Until at least the end of the Middle Triassic, high sea levels enabled shallow water to cover much of the South China Block, a tectonic plate that today consists of the stable Yangtze Craton and the less stable South China Fold Belt. A mountain-building event known as the Indosinian orogeny uplifted Precambrian rocks to form four major landmasses on the South China Block: Khamdian to the west, Jiangnan in the centre, Yunkai to the south, and Cathaysia to the east. Island chains also stretched between Yunkai and Cathaysia in the east. Located between Khamdian and Jiangnan was a deep oceanic basin known as the Nanpanjiang Basin. Along the western edge of this basin, fossil-bearing sediments were laid down to become what are now the Lagerstätten (sedimentary deposits characterized by exemplary preservation) of Panxian, Luoping, and other localities.