Hujialiang Fm

Lithology and Thickness:

The Hujialiang Fm is divided into three members at the type section. Lower Member is ~15 m gray and yellow loose-cemented (can be locally cemented into hard plates) pebbly sandstones; the sandstone is coarser, mostly medium grain and contains more small gravel; large cross-bedding is commonly seen. Middle Member is interbedded thin layers of light brown and light yellowish brown mudstones; the thickness of this layer is unstable and becomes very thin locally, with a thickness of 0-6 m. Upper Member is ~10 m gray and rust yellow loose-cemented sandstone and conglomerate; the gravels (subangular and 0.3-0.5 cm diameter) are simplely composed of gray neutral igneous rocks, including diorite and quartz diorite; this layer is unstable in lithology and thickness, and may locally become fine sandstone or yellowish-green marl.

Lithology-pattern: Conglomerate

Relationships and Distribution:

Lower contact:

It is conformable with the underlying Dongxiang Fm.

Upper contact:

It is conformable with the overlying Liushu Fm.

Regional extent:

The Hujialiang Fm is distributed in the eastern part of the Linxia Basin, especially in Hezheng and Guanghe Counties. The thickness of Hujialiang Formation varies greatly in various locations. The thickest known is over 50 m at Shilidun, Chengguan Township, Guanghe County; the thickness at Longdan in Nalesi Township, Dongxiang County is 30 m, the thickness at Hujialiang and Zhujiachuan in Maijiaxiang Township, Guanghe County is about 10-20 m, and the thickness at Laogou in Sanhe Township, Hezheng County is only 6 m.

GeoJSON:

Fossils:

Insectivora: Mioechinus sp., Talpidae gen. et sp. indet; Primates: Pliopithecus sp.; Lagomorpha: Alloptox gobiensis, Alloptox guangheensis, Ochotonidae gen. et sp. indet.; Rodentia: Eutamias sp., Atlantoxerus sp., Castoridae gen. et sp. indet., Sayimys cf. obliquidens, Sayimys sp., Gobicricetodon sp., Megacricetodon sinensis, Heterosminthus orientalis, Protalactaga? sp., Eomyidae gen. et sp. indet.; Carnivora: Amphicyon tairumensis, Gobicyon sp., Hemicyon teilhardi, Percrocuta tungurensis, Pseudaelurus guangheensis; Proboscidea: Gomphotherium sp., Serbelodon zhongningensis, Platybelodon granger, Zygolophodon sp.; Perissodactyla: Anchitherium gobiense, Chalicotherium sp., Alicornops laogouense, Hispanotherium matritense; Artiodactyla: Listriodon mongoliensis, Kubanochoerus gigas, Kubanochoerus sp., Stephanocemas thomsoni, Palaeotragus tungurensis, Turcocerus sp. (Deng et al., 2013).

Age:

T. Deng et al. (2019; Neogene chapter of China Integrated Stratigraphy and Timescale) show span of mid-Langhian through Serravallian.

Age Span:

Beginning stage: Langhian

Fraction up in beginning stage: 0.5

Beginning date (Ma):

Ending stage: Serravallian

Fraction up in ending stage: 1.0

Ending date (Ma):

Depositional setting:

It is a fluvial conglomerate deposit.

Depositional-pattern:

Additional information

When Deng et al. (2004) re-subdivided the Cenozoic strata of Linxia Basin, they found that the strata rich in middle Miocene Platybelodon fauna were quite different from the underlying Dongxiang Fm and the overlying Liushu Fm in lithology. Therefore, a new lithostratigraphic unit should be established and named as the Laogou Fm. However, Laogou Fm was once used as a formation name of the Middle Jurassic in the Heilongjiang Basin, but was synonymous with the Qilinji Fm (Wang et al., 2000). According to the new stratigraphic specification, abandoned names should not be used as new stratigraphic unit names. Therefore, Deng (2004) named a set of fluvial facies conglomerate strata above the purplish red mudstone of the middle Miocene Dongxiang Fm and below the red clay of the upper Miocene Liushu Fm in the Linxia Basin as the Hujialiang Fm, and corelated it to the Middle Miocene Tunggurian Stage.