藏南江孜盆地晚侏罗世至早白垩世重力流沉积

GRAVITY FLOW SEDIMENTS OF THE LATE JURASSIC-EARLY CRETACEOUS OF JOMZI BASIN IN SOUTHERN TIBET

西藏南部江孜盆地的沙拉岗矿区发育一套晚侏罗世至早白垩世的碎屑流、滑动流与浊流等重力流沉积 ,主要由斜坡相碎屑岩夹硅质岩和灰岩构成。在这个斜坡背景中出现了上斜坡相、下斜坡相与海底扇相等 3种类型的岩相组合。其中 ,上斜坡以各种规模的滑动沉积为特色 ,下斜坡以不同性质的碎屑流沉积为特征。海底扇具有完整的内扇、中扇与外扇组合 ,可划分出进积型和退积型两种序列类型 ,它们多半是由浊流形成的各种砂体组成的。

The well known gravity flow sediments were formed by the debris, slide and turbidity flows in the Late Jurassic-Early Cretaceous in Shalagang mining area of Jomzi Basin in southern Tibet, which consisted of the slope clastic rocks and interbeds of siliceous rocks and limestones. Three lithofacies assemblages of upper slope, lower slope and submarine fan emerged in the slope. The upper slope was characterized by all kinds of sliding sediments and lower slope by all kinds of debris flow sediments. The submarine fan with completely inner, middle and outer fan can be divided into progressive and regressive sequence, which were composed of sandstone bodies formed by turbidity flow.