摘要
北部湾盆地经历了古近纪裂陷阶段和新近纪张裂后热沉降阶段,其中裂陷期是盆地内各凹陷形成的主要时期,亦为断裂最为活跃的时期。裂陷期内,由于控凹断裂活动的差异性,使得北部湾盆地在不同时期沉降中心有所不同,各凹陷在裂陷期所沉积的地层厚度差别较大,根据地层相对厚度关系,可将凹陷划分为厚长流薄流沙港型、厚流沙港型和厚涠洲薄流沙港型。北部湾盆地的断裂按走向可分为NE向、NEE向和近EW向3种类型,其中NE向断裂是盆地内最为重要的断裂,控制了盆地的沉积、局部构造形态及构造类型。北部湾盆地裂陷期的构造演化经历了古新世的初始断陷阶段、始新世的断陷鼎盛阶段、渐新世的断-坳转换阶段,不同阶段在区域构造应力场、断裂走向、形成的局部构造、沉积沉降中心展布、沉积充填特征等方面均有所差异。
The evolution of Beibuwan Basin experienced chasmic stage of Eogene and thermal-subsidence stage of Neogene.The sags formed mainly during chasmic stage and the faulted system was mostly active.The deposition and subsiding center was different at chasmic stage which caused different thickness in every sag because of the differences of depression-controlled faults.According to the relation of related formation thickness,the sags in Beibuwan Basin could be divided into three kinds: such as 'thick Changliu Formation and thin Liushagang Formation','Thick Liushagang Formation' and 'Thick Weizhou Formation and thin Liushagang Formation'.There are three kinds of faults,divided by the strike direction of NE,NEE and EW.The NE faults are the most important,which control the tectonic,sedimentary and structural types.The structural evolution of Beibuwan Basin experiences the initial chasmic stage of Eogene,the peak chasmic stage of Eocene and the chasmic-depression transforming stage of Oligocene,which deposites in Changliu Formation,Liushagang Formation and Weizhou Formation.At every evolution stage,the areal stress,fault strike direction,local structure,the deposition and subsiding center,sedimentary facies are very different and have singular features.
出处
《石油天然气学报》
CAS
CSCD
2013年第1期6-10,172,共5页
Journal of Oil and Gas Technology
基金
国家科技重大专项(2011ZX05023
2011ZX05025)
国家重点基础研究发展计划项目(2009CB219400)
关键词
北部湾
裂陷期
构造演化
控凹断裂
沉降中心
Beibuwan Basin
chasmic stage
structural evolution
controlling faults
subsiding center