TECTONIC DEVELOPMENT OF THE YARKAND SECTOR OF THE KUN LUN SHAN

The Yarkand sector of the Kun Lun Shan, western Sinkiang, China, was studied jointly with Chinese geologists in 1957. During the Paleozoic, this area represented the junction between the Kun Lun geosyncline and the Tarim platform. The principal events in the development of the marginal part of the geosyncline were its initiation in the Sinian; a temporary stabilization of conditions common with the platform in the Cambrian‐Devonian; pre‐Upper Devonian folding; expansion of the geosyncline at the expense of the platform in early Hercynian; and a final folding at the close of the Paleozoic. The junction was effected by means of marginal uplift and deep‐seated faults. The Alpine Kun Lun presented an epi‐Hercynian platform developed as a low‐angle uplift, adjacent to the subsidence in the margin of the Tarim platform. The most recent uplift in this region involved also the pre‐Paleozoic platform margin. The pre‐Paleozoic stage culminated in an intense folding as evidenced by a sharp unconformity between the Proterozoic and lower Paleozoic rocks. A neotectonic stage caused uplift of a lower Quaternary erosion surface to an absolute elevation over 3,000 meters and a relative uplift of up to 800 meters. Relation of older structural trends to later ones is considered. Structural elevation of the area is summarized under six conclusions.‐‐W. D.