The exposed strata in the study area span six stratigraphic communities of Altay, Ertai, Beitashan, Kalamaili, Jiangjunmiao and Bogduo according to the stratigraphic division plan of the northwest region. The oldest exposed strata are the Ordovician. Except for the Lower Silurian, which is not exposed, they are distributed from the Middle Silurian to the Quaternary. Among them, the Late Paleozoic strata are the most developed. See Table 1-1. The strata of each era are briefly described below from oldest to newest.
1. Paleozoic
(1) Ordovician System
The middle and lower Qinghe Group (O1-2gh) is distributed in Chaganguo, northern Ertai Le area is a set of shallow marine flysch-like deposits. The Upper Bastawu Formation (O3bs) and Gaposal Formation (O3j) are composed of terrigenous clastic rocks and carbonate rocks and are distributed south of Gaposal. The Habahe Group (O2-3hb) of the Middle and Upper Series is widely distributed in Fuyun and Qinghe areas. It is a set of shallow marine and coastal facies metamorphic clastic rocks. The middle and upper Huangcaopo Group (O2-3h) is made of siliceous volcanic rocks and is mainly distributed on the southern slope of Moqinwula Mountain and the northern slope of Harlek Mountain in the Paleozoic active continental margin plate of the North Tianshan Mountains.
(2) Silurian System
The Baishanbao Formation (S2b) of the Middle Silurian System (S2b) and the Hongliugou Formation (S3h) of the Upper System distributed at the southern foot of the Kalamaili Mountains are one set Stable coastal and shallow marine facies terrestrial clastic sediments, whose lithology is feldspathic hard sandstone, hard sandy feldspathic sandstone, intercalated with argillaceous siltstone and calcareous sandstone. Contains abundant brachiopod and coral fossils. The thickness is small, the lithofacies and lithology change little, and it has the characteristics of stable continental margin sedimentation. The main lithology of the Middle Silurian Hongliuxia Formation (S2h) distributed on the east side of Hongliuxia is quartz-feldspathic sandstone, siltstone, calcareous sandstone, conglomerate and limestone, etc. It is a set of stable coastal-neritic facies terrestrial sources. Clastic sediments, intercalated with carbonate rocks. The tectonic environment is roughly the same as the southern foot of Kalamaili Mountain. The Kubusu Group (Skp) exposed south of Yema Spring has the same stratigraphy and is of Middle Silurian age. Its lithology is divided into upper and lower parts. The lower part is composed of silty phyllite and strips. Banded siliceous siltstone, mudstone and slate; the upper part is siliceous siltstone, slate and banded siltstone intercalated with andesitic crystal debris tuff and andesite, forming a set of distal fine clastic rocks in the lower part Sandwiched with siliceous rocks, the upper part is composed of terrigenous-volcanic sedimentary rocks. The Upper Silurian Kokselgai Formation (S3k) is distributed in the northern foothills of the Kokselgai Mountains, Dongquan, Beitashan, Sujiquan and other places. Its lithology is tuffaceous sandstone and andesitic crystalline tuff. , biological limestone, tuffaceous siltstone, etc., which is a set of shallow marine volcanic deposits.
