深水斜坡沉积特征与控制因素以澳大利亚柔布克盆地为例

    Characteristics and the controlling factors of sedimentation in deep-sea slopes: an example of the Roebuck Basin, Australia

    • 摘要: 深水斜坡沉积规律对深水油气勘探开发以及深水地质灾害防护具有重要的研究意义。为揭示澳大利亚柔布克盆地新近纪深水斜坡沉积特征与控制因素,利用高分辨率二维地震资料,划分了斜坡沉积地层层序,在地震剖面上识别出7个三级层序界面和6个地震层序。研究结果表明:研究区新近纪主要形成了进积型、加积-进积混合型和退积型沉积层序;柔布克盆地深水区发育前积型碳酸盐岩、硅质碎屑三角洲和滑塌3种斜坡沉积;研究区深水斜坡沉积受多种因素共同控制,中渐新世—晚中新世,斜坡沉积主要受相对海平面升降、古气候变化和物源供给的控制,而晚中新世之后,向北漂移的澳大利亚板块与班达岛弧发生碰撞,深水斜坡沉积主要受构造活动的控制。

       

      Abstract: Understanding deep-water slope depositiona is of great significance for deep-water oil and gas exploration and development as well as deep-water geohazard protection. To reveal the characteristics and controlling factors of the Neogene deep-water slope deposition in the Roebuck Basin, Australia, the stratigraphic sequences of slope deposition were delineated by using high-resolution 2D seismic data, and seven third-level sequence interfaces and six seismic sequences were recognized on seismic section. Results show that the Neogene in the study area are mainly the sedimentary sequences of progradational, aggradational-progradational, and retrogradational sedimentary sequences. The deep-water area of the Roebuck Basin developed three types of slope deposits: progradational carbonate rock deposits, siliceous debris deltaic deposits, and olistostrome deposits. The deep-water slope deposits were controlled by various factors. In the Middle Oligocene and the Late Miocene, the slope deposits were controlled by the relative sea level fluctuation, paleoclimate, and material supply, while after the Late Miocene, with the collision of the northward drifting Australian plate against the Banda Island Arc, the deep-water slope deposition was mainly controlled by tectonic activities.

       

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