Halas Gr

Altay-Hinggan region. The type section of Halas Group is a composite section, the Baihaba section in Habahe County, Altai Prefecture, Xinjiang Uygur Autonomous Region (87°30’10” E, 48°30’20” N). The section in the east bank of the upper reaches of Haba River lies about 95 km northeast of the seat of Habahe County, and was measure by the No. 6. Brigade of Regional Geological Survey Team of Xinjiang Uygur Autonomous Region in 1980. The Halas Group was first published by Wang and Zhang (1984). The name is derived from Halas (also Kanas or Kanasi) Village close to Halasikule in Burqin County, Altai Prefecture, Xinjiang Uygur Autonomous Region. Originally it was used during regional geological survey in 1978−1979 by No. 6 Brigada of Xinjiang Regional Geological Surveying Team. The geographic name Halas was translated from the local language. It also often translated as Kanas, leading some authors to use the invalid name Kanas Group (e.g. Cai, 1999; Liu et al., 2013; Li et al., 2018). However, the name of Halas Group is valid only in 1984 as Wang and Zhang (1983) had only mentioned the name of the group with no description on its lithotrity and section as well.

Synonym: （哈拉斯群）, Halasi Gr, Kalasi Gr, Kanas Gr

The Halas Group is a marine flysch sequence consisting greyish green, purplish red, thin- to medium fine-grained epi-metamorphic, sandstone and siltstone, which are alternated in non-uniform thickness. It includes cyclothems of thick-, medium- to thin-bedded meta-sandstone, siltstone and minor mudstone intercalated with red purple or dark purple sandstone, siltstone and grayish black shale, locally sericitized or chloritized, part of sandstone with locally microscale cross-beddings and scour structures in sandstone, and some pyrite crystals mudstone. The group has huge thickness and is in lack of marker beds, with oblique bedding in part. The Halas Group is recorded in the type-section outcrop as more than 7760 m

The Halas Group yields well-preserved Sinian microplants: Conusmorpha brevis, Leiofysa biconuta, Leiopsophosphaera solida, Lophosphaeridium acietatum, Taeniatum crissum, Trachysphaeridium planum, Trematosphaeridium holtedahlii, etc.

Marine flysch