摘要
本文对合肥盆地侏罗系之下前中生代海相构造层的归属进行了总结,将其划分为北淮阳型、华北板块型及其大陆边缘过渡型3种类型,探讨了该盆地的构造演化,认为该盆地曾经历了裂谷-被动大陆边缘(Pt_3—O_2)、弧后盆地(O_3—D_2)、(弧后)前陆盆地(D_3—T_1)、再生前陆盆地(J—K_1)及后继盆地(K_2—E)等盆地发育阶段,并探讨了该盆地的生储盖组合及油气生成、运移、聚集与构造的基本关系,认为印支期不整合面(侏罗系底)下伏的古生界风化淋滤带和中、下侏罗统是最具意义的油气勘探目的层。
The Hefei basin is a Meso-Cenozoic continental basin intimately related with the Dabie oro-genic belt. Seismic exploration has revealed that there is a good reflector about 10 km thick under the continental cap rocks in the Hefei basin. Further study indicates that it is a pre-Mesozoic marine formation. The upper Palaeozoic belongs to deposits of a back-arc foreland basin. Separated by the Feizhong fault and Liu'an fault, the Neoproterozoic - Lower Palaeozoic under the Hefei basin is divided into 3 types of deposits; North China platform type (Pt3-O2) located north of the Feizhong fault, rift-back-arc basin type (North Huaiyang type, Pt3-P21) located south of the Liu'an fault, and North China continental-margin type (Pt3-Pz1) located between the two faults. The basement of the Hefei basin is composed of the above-mentioned marine formation and Late Archaean and Mesoproterozoic metamorphic rocks and is correspondingly divided into 3 types-North China platform type. North China continental-margin type and North Huaiyang type. The tectonic evolution of this area is reconstructed. The tectonic stages included those of the rift-passive continental-margin basin (Pt3-O2). back-arc basin (O3-D2), back-arc foreland basin (D3-T1), continent-continent collision (T2 - T3 >. rejuvenated foreland basin (J-K1), sequent basin (K2- E) and draping-deposit basin (N-Q).The rift-passive continental-margin basin (Pt3-O2), back-arc foreland basin (D3-T1 ) and rejuvenated foreland basin (J-K; ) constitute the favourable tectonic environment for source rocks. It is also testified by exploration and research that the 3 sets of source rock exist in the Hefei basin and make up 2 assemblages of source-reservoir-cap rocks. The results of basin modelling show that the peak hydrocarbon formation periods for the three sets of source rocks occurred from the Middle Jurassic to Early Cretaceous, simultaneously with intense thrusting in this area. The strong tectonic stress and surface of unconformity formed in the Indosinian (T2-T3) offered advantageous conditions for migration of oil and gas. The structural traps formed by thrusting in the Indosinian and Middle Jurassic to Lower Cretaceous as well as stratigraphic traps associated with Indosinian unconformity are important places of gathering oil and gas and also major targets of oil and gas exploration in the Hefei basin.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1999年第1期15-24,共10页
Acta Geologica Sinica
关键词
构造演化
含油气性
合肥盆地
储层
盖层
油气藏
tectonic evolution
assemblage of source-reservoir-cap rocks
analysis of petroleum potential
Hefei basin
