believed to be the Szechuan movement happened at the end of Cretaceous.Next important is the Yenshanian between Jurassic and Cretaceous.The movements of Indosinian cycle are not intensive,although faulting and igneous activities took places.While the influences of the Caledonian and Variscian movements are both very limited in this region.
出处
《地质学报》
1963年第3期214-229,共16页
Acta Geologica Sinica
