Liushui Fm

The type section of Liushui Formation is the Liushui section, measured between Liushui and Xiangshui villages, Shidian, Baoshan, Yunnan Province by the No. 20 Yunnan Geological Team of Yunnan Bureau of Gologye in 1962. It lies about 11.5 km southwest of the seat of Shidian County. However, the Liushui Formation is incomplete in the type section as its basal part is not exposed. For this reason a section, the Yiwanshui section, with more complete sequence of the formation is selected as representative section of the Liushui Formation although the top part of the Liushui Formation in this section may be still cut off by fault. The Yiwanshui section is measured at Yiwanshui Village in Banqiao Township, Longyang District, Baoshan City by the No. 1 Brigade of Yunnan Regional Geological Survey Team (1979). It lies about 32 km southeast of the seat of Baoshan City (99°07’07”E, 25°15’27”N). The Liushui Formation was firstly published by Yunnan Bureau of Geology (1974). The name is derived from Liushui Village in Shidian County, Baoshan City, western Yunnan Province. Originally it was appeared in a 1964 manuscript by Cao Renguan from the Yunnan Institute of Geological Sciences.

Synonym: （柳水组）; The strata named originally Liushui Formation was subsequently named once again Shahechang Formation by No. 3 Brigade of Yunnan Regional Geological Survey Team (1980). The latter formation is apparently an invalid synonym of Liushui Formation.

The Liushui Formation is an alternated sequence of classic and carbonate rocks. It is roughly divided into three lithological parts. Lower part, 86 m thick, is dominated by greyish green and grey, silty and platy calcareous shale with sedimentary rhythm and is often intercalated with grey limestone and striped argillaceous limestone; Middle part, 201 m thick, is mainly composed of grey oolitic limestone, intercalated with striped argillaceous limestone and argillaceous limestone; the oolitic limestone can be served as key horizon because of its stability in position; Upper part, 218 m thick, is dominated by light green shale and siltstone. In the representative section, the Liushui Formation is 505 m thick.

The Liushui Formation yields rich fossils, including trilobites Chuangia, Changia, Dikelocephalites, Geragnostus, Homagnostus, Kaolishanella, Kaolishania, Longlingaspis, Maladioides, Mansuyia, Palaeoharpes, Parachangshania, Parakaolishania, Prochuangia, Pseudagnostus, Rhaptagnostus, Sanduspis, Shidiania, Shirakiella, Wafangia, Tiantouzhania and Zhuitunia; and brachiopods Billingsella, Eoorthis, and Finkelnburgia.