Primary dolostone formation related to mantle-originated exhalative hydrothermal activities, Permian Yuejingou section, Santanghu area, Xinjiang, NW China

Abstract

The Permian Lucaogou Formation is an important hydrocarbon source rock in the Junggar, Turpan, and Santanghu basins in Xinjiang, NW China. For the first time, dolostones associated with mantle-originated exhalative hydrothermal fluid flows are discovered in Yuejingou section in the Santanghu Basin area. They include dolomicrite, doloarenite, and a small amount of dolorudite, and are finely (0.05-0.15 cm thick) interlaminated with lime micrite and dolomicritic analcime laminites. Alkali feldspar and analcime grains are common in doloarenite and are interpreted as having been derived from analcime phonolites and peralkaline magmatic rocks. These magmatic fragments were brought up from subsurface by hydrothermal fluid flow and had experienced exhalative brecciation, transport, and deposition on the lake floor. The matrix consists dominantly of dolomite and ankerite smaller than 0.01 mm. The dolostones can be subdivided into four types on the basis of mineral composition and content. The detrital analcime and alkaline feldspar grains and tuff lithics are interpreted as intraclasts, which were deposited in an under-filled starved lake basin. The  18 O PDB values of dolostones are 5‰ to 21.1‰, and 11.9‰ on average; the 87 Sr/ 86 Sr ratios of dolostones are 0.70457 to 0.706194, and 0.705005 on average. These values, in combination with evidence of multiepisodes of peralkaline extrusion, suggest a mantle origin of the hydrothermal fluids, which may have promoted primary dolomite formation. The fluid from the upper mantle caused serpentinization of ultramafic rocks that intruded into the lower crust to obtain Mg 2+ and Fe 2+ , and injected the ions into the lake water as the Mg and Fe sources for dolomite and ankerite. Hydrothermal fluids associated with peralkaline magmatic rocks also provided Ca 2+ , Mg 2+ , Fe 2+ , and CO 3 2 . Explosive breccias formed and dolostones were convoluted near the vent of hydrothermal fluid exhalation, whereas laminated dolostones formed farther away from the vent. The dolostones are primary dolomite deposition in an intracontinental rift basin and associated with mantle-originated hydrothermal fluids. They provide an insight into the origin of dolomite formation in the geologic history and clues to understand the sedimentary environments and tectonic conditions in northern Xinjiang during the late Paleozoic. primary dolostone, mantle-originated hydrothermal exhalative deposits, intracontinental rift, Permian, Santanghu Area Citation: Liu Y Q, Jiao X, Li H, et al. Primary dolostone formation related to mantle-originated exhalative hydrothermal activities, Permian Yuejingou section,

Hydrothermal-sedimentary dolomite — a case from the Middle Permian in eastern Junggar Basin, China

“…7. Dolomites in this study have positive δ 13 C PDB and negative δ 18 O PDB values, similar to those of the two representative hydrothermal-sedimentary dolostones in China, the Cretaceous dolostones in the Jiuquan Basin (Wen et al 2013) and the Permian dolostones in the Santanghu Basin (Liu et al 2012;Jiao 2017). The δ 18 O PDB values of the studied dolostones are in the same range as those of the hydrothermal dolostones in the Jiuquan Basin, in Sardinia in Italy (Boni et al 2000), and in the Western Canada Sedimentary Basin (Al-Aasm 2003).…”

“…Among the paragenetic minerals associated with dolomite in this study, analcime (Zheng et al 2003;Liu et al 2010Liu et al , 2012Wen et al 2013), albite (Zheng et al 2003;Liu et al 2010;Zhang et al 2010) and chalcedony (Tao et al 2016) have all been reported in hydrothermalsedimentary rock studies. Given the diverse genetic types of analcime and scarce reports of buddingtonite, these two minerals are analysed further.…”

“…Nevertheless, hydrothermal-sedimentary dolomites did not become widely known until Zheng et al (2003) claimed, nearly 30 years later, that the Early Cretaceous dolomites in the Jiuquan Basin of China were of hydrothermalsedimentary genesis and belonged to a lacustrine white smoker. Since then, more hydrothermal-sedimentary rocks comprising dolomite and other hydrothermal minerals have been found in Chinese basins (Zheng et al 2006(Zheng et al , 2018Dai et al 2008;Liu et al 2010Liu et al , 2012Zhang et al 2010;Guo et al 2012;Wen et al 2013;Fu et al 2015;Zhong et al 2015Zhong et al , 2018Chang et al 2016;Tao et al 2016;Jiao et al 2017aJiao et al , 2018Jiao et al , 2020Li et al 2017a;Chen et al 2018;Su et al 2020;Yang et al 2020). Generally, hydrothermal-sedimentary rocks are composed of ankerite or ferrodolomite microcrystals; low-temperature hydrothermal minerals, such as zeolite, albite, barite and quartz; and a few metal sulfide minerals, such as pyrite, galenite and sphalerite.…”

Mechanism of Biomineralization Induced by Bacillus subtilis J2 and Characteristics of the Biominerals

“…The biggest difference between biomineralization and general mineralization lies in the participation of bio-macromolecular metabolism, cells, and organic matrix. The product of biomineralization, namely, biominerals, can be carbonate, phosphate, sulfate, sulfide, silicate, hydroxide or oxide, and involve different species of cations such as calcium, magnesium, iron, and/or manganese [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. In the process of bacterially induced mineralization, microorganisms can release metabolic products to react with metal ions in the environment, and the process usually results in the subsequent precipitation of mineral crystals [16][17][18][19][20][21].…”

Biomineralization of Monohydrocalcite Induced by the Halophile Halomonas smyrnensis WMS‐3

“…Calcium carbonate minerals at Earth's surface conditions include the common polymorphs calcite, aragonite, and vaterite, and the less common hydrated phases of monohydrocalcite (CaCO 3 •H 2 O) and ikaite (CaCO 3 •6H 2 O) [15][16][17][18][19][20][21][22][23][24][25][26][27]. It has been reported that monohydrocalcite is metastable compared with calcite and aragonite at all temperatures and pressures [28].…”