Active Mud Volcanoes Research Articles

STRUCTURE AND FORMATION OF MUD VOLCANOES IN THE SOUTH CASPIAN BASIN ACCORDING TO SEISMIC DATA

The South Caspian Basin (SCB) constitutes a classic province to study mud volcanoes and their associated processes. About 280 active mud volcanoes have been documented in the offshore and the onshore areas of Azerbaijan, emitting water, hydrocarbons (oil and mainly methane), and fluidized muds that transport solid fragments from deep sedimentary sequences. Seismic characteristics of mud volcano systems in the Azerbaijan area of the SCB are used to address: (1) the nature of the mud volcano source layer, (2) the internal geometry of the feeder systems, and (3) the processes associated with shale mobilization and extrusion. We confirm that the source layer is mainly the Maykop Suite (Oligocene–Lower Miocene), which is a thick (up to 3 km) and deep (>10 km) clayey sequence rich in organic matter. This layer was quickly buried due to basin subsidence and the rapid deposition (since the Middle Miocene) of thick fluvio-lacustrine sediments of the Productive Series (Upper Miocene–Upper Pliocene), which contributed to the creation of high pore pressures and the transformation of organic matter into methane (through thermal cracking). Since the Middle Miocene, and more importantly during the Upper Pliocene, the Maykop shales mobilized due to an increase in shear stresses and pore pressures, which promoted a decrease in effective stresses and, as a consequence, facilitated the achievement of critical state conditions in the shales that began to flow. This process repeated over time, allowed multiple pulses of shale mobilization to originate (as in a loading piston system). Shale piercing transporting deep-sourced fluids (and hydrocarbons) was carried out through fractures in the outer arc of anticlines, forming subvertical feeder systems. The mobilized hydrocarbons and fluids also recharged some of the younger and more permeable layers of the Productive Series, creating shallower reservoirs in the vicinities of the mud volcano structures.

INNOVATIVE ANALYSIS OF MUD VOLCANO PATTERNS IN WESTERN AND SOUTHWESTERN PAKISTAN THROUGH SATELLITE IMAGERY

Mud volcanoes are geological features formed due to pressurized mud, water, gases accompanied by rocks that are expelled to the surface from underground. In Pakistan, there are more than 80 mud volcanoes. However, there is a lack of extensive, thorough mapping and analysis of Pakistan's mud volcanoes in the West and Southwest utilizing satellite image technologies. The present study aims to locate various clusters in South Western and Western regions of Pakistan, and to make a laboratory scale and conceptual model of mud volcanoes in this region to understand the underlying geological and tectonic processes. Firstly, we have used high-resolution satellite images to demarcate and identify various clusters and individual mud volcanoes. Secondly, mud volcanoes of a lesser-known western segment of Pakistan are the unexplored Pishin Basin (Qila Saifullah, Babu Cheena, Zhob). These mud volcanoes occur in distinct patterns which is the regional trend of Makran subduction zone and Pishin Basin. These mud volcanoes occur in clusters (Hingol National Park), and follow the regional structural trend of lineaments. Tracing these lineaments can help in the identification of more mud volcanoes. These active mud volcanoes release methane and hydrocarbons along with mud and water and can be identified by changes in the tone, and texture (Ormara) of the satellite image. However, few fossil or extinct mud volcanoes still have eroded (Gwadar) craters and are relatively diminished in size (~50m). They exhibit a wide variety of surface structures extruding gas and sometimes with bubbles having viscous hot fluid of mud. It could signify the presence of hydrocarbons beneath the surface. Chandragup mud volcano is an attractive place for Hindus, as they consider it a holy place. They are also important as a geoheritage and tourist sight and can generate significant revenue. Hingol National Park is a captivating site for those all over the world who adore to grasp nature thoroughly. These are significant as similar settings in other countries like Azerbaijan, Romania and New Zealand hold immense petroleum, geoheritage, geotourism and geothermal potential.

