Инд. авторы: | Sokol E.V., Kokh S.N., Kozmenko O.A., Lavrushin V.Y., Belogub E.V., Khvorov P.V., Kikvadze O.E. |
Заглавие: | Boron in an onshore mud volcanic environment: Case study from the Kerch Peninsula, the Caucasus continental collision zone |
Библ. ссылка: | Sokol E.V., Kokh S.N., Kozmenko O.A., Lavrushin V.Y., Belogub E.V., Khvorov P.V., Kikvadze O.E. Boron in an onshore mud volcanic environment: Case study from the Kerch Peninsula, the Caucasus continental collision zone // Chemical Geology. - 2019. - Vol.525. - P.58-81. - ISSN 0009-2541. - EISSN 1878-5999. |
Внешние системы: | DOI: 10.1016/j.chemgeo.2019.07.018; РИНЦ: 41620102; SCOPUS: 2-s2.0-85069571812; WoS: 000501715700006; |
Реферат: | eng: Numerous mud volcanoes (MVs) of the Kerch Peninsula emit water and mud with extreme boron enrichment. Boron content correlates with the burial depth of the source Oligo-Miocene Maykop mudrocks yielding the highest boron contents in illite-dominated mud (up to ~900–1500 ppm B) and clay fractions found in the Bulganak MV, which represent the deep endmembers (up to 3.5 km) in the Kerch Peninsula. Smectite-dominated mud and clay fractions from shallow depths (1–1.5 km) at small MVs are poorer in both illite and boron (66–250 ppm). B-enrichment of the parent shale and diagenetically-driven smectite illitization and dewatering may be main prerequisites for boron enrichment in MVs. The majority of both Cl-HCO3/Na and HCO3-Cl/Na highly evolved saline MV waters sampled in large MVs are enriched in 18O (δ18O = +9.8 to +14.5‰ VSMOW) and D (δD = −30 to −4‰ VSMOW) isotopes being also rich in boron (average 650 ppm). Waters of small MVs with shallow roots are poorer in 18О (δ18O = +3.6 to +6.1‰ VSMOW) and B (average 130 ppm). MV waters are mainly related to diagenetically altered basinal water diluted by 18O-enriched fresh water released during smectite illitization. The fluid generation temperatures inferred to be ТMg/Li = 34 to 117 °С correspond to source depths of 1.0 to 3.5 km, at 30–35 °C/km regional geothermal gradients. In the hot season, MV waters reach a salinity of 40–70 g/L total dissolved solids and precipitate halite, ulexite, borax and tincalconite. At the Bulganak MV field, there is a unique accumulation of MV-related non-marine borates. Such borate deposits can form at the following essential conditions: venting of B-rich MV waters; environment akin to playa lake; long dry and hot seasons; evaporation and ensuing increased boron concentration in shallow close MV pools; pH of MV water between 8.5 and 9.5; low permeability of clayey mud cover. © 2019 Elsevier B.V.
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Ключевые слова: | Mud volcanism; Ukraine; Kerch Peninsula; Crimea; mud volcano; evaporite; continental collision; concentration (composition); collision zone; boron; borate; Boron deposits; Ulexites; Total dissolved solids; Smectite illitization; Mud volcanism; Marine evaporites; Hydrated Na borates; Generation temperature; Continental collisions; Volcanoes; Sodium chloride; Sodium borate; Clay minerals; Boron; Borate minerals; Ulexite; Non-marine evaporites; Boron; Hydrated Na borates; |
Издано: | 2019 |
Физ. характеристика: | с.58-81 |