琼东南盆地南部中新统“丘”形反射成因探讨

An origin discussion of mound-shaped reflections in Miocene , southern Qiongdongnan Basin

在琼东南盆地南部中新统梅山组广泛发育"丘"形反射,对其识别分析具有重要的意义。这些"丘"形反射主要分布在北礁凹陷及周缘斜坡带上,在顶底界面呈强反射,在内部成层、杂乱或为空白反射,有时在顶部见披覆沉积,从盆地中心北礁凹陷向边缘斜坡带迁移生长。通过对"丘"形反射的古构造和古地理背景、几何学特征及地震响应特征等方面综合分析,对其成因进行了探讨,排除了其为生物礁、泥底辟以及火山丘的可能,认为其可能为深水环境底流作用下形成的等深流沉积或某种沉积物波。

Mound-shaped reflections of Miocene Meishan formation are widely developed Basin. Their identification and analysis are of important significance both for sedimento bon exploration. They are mainly located in the Beijiao depression and its surrounding s in southern Qiongdongnan ogy research and hydrocar opes, with high amplitudes on top and bottom interfaces and weak reflections in its interior. Sometimes lateral drape reflections exist on the mound top and mounds migrate in a way of growth from structural depression toward higher slopes. In addition of the comprehensive analysis of the palaeotectonic and paleogeographic background, geometry and distribution and impedance of mound-shaped reflections suggest that they should not probably originated by reef or/and mud diapirs and volcanoes. Instead they may be contour currents deposits or some kind of sediment wave formed under the bot- tom currents in deep water environment.