Xiariduo Fm
Period:
Triassic
Age Interval:
Middle Triassic (TJ33)
Province:
Xizang (Tibet)
Type Locality and Naming
Rao Rongbiao et al. named in 1987. The named section is located in the summer in Xiariduo, Yuqu Township, Laduo District, Changdu County, Tibet.
Synonym:
Lithology and Thickness
Characterized by a set of gray thick limestone sand shale; the bottom is sandstone. Thickness is 270 to 300 m.
Lithology Pattern:
Clayey limestone
Relationships and Distribution
Lower contact
This formation is unconformable with the underlying metamorphic rocks of unknown age. Regionally, the next older unit is the Jiazhila Fm of Early Triassic.
Upper contact
This formation is unconformable with the purple red clastic rocks of the overlying Upper Triassic Jiapila Fm.
Regional extent
Distributed in Xiariduo, Shanqiongnong, Yuqu Township, Laduo District, Changdu County, Tibet.
GeoJSON
null
Fossils
Age
This formation originally represented the strata in the area of Chengdu, Tibet, between the underlying metamorphic rock series with age unknown and the overlying purplish red clastic rocks, which were mainly limestone, and dated to the Middle and Late Triassic. In 1992, the Chengdu Institute of Geology and Mineral Resources of the Chinese Academy of Geosciences and the Sichuan Regional Geological Survey team changed its age to the Middle Triassic. Schematic stratigraphic section indicates middle Anisian through Ladinian.
Age Span:
Beginning stage:
Anisian
Fraction up in beginning stage:
0.25
Beginning date (Ma):
245.39
Ending stage:
Ladinian
Fraction up in the ending stage:
1.0
Ending date (Ma):
237.00
Depositional setting
Depositional pattern:
The formation is marine sedimentary.
Additional Information
Compiler:
Zhang Shunxin, Yu Yingyue and Tong Jinnan.