松辽水系的变迁

现代松辽水系是在松辽盆地地质构造、古地貌发育的基础上,几经变迁逐渐演变而成的。晚第三纪以来,古松辽水系经历了几次大规模的河湖交替。中新世早期,形成了古嫩江—西辽河向心状水系。中新世晚期,形成了大安—大布苏湖和盘山—田庄台湖。上新世为新生代以来的河湖全盛期,泰康期水文网再度出现向心状内陆水系。早更新世末或中更新世初,松花江和下辽河分别切穿了三姓附近的分水岭和铁法丘陵,古松辽向心状水系逐渐转变为现代状态的外流水系。

THE CHANGES OF SONGHUA-LIAO RIVER SYSTEM

Since the Neogene,the ancient Songhua-Liao River system have undergone several changes with the alternation of fluvial and lacustrine formation on a large scale.In the early Miocene, ancient NenJiang-West Liao R. formed a centripetal interior drainage; and in the Late Miocene, Daan-Dabusu Lake and Panshan-Tienzuang tai Lake were formed.During the Pliocene, a fluvial and lacustrine climax had reached ever since the cenozoic time Subsequently, in the Tai-Kang Stage,the hydrographic not had become centripetal interior drainage once more.At the end of the early Pleistocene or the early stage of the Middle Pleistocene, Songhua R. had cut through the divide near the neighbourhood of Shanxing, and sabsequently the Liao R.also had cut through the Tieling-Faku Hill.Thus the centripetal interior drainage of the ancient Songhua R.Liao R. become the recent exterior drainage.