TY - JOUR

T1 - Lower Moscovian Limestones of the Bogdashan Range (NW China) as an Indicator of Cessation of Arc Magmatism in the Junggar Region

AU - Alexeiev, D.V.

AU - Biske, Yu.V.

AU - Djenchuraeva, A.V.

AU - Wang, B.

AU - Kossovaya, O.L.

AU - Zhong, L.L.

AU - Savitsky, Yu.V.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Abstract—: The field revision of the Carboniferous and Lower Permian stratigraphy of the northern Bogdashan (South Junggar, Northwest China) shows that the Lower to Middle Carboniferous island arc volcanic rocks, widely developed in this region, are overlapped everywhere by carbonate and terrigenous-carbonate sediments, containing occasional lava flows and overlain up the section by thick terrigenous series practically devoid of volcanic rocks. The deposition of limestone occurred at the stage of dying off of a volcanic arc, and the question of their age is of fundamental importance for dating this event. Carbonates are represented by facies of lagoons, shoals, and bioherms that formed on the leveled surface of the arc and on the slopes of the last active volcanoes. Bioherms are Waulsortian mounds and are mainly composed of algal limestones and carbonate mud. There are no framestones composed of corals and sponges (chaetetids) typical of the tropical zone. The facies of shallow crinoid-fusulinid limestones typical of the adjacent territories of the Southern Tien Shan and Tarim are poorly represented. Paleogeographically, the position of bioherms corresponds to the northern boundary of the realm of Pennsylvanian reefs. On the basis of foraminifers, brachiopods, and corals, the age of carbonates is early Moscovian (ca. 315–310 Ma). Cessation of island-arc volcanism, followed by the accumulation of limestone in Bogdashan, occurred sub-synchronously with formation of the West Junggar (Bayingou) suture and may reflect docking of the Bogdashan arc to the Yili active margin of the Kazakhstan continent. Further subsidence of Bogdashan and adjacent regions of the Junggar and Turfan basins, which was somewhat slower at the end of the Carboniferous and more intense in the Early and Middle Permian, may reflect the development of the foreland basin that formed along the northern flank of the Tien Shan orogen. Marine facies were locally preserved in this basin until the Artinskian (ca. 285 Ma), and later the Junggar and Turfan basins lost connection to the ocean and developed in continental environments.

AB - Abstract—: The field revision of the Carboniferous and Lower Permian stratigraphy of the northern Bogdashan (South Junggar, Northwest China) shows that the Lower to Middle Carboniferous island arc volcanic rocks, widely developed in this region, are overlapped everywhere by carbonate and terrigenous-carbonate sediments, containing occasional lava flows and overlain up the section by thick terrigenous series practically devoid of volcanic rocks. The deposition of limestone occurred at the stage of dying off of a volcanic arc, and the question of their age is of fundamental importance for dating this event. Carbonates are represented by facies of lagoons, shoals, and bioherms that formed on the leveled surface of the arc and on the slopes of the last active volcanoes. Bioherms are Waulsortian mounds and are mainly composed of algal limestones and carbonate mud. There are no framestones composed of corals and sponges (chaetetids) typical of the tropical zone. The facies of shallow crinoid-fusulinid limestones typical of the adjacent territories of the Southern Tien Shan and Tarim are poorly represented. Paleogeographically, the position of bioherms corresponds to the northern boundary of the realm of Pennsylvanian reefs. On the basis of foraminifers, brachiopods, and corals, the age of carbonates is early Moscovian (ca. 315–310 Ma). Cessation of island-arc volcanism, followed by the accumulation of limestone in Bogdashan, occurred sub-synchronously with formation of the West Junggar (Bayingou) suture and may reflect docking of the Bogdashan arc to the Yili active margin of the Kazakhstan continent. Further subsidence of Bogdashan and adjacent regions of the Junggar and Turfan basins, which was somewhat slower at the end of the Carboniferous and more intense in the Early and Middle Permian, may reflect the development of the foreland basin that formed along the northern flank of the Tien Shan orogen. Marine facies were locally preserved in this basin until the Artinskian (ca. 285 Ma), and later the Junggar and Turfan basins lost connection to the ocean and developed in continental environments.

KW - Bogdoshan

KW - Carboniferous

KW - Junggar

KW - Moscovian

KW - Permian

KW - Rugosa corals

KW - arc magmatism

KW - brachiopods

KW - carbonates

KW - foraminifers

UR - http://www.scopus.com/inward/record.url?scp=85064887348&partnerID=8YFLogxK

U2 - 10.1134/S0869593819010027

DO - 10.1134/S0869593819010027

M3 - Article

VL - 27

SP - 51

EP - 72

JO - Stratigraphy and Geological Correlation

JF - Stratigraphy and Geological Correlation

SN - 0869-5938

IS - 1

ER -