(3) Devonian System
The lower Asu Mountain Formation (D1a) and the Zhuomubas Formation (D1zh) are distributed in the Kaoksergai Mountains and Wutong The area around Suyiquan, Kamster, Zhifang and Qiongheba is a set of green and purple-gray pyroxene andesite porphyry, almond-shaped basalt porphyry, crystal lithic tuff, tuff conglomerate intercalated with biogenic limestone and calcareous sandstone. The Dananhu Formation (D1d) is distributed in the West of the Bogdo area, south of the Hongliu Gorge in the Dajia Mountains, and in the Nanshan Mountains of Barkol. It is a set of tuffaceous sandstone, siltstone, sandy conglomerate, calcareous sandy conglomerate, and complex mineral sandstone. , conglomerate interbedded with andesite porphyry, basalt porphyry, fine rock and limestone lenses. The Kangbutiebao Formation (D1k) is distributed along the north side of the Mayin Obo fault and is a set of quartz porphyry, quartz albite porphyry, metamorphic fine rock intercalated with volcanic breccia, volcanic ash tuff and marble. The Central Tuorangge Kuduk Formation (D2t) is a set of shallow marine volcaniclastic rocks-normal clastic rocks, characterized by being rich in calcium. The main lithology is tuff, tuffaceous siltstone, tuffaceous sandstone, calcareous sandstone intercalated with limestone lenses. The Beitashan Formation (D2b) is a deep-sea-shallow-sea-sea-continent alternating sedimentary structure. It is mainly composed of medium-basic volcaniclastic rocks and lava, with a small amount of carbonate rocks and radiolarian-containing siliceous rocks. It is distributed north of Qingshui and the southern slope of Beita Mountain. The Urubas Formation (D2w) is relatively scattered and is mainly exposed in places such as the Haftik Mountains and the south of the Kokselgai Mountains. It is mainly composed of shallow marine-littoral facies clastic rocks, intercalated with carbonate rocks. The properties are coarse sandstone, lithic sandstone, bedded tuff, tuffaceous siltstone, tuffaceous sandstone, phyllitized tuff silty mudstone, fine sandstone, and intercalated limestone lenses. The Zhifang Formation (D2z) is distributed in the south of Utongsu Yiquan and the south of Kokselgai Mountain. It is a set of thin to thick layered coarse sandstone, gravelly coarse sandstone intercalated with conglomerate and limestone masses. The Altay Formation (D2a) is distributed on the north side of the Mayin Obo fault. Its upper lithology consists of gray and dark gray metamorphic fine sandstone, metamorphic siliceous mudstone, metamorphic siltstone, and unevenly interbedded mudstone, interbedded with marbleized limestone, and Sandy limestone lens; the lower part is composed of metamorphic silty mudstone, tuffaceous sandstone, schist and limestone lens. The Tousuquan Formation (D2ts) is mainly distributed in the Gamansu area south of Daga Mountain and Hongliu Gorge. Its lithology is a set of sandstone, siltstone, siliceous slate, phyllite, andesite porphyry, and dacite porphyry. Rock, rhyolite, tuff intercalated limestone lens. The upper Kashion Formation (D3kx) is distributed in Zhaheba, northeast of Ertai, north of Kamster, south of Beitashan, Dahavtik Mountain, Kokselgai Mountain and other places. It is a set of tuff Sandstone, layered tuff, fine sandstone, siltstone, mudstone with limestone lenses and basaltic andesite porphyry, etc. The K'ankuduk Formation (D3kn) is mainly distributed in the Kokeselgai Mountain area and is a set of gray-green volcanic ash tuff, lithic tuff, layered tuff intercalated with tuffaceous conglomerate, sandstone, etc.
The Gyantsil Kuduk Formation (D3j) is scattered in Gyantsil Kuduk, Gamat and other places and is a set of volcaniclastic rocks, tuffs, tuffaceous breccias, tuffaceous sandstones, sandstones, siltstones, etc.
