The Kurai Fault Zone (KFZ) is one of the most hazardous seismogenic structures in the Gorny Altai (Russia), which bounds the largest Kurai and Chuya intermontane basins from the north. Trenching studies, radiocarbon dating of colluvial wedge deposits, and ²³⁰Th-U dating of seismogenic travertine of the Meshtuyaryk field showed that the fault scarp in the northwestern part of the Chuya Depression was formed by earthquakes that occurred ca. 9.5, 7.7, 5.8, and 4.8–3.4 ka BP. The last two palaeoearthquakes are younger than 3.2 ka BP. The parameters of seismogenic ruptures, as well as the distances between coeval seismogenic travertines along the KFZ, yielded estimates of the M_w of the four oldest palaeoearthquakes as 6.8–7.6 and ESI 2007 shaking intensities of VIII–XI. The results of ²³⁰Th-U dating suggest that deposition of the Meshtuyaryk travertines was triggered by three strong palaeoearthquakes at ca. 9.5, 7.7, and 4.8–3.4 ka BP, which activated faults and caused a rapid rise along them of ambient-temperature bicarbonate groundwaters previously sealed in deep-seated limestone aquifers.

10.6084/m9.figshare.21630113

Cite

Citations (0)

Natural analogs of belite sulfoaluminate cement clinkers from Negev Desert, Israel

American Mineralogist (2014)

É. V. Sokol Svetlana N. Kokh Yevgeny Vapnik Vincent Thiéry Sophia Korzhova

Ye'elimite-larnite rocks in the Hatrurim formation of the Negev Desert, Israel, are natural analogs of belite sulfoaluminate (BSA) cement clinkers. They have been produced by ultrahigh-temperature combustion metamorphism at ambient pressure of a calcareous sedimentary precursor. Their mineralogy consists of 35-50 vol% β-Ca2SiO4, 15-20 vol% ye'elimite, 7-15 vol% ferrites, and 15-20 vol% fluorapatite and/or fluorellestadite. A few grains of hatrurite (Ca3SiO5) and α′-Ca2SiO4 have been observed as well. The composition of α′- and β-Ca2SiO4 polymorphs by EPMA are near Ca1.96-1.98Na0.01-0.02 Si0.96P0.03Al0.01O4, whereas ye'elimite has an approximate composition by EPMA of Ca3.99Mg0.02Ba0.01 Na0.02K0.02Al5.73Fe3+0.16Si0.10S0.97P0.02O16. The Al content of brownmillerite Ca2(Fe1-xAlx)2O5 ranges from x = 0.20-0.27. Fe-analog of shulamitite (Ca3Fe2TiO8) contains up to 15.1 wt% TiO2. Ye'elimite-larnite rocks were derived from chalky sediments by burning of combustible gas with a Tmax at 1200-1350 °C. The mineral content, microstructure, and texture/fabric of the ye'elimite-larnite rocks imply that chalky and/or marly sediments with randomly distributed clay, phosphorite, and gypsum may be utilized as cheap naturally homogenized and pulverized mixtures for industrial production of BSA cement clinker, as an environment-friendly alternative to ordinary Portland cement (OPC).

Belite

10.2138/am.2014.4704

Cite

Citations (39)

Rare Earth Phosphates in the Kerch Caviar Ironstones

Russian Geology and Geophysics (2021)

Anna V. Nekipelova É. V. Sokol Svetlana N. Kokh P. V. Khvorov

Authigenic

10.2113/rgg20214359

Cite

Citations (1)

Heavy carbon travertine related to methane generation: A case study of the Big Tarkhan cold spring, Kerch Peninsula, Crimea

Sedimentary Geology (2015)

Svetlana N. Kokh Ye.F. Shnyukov É. V. Sokol S. A. Novikova O. A. Kozmenko

Halite

Isotope Geochemistry

10.1016/j.sedgeo.2015.05.005

Cite

Citations (19)

Mercury Anomaly in Oligocene–Miocene Maykop Group Sediments (Caucasus Continental Collision Zone): Mercury Hosts, Distribution, and Sources

Minerals (2021)

Svetlana N. Kokh É. V. Sokol M. A. Gustaytis

The Oligocene–Miocene Maykop Group sediments, mainly composed of illite–smectite, store mercury in strongly variable concentrations from 10 to 920 μg/kg. Extremely high Hg levels (98–920 μg/kg) coupled with abnormal mercury-to-total organic carbon (TOC) ratios (Hg/TOC = 109 to 3000 μg/kg/wt%; TOC = 0.2 wt% to 1.2 wt%) were measured in the Middle Maykop marine shales that were deposited in the deepwater Indol–Kuban Basin under anoxic conditions. The Middle Maykop shales contain up to 70% of total mercury in sulfide form. In heavy mineral fractions, abundant Hg-bearing pyrite (with up to 4810 µg/kg Hg in hand-picked concentrates) is accompanied by sporadic cinnabar. Relative to the Middle Maykop sediments, the Upper Maykop shales have much lower Hg concentrations and Hg/TOC ratios: 10 to 63 μg/kg (34 μg/kg on average) and 7.7 to 137 μg/kg/wt% (39 μg/kg/wt% on average), respectively. Mercury sequestration is inferred to occur mostly by binding in sulfide hosts in the Middle Maykop anoxic deep-sea sediments and in organic matter, Fe3+-(oxy)hydroxides, and clay particles in the Upper Maykop shales which were deposited in a more oxygenated environment. Mercury inputs to the marine shales during Maykopian sedimentation were possibly associated with local Oligocene–Lower Miocene volcanic activity in the Caucasus Continental Collision Zone. At the same time, the mode of Hg binding in sediments was controlled by redox conditions which changed from anoxic to disoxic and suboxic at the Middle-to-Upper Maykop transition.

Mercury

Cinnabar

Illite

10.3390/min11070751

Cite

Citations (7)