论文部分内容阅读
本文提出了大西洋型被动陆缘在最终与岛弧或大陆碰撞之前,向具反转极性的主动陆缘转化的一种模式。据认为,体现这种转化特征的重要形态型式或地层型式有:1)在陆缘最近引张期间形成的先存犁形正断层(非湾岸型生长断层,但对基底有影响者)以逆断层形式发生的活化;2)这种断层活化作用随时间推移而发生的向陆迁移;3)陆缘上深—浅—深水相或深水相—不整合—深水相地层组合的发育;4)俯冲带向陆侧大陆边缘的区域性挠曲(类似于大洋板块外部隆起区的挠曲);5)主要不整合面与陆缘挠曲的同时向陆迁移。本模式对油气勘探具有一定意义,这是因为:1)它能预测不整合面的存在与否,从而可推断某特定盆地内各层组之间有否潜在的地层圈闭;2)它能提供潜在储油层中次生孔隙发育的时、空范围;3)它能使人们更准确地解释为确定潜在生油层系的相对成熟度而绘制的热演化曲线或掩埋史曲线;4)它能帮助鉴别基底活化作用与脱顶构造作用,或湾岸型生长断层作用。然而,这些形态和地层型式后来在陆缘发育的遣山作用期间,可能受到迭加或掩盖,以至再也无法辨认。由于这些形态和地层型式在学术和经济两方面都有着重大意义,故它们在陆缘演化中的作用不容忽视。
This paper presents a model for the conversion of an active continental margin to an inverting polarity before finally colliding with an island arc or continent. It is believed that the important morphological patterns or stratigraphic patterns that characterize this transformation are: 1) Pre-existing plow-shaped normal faults formed during the recent extension of the margins (non-gulf type growth faults but those with an impact on the substrate) 2) activation of the fault to landward migration over time; 3) development of deep-shallow-deepwater or deepwater-unconformity-deepwater facies combination on the margin; and 4) Regional deflection of the subduction zone towards the continental margin (similar to the deflection of the outer bulge of the oceanic plate); 5) The main unconformity migrates to the continent while the continental margin deflects. This model has some implications for hydrocarbon exploration because it: 1) predicts the existence of unconformities, and thus may infer potential formation stratigraphy between layers in a given basin; 2) that it can 3) it allows one to interpret more accurately the thermal evolution curves or burial history curves that are used to determine the relative maturity of potential oil-bearing formations; 4) that it can Helps to identify substrate activation and detachment, or shoreline growth faults. However, these forms and stratigraphy types may later be superimposed or concealed until they are no longer identifiable. As these morphologies and stratigraphic patterns are of great academic and economic significance, their role in continental evolution can not be ignored.