Gigantoproductid brachiopod storm shell beds in the mississippian of South China: Implications for their palaeoenvironmental and palaeogeographical significances

Abstract

Late Viséan to Serpukhovian (Mississippian, Carboniferous) storm shell beds of Gigantoproductus (Brachiopoda) are documented for the first time in South China. The shell beds are characterized by sharp and erosional base, internal accumulations of amalgamated shells with erosional structure, and parallel lamination and ripple bedding structures in the uppermost part, indicating obvious characteristics of tempestites. In the shell beds, three taphonomic and sedimentologic types have been distinguished, which are: type A: mostly articulated and convex-down shells in wackestone and packstone, which are developed in distal tempestites with weak water energy around the storm wave-base; type B: dominated disarticulated and convex-up shells in packstone that occur between distal and proximal tempestites in medium hydrodynamic force between the storm wave-base and fair-weather wave-base; and type C: highly fragmented shells in grainstone formed in proximal tempestites under strong hydrodynamic energy above the fair-weather wave-base. The occurrences of proximal and distal tempestites suggest that they were formed by winnowing and transporting under storm surges. During the late Viséan to Serpukhovian, the widely distributed storm shell beds in South China reflect that the South China Block was located in hurricane zone between latitude 10° and 30° during this time interval, when ice caps formed on the Gondwana continent.