Nanbaishuihe Fm
Type Locality and Naming
NW Gansu-south Qinghai border region (middle Qilian). The Nanbaishuihe Fm was named by Qian Jiaqi and Gong Baojun in 1986. The type section is around Nanbaishui River, 25 km northwest of Suli Township, Tianjun County, Qinghai Province. Lower formation in Tuolainanshan Gr.
Synonym: （南白水河组）; Wulandawu Fm and the Suli Fm are considered as different names for the Nanbaishuihe Fm.
Lithology and Thickness
In the type section, the formation is composed of rhythmic layering series of low-grade metamorphosed clastic rock and minor carbonate rock. It is about 4000 m thick.
Relationships and Distribution
Lower contact
The Nanbaishuihe Fm unconformably overlaps on different stratigraphic units, namely on the Aoyougou Fm and on the Huashugou Fm of Zhulongguan Gr from southeast to northwest direction.
Upper contact
It is in conformable contact with the Hua'erdi Fm.
Regional extent
NW Gansu-south Qinghai border region (middle Qilian). The formation is widely distributed in the west sector of Middle Qilian Mountain. It is rather changeable in lithological character, lithofacies and thickness. For example, it consists of siltstone with phyllitoid muddy slate, calcareous quartz siltstone (699 m) with microplants in Hua'erdi area, but in Wulan-dawu, it is an interbedding of sandy slate with siliceous muddy slate with limestone (860 m thick), and in central sector of Yemananshan Mountain, it is dominated by quartzite and metamorphosed siltstone with schist and marble with neither the top nor base being exposed.
GeoJSON
Fossils
The stromatolites in formation are: Paracolonnella, cf. laohudingensis, Conophyton f., Colonella f.
Age
Depositional setting
Additional Information