Table 1-1 A brief table of stratigraphic divisions in the eastern Junggar region
(4) Carboniferous system
The lower Tamugang Formation (C1t) is distributed in Tamu Gang, Shuangjingzi and other places are a set of continental normal clastic rock deposits, whose lithology is fine sandstone, medium-coarse sandstone, fine conglomerate and tuffaceous conglomerate. The Heitoushan Formation (C1h) is mainly distributed in the south of Zhaheba, Ertai, and Kokeselgai Mountains. It is composed of argillaceous siltstone, sandy conglomerate, tuff, tuffaceous sandstone, and tuffaceous sandy conglomerate, intercalated with dacite. Tuff and calcareous sandstone, etc. The East Gurubas Formation (C1d) is not widely distributed and exposed sporadically. It is mainly distributed in the Kalamaili Mountains and the Sino-Mongolian border in the northeast, the northern slope of the Moqin Ula Mountains and the Kokselke Mountains. It is composed of a set of muddy Mainly sandstone, intercalated with calcareous sandstone, tuff, crystal lithic tuff, tuffaceous sandstone, etc. The Hebukehe Formation (C1hb) has a small distribution area and is exposed sporadically. It is found from the northeastern side of Beita Mountain to Suhaitu Mountain, Ulusu and Baiyun Mountain. The lithofacies and lithology change drastically, reflecting the extremely extreme depositional environment. Unstable, it is a set of medium-basic volcanic rocks, tuffaceous siltstone, sandstone, phyllite, siliceous rock, limestone, carbonaceous shale, etc. The Nanmingshui Formation (C1nm) is distributed from Beita Mountain, Kalamaili Mountain, Nanmingshui to the eastern Kaoksergai Mountain, Moqinwula Mountain, Santang Lake and other places. It is mainly a set of coastal shallow marine facies normal clastic rocks and volcanic rocks. Clastic rock deposition, the lithofacies and thickness vary greatly from place to place, the lithology is tuffaceous sandstone, hard sandstone, tuff, siliceous slate, intercalated with tuffaceous breccia, calcareous sandstone, feldspar sandstone, sandy conglomerate, gravel Rock and medium-acidic tuff lava, lava breccia, andesite porphyry, volcanic breccia, etc. The Jiangbas Formation (C1j) is distributed on the northern slope of the Kalamaili Mountains. It is a marine-continental alternating normal clastic rock and volcaniclastic rock deposit. It is a set of tuffaceous siltstone, tuffaceous silty mudstone, and tuffaceous fine sandstone. , tuffaceous sandy conglomerate, calcareous sandstone, silty mudstone, clastic rock, etc. The Nalinkala Formation (C1n) is distributed on the northern slope of the Kalamaili Mountains, Almantai and other places. It is a set of marine-continental alternating facies and coastal-continental facies deposits. Its lithology is thin-bedded sandstone, fine sandstone, and feldspathic hard sandstone. , coarse sandstone, layered tuff, tuffaceous sandstone, siliceous mudstone, etc. The Dishuiquan Formation (C1ds) is distributed in the south of Sujiquan, Shuangjingzi and the areas east of it. It is a set of continental normal coarse clastic deposits. The lithology is conglomerate, gravelly coarse sandstone, fine sandstone, siltstone, and carbonaceous. Shale, coal line. The Yamansu Formation (C1y) is distributed in the south of Hongliu Gorge in the Bogdo area and north of Barkol Lake. It is a coastal facies deposit. The upper part is composed of tuffaceous conglomerate, fine sandstone, siltstone, tuff, and layered tuff; the lower part is unevenly interbedded with diabase, basalt, and tuffaceous siltstone, interbedded with tuffaceous sandstone, tuff, siliceous rock, and dacite porphyry. , sandstone, conglomerate and limestone, etc. The Hongshanzui Formation (C1hs) is distributed in the northern part of Qinghe County and is exposed sporadically. Its main lithology is sandstone and slate, intercalated with marl, andesite porphyry and medium-acid volcanic rocks. The Batamayi Neishan Formation (C1b) is widely distributed in the Ertai, Beitashan, Kokselgai Mountains and Kalamaili Mountains. This group is covered by eruption unconformity on various strata. It is continental medium-basic and acidic volcanic rocks and volcaniclastic rocks intercalated with normal clastic sediments. The main lithologies include andesite porphyry, basalt porphyry, rhyolite, and volcanic porphyry. Rock, perlite, interbedded with tuff, volcanic breccia, siltstone, sandstone, conglomerate, carbonaceous siltstone and coal line. The Curideneng Formation (C1jl) is distributed in the northern part of Barkol in the Bogdo area and other places. It is a set of continental, marine-terrestrial alternating sandstone, conglomerate, siltstone, etc. The