东亚陆缘扩张带──一条离散式大陆边缘成因的探讨

亚洲东部大陆边缘，介于大陆与大洋之间，存在着一条巨型的“沟弧盆”地带。该构造带的出现是亚洲大陆岩石圈演化－运动史上的重大事件之一，它的成因问题流行假说颇多，本文侧重从亚洲东部壳体演化运动历史背景的分析入手，探讨该构造带形成时期的历史动力环境，地壳结构及性质、壳体演化过程的特点，以及壳体增生扩展过程等，阐明了它是由于东亚陆缘扩张所成。并探讨了该陆线扩张带的形成与壳体演化运动的关系及其扩张机因。研究表明：亚洲陆缘扩张带的形成机理，并非“洋壳俯冲、弧后引张”所致。它们主要是陆缘壳体上的大陆类型活动区（华夏地洼型造山带），在其发展的余动期，由于陆缘扩张及陆壳薄化所致。作者认为，从壳体大地构造学这一新思路入手，对该陆缘扩张带成因的深入研究，有助于正确认识该大陆架上广泛分布的有色、稀有金属内生矿床，以及泥炭、褐煤、油气田的构造类型、特点、分布规律及其经济价值。

THE MARGINAL EXTENSIONAL BELT OF EAST ASIA CONTINENT INVESTIGATING THE ORIGINOF A DISCRETE CONTINENTAL MARGIN

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.