Organofacies and paleoenvironment of lower Carboniferous mudstones (Dishuiquan Formation) in Eastern Junggar, NW China

Zhang, Shengyin; Wu, Tianyu; Cao, Chunwei; Ma, Wanyun; Shi, Jianrong; Sun, Guoqiang

doi:10.1016/j.coal.2015.08.004

Cited by 22 publications

(10 citation statements)

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“…It is generally accepted that Pr/Ph values <1.0 suggest anoxic conditions, whereas oxic environments are generally expected to have high Pr/Ph values >3.0 . The Pr/Ph values (0.09–0.69) in the Batamayineishan Formation is lower than that of the lower Carboniferous Dishuiquan Formation (0.77–1.76) . In this study, these low Pr/Ph values indicate that anoxic conditions prevailed during the deposition of the Batamayineishan Formation.…”

Section: Discussionmentioning

confidence: 55%

“…β-Carotane is generally related with reducing hypersaline lacustrine or highly restricted marine depositional environments . β-Carotane has been widely detected in worldwide sedimentary rocks and crude oils. − This compound has also been reported in the lower Carboniferous Dishuiquan Formation and the upper Permian Lucaogou shales and oils from Junggar Basin. ,, Moderate amounts of β-carotane has been detected in the studied samples (Figure b), further indicating highly anoxic hypersaline stratification during their deposition in the Wulungu area.…”

Section: Discussionmentioning

confidence: 75%

“…T max values are widely used to determine the thermal maturity of OM. ,,− Samples with T max values <435 °C are considered as being immature, whereas the samples with T max values ranging 435–445 °C, 445–450 °C, 450–470 °C, and >470 °C are regarded to be early, peak, late, or post mature, respectively . On this basis, T max values (∼436–566 °C) (Table ) in the studied samples suggest that they are primarily in the early to post mature.…”

Section: Discussionmentioning

confidence: 99%

“…Numerous studies of the geochemistry and chronology of the volcanics from the Junggar Basin have helped to explain the Paleozoic tectonic evolution and continental growth of East Junggar. , Zhang et al determined the hydrocarbon potential and sedimentary environments of sediments from the Dishuiquan Formation in the Wucaiwan area. However, the organic petrological and geochemical characteristics of organic-rich mudstones in the Carboniferous Batamayineishan Formation have not been well documented.…”

Section: Introductionmentioning

confidence: 99%

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Organic Geochemistry and Petrology of Mudrocks from the Upper Carboniferous Batamayineishan Formation, Wulungu Area, Junggar Basin, China: Implications for Petroleum Exploration

Luo

Chen

et al. 2017

Energy Fuels

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The hydrocarbon generation potential of the Carboniferous Batamayineishan mudrocks has been overlooked for a long time. In this study, organic petrology and geochemistry were used to determine the sedimentary environments, organic matter (OM) type, and organic maturity of the Carboniferous Batamayineishan source rocks, collected from outcrops, Wulungu area, Junggar Basin, China. The maceral composition of the studied samples is dominated by vitrinite and inertinite, ranging from 40 vol % to 100 vol % and from 0 vol % to 60 vol % on a mineral matter free basis, respectively. Liptinite macerals, mainly as lamalginites, are only present in trace amounts in several sediments. Vitrinite reflectance values are 0.67% to 2.78%. TOC values are high in these samples, whereas the S1, S2, and HI are very low. Pr/Ph ratios, the plot of Pr/n-C17 versus Ph/n-C18, DBT/P versus Pr/Ph, and ternary of fluorene, dibenzothiophene, and dibenzofuran indicate that anoxic saline environments prevailed during deposition of the Batamayineishan Formation. This is consistent with the presence of β-carotane and high abundances of gammacerane in the studied samples. The major biological source is from vascular plants, and the kerogen type is humic (type III) as indicated by the maceral composition and rock pyrolysis data. The samples from the No. 4 and No. 6 sections occur in the oil window, whereas the other samples are overmature in terms of hydrocarbon generation. The abundant organic richness, humic kerogen, and high thermal maturity demonstrate that these rocks are effective gas source rocks. The volcanics and mudrocks in the Carboniferous Batamayineishan Formation collectively constitute a self-generation and self-storage petroleum system, and represent a main exploration target for gas discovery for the Carboniferous in the Wulungu area.