Middle Arc Liang Formation (C2h) is distributed in Shuangjingzi, Qingjulingshan, Duanjiadi and other places. It is a continental coal-bearing coarse clastic rock deposit, consisting of conglomerate, feldspathic sandstone, carbonaceous siltstone, siltstone, etc. It is composed of sandy mudstone and coal lines. The Shiqiantan Formation (C2s) is distributed in the south of Kalamaili Mountain, Shuangjingzi, Laojunmiao and other places. It is a set of shallow marine clastic rocks intercalated with limestone. Its lithology is silty mudstone, argillaceous siltstone, siltstone, etc. Sandstone, fine sandstone, sandy conglomerate, conglomerate and limestone, etc. The Liushugou Formation (C2ls) is distributed in places such as the north of Barkol and the south of Hongliuxia in the Bogdo area. The upper part of its lithology is thick-massive volcanic breccia, agglomerate, tuff intercalated with andesite and dacite. Porphyry; the lower part is layered tuff intercalated with andesite porphyry, silicate rock, basalt porphyry, siliceous rock, etc. The Qijiagou Formation (C2q) mostly exists together with the Liushugou Formation. It is a shallow marine sedimentary. Its lithology is limestone, marl, argillaceous siltstone, and sandy conglomerate. The middle and lower parts are medium-acidic tuff and volcanic breccia. wait. The upper Liukeshu Formation (C3lk), its distribution is limited to a small area west of Shuangjingzi, consists of coastal facies sandstone, siltstone, mudstone intercalated with conglomerate. The Kongqueping Formation (C3k) is limited to the Kongqueping and Shuangjingzi areas. Its main lithology is medium-thick layered gravel-bearing coarse-grained lithic sandstone, fine sandstone and siltstone interbedded with calcareous siliceous siltstone. The Hamagawu Formation (C3h) is distributed in Beitashan, Kupu and other places. Its lithology is andesitic porphyry, medium-basic tuff, tuffaceous breccia, volcanic breccia and a small amount of basalt porphyry and rhyolite. Porphyry, medium-acidic tuff, etc. The Ortu Formation (C3ao) is sporadically distributed from Bogda Mountain to Dashitou. Its lithology is siltstone, fine sandstone, calcareous siltstone, calcareous conglomerate, sandy limestone, limestone, etc.
(5) Permian
The Lower Permian Lower Jijitao Group (P1jj) is distributed in the Shuangjingzi area on the southern slope of the Kalamaili Mountains. It is a coastal delta-facies sandy Mudstone, sandstone, sandy conglomerate, and marl deposits. The Kalagang Formation (P1k) is scattered in the intermountain depressions in the southern Almantai Mountains, the southwest edge of the Santanghu Piedmont Depression, and other places. The lithology is rhyolitic tuff, rhyolite porphyry, fine porphyry intercalated, and acidic volcanic Clastic rocks, etc. The Aqiqilaq Group (P1aq) is occasionally exposed in the Daga Mountain area. Its lithology is variegated conglomerate, sandy conglomerate, sandstone, basalt, fine rock, rhyolite, with a small amount of mudstone and andesite. The Upper Permian Upper Jijitao Group (P2jj) is distributed on the southern and eastern edges of the Junggar Basin. The lithology is relatively complex and consists of marine and continental alternating phases of sandstone, mudstone, carbonaceous shale, lagoon phase oil shale and coastal phase. Feldspar sandstone, tuffaceous sandstone, tuff, etc. The Jiangjunmiao Formation (P2jm) is only sporadically exposed in the southern part of the Kalamaili Mountains. It is a fluvial clastic rock deposit with lithology of conglomerate, sandstone, sandy mudstone, etc. The Pingdiquan Formation (P2p), whose exposure range is roughly the same as the Jiangjunmiao Formation, is lacustrine and swamp-facies sedimentary. Its lithology is mudstone, sandy mudstone, sandstone, conglomerate, intercalated with carbonaceous mudstone, coal and marl. The Wulabo Formation (P2w), Jingjingzigou Formation (P2jz), Lucaogou Formation (P2l), and Hongyanchi Formation (P2h) are mainly distributed in Santang Lake and its west in the Beitashan area, and in the Bogduo area. Akzal area. The Wulabo Formation (P2w) is a coastal facies deposit, composed of feldspathic sandstone, siltstone intercalated with tuffaceous sandstone, tuff, etc. The lithology of the Jingjingzigou Formation (P2jz) is a set of tuff, tuffaceous sandstone, conglomerate and mudstone. The lithology of Lucaogou Formation (P2l) is siltstone intercalated with black siliceous carbonaceous shale, volcanic ash tuff, oil shale, conglomerate, etc. The lithology of the Hongyanchi Formation (P2h) is mudstone, sandstone, carbonaceous shale intercalated with marl, limestone, etc.
