Sequence stratigraphy and tectono-depositional evolution of a late Ediacaran epeiric platform in the upper Yangtze area, South China

The Pearl River Mouth Basin (PRMB), located on the northern continental margin of the South China Sea, underwent a complex evolution during the Paleogene. We have focused on the Baiyun Sag in the PRMB with the goal of constructing the architecture and depositional evolution of the Eocene–Early Oligocene synrift stage to the Late Oligocene early postrift stage of basin evolution. Based on analysis of 3D seismic data complemented by well logs and cores, the Paleogene basin fills can be classified into three composite sequences bounded by regional unconformities and 14 sequences bounded by local unconformities. We identify seismic facies on the basis of different internal reflection configurations, external shapes, and contact relationships. The distribution of seismic facies and lithologies interpreted from gamma-ray curves reveal that the synrift basin fill consists mainly of fan delta deposits adjacent to the southern fault scarp, braid delta deposits on the adjacent hanging-wall blocks, and lacustrine mudstones and sublacustrine fan deposits in the center of the basin. The overlying early postrift stage is dominated by shelf and shelf-slope environments, with widespread developed southward-prograding deltas and submarine fans. Tectonics is the principal controlling factor on the development and distribution of depositional systems during the synrift stage. In contrast, sea-level changes superimposed on long-term subsidence related to thermal cooling determined the stacking patterns of sequences during the postrift stage. The results provide new insights on synrift and early postrift tectonics and sedimentation patterns along an evolving passive margin.

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Belgian substages as a basis for an international chronostratigraphic division of the Tournaisian and Viséan

Geological Magazine ◽

10.1017/s0016756813000587 ◽

2013 ◽

Vol 151 (2) ◽

pp. 229-243 ◽

Cited By ~ 12

Author(s):

EDOUARD POTY ◽

MARKUS ARETZ ◽

LUC HANCE

Keyword(s):

Sequence Stratigraphy ◽

South China ◽

International Division ◽

Time Intervals ◽

Rugose Corals ◽

First Occurrence ◽

Three Stages ◽

Surrounding Areas ◽

Visean Stage

AbstractThe Tournaisian and Viséan were formerly considered as series and in Belgium were divided into two (Hastarian and Ivorian) and three stages (Moliniacian, Livian and Warnantian), which are now considered as substages. The Belgian substages are based on conodonts and foraminifers, and incidentally on rugose corals, and are described here. Their boundaries, biostratigraphy and sequence stratigraphy are well detailed and clearly defined. The base of the Hastarian (lower Tournaisian) corresponds to the base of the Tournaisian (base of Carboniferous); the base of the Ivorian (upper Tournaisian) corresponds to the appearance of the conodont Polygnathus communis carina, a little above the last Siphonodella; the base of the Moliniacian (lower Viséan) corresponds to the base of the Viséan stage defined by the first occurrence of the foraminifer Eoparastaffella simplex; the Livian (middle Viséan) corresponds to the foraminiferal MFZ12 Zone and is marked by the appearance of Koskinotextularia and Pojarkovella nibelis; the base of the Warnantian (upper Viséan) is marked by the appearance of Neoarchaediscus, Vissariotaxis, Planospirodiscus, and Palaeotextularia with a bilaminar wall, the index taxa of the MFZ13-Neoarchaediscus Zone. The up-to-date chronostratigraphic subdivision of the Tournaisian and Viséan is not limited to Belgium and the surrounding areas. It can be applied through Eurasia as far as South China. The Belgian units could therefore be the basis for a future international division of the Tournaisian into two parts (Hastarian and Ivorian) and of the Viséan into three parts (Moliniacian, Livian and Warnantian), corresponding to time intervals of c. 5–8 Ma.

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