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Section: Discussionmentioning

confidence: 55%

Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Organic Geochemistry and Petrology of Mudrocks from the Upper Carboniferous Batamayineishan Formation, Wulungu Area, Junggar Basin, China: Implications for Petroleum Exploration

Luo

Chen

et al. 2017

Energy Fuels

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“…Previous studies have also indicated that the organic matter of the Lower Carboniferous source rocks is a mixture of terrestrial and marine types, deposited in strongly reducing conditions (Zhang, Bei, Xuyong, Wei, & Wang, ; Zhang, Wu et al, ). Although the source rocks of the Lower Carboniferous have been the subject of extensive organic geochemistry studies (He et al, ; Zhang et al, ; Zhang et al, 2015), fundamental problems still remain.…”

Section: Introductionmentioning

confidence: 97%

An integrated approach to understanding the depositional environment and organic matter enrichment factor in Carboniferous source rocks, Junggar Basin, NW China

Tao

Qiu

et al. 2018

Geological Journal

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Multiple indicators (trace fossils, trace metals, and δ 13 C org ) are used to assess the depositional environments and controls on organic carbon accumulation in the Lower Carboniferous Nanmingshui Formation, Junggar Basin, NW China. The majority of trace fossils belong to the Nereites ichnofacies, representing low energy, oxygen-poor, and relatively quiet bottom water environments. However, the shallow water trace fossil Planolites also appears in the strata, possibly reflecting variations in the bottom water oxygen contents of the turbidite succession. Redox proxies Th/U, V/Sc, and V/ (V + Ni) reveal variable redox conditions; most of the samples are in the range from suboxic to anoxic depositional conditions. Ni and Cu show a positive correlation with TOC, but U and V have no correlation with TOC, also suggesting the redox conditions were mainly suboxic. The P/Al and Cu/Al ratios of all samples are higher than those of Post-Archean Australian Shales (PAAS), and about two-thirds of the samples' Ba/Al and Ni/Al ratios are close to or higher than PAAS, suggesting the Early Carboniferous Junggar Basin had relatively high palaeo-productivity levels. δ 13 C org values average − 23.75‰, reflecting a mixture of terrestrial organic and marine organic matter. The indexes of Ba/Al, Cu/Al, Ni/Al, and δ 13 C org show good positive correlations with TOC, indicating the palaeo-productivity played an important role for the organic matter accumulation. On the other hand, the TOC correlates inversely with redox proxies (Th/U, V/Sc, and V/(V + Ni)), suggesting the preservation conditions (anoxia) are not the control factor of organic matters accumulation. Using these multiple approaches, our results indicate that productivity was the primary factor controlling organic matter accumulation.

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Geochemistry of organic-rich shales in the Miocene Miadol Formation, Melut Rift Basin, South Sudan: implications for their organic matter input and oil/gas generation potentials

Abass¹,

Hakimi

Lashin

et al. 2021

Arab J Geosci

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Organofacies and paleoenvironment of lower Carboniferous mudstones (Dishuiquan Formation) in Eastern Junggar, NW China

Cited by 22 publications

References 63 publications

Organic Geochemistry and Petrology of Mudrocks from the Upper Carboniferous Batamayineishan Formation, Wulungu Area, Junggar Basin, China: Implications for Petroleum Exploration

Organic Geochemistry and Petrology of Mudrocks from the Upper Carboniferous Batamayineishan Formation, Wulungu Area, Junggar Basin, China: Implications for Petroleum Exploration

An integrated approach to understanding the depositional environment and organic matter enrichment factor in Carboniferous source rocks, Junggar Basin, NW China

Geochemistry of organic-rich shales in the Miocene Miadol Formation, Melut Rift Basin, South Sudan: implications for their organic matter input and oil/gas generation potentials

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