Gudongjing Gr
Type Locality and Naming
Beishan (Gansu-Inner Mongolia border region). The Gudongjing Gr was named by Xiu Zelei, Zhao Xiangsheng in 1964. The type section is at Hongshankou, north of Gudongjing, Ejin Qi, Inner Mongolia.
Synonym: （古硐井群）
Lithology and Thickness
The Gudongjing Gr is composed of purple-red to grey-green metamorphosed fine clastic rocks, quartzite and sericite quartz schist, sandwiched with marble beds. The group is characterized by obvious rhythmic cycle, rain marks, ripple marks and cross-bedding. It is subdivided into lower and upper formation complexes. Lower formation complex consists of phyllite, quartz schist with quartzite; while the Upper formation complex is meta-sandstone intercalated with marble. The total thickness is recorded to 4638 m.
Relationships and Distribution
Lower contact
The contact with the underlying Dunhuang Gr is unknown.
Upper contact
It has a conformable contact with the Pingtoushan Fm
Regional extent
Beishan (Gansu-Inner Mongolia border region). The group is distributed mainly in the Beishan Mountain area. It is extremely changeable laterally in lithological character, thickness or in metamorphism grade. For example, at Wangxu Mountain and Jixin Mountain in the east it is composed of calcareous sandstone and quartzite (3872 m thick), but at the Wutongjing (1140 m thick) and around Baihu (4730 m thick) in the west, the argillaceous rock increases, and appear marble and siliceous slate; but in Shibanjing (1963 m thick) and Baihu, the intermediate and basic volcanic rock and meta-andesite occur in upper formation complex.
GeoJSON
Fossils
Age
Depositional setting
Additional Information