THE MARGINAL EXTENSIONAL BELT OF EAST ASIA CONTINENT INVESTIGATING THE ORIGINOF A DISCRETE CONTINENTAL MARGIN
CHEN Guoda(Changsha Institute of Geotectonics, Academia Sinica; International Research Center forGeodepressional (Diwa ) Tectonics and Metallogeny; WG4, Tectono - Magmatic Activization(Diwa ), IAGOD/CTOD, Changsha 410013, China )
There occurs megatectonic belt of " trough - arc - basin" between the continent and theocean in East Asia continental margin. its occurrence is an important event of the evolution-movement history of the Asia continental lithosphere. Its origin problem is the key to testcurrent hypothesis. This paper elaborates the extensional mechanism and the relationshipbetween the continental marginal extension and the crustobody evolution-movement, dealingwith the nature of the earth's crustal structure of the region, the characteristics of theevolutional process of the crustobody and crustobody composition as well as its extension orprocess of growing, mainly from the point of view of the setting of evolution-movement historyof East Asia crustobody, the environment of history-dynamics during the period of formingthe continental marginal extensional belt, and the close relation between the both. The studyindicates that the original mechanism of Asia continental marginal extensional belt is not "theresult from either oceanic crust subduction or arc-back extension". They are mainly ofcontinental crust type of active regions on the continental marginal crustobody (Cathaysian diwatype of orogenic belt) formed with seawater submergence resulting from the earth,s crustdownpunching, because of continental marginal extension along with continental crustthinning during its development of residual - mobility period. Detail study of the origin of EastAsia dispersion continental marginal extensional belt from the point of view of crustobodygeotectonics is favorable to recognize the structural type, characteristics and distributionregularity as well as the economic values of endogenic ore deposits of nonferrous and raremetals, and fields of peat, brown coal and oil-gas widely distributed in the continental shelf.
【CateGory Index】： P542