TECTONO-THERMAL MODEL OF THE DANBA AREA,WESTERN SICHUAN

The Danba area in western Sichuan is located in a passive continental-margin setting on thenorthwestern margin of the Yangtze plate. Two different rock suites are exposed there:one isthe crystalline basement of the Yangte plate the Kangding complex and Baoxing complex;the other is metasedimentary rocks of marginal sea type distributed in the north.In the In-dosinian period ,the area underwent N-S compression,forming a lot of compressive structure. Under the influence of the uneven distribution of hard crystalline basement,the degree of defor-mation varies from place to place. The authors analyzed the amount of deformation at variouslocalities using the strain measuring technique. It has been found that the Danba area where thebasement is convex northward has a larger deformation amount and higher metamorphic grade,while the Jintang arc area concave southward has a smaller amount of deformation,In the paperthis phenomenon is interpreted qualitatively using the tectono-thermal model.