摘要
本文主要讨论扇三角洲和辫状河三角洲的成因和沉积特征。扇三角洲是由风暴型流量控制的;辫状河三角洲通常是由湍急洪水控制的。这两种三角洲象正常的三角洲那样经受过海洋的改造。根据沉积过程和海洋改造的性质,可把三角洲体系划分为9种类型。扇三角洲和辫状河三角洲对勘探石油具有重要的意义。在前陆盆地和板内裂谷沉降盆地中,人们发现扇三角洲常常形成聚集油气的复合圈闭。
Fan-deltas are alluvial fans prograding directly into a standing body of water from an adjacent highland. Braid deltas are sand and gravel-rich deltas that form where a braided fluvial system progrades into a standing body of water. Fan-deltas are storm discharge-dominated, displaying a record of epherneral, even catastrophic depositional processes. Braid deltas are commonly produced by flashy, flood-dominated, and often seasonal depositional processes. Fandeltas and braid deltas, like common deltas, are reworked by marine processes. Delta systems are classlfied into nine delta types based on the subaerial depositional processes and nature of marine reworking. Fan-deltas, braid deltas and common deltas can be distinguished in the rock record by distinctive subaerial facies assemblages. Fan-delta sequences are capped by alluvial fan facies. In contrast, braid deltas have a subaerial facies component consisting dominantly of braided-river or braidplain facies. The subaqueous components of fan-deltas also differ.
The importance of fan-delta and braid delta deposits as hydrocarbon reservoirs is increasingly being realized, Fan-deltas are found in divergent margin foreland and intraplate riftsubsided basin settings, where combination structural-stratigraphic hydrocarbon traps are common.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1991年第2期141-153,共13页
Acta Geologica Sinica
