Geological Characteristics of Mud Volcanoes and Diapirs in the Northern Continental Margin of the South China Sea: Implications for the Mechanisms Controlling the Genesis of Fluid Leakage Structures

Figure 9

(a) Developmental pattern of mud diapirs in Yinggehai Basin. Mud diapirs developed based on the sediments from the Neogene Sanya Formation to Yinggehai Formation. Mud diapirs vertically pierce through to the Quaternary strata. The grey-purple part indicates the Paleogene stratum. The source of MD-1 and MD-5 is deeper than other mud diapirs, and MD-1 pierces the shallower stratum; the sources of MD-2, MD-3, and MD-4 are shallow, and they pierce through strata at different depths. (b) Developmental pattern of mud diapirs in Qiongdongnan Basin. Mud diapirs are derived from Paleogene (Eocene-Oligocene) shale, which penetrates the Neogene strata vertically. The grey-purple part indicates the Paleogene stratum. The source of MD-1 and MD-3 is deeper than other mud diapirs, and MD 1 pierces the shallower stratum; the sources of MD 2 and MD-4 are shallow, and they pierce through strata at different depths. (c) Developmental pattern of mud diapirs in Baiyun sag of Pearl River Mouth Basin. The source of the diapir material is Paleogene (Eocene-Oligocene) shale, and diapirs pierce the Neogene strata vertically. The grey-purple part indicates the formation below the T50 interface. The source of MD-1 and MD-4 is deeper than other mud diapirs, and MD-1 pierces the shallower stratum; the sources of MD-2, MD-3, and MD-5 are shallow, and they pierce through strata at different depths. (d) Developmental pattern of mud volcanoes and mud diapirs in Southwest Taiwan Basin. The source of mud volcanoes and mud diapirs is Neogene (Miocene and Pliocene) shale, and the fluid penetrates through the Quaternary strata or the seafloor. The grey-purple part indicates the Paleogene stratum. MV-1 and MV-2 represent mud volcanoes of different scales; MD-1 indicates the shallow diapir of the source, and the vertical piercing is close to the seabed; MD-2 and MD-3 have deeper sources and pierce through different horizons.

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