The Generation and Mineral Associations of Rock Assemblages at Mud Volcanoes: Southeastern Siberia A
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ISSN 0742-0463, Journal of Volcanology and Seismology, 2016, Vol. 10, No. 4, pp. 248–262. © Pleiades Publishing, Ltd., 2016. Original Russian Text © A.V. Tatarinov, L.I. Yalovik, S.V. Kanakin, 2016, published in Vulkanologiya i Seismologiya, 2016, No. 4, pp. 34–49. The Generation and Mineral Associations of Rock Assemblages at Mud Volcanoes: Southeastern Siberia A. V. Tatarinov, L. I. Yalovik, and S. V. Kanakin Geological Institute, Siberian Branch, Russian Academy of Sciences, ul. Sakh’yanovoi 6a, Ulan-Ude, 670047 Russia e-mail: [email protected] Received January 29, 2014 Abstract—We consider the main features in the formation of rock assemblages in the southern Siberian Meso- zoic–Cenozoic mud volcanism area that the present writers identified. The related mineral associations and mechanism of generation were found. We identified fluid dynamic regimes of mud volcanoes with different mechanisms of mineral generation, viz., root (chamber) structures of fluid generation, as well as the channels for the transmission of the fluid–rock substratum and of hydrothermal fluids. DOI: 10.1134/S0742046316030052 INTRODUCTION and Cenozoic basins in the Baikal region, as well as for Gas manifestations of mud volcanism in the Baikal soda and salt lakes, and mineral springs (Tatarinov Rift Zone have been known since the 1930s and Abramov, 2001; Tatarinov and Yalovik, 2006). (Ryabukhin, 1933). A gas volcanic feature was identi- Numerous mud-volcanic features have been iden- fied in the Patom Upland and called the Dzhebolda tified in Lake Baikal itself (De Batist et al., 2000; Isaev (Patom) crater. S.V. Obruchev believed that its forma- et al., 2002; Isaev, 2001; Colman et al., 2002), in the tion was related to a breakthrough of gas fluids (Kol- Barguzin basin (Isaev, 2006), and on the Barguzin– pakov, 1951). Chivyrkui isthmus (Dzyuba et al., 2002). Subsequent results from studies of the Patom crater The occurrence of the present-day mud volcanism corroborated the hypothesis of its fluid origin (Antipin has its most intensive form in the Baikal Rift Zone et al., 2011) and gave support to the hypothesis of its (BRZ) during large earthquakes, especially near epi- being one of the gas volcanic (gas–lithoclastic) variet- centers. Catastrophic earthquakes produce numerous ies of mud volcanoes (Isaev et al., 2012). A feature like small gryphon–salse cone-shaped edifices (Solonenko the Patom crater was found in the western Baikal and Treskov, 1960). region (the Levosarminskii crater) (Tatarinov, 1993). This study is concerned with the southern Siberian Occurrences of mud volcanism in the form of salses mud-volcanic region. We show distinctive miner- were discovered in some depressions of the eastern alogic features and indicators of mud volcanoes in Baikal region (Krendelev and Shamsutdinov, 1987; Cenozoic and Mesozoic intraplate riftogenic struc- Krendelev et al., 1988; Frish, 1967). tures and discuss how they came into being. The near-Sayan depression was found to contain basins surrounded by low earth ridges that mark the METHODS OF STUDY craters of mud–volcanic features with spatially and We studied the structural material complexes of the genetically related Fe–Mn mineralization (Tatarinov, Cenozoic, primarily present-day, occurrences of mud 1988). volcanism (Fig. 1). The mud–volcanic origin of the Lower Cretaceous Mineralogic studies were preceded by structural gold-bearing rock sequence in the Balei graben was geological observations to identify structural elements discussed by Gladkov et al. (1989). These authors in mud-volcanic edifices, such as the central hum- established the fact that the Balei ore field is a subver- mock, ring bank, gryphon, salse, compensation trough, tical degassing pipe that was composed of geyserites crater, caldera, and other elements, as well as by a lith- and carbonitized pelite–aleurite–psammite, breccia ologic and petrographic study of ejecta from mud-vol- conglomerate mud–volcanic complexes (Tatarinov canic eruptions. We used heavy concentrate sampling et al., 2011a). of unconsolidated mud-volcanic deposits. Crushed A predominantly mud-volcanic origin has been rock samples of 4–10 kg were used for studying the corroborated for rock assemblages of the Mesozoic mineral composition of travertines, geyserites, and 248 THE GENERATION AND MINERAL ASSOCIATIONS 249 P 12 34 5 12 80 160 240 km Bodaibo 56° B 1 8 7 G L 6 Lake Baikal Irkutsk 5 Chita 52° А 4 11 2 3 9 Zh Ulan-Ude 13 10 102° 108° 114° Fig. 1. A map showing the occurrences of mud volcanism in southeastern Siberia (the South Siberian mud-volcanic region). (1) Cenozoic and Mesozoic riftogenic troughs with mud-volcanic complexes (1 troughs in the Near-Sayan depression, 2 Tunka, 3 Ust’-Selenga, 4 Uda, 5 Kotokel’, 6 Ust-Barguzin, 7 Barguzin, 8 Baunt, 9 Chita–Ingoda, 10 Torei, 11 Unda–Dai, 12 Bodaibo, 13 Gusinoe Ozero); (2) areas of mud-volcanic features studied by the present authors; (3) craters of gas–explosive origin (L Levaya Sarma, P Patom); (4) mud volcanoes in Lake Baikal; (5) deposits of thermal springs (studied by these authors): A, Arshan; B, Baunt; G, Garga; Zh, Zhemchug. lithified sediments. Special attention was paid to bac- minerals from the crystalline basements of the basins terial organic and mineral aggregates that are widely (see Table 1), which were sometimes transported from abundant in the sand and mud deposits of thermal great depths (7–15 km). springs and crater lakes, travertines, and geyserites. We Rounded and oval-shaped massifs of gryphon used several techniques for detection, the study of sands, which are occasionally as high as 200 m, have mineral and rock compositions; ordinary mineralogic areas as large as 400 km2 and occupy 70–75% of the analysis; microprobe, electron microscopy, and X-ray Tunka, Barguzin, and Chara basins. They also com- structural analysis; various kinds of chemical analysis; pose small cones and ridge-shaped uplifts (Fig. 2). and Ram spectroscopy. Gryphon sands make, apart from ridge-shaped and isometric (in map view) massifs, also dike-like, vein- RESULTS AND DISCUSSION shaped, and tubular bodies. One frequently observes patches of secondary stalagmite- and coral-like, crus- The Main Features of the Structures and Rock tose, sulfate carbonate formations at the vents of cold Assemblages of Mud Volcanoes in Southeastern Siberia gas jets (seeps) on the surface of sand massifs (Fig. 3). The overwhelming majority of mud-volcanic com- Carbonitization involves considerable parts of sec- pensation basins (see Fig. 1) are shallow (less than tions of compensation basins, as far as forming traver- 2 km), and the conduits of mud volcanoes penetrate tines and silicate carbonate marl-like deposits (see deep into the Precambrian basement. Their sources Table 1). While sand massifs (diapirs) usually occur on are estimated to lie at depths of 3.5–15 km (Table 1). the tops of Cenozoic mud-volcanic basins, the sec- The ejecta of mud-volcanic eruptions are largely rock tions of sheet-like cone rock assemblages in the older assemblages of the psammite–gravelite–conglomer- (K1) Unda–Dai basin are crowned with geyserite ate dimension, with abundant gryphon sands, whose domes. massifs (diapirs) were called “kuituns” (Florensov, One remarkable feature of the southern Siberian 1960). They were found to contain clasts of rocks and mud-volcanic area consists in a wide abundance of JOURNAL OF VOLCANOLOGY AND SEISMOLOGY Vol. 10 No. 4 2016 Table 1. The main characteristics of mud-volcanic depressions in the southern Siberian region based on materials from Bulin, 2005; Granin and Granina, 2002; Kis- 250 sin, 2001; Krendelev and Shamsutdinov, 1987; Krendelev et al., 1998; Krylov et al., 2008; Kulikova, 1961; Lishnevskii and Distler, 2004; Lomonosov and Lysak, 1967; Lunina, 2009; Mineral’nye vody …, 1961; Moiseenko and Smyslov, 1986; Pospeev, 1988; Shabynin et al., 2002; Shpeizer et al., 1999; Ufimtsev et al., 2008) Geological peculiarities Fluid-dynamic system crystalline basement Structures (parentheses enclose fluid-charged layers, rock assemblages geothermal hydrogeological (age) the age or hypothetical inferred from composition of gas fluids of mud volcanoes characteristics conditions depth to chambers of mud geophysical data volcanoes) Baikal basin 4–15 км – sedimentary Upper parts of sections Baikal–Sukhoi-Log Heat flow 50–100 mW/m2, Bottom waters chloride– Ethane and methane (age) metamorphic rock of underwater mud volca- upper crustal seismic in fault zones it is 115– hydrocarbonate, sodium– (ethane up to 14.9 vol %), sequence and granitoids noes down to about 100 m waveguide zone of thick- magnesium–calcium, pore methane (99 vol % of 155 mW/m2, with up to (Precambrian and Paleo- depth that contained gas ness 2.5–10 km. Wave- 2 waterWater of an underwa- CH4), nitrogen with an JOURNAL OF VOLCANOLOGYANDSEISMOLOGY Vol.10 No.4 2016 hydra-tes, occasionally oil. guide layer 5 km thick 7900 mW/m in zones zoic); 15–28 км – “basaltic ter thermal spring on Fro- admixture of CH4 layer”: Precambrian ortho- Sand aleurolites, mud with the top at depths of discharge of thermal likha mud volcano, water. Temperatures in (up to 5.9 vol %) in gas amphibolites, gneisses, dio- breccia, clay with carbon- of 12–18 km. Electri- hydrocarbonate–sulfate– hydrates. Methane and rites, and gabbro diorites; 28 ates of the rhodochrosite– cally conductive layers in chamber zones of mud sodium. Concentrations of volcanoes – 200–500°C nitrogen of gas jets in км – Moho interface: ultra- siderite family and with depth ranges (km): 6–10, dissolved petroleum hydro- holes in the Baikal ice basite–basite assemblages dolomite. Contain xeno- 10–20, 12–18, 18–28, carbons – 0.02–0.67 mg/L TATARINOV et al. of Riphean (?) stratified genic minerals of crystal- 10–36 massifs: 7–32 км – a frag- line basement (pyroxene, ment of a block of Early olivine, garnet, pla- Precambrian metamor- gioclase, and fuchsite). phosed ultrabasites and thickness of bottom sedi- basites (5.4–15 l km) ments reaches 7.5–8 km Barguzin basin 3.5–15 km – Early Pre- A 1400-m thick section.