Maping Fm

The type section has two sites: one is Baiziyi about 45 km southwest of Liuzhou City of Guangxi, and the other is Loutishan about 6 km northeast of the city (Yin Zanxun et al., 1966).. It was named by Ding Wenjiang in 1928.

Limestone. At Loutishan, it consists of gray-white and gray moderately thick-bedded to massive limestone, with dolomitic limestone in the lower part, 600−800 m.

Can be divided into three members in eastern Yunnan and western Guizhou (Wu Wangshi et al., 1974; Chen Gengbao et al., 1991): The Lower Member is composed of gray-white moderately thick- to thick-bedded limestone, intercalated with gray-yellow and purple-red clayey limestone, nodular limestone or containing yellow-green and purple-red clayey matter and shale, locally with dolomitic matter and dolomite, or chert nodules and thin-bedded siliceous rock; 0−519 m thick; the Middle Member consists of light-gray and gray-white thick-bedded limestone, containing Girvanella nodules, locally with minor dolomite and dolomitic limestone, or purple-red and gray-yellow nodular limestone, shale, siltstone and sandstone, or chert nodules; totaling 3−257 m; and the Upper Member is light-gray and gray moderately thick- to thick-bedded limestone, occasionally with dolomitic spots or limy dolomite, and locally containing chert nodules and bands, 0−61 m thick.

At Desheng of Yishan, it can be divided into two Fusulinid zones: the lower part Triticites zone, 256 m thick; the middle and upper part Pseudoschwagerina zone, 224 m thick, mostly Staffella in the upper part (Sheng Jinzhang, 1959).

In eastern Yunnan and western Guizhou, Lower Member lower part is the Fusulinid Montiparus zone, containing Ammonoid Agathiceras sp., brachiopod Meekella sp., etc.; the upper part is the Fusulinid Triticites peak zone, containing fusulinid Quasifusulina phaselus, Corals Antheria sp. and Pseudotimania sp. For Middle Member, two fusulinid zones can be identified along Liuzhi-Panxian County of Guizhou (Xiao Weimin et al., 1986): the lower Pseudoschwagerina uddeni range zone, containing coral Nephelophyllum sp., and the upper Sphaeroschwagerina range zone, containing coral Kepingophyllum sp., which can be further divided into two subzones, the Sphaeroschwagerina constans subzone and the Eoparafusulina subzone. The Upper Member is rich in fusulinid Staffella sp. belonging to the Pamirina darvasilca zone,

It is interpreted as a carbonate platform.

Normal-polarity magnetization was measured on the bottom of the Pseudoschwagerina and Sphaeroschwagerina zones at Yishan of Guangxi and in the middle of Sphaeroschwagerina at the Houchang section of Ziyun (Guizhou), but all the other horizons of the formation show reversed-polarity magnetization.

The present Maping Fm generally includes the Late Carboniferous slope or basin-facies deposits in the southwestern region, i.e. the “Black Maping”. Areas such as Ziyun of Luodian in southern Guizhou are the most typical, which are composed of gray-black and dark-gray micritic limestone, and chert-nodules-bearing marl, containing abundant Conodonts, which are divided ascending into 8 zones (Wang Zhihao, 1991): the Streptognathodus elegantulus, S. elongatus, S. wabaunsensis, S. barskovi, Neogondolella dentiseparata, N. bisselli, S. inornatus and S. whitei zones. As the “Black Maping” of slope or basin origin is different with the Maping Fm of platform facies in lithologic characters and biologic features, it is unsuitable to use the same stratigraphic name; therefore the name “Xiaolangfengguan Fm” is used to represent the “Black Maping” in this lexicon.