Youfangzhuang Fm

Petroleum Geology Team of Henan Geological Bureau was named in 1960 and quoted publicly for the first time by Henan Geological Bureau in 1965. The named section is located in Youfang Village, Jiyuan County, Henan Province. The reference section is located in Xiankou-Qiushugou, Jiyuan, Henan Province.

Synonym: Shangyoufangzhuang Formation and Xiyoufangzhuang Formation, first developed by Henan Petroleum Geology Team (1960), refer to a set of strata in the lower part of Yanchang Group. Henan Institute of Geology (1962) and Henan District Survey Team (1964) followed this plan, and determined the age as the early Late Triassic. In 1974, the compilation group of regional stratigraphic table in central and southern China combined the upper and lower Youfangzhuang and called it Youfangzhuang Formation, which was of Late Triassic.

Lower member is interbedded with yellow-green feldspar sandstone and purplish gray fine sandstone and claystone. Upper member is medium-coarse feldspar sandstone in apricot yellow thick layer and medium-fine feldspar sandstone interbedded with purplish red claystone. Its thickness is 975.8 m

Plants: Neocalamites carrerei, N. cf. carcinoides, Equisetites, Danaeopsis fecunda, Bernoullia zeilleri, Todites shensiensis, Cladophlebis gigantea