Denglouku Fm
Type Locality and Naming
Songliao Basin. The Denglouku Formation was erected by the Comprehensive Study Team of the Songliao Petroleum Exploration Bureau in 1959. The section for the designation was measured at the section 2641-4188 m of Songji No.2 borehole at Denglouku 5 km southeast of Qian Gorlos of the Jilin Province. The reference section is down the borehole No. Songji-2 about 10 km away from Sartu of the Anda City, Heilongjiang. Lowermost formation (1 of 7) in the Songhuajiang Gr.
Lithology and Thickness
The Denglouku Formation is built up by a set of continental microclastic sediments, which is divided in ascending order into four members. First member is built up by light gray and gray white conglomerate and sandy conglomerate. Second member is gray black sandy mudstone differently thick interbedded with gray and gray white clayey siltstone and fine sandstone. Third member is gray white medium and fine-grained sandstone differently thick interbedded with gray and purple brown clayey silt and silty mudstone, with gray green mudstone, locally with calcareous matters. Fourth member is light green, gray and brown sandstone, clayey siltstone and silty mudstone. The Denglouku Formation is 1547 m thick.
Relationships and Distribution
Lower contact
The base of the formation of gray white conglomerate lies unconformably on the light gray tuff of the Jurassic strata. However, in Songliao Basin column, it unconformably overlies volcanics of the mid-Cretaceous (Aptian-lower Albian) Yingcheng Fm.
Upper contact
The top of light green fine sandstone is in conformable contact with the gray brown silty mudstone of the overlying Quantou Fm.
Regional extent
The present formation occurs in the Denglouku-Shuangtuozi area of Qian Gorlos and in the Gongzhuling area of the Huaide County of Jilin. It crops out sporadically in the area north of the Liaoyuan City, Fangmaling of the Shuangyang County, Wangtun of Shulan, Wujiatun of the Lishu County and Wutaizi of the Huaide County. In Heilongjiang it mainly occurs in Anda, Putaohua, Chaoyanggou of Zhaozhou. In the Shuangtuozi area of Qian Gorlos, it is dominated by light gray sandy conglomerate and gravel-bearing sandstone, measuring 362 m thick. In the area of the Fuyu County, it is dominated by gray and dark purple clayey siltstone and mudstone, with a thickness of more than 500 m. In the Wangtun-Wutaizi area on the margin of the basin, it is dominated by yellow brown and gray gravel-bearing sandstone and sandstone, ranging from 325 to 420 m in thickness, called the Xihe Fm by the Jilin Regional Geological Survey Team, which has now been assigned to the Denglouku Formation. In the Gongzhuling area of Huaide County, it is mainly represented by green gray and gray black silty mudstone, tuffaceous arkose, brecciated conglomerate and gray purple mudstone and sandy mudstone, with a thickness of 300 m. In the Erlongshan area of the Lishu County there crop out gray white conglomerate, sandstone, siltstone and mudstone, once called the Erlongshan bed, which has now been also assigned to the Denglouku Formation. In the Yehe area of the Lishu County there occurs a set of gray white clastic sediments, once designated the Yehe Fm, which has now also been assigned to the Denglouku Formation. In the area from the borehole No Songji-6 to Gulong through Putaohua, the rocks of the formation are fine in grain size and dark in color, while in Heiyupao, Erzhao and the east Uplift zone, the rocks are coarser in grain size and the mudstone is mainly red. The formation is 1547 m thick in the Anda and Putaohua areas and exceeds 1018.97 m in the Chaoyanggou area.
GeoJSON
Fossils
It contains plant mega- and microfossils, charophytes, conchostracans, and the brackish-water Vesperopsis zhaodongensis dinocyst assemblage, which has been recorded from the top of the formation. The formation bears the sporopollen assemblage Leiotriletes-Gleicheniidites- Clavatipollenites; floras Asplenium dicksonianum, Sphenolepis dernbergianum, Trochodendroides sp. in Wangtun; and Coniopteris cf. nympharum in Binxian. The formation also yields the Pseudofrenelopsis - angiosperms flora assemblage also identified in the Dalazi Fm, Houshigou Fm and the lower part of the Quantou Fm.
Age
Depositional setting
It is river flat and shore-shallow lake in facies.
Additional Information
Enhanced with Igor N. Kosenko, Jingeng Sha and Boris N. Shurygin (2021). Upper Mesozoic stratigraphy of Sikhote-Alin (Russian Far East) and northeastern China: Non-marine and marine correlations. Part 1: Upper Jurassic-Hauterivian AND 2. Barremian-Aptian. Cretaceous Research, 124: articles 104811 (https://doi.org/10.1016/j.cretres.2021.104811) AND 104812 (https://doi.org/10.1016/j.cretres.2021.104812)