2. Mesozoic The Mesozoic is mainly distributed on the edge of the Junggar Basin in the west of the study area, the Naomaohu-Santanghu Depression Basin in the east, and the Kairen Tuorangge, Barkol, and Dongquan and other intermountain basin areas.
(1) Triassic
It is divided into the Lower Triassic and Upper Cangfanggou Group and the Middle and Upper Triassic Xiaoquangou Group.
The Shangcangfanggou Group is distributed at the southern edge of Kalamaili Mountain, the southern foot of Xiaohafti Mountain and Shuangjingzi area. It is mainly composed of purple and purple conglomerate, followed by sandy mudstone and sandstone. Fluvial and lacustrine sediments. Thickness 192~600m. Produces Sinosemionotusurumchia (fish fossil), Ly sl-rosaurushedini (water dragon), Chasmatosaurus yuandi (keel bone) and ostracod fossils. It is in conformable (locally unconformable) contact with the underlying Upper Permian Lower Cangfanggou Group.
The Xiaoquangou Group is distributed in the southern edge of Kalamaili Mountain. It is mainly made of mudstone, interspersed with marl, thin coal seams, and siderite. It is a swamp facies deposit with a thickness of 88 to 535m. It produces fossils such as brachiopods Planobis dgunariensis and Clad ophlehis sp., and is in integrated contact with the underlying upper Cangfanggou Group.
(2) Jurassic System
The Jurassic System is exposed in a wide range and is distributed in large and small depression basins in the area. It is divided into three series: upper, middle and lower. The Lower Series is the main coal-bearing stratum in Xinjiang, with huge coal seam thickness and stable layers.
1. Lower Jurassic, divided into Badaowan Formation and Sangonghe Formation
The Badaowan Formation (J1b) is fluvial-lacustrine sandstone, mudstone intercalated with conglomerate and coal seams, thick 88~495m. In the Barkol Coal Mine, the thickness of this group is up to 1800m, among which the minable coal seam is 1 to 12m thick and contains bivalve, fish and plant fossils. It is in angular unconformity contact with the underlying Upper Triassic Xiaoquangou Group and old strata.
The Sangonghe Formation (J1s) is fluvial-lacustrine mudstone, sandstone, limestone intercalated with agate conglomerate. The Zhifang and Barkol areas in the east are dominated by conglomerate, with a thickness of 50-800m, and are closely related to the underlying The Badaowan Formation is in conformable (locally unconformable) contact. To the north of Naomao Lake, this formation, together with the Xishanyao Formation in the lower part of the Middle Jurassic, is called the Shuixigou Group, with a thickness of 957m.
2. Middle Jurassic, divided into Xishanyao Formation and Toutunhe Formation
The Xishanyao Formation south of Kalamaili is composed of lacustrine quartz sandstone and sandstone intercalated conglomerate. , coal seams and siderite, and other areas are fluvial and lacustrine sandstone, mudstone intercalated with conglomerate and coal seams, 62 to 385m thick. The thickness of the coal seam is huge. The thickest coal seam in Beishan Coal Mine is 29m. It produces bivalve and plant fossils and is in integrated contact with the underlying Sangonghe Formation.
The Toutunhe Formation, only found in the Santang Lake area, is composed of lacustrine sandstone, siltstone, and mudstone, with local phases changing to conglomerate. It is 455-993m thick and is integrated with the underlying Shuixigou Group. touch.
3. The Middle and Upper Jurassic is divided into the lower Qigu Formation and the upper Karazha Formation
The Middle and Upper Jurassic is mainly distributed to the west of Yanchi. The Qigu Formation is fluvial-lacustrine argillaceous siltstone, sandstone and conglomerate, 103m thick, in unconformable contact with the underlying Middle Jurassic Toutunhe Formation. The Kalazha Formation is composed of lacustrine mudstone, argillaceous siltstone and limestone, contains a large amount of silicified wood fossils, is 140m thick, and is in integrated contact with the underlying Qigu Formation.
