Lacustrine Deposits of the Upper Permian Pingdiquan Formation in the Kelameili Area of the Junggar Basin, Xinjiang, China

Abstract The groundwater of several regions in Xinjiang, China, including the Kuitun and the Manas River Basins in the Junggar Basin, is heavily polluted with arsenic. However, the arsenic content of the groundwater of the Karamay area located within the Junggar Basin is relatively low and below the recommended drinking water limit. In our study, we analyze the factors that result in this anomaly. The geological and geochemical characteristics of the water-bearing system in this area were investigated by analyzing water samples, carrying out hydrogeological surveys, and statistical techniques. Since the Carboniferous, the geological development and subsequent structural evolution resulted in a lower arsenic concentration in groundwater of the Karamay region than that of the Kuitun River Basin and the Manasi River Basin. The missing high-energy sedimentary environment in the Middle-Upper Permian and the composition of sediments controlled the characteristics of the multi-layer aquifer in this area. We find that the lack of arsenic sources, neutral and slightly alkaline environment, water injection to extract oil, and the Irtysh River Diversion to Urumqi Project, result in better groundwater quality and lower arsenic pollution in this area.

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Geology and geochemistry of bitumen vein deposits at Ghost City, Junggar Basin, northwest China

Geological Magazine ◽

10.1017/s0016756800010712 ◽

1994 ◽

Vol 131 (2) ◽

pp. 181-190 ◽

Cited By ~ 13

Author(s):

John Parnell ◽

Geng Ansong ◽

Fu Jiamo ◽

Sheng Guoying

Keyword(s):

Crude Oil ◽

Junggar Basin ◽

Northwest China ◽

Source Rocks ◽

Late Triassic ◽

Upper Permian ◽

Hydrocarbon Generation ◽

Burial History ◽

Ghost City ◽

Maturity Parameters

AbstractVeins of solid bitumen occur in Cretaceous sandstones at the northwest margin of the Junggar Basin, China. The bitumen has a low aromaticity and a composition comparable to gilsonite. The bitumen contains abundant steranes and terpanes, and β-carotane, although most n- and i- alkanes have been removed, which is characteristic of the local crude oil. The sterane and triterpane maturity parameters show that the bitumen, local crude oil, and source rocks are all mature. Bitumen–wallrock relationships suggest that the host sandstone was not completely consolidated at the time of emplacement of the bitumen veins, although bitumen emplacement was a relatively late diagenetic event. The burial history for the northwest Junggar Basin shows that hydrocarbon generation from the assumed upper Permian source rocks commenced in late Triassic/early Jurassic times and suggests that rapid hydrocarbon generation may have resulted in overpressure contributing to the bitumen emplacement.

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