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

Mineralogy and Geochemistry of Mud Volcanic Ejecta: A New Look at Old Issues (A Case Study from the Bulganak Field, Northern Black Sea)

“…The study area is located in the northwestern Kerch Peninsula, on the southern side of the Indol-Kuban Trough (Figure 1) [51,53,59]. The present tectonic framework of the area comprises numerous small W-E folds with curved axes (Figure 1b).…”

“…The Kerch mud volcanoes are currently undergoing a gryphon-salsa activity phase, with moderate gas emanation and expulsion of mud and saline waters. Their features have been exhaustively covered by previous workers [3,18,[59][60][61] and will be left beyond this consideration.…”

“…The highest trace element concentrations were measured in the Bulganak gryphon and salsa waters (B-305-1635 ppm; Li-1.5-8.2 ppm) [18]. Abundant current precipitates growing from the MV waters of the area are chiefly Na-Ca and Na borates (ulexite NaCa(B5O6(OH)6)•5H2O; probertite NaCa(B5O7(OH)4)•3H2O; borax Na2(B4O5(OH)4)•8(H2O); tincalconite Na6(B12O15(OH)12)•8H2O) with lesser amounts of Na-bearing carbonates (gaylussite Na2Ca(CO3)2•5H2O and northupite Na3Mg(CO3)2Cl), and sporadic CaCO3 [18], unlike the calcite-dominated active and dormant travertine springs from the adjacent Big Tarkhan locality [59].…”

“…The respective depths (НMg/Li) of mud volcanic roots, as inferred from these temperatures and measured local geothermal gradients (30-35 °C/km) [66,67], vary from 2.5 to 3.5 km. The ТMg/Li range for the Big Tarkhan travertine springs is 68-78 °C, which corresponds to a depth of 2.0-2.5 km [59]. Compared with the Big Tarkhan and Taman MVs [64,68], those from the Bulganak field expulse fluids from greater depths.…”

“…Compared with the Big Tarkhan and Taman MVs [64,68], those from the Bulganak field expulse fluids from greater depths. The Bulganak mud volcanoes extrude solid material from deep parts of the Middle Maykop section, as it was reconstructed proceeding from the geological setting, drilling data, composition of mud masses [3], micro-palaeontological data [24], and estimates of fluid generation temperatures [18,59]. Earlier results show that waters released by different Kerch MVs are similar to pore waters in the Middle Maykop strata [3,18,24,35,61,63,64].…”