Qingtianpu Fm
Type Locality and Naming
Qingtianbao Fm is a set of purplish red clastic deposits distributed in the salt source area of Sichuan, between the Upper Permian Leping Fm and the Middle Triassic Yantang Fm, and its age is the Early Triassic. It was named in 1971 by the Second Team of the First Area Survey Team of Sichuan Geological Bureau. The naming section is located in Qingtianbao, Pingchuan, Yanyuan County, Sichuan Province. After naming, it was adopted by each family (Sichuan District 1 Survey Team, 1974; Sichuan Branch of Regional Stratigraphic Tables in Southwest China, 1978; Research Institute of Sichuan Geological Bureau, 1987; "Regional Geology of Sichuan Province", 1991), but the classification standard is not completely consistent. In 1992, Wang Zunzhou et al. expanded the lithostratigraphy range of Qingtianbao Fm, and classified the purplish red clastic rocks in the lower part of Yuanyantang Fm into Qingtianbao Fm. The top boundary was limited by the large set of limestone of Yantang Formation or the dolomite of Baishan Formation, and its age was limited to the Early Triassic to the Middle Triassic Anisian Stage. The original meaning of Qingtianbao Fm was used in this lexicon.
Synonym: Qingtianbao Fm (spelling), Qingshanbao Fm (spelling). The name "Feixianguan Group" was used before the Xichang Team in 1960 and the First Area Survey Team in Sichuan in 1961
Lithology and Thickness
"Strata are mainly a set of purple, celadon pyroclastic sedimentary rocks, the purple, gray, purple, dark purple, the upper clip in the ash green, yellow, green, etc. - thick layer of fine-grain basaltic lithic sandstone, tuffaceous shale, silty mudstone formation, and in part for the thin layer and massive fine-grain basaltic lithic sandstone and lithic sandstone, purple, dark red, tuffaceous shale, silty mudstone, mudstone. From south to north, the grain size becomes finer and the thickness increases from west to east, generally ranging from 337 m to 980 m. At the bottom is a thick conglomerate, interbedded with gravel sandstone, the gravel composition is dominated by basalt gravel, the thickness of Jiami area of salt source is more than 100 m, and gradually thin towards the east and west ends." [Note: portions of this original English text provided to this on-line lexicon require clarification.]. Lithology and thickness vary greatly. The grain size changes from coarse to fine from bottom to top, from south to north and from vertical to vertical directions.
Relationships and Distribution
Lower contact
"The boundary between the bottom boundary and the underlying Heinishao Fm (Wuchiapinging of early-Late Permian) coal-bearing sand and mudstone is clear." It is mainly underlain by the Leping Fm of Late Permian. [Locally, the underlying unit is the Changxing Fm, also of latest Permian.] The bottom boundary is generally marked by basaltic bottom conglomerate or pebbled sandstone with thickness of more than 10 to 100 meters.
Upper contact
Top boundary to the overlying Yantang Fm is marked by the disappearance of purplish pyroclastic rock. The contact is mostly transitional from purple red to yellow-green, the grain size becomes finer, and the carbonate interlayers increase, and the boundary can be recognized on a macro scale.
Regional extent
Qingtianbao Fm is a set of purplish red clastic deposits distributed in the salt source area of Sichuan.
GeoJSON
Fossils
It contains bivalve fossils Pseudoclaraia wangi assemblage and Eumorphotis inaequicostata assemblage.
Age
Depositional setting
It is interpreted as littoral and shallow sea pyroclastic deposit.
Additional Information