Migration of the carbonate ramp and sponge buildup driven by the orogenic wedge advance in the early stage (Carnian) of the Longmen Shan foreland basin, China

The marine Carnian the Maantang Fm. overlies a flexural forebulge unconformity and records the initial establishment, drowning and migration of a carbonate ramp and sponge buildup along the forebulge margin of the Longmen Shan foreland basin. The Maantang Fm. is of wedge-shaped geometry, and is composed of oolitic and bioclastic limestones, siliceous sponge reef and shale in an upward-fining succession. The formation shows the establishment and...