太子河流域本溪期沉积相特征

太子河流域是华北地台区本溪组最发育的地区之一。本文从典型剖面分析入手,对本溪期的沉积相进行分析讨论。本溪的牛心台剖面海相层位出现最早,晚期出现浅水生物碎屑滩沉积,底部之滨海湖沼相中的铝土矿厚度大品位高;大葫芦套村剖面以泥岩广泛发育,且灰岩层数多而薄为特征,代表滨海平原湖泊的沉积;田师付太平沟剖面以下部发育一完整的三角洲沉积而有别于其它地区;在最北部的暖河子剖面,下部为滨岸冲积平原的沉积,代表了近陆环境中的沉积。本溪期沉积可分为两个演化阶段,早期沉积受古地形的制约,为一填平补齐作用,沉积环境主要为滨岸冲积平原、滨海湖泊、沼泽以及三角洲;晚期是随着海侵范围的扩大和地形差异的缩小,基本上为一海湾—泻湖环境,但局部有浅水生物碎屑滩的存在。

CHARACTERS OF THE SEDIMENTARY FACIES AT BENXI AGE OF TAIZIHE VALLEY

Taizihe River Basin is one of the most development areas in Benxi Formation of North China platform. In the paper the sedimentary facies of Benxi Age are analysied profilingly.The earliest strata is marine facies and the late is shallow sea biodetritus bank in Niuxintai strata section of Benxi. The bauxite in littoral lacustrine facies of the section bottom is larger in thickness and higher in tenor of ore. Dahulutao section, standing for the sediment of littoral plain, characters as the wide development of mudstone and polylaminate and thin limestone. Benxi Formation in Taipinggou of Tianshifu is different from the other areas in a complete delta facies at its bottom. On the northest of Nuanhezi section, the lower of Benxi Formation, representing the beach sedimentary environment, is lottoral alluvial plain sediment.The sediment of Benxi Age can be divided into two phases. The early is a falling and rasing process for the rise and fall of palaeotopography, and the sedimentary environments are littoral-alluvial plain facies, littoral-lacustrine facies and swamp and delta facies. The late is a gulf-lagoon facies gradually due to the extending of brasional range and diminising of paiaeotopographic difference of elevation ap artfrom shallow sea biodetritus bank partly.