Influence of geotemperature conditions on the oil and gas potential of the South Caspian depression (the case of the Lower Kura depression and Baku archipelago)


 
 
 In the article, the oil and gas potential of the deep-lying sediments of the Lower Received in revised form 13.08.2023; Kura depression and the Baku archipelago, which are geostructural elements of the South Accepted 13.11.2023 Caspian depression, are investigated according to the geotemperature conditions. The main aim of the research is identifying the oil-gas «windows» in the 22-24 km thick sedimentary rock complex of the South Caspian depression based on the geothermal factor. Using temperature values measured at different depth sections in different structures of the Lower Kura depression and Baku archipelago, temperature distribution maps of the area and a graph of changing temperature by depth were constructed. According to the geothermal maps constructed for the Lower Kura depression, a relatively high temperature value is observed in the north-west part of the area. This anomalous value is related to the location of active, periodically erupting mud volcanoes, which play an important role in temperature distribution, as well as local uplifts, which are more complicated by tectonic landslides and upthrusts. At great depths (5,500-6,500 m) within the research region, almost everywhere, anomalously high pore and reservoir pressures are observed, which create the conditions for the manifestation of tectonic-physical processes and the generation of great energy affecting the oil and gas potential of the area. In all the geotemperature maps constructed for different depth intervals in the Baku archipelago, high temperature values are observed in the north zone where the Sangachal-deniz-Duvanni-deniz-Khara-Zira island and Alat-deniz structures are located. This is due to the complication of uplifts by active mud volcanoes, which play an important role in the formation of local heat sources. The Khara-Zira island mud volcano, the largest in the Baku archipelago, is also located here. Based on the analysis of the temperature values in the research areas, a decrease in the temperature values is observed due to increase in the thickness and the clay content of the sedimentary layer in the direction from the Lower Kura depression to the South Caspian basin. The temperature is 990C at 5,000 m in the Lower Kura depression, 900C in the Baku archipelago. So, a decrease in temperature is characteristics for all depths. The analysis of the compiled graphs shows that the top of the main zone of oil formation in the Lower Kura depression starts at a depth of 2,000-2,500 m, and the lower limit is located at a depth of about 9,000 m (1500 C). The top of the main zone of oil formation in the Baku archipelago starts at a depth of 3,000 m, and the lower limit is located at a depth of 9,000-11,000 m. So, it shows that as the oil and gas formation sources the potential oil source rocks in the Lower Kura depression and the Baku archipelago at the depth range from 2,000-2,500 m to 8,000-11,000 m can produce industrially important oil and gas.
 
 

Geochemical proxies of the gryphon breccia of mud volcanoes in East Azerbaijan: regularities in the distribution of chemical elements and spatial characteristics of sedimentation

The paper is devoted to the study of the patterns of distribution of major oxides and trace elements in the gryphon breccia of 12 active mud volcanoes located in various oil and gas regions (Absheron, Gobustan and Lower Kura) of Azerbaijan. Interpretations of the chemical elements found in gryphon breccia samples have allowed the composition of their source rocks, sedimentation conditions, and sedimentation areas to be determined. Purpose. The main goal of the study is to conduct geochemical studies of gryphon breccias belonging to various oil and gas regions, determine spatial patterns, achieve their explanation, and at the same time determine the conditions for the deposition of mud sediments. Methods. The chemical composition of mud volcanic breccia samples was analyzed using an “S8 TIGER Series 2” spectrometer and an “Agilent 7700 Series ICP-MS” mass spectrometer. Based on the results obtained, in addition to identifying patterns in the areas, modern approaches based on geochemical interpretation were used to explain them. The results on the genesis of breccias are consistent with the results of the published literature on the development of geodynamic and paleobasin conditions in the region. Results. Samples with the lowest Si content are characteristic of the Lower Kura mud volcanoes, where the youngest (Quaternary) deposits are recorded. In samples from these mud volcanoes, relatively high contents of Mg and P are also noticeable. High contents of Ca are characteristic of volcanoes located near the Caspian Sea. These mud volcanoes are also rich in trace elements such as Li, Ga, Rb, Zr, Mo, Cs, Pr, Tl, Pb, Th, U and others, but depleted in Ni, Sr, Ba and etc. Conclusions. Plagioclase-rich source rocks and oxygen-dominated paleobasin environments played a key role in the formation of breccia deposits belonging to the mud volcanoes of Azerbaijan. Geochemical proxies make it possible to link the paleobasin conditions of the formation of the gryphon breccia of the most mud volcanoes of South and Central Gobustan with the continental setting, especially in comparison with some volcanoes of the Lower Kura, as well as Gobustan and Absheron, located on the shores of the Caspian Sea and relatively close to it. The breccias of mud volcanoes located at a relatively large distance from the modern sea boundary and in the steepest northern part of the Lower Kura are associated with marine conditions, as are breccias of mud volcanoes located in the south of this tectonic zone (subjected to intense subsidence) and at a short distance from the Caspian Sea, may be due to geological factors.

