末次冰期深切谷的识别及其在生物气勘探中的意义──以钱塘江深切谷为例

本文通过钱塘江深切谷的论述对末次冰期深切谷的恢复主要依据下列证据进行：（1）谷底为侵蚀不整合面，为末次冰期海平面下降，河流侵蚀切割所致；（2）谷内为异常厚的河流沉积物所充填，是冰后期海平面上升时形成，其中河漫滩沉积年代约14000～7500a以前；（3）深切谷之上被海相地层覆盖。超浅层生物气田分布在深切谷内，当今河流及全新世晚期河口湾与末次冰期深切谷既有区别又有继承性，其流域是浅层生物气藏分布的有利地段。

RECOGNITION OF THE LAST GLACTATION INCISED VALLEY AND ITS SIGNIFICANCE IN BIOGAS PROSPECTION: FOLLOW THE EXAMPLE OF THE QIANGTANGJIANG INCISED VALLEY

Reconstruction of the last Glaciation incised valley is mainly performed on the basis of the following proofs: (1) the valley floor is sndace of unconformity by ercoion as a result of erosion and dissection of river during sea level flood land sediment in the valley deposited during late glacial sea level ascension, with an age of 12000-7500 year;(3) There is a marine facied stratum overlying the incised valley. Ultra-shallow layer biogas area is distributed in the ineised valley,modern river and the last Holocene estruary are different and successive with the last Glaciation incised valley, its flood area is a land belf which is the most favorable of prospection for shallow layer biogas pool.