Qianshan Fm
Type Locality and Naming
The type section of the Qianshan Formation is the Line No. 27 section of the Xiaoxilin Lead-Zinc Mine, Jinlin, Yichun, Heilongjiang Province. It is located at the Lead-Zinc Mine Area (129°08’30” E, 47°23’30” N), about 22 km west of the seat of Jinlin District. The formation is over 1329 m thick in the type section. The Qianshan Formation was first published by Heilongjiang Bureau of Geology and Mineral Recourses (1993). The name is derived from Qianshan (Lead Hill) in Xiaoxilin Lead-Zinc Mine, Xiaoxilin Village, Jinlin District, Yichun City, central Heilongjiang Province. Originally the name was appeared in a 1965 unpublished report by Zhao Tongji et al. from the Third Geological Team of Heilongjiang Bureau of Geology.
Synonym: （铅山组）
Lithology and Thickness
The Qianshan Formation is mainly a magnesium-rich carbonate sequence, consisting mainly of dolomite, dolomitic crystalline limestone, carbonaceous, siliceous shale, striped marble, dolomitic marble, and muddy limestone, with interbeds of volcanic rock and slate.
Relationships and Distribution
Lower contact
The Qianshan Fm rests conformably on the underlying Laodaomiaogou Fm, with lower boundary defined by the disappearance of shale and siltstone of the Laodaomiaogou Fm, and appearance of limestone at the base of the Qianshan Fm.
Upper contact
As incomplete exposure, the upper boundary of Qianshan Fm is unknown in the type section and surface outcrops elsewhere in Yichun. However, a drill hole at Wuxingzhen reveals it is in conformable contact with the overlying Wuxingzhen Fm.
Regional extent
The Qianshan Formation is exposed in Hinggan Region. It is outcropped in south-central Yichun City in NW‒SE orientation, stretching from Xiaoxilin Village to Wuxingzhen Township. It is also sporadically distributed in Langxiang Village of Tieli County, southern Yichun City, and Tonghe County of Harbin City, where the thickness of the formation decreases significantly, being merely 150 m thick.
GeoJSON
Fossils
No fossil has been found from the type section of the formation, but in a section at the Xiaoxilin Lead-Zinc Mine the formation yields acritarchs Synsphaeriduun sp. and Leiosphaeriadia sp. and colony of coccoid algae (Chen et al., 2011).
Age
Depositional setting
Additional Information