Gravity Data Allow to Image the Shallow‐Medium Subsurface Below Mud Volcanoes

AbstractThe debate about the conceptual model of mud volcanoes functioning is still alive in the literature. A large part of the literature focuses on the characterization of the deep reservoir where expelled fluids are expected to originate. Another part of literature is focused on the study of the shallow system of mud volcanoes, which could influence the short‐term variations in mud volcanoes activity. We present and analyze a new data set of micro‐gravimetric data to study the area of the Nirano Salse, Italy. Unlike what is commonly assumed for the study area, our results suggest that the geomorphology of the Nirano Salse is not related to a caldera collapse above a shallow mud chamber, but to the surface expression of slip distribution of a fault termination along which the fluids ascended to the surface. We believe that gravimetric data can significantly improve the study of hydrocarbon seeps and mud volcanism.

Rare Earth Element Characterization of Bledug Kuwu Mud Volcano, Central Java, Indonesia, based on Geochemical Analyzes (Susceptibility, XRF, XRD, SEM-EDS and ICP-EOS)

Mud volcano material is generally rich in oxides, while oxides are the main compounds forming rare earth elements. Bledug Kuwu, Central Java, Indonesia, is one of the active mud volcanoes, so there may be rare earth elements. This research is the characterization of rare earth elements (REE) in the Bledug Kuwu mud using magnetic and geochemical methods. Magnetic characterization uses magnetic susceptibility measurements. The geochemical characterization of the mud samples consisted of the XRF (X-Ray Fluorescence), XRD (X-Ray Diffraction), ICP-EOS (inductively coupled plasma) test, and the SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy) test. The results of the geochemical analysis of the Bledug Kuwu mud sample were the content of quartz, kaolinite, and calcite with an average concentration of 42.26%, 23.67%, and 33.96%. The susceptibility of Kuwu's mud is 0 because the concentration of metal elements is low; according to the results of XRF, XRD, and SEM tests identified the main mud elements as C, O, Si, Ca, and Al. The rare earth elements in Kuwu's mud are Ce, Dy, Eu, Gd, Ho, La, Nd, Pr, Sm, Tb, Y, and Sc. The highest concentrations were Ce 52.22 ppm and La 47.95 ppm.

Analysis of structural-tectonic and petrophysical features of productive horizons of Mishovdag fold


 
 
