Kunyang Gr

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) and a modified version of the schematic stratigraphic column (2022) for Middle Yunnan (which also placed some previous "Kunyang Gr" units into a separate Dongchuan Gr), then the current subdivisions of the Kunyang Gr are an upward succession of a lower set of Etouchang Fm, Luzhijiang Fm; and an upper suite of Reshuitang Fm, Chengjiacheng Fm, Huangcaoling Fm, Heishantou Fm, Fulianpeng Fm, Dalongkou Fm, and Meidang Fm (of which the Reshuitang Fm and Chengjiacheng Fm are only shown on a strat column and no mentioned in Lexicon). In the Dongchuan area (column 37), it is an upward succession of the Dayinpan Fm, Xiaohekou Fm and Madi Fm.

Synonym: （昆阳群）, The Huili Gr, Dongchuan Gr and Huodiya Gr are equivalent (coeval) to some parts of Kunyang Gr.

Lithology and Thickness:

The Kunyang Gr is composed of carbonate rock, stromatolite-bearing magnesium carbonate (dolomitic) rock, phyllite, slate, metamorphosed quartz sandstone, metamorphosed siltstone and chert, in which the copper and iron sedimentary deposits occur in different stratigraphic horizons. The thickness is over 10000 m.

Lithology-pattern: Dolomitic limestone

Relationships and Distribution:

Lower contact:

Bottom is not seen.

Upper contact:

The group is unconformably overlain by Chengjiang Fm of Sinian (Ediacaran), or an intervening Liubantag Fm of Qingbaikouan (Tonian) in Central Yunnan.

Regional extent:

East-central Yunnan. It widely distributed in Dongchuan (but this is now a separate Dongchuan Gr), Yimen-Eshan central and Eastern Yunnan Province.

GeoJSON:

Fossils:

The Group is rich in stromatolites and microplants.

Age:

Schematic stratigraphic section assigns as Jixian (Calymmian), then Yuxian (Stenian) with intervening Jixian absent between Luxzhijiang Fm and Huangcaoling Fm

Age span:

Beginning stage: Calymmian

Fraction up in beginning stage: 0.0

Beginning date (Ma):

Ending stage: Stenian

Fraction up in ending stage: 1.0

Ending date (Ma):

Depositional setting:

Depositional-pattern:

Additional Information

There is a long-debated problem on the stratigraphic sequence of each formation included within the Kunyang Gr, the stratigraphic sequence cited in the Lexicon was the stratigraphic sequence programme used by the Yunnan Bureau of Geology and Mineral Resources in 1990, 1996.

For example, an earlier version (year 2000) of this entry said: "Kunyang Group is subdivided into two a lower subgroup of the Huangcaoling Fm, Heishantou Fm, Fulianpeng Fm (which are widespread only in central Yunnan Province), Dalongkou Fm, Meidang Fm, and an upper subgroup that includes the Yinmin Fm, Luoxue Fm, Etouchang Fm, Luzhijiang Fm, Liubatang Fm (seen only in central Yunnan Province), Dayinpan Fm, Xiaohekou Fm and Madi Fm (the last three formations are distributed only in Dongchuan area)."