Anxian Bioherm-Karst National Geopark, Sichuan
This geopark is located in northwestern An County, Sichuan Province. It is in the north-central segment of the Longmen mountain range in the Sichuan Basin and borders the Minjiang alluvial plain, hills and mountains. It became a national geopark in 2002. The northwestern part is in the Longmen Mountains, and the highest peak has an elevation of 2,922 m. The park features deepwater siliceous sponge reefs, including hexactinellids in large-scale reefs that formed in the Late Triassic (approximately 230 million years ago). In Anxian County, 6 new sponge families, 31 new families and 55 new species have been identified. The sponge reefs have sizes of 40–60 m. More than 100 reefs can be observed at the surface in Anxian County and the vicinity. The spacing between the reefs ranges from 100 m to 2 km. Rocky hills, which are prominent landforms, are distributed in front of the and Longmen Mountains and cover an area of 266 km2.