 The article analyzes the geological structure, lithofascial, tectonic, and morpho- logical features of the Mishovdag oil field, which is a productive area in terms of oil content. Morphologically, it represents a brachianticlinal fold located in the north-west and south-east directions. The Mishovdag fold is located on the Kalamaddin-Bandovan anticline zone between the Kichik Harami (in the northeast) and Galmaz (in the northwest) structures. The Mishovdag-Galmaz part of the anticlinal zone extends in the sub-southern direction. The structures included in the zone are represented on the surface mainly by Aghjagil, Absheron, and ancient Khazar sediments. Productive layer sediments come to the surface in few areas. The tectonic movements and activity of mud volcanoes (active or buried) have left characteristic traces in the geological structure of the research area. Brachianticlinal and other types of structures were formed here. Under the strong influence of tectonic movements, the layers forming them were deformed and broken into blocks by regional tectonic faults. The anticlinal structures of the zone are complicated by longitudinal and latitudinal faults. The Mishovdag fold is represented by a brachianticline, 20-25 km long and 4-6 km wide. Brachianticline has a sharply asymmet- rical structure. The southwestern limb is steep, and inclined at an angle of 25-450, while the northeastern limb is flat and characterized by an inclination angle of 7-250. As a result of the analysis of the cross-sections of deep wells drilled in the field, it was determined that Mesozoic, Paleogene-Miocene, and Pliocene-Anthropogenic sediments are developed in the section of the fold. Sediments repre- senting the cross-section are characterized by high reservoir properties. Geological-geophysical works are carried out in the field. Core materials were taken from wells. The lithological-petrophysical characteristics – carbonate, porosity, and permeability of reservoir rocks have been determined according to core samples taken from exploration wells drilled in the field. The lithological-petrophysical characteristic regularities of change were investigated depending on depth.
 
 

Новые данные об интенсивной дегазации Земли в Арктике на севере Западной Сибири: термокарстовые озера с кратерами выбросов газа и грязевыми вулканами

In the last decade, in the north of Western Siberia, the authors carried out a large amount of comprehensive research, which made it possible to obtain fundamentally new information about the gas-dynamic mechanisms of dangerous processes in the Arctic permafrost. According to remote sensing data, at the bottom of thermokarst lakes, rivers and coastal zones of the Kara Sea, more than 4.5 thousand zones of powerful gas blowouts with the formation of craters (pockmark) were found. There are reasons to believe that powerful gas emissions mainly come from shallow deposits with ultrahigh (superlithostatic) pressures. For the first time, large mud volcanic uplifts with pronounced craters have been found at the bottom of the Arctic thermokarst lakes. Based on the monitoring of the ice situation and the water environment on the basis of retrospective satellite images on lakes Otkrytie, Labvarto and Yambuto, the presence of periodic emissions of formation fluids, including gas, is shown. Based on the combination of a number of features, the discovered objects can be classified as active mud volcanoes with a high level of probability. The results of the studies allow us to state that mud volcanism is widespread in the Circum-Arctic megaregion.

NEW DATA ON MUD VOLCANISM IN THE ARCTIC ON THE YAMAL PENINSULA

A wide range of geological and geophysical methods was carried out on the Yamal Peninsula in the Arctic in the period 2014–2022. The results were analyzed together with data from remote sensing of the Earth. Fundamentally new data on the gas-dynamic mechanisms of dangerous processes in permafrost have been obtained. These data included catastrophic gas blowouts and explosions with the formation of giant craters. More than three thousand zones of powerful gas blowouts with the formation of craters at the bottom of thermokarst lakes, rivers, and the coast of the Kara Sea have been discovered. According to data on remote sensing of the Earth, large mud volcanic structures, located at the bottom of the Labvarto and Yambuto thermokarst lakes, were discovered on the Yamal Peninsula in 2022–2023 for the first time. Monitoring of their state with the use of retrospective satellite images showed the presence of periodic release of underground fluids, including gas. A conclusion was made about the discovery of active mud volcanoes on the Yamal Peninsula

Surface Geology Analysis on the Relationship between Fault Creep and Overpressure in Grobogan, Central Java, Indonesia

The Grobogan Regency is a significant location for oil and gas exploration due to its proximity to active oil and gas fields. Geologically, this area is intersected by the Kendeng thrust fault and exhibits several surface manifestations of mud volcanoes near the fault. However, there have been limited studies examining the activity of the Kendeng thrust fault and its relationship to overpressure and earthquakes, which could affect oil and gas exploration and natural disaster mