Manto Fm

At the type section, the Manto Fm rests conformably on the Chushatung Fm. It is also rests conformably on both the Chushatung Fm or Haojiashan Fm in southern Shanxi, northern Henan and northern Anhui.

It is overlain conformably by the Changhia Fm at the type section. However, in many other places the formation is in disconformable contact with the underlying Changping Fm or Jianchang Fm, or in unconformable contact with Archean gneiss.

Except for the Western Margin Area, the Manto Formation is exposed in all other areas of the of North China Region, i.e., the Shanxi-Henan-Shaanxi, Xuzhou-Huaibei, Western Shandong, Northern Hebei-Western Liaoning and Liaoning-Jilin areas. It is widely exposed in Jilin, Liaoning, Hebei, Shaanxi, Gansu, Shanxi, Shandong, Henan, northern Anhui and northern Jiangsu provinces and Inner Mongolia Autonomous Region. In general, the formation is thicker in southeast, and thinner in northwest. Stratigraphic hiatus may occur, varying with outcropping places.

In Jilin Province, the Manto Formation is mainly exposed around Hunjiang Valley. The Lower part of the formation consists of brick-red, purple, purplish red siltstone and shale intercalated with calcareous sandstone and limestone, and contains gypsum and halite pseudocrystal, and yields Redlichia sp.; Middle part consists of dark brown, dark purple micaceous siltstone, silty shale and oolitic limestone, and contains Shantungaspis sp.; Upper part comprises varicolored shale and sandy shale intercalated with limestone and oolitic limestone.

In Liaoning Province, the Lower part of the formation, consisting of purplish red shale with interbeds of limestone, was previously called Sanqi Fm (Yamazaki Fm) by Endo (1931), the Manto series by Wang et al (1954), the Yamazaki Stage by Kobayashi (1956), and then the Manto Formation by the No. 2 Brigade of Liaoning Regional Geological Survey Team (1967); Middle part, dominated by micaceous shale and silty shale intercalated with thin-bedded and lenticular limestone, was named the Hualienchai Shale by Kobayashi (1930, 1931), the Shiqiao Fm or the Mopan Fm by Endo (1931), and the Maozhuang Fm by Zhang (1958) and the No. 2 Brigade of Liaoning Regional Geological Survey Team (1967); Upper part consists of yellowish brown shale intercalated with limestone, and was called Dangshi Fm by Endo (1931), the Dangshian Series by Wang et al (1954), the Xuzhuang Fm by Zhang (1958), Lu (1962), and the No. 2 Brigade of Liaoning Regional Geological Survey Team (1967). In eastern Liaoning Province, the Manto Formation has maximum thickness at Dalian, reaching about 350 m, and decreases to only 150 m in the Taizihe River valley northward, where the formation usually contains gypsum.

In Inner Mongolia Autonomous Region, the Manto Formation is exposed mainly in the Qingshuihe River area, where the Lower part of the formation consists of greyish white and pink quartzose sandstone intercalated with purplish red shale, lying unconformably on the Archean gneiss; Middle part consists of purplish red shale, micaceous shale, phosphoric silty shale intercalated with minor sandy limestone, and contains trilobite Probowmaniella; Upper part consists of calcareous fine-grained sandstone and silty argillaceous limestone, intercalated partly with micro-conglomerate, and yields trilobites Inouyops sp. and, Chengshanaspis sp.

In Hebei Province, the Manto Formation rests disconformably on either the Changping Fm or the Precambrian. It is universally in lithologic assemblage of purplish red clastic rock intercalated with carbonate rock, usually containing halite pseudocrystals.

In Shaanxi Province, the Manto Formation is mainly exposed in Longxian, Qishan, Luonan and Hancheng counties and is dominated by purplish red shale, intercalated with dolomite, dolomitic shanle in mid-lower part, with purplish red marlstone, oolitic limestone and siltstone in the middle and lower parts, and with edgewise limestone, calcarenite and instable quartzose sandstone, in the upper part, The formation yields rich trilobites Probowmania, Sunaspis, Proasaphiscus, Inouyops, Wuania, and Redlichia.

In Shanxi Province, most complete strata of the formation are exposed in the Zhongtiaoshan Mountain and the southern Taihangshan Mountain, where the Lower part of the formation consists of grey, dark red argillaceous dolomite, dolomitic marlstone, dolomite and limestone and yields trilobite Redlichia chinensis; Middle part is composed of brick-red, dark purplish red marlstone and shale intercalated with minor interbeds of sandstone and limestone and contains Shantungaspis sp., Probowmaniella sp., and Plesiagraulos sp.; Upper part is characterized by a lithologic assemblage of purplish red shale, intercalated with sandstone, biocalcarenitic limestone and oolitic limestone, yielding trilobites Hsuchuangia, Ruichengella, Ruichengaspis, Pagetia, Eosoptychoparia, and Inouyops.

In Henan Province, the lower part of Manto Formation, lying conformably on the Chushatung Fm, is dominated by marlstone, limestone and dolomite, intercalated with limestone and oolitic limestone, and contains scarce fossils of Redlichia chinensis and R. nobilis. Gypsum and anhydrite are found in a few of localities in Lushan County; Middle part of the formation mainly consists of dark purple micaceous shale and siltstone intercalated with limestone and oolitic limestone, yielding trilobites Yaojiayuella and Shantungaspis; Upper part is composed of limestone, intercalated with shale, siltstone and sandstone and yields trilobites Hsuchuangia, Ruichengella, Pagetia, Sunaspis, Poriagraulos, Inouyia, and Inouyops.

In northern Anhui and Jiangsu provinces, the Manto Formation outcrops chiefly in Huinan and Xuzhou areas respectively, consisting of dark purple shale with interbeds of limestone and yielding trilobites Redlichia, Tingyuania, and Bonnia sp. in the lower part, grey oolitic limestone and silty shale in the middle part, yielding trilobites Shantungaspis, Chittidilla, and Probowmania, and grey, greyish yellow and greyish red dolomitic limestone, limestone, and brownish yellow and purplish red quartzose arkose, intercalated with argillaceous siltstone in the upper part, yielding trilobites Hsuchuangia, Pagetia, and Zhongtiaoshanaspis.