The Toutunhe Formation in the upper part of the Middle Jurassic and the Qigu Formation in the lower part of the Upper Jurassic in the south and north of the Kalamaili Mountains and Beitashan are collectively called the Shishugou Group. They are variegated sandy mudstone, Interbedded sandstones, locally intercalated with tuffaceous rocks.
It contains a large amount of petrified wood (giant cypress) fossils and dinosaur (Tienshansaurus chitaiensis) fossils, with a thickness of 123 to 1055m, thin in the west and thick in the east. It is in conformable contact with the underlying Xishanyao Formation in the west, and is in parallel unconformity or unconformity in the east. Disconforming contact.
(3) Cretaceous system
Mainly distributed in the Wucaiwan-Jiangjunmiao and Santang Lake areas, it is divided into the Lower Cretaceous Tugulu Group, the Upper Cretaceous Erichu Formation, the East ditch group.
The Lower Cretaceous Tugulu Group consists of fluvial and lacustrine facies light green dark brown sandy mudstone, siltstone, and fine sandstone. To the north of Naomao Lake, the facies changes to sandstone interspersed with siltstone and mudstone, with a thickness of 116 to 386 m. It contains ostracods, phyllodes, crocodile teeth and plant fossils, and is in unconformable contact with the underlying Karazha Formation of the Upper Jurassic.
The Upper Cretaceous Eric Lake Formation is distributed in the Santang Lake area. It is fluvial and lacustrine facies purple conglomerate, sandstone and argillaceous siltstone, with a thickness of more than 22m. The Donggou Formation is distributed in the Jiangjunmiao and Laojunmiao areas. It is fluvial-lacustrine sandy mudstone, sandstone and conglomerate containing calcareous concretions. It is 1-45m thick and produces dinosaur bone fragments and egg-skin fossils (Qolithes yuguslus, etc.). The underlying Tulu Valley Group is in conformable contact.
3. Cenozoic
The Cenozoic is widely distributed and is very developed in the Junggar Basin, Santang Lake and Naomao Lake Basin.
(1) Tertiary System
The Paleocene and Eocene of the Old Tertiary System are collectively called the Red Gravel Mountain Facies, and the Eocene and Oligocene are collectively called the Ulunguhe Formation. It is composed of lacustrine variegated argillaceous siltstone, feldspathic quartz sandstone and conglomerate, with a thickness of 83m. It contains Eocene mammal fossils and is in unconformable contact with the underlying Upper Cretaceous Eric Lake Formation.
The Neotertiary Oligocene-Miocene-Pliocene system is collectively called the Changjihe Group, which is purple-red to brown-red conglomerate, sandy conglomerate, sandstone, intercalated with gypsum layers and yellow-brown sandy mudstone and mud. Quality sandstone, 187-585m thick, in unconformable contact with the underlying Ulunguhe Formation. To the east of Jiangjunmiao, the upper part of the Changji River Group is composed of brick-red sandy mudstone and siltstone, which is called the Dushanzi Formation, and the lower part is called the Shawan Formation.
(2) Quaternary Series
The Lower Pleistocene is not very developed and sparsely distributed. It is only found on the valley terraces south of Laojun Temple and Beita Mountain. It is a calcareous cemented conglomerate deposited by flood sediments and ice water, with a thickness of 2 to 25m.
Mid-Pleistocene, less distributed, semi-cemented calcareous conglomerate, sandstone and sub-sand soil deposited by alluvial, diluvial and ice-water deposits, 3-26m thick.
Upper Pleistocene, extremely widely distributed, composed of alluvial-fluvial semi-cemented or loose gravel, sand and subsoil, commonly known as "black gravel pebble Gobi", 3 to 100m thick.
Holocene, widely distributed, including alluvial and diluvial gravel, sand, and sandy soil; aeolian sand and sandy loess; lake sedimentary sandy soil and chemically deposited Glauber's salt, salt, etc., at the snow line There are still ice and ice water deposits in the area.
The Quaternary system is in unconformable contact with the underlying Neotertiary system.