Ganhe Fm
Type Locality and Naming
Jiayin/Hailar Basin region. In 1929 Tan Xichou and Wang Hengsheng erected the Ganhe volcanic series. The reference section is down the borehole No.67-215 east of Ganhe of the Dayangshu Coalfield of Oroqen, Inner Mongolia (124°35′E; 49°46′N => midway between Hailar and Jaiyin basins). Upper formation in Xinganling Gr version in this region.
The Ganhe volcanic series erected by Tan Xichou and Wang Hengsheng represents the volcanic series developed on the east slope of the Da Hinggan Ling, which was defined as Late Cretaceous. In 1973 the No.109 team of the Heilongjiang Coalfield divided the series into two parts. The upper part is called the Ganhe Fm, while the lower coal-bearing strata the Jiufengshan Fm, which have been used continuously until today. During the stratigraphic sorting of Inner Mongolia in 1994, it was considered that the Jiufengshan Fm and the Damoguaihe Fm (of Hailar Basin) are synonymous.
Lithology and Thickness
The Ganhe Formation is consists of greyish-green to green basalts and off-white tuffs and tuffaceous siltstones interbedded with dark-grey conglomerates and dark-grey to black mudstones, silty mudstones and muddy siltstones, occasionally intercalated with yellow shales in the upper part of the formation. It is 403 m thick.
Relationships and Distribution
Lower contact
Its base marked by basalt lies conformably on the underlying Damoguaihe Fm of tuffaceous sandstone (in Hailar Basin); and major disconformity onto Wuying Gr in Jiayin Basin (according to Jiayin Basin stratigraphy column of D.P. Xi et al, 2019, Cenozoic chapter of China Integrated Stratigraphy and Timescale). [HOWVER, the Jiayin basin column of Jingeng Sha in Kosenko et al (2021) does not show a Ganhe Fm, but show a conformable contact onto a volcanic Fuminhe Fm, with a tuff-rich Yongqing Fm below, then the Wuying Gr.]
Upper contact
Its top marked by gray white tuff lies unconformably under the overlying Nenjiang Fm of black shale, or Taoqihe Fm of conglomerate.
Regional extent
The present formation occurs along the Santa Highway, on the right bank of the Heilongjiang river, along the middle reaches of the Wubei River of Oroqen, Ergun Youqi, southwest Manzhouli on the west slope of Da Hinggan Ling, the upper reaches of the Yimin River, Moguai-Haiman-southeast Dayan of the Inner Mongolia, and in Xishan and Yangshutun of the Aihui County, southwest of the Gannan County, Xiaoyushu-Heigangzi of the Longjiang County of the Heilongjiang Province. It is 150-1772 m thick in the Aihui County of Heilongjiang, 665 m in the Gannan County, 150-600 m on the west slope of Da Hinggan Ling, and 330-619 m in Ergun Youqi.
GeoJSON
Fossils
It yields plant fossils, conchostracans, insects including Ephemeropsis trisetalis, bivalves
including Arguniella spp., and fish such as Lycoptera davidi. The formation bears floras Podozamites sp., Ginkgo sp. and Pityophyllum sp.
Age
Depositional setting
It is of volcanic 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)