湘南中晚泥盆世碳酸盐台缘斜坡类型及其演化

CARBONATE PLATFORM MARGIN OR SLOPE TYPES AND THEIR EVOLUTION OF MIDDLE AND LATE DEVONIAN IN SOUTHERN HUNAN

蒋德和

Jiang Dehe

湘南中晚泥盆世碳酸盐台缘斜坡有如下四种不同类型:(1)同斜缓坡,(2)末端变陡缓坡,(3)加积型镶边边缘,(4)沟槽型或跌积型边缘。台盆东西两侧碳酸盐台地斜坡类型演化不同。西侧由同斜缓坡(Dq)→加积型镶边边缘(Dq)→沟槽型或跌积型边缘(Ds)→同斜缓坡(Ds—Dx)。东侧由:同斜缓坡(Dq)→加积型镶边边缘(Dq)→末端变陡缓坡(Ds)→加积型镶边边缘(Ds)→同斜缓坡(Dx)。

Carbonate rocks were distributed widely during Middle to Late Devonian in South Hunan Province. Carbonate platform margins can be divided into four types:1. Carbonate ramp; 2. Distally steepened ramp; 3. Accretionary rimmed platform margin; 4. Gully or colluvial margin. Except the influences of sedimentution, eustatism and the migration of basin, the evolution of platform margins or slopes were mainly controlled by synsedimentary fault activities. Since the synsedimentary fault activities in the east and the west sides of the basin unsynchronized, there was distinct differences in the evolution of platform margins or slopes in both sides. The evolution process of the platform margin or slope in west side is considered as:carbonate ramp (Dq)→accretionary rimmed platform margin (D)→gully or colluvial margin (Ds)→carbonate ramp (Ds-Dx); the eastern side is: carbonate ramp (Dq)→accretionary reefs rimmed margin (Dq)→distally steepened ramp (Ds)→accretionary shoals rimmed margin (Ds)→carbonate ramp (Ds).

10.11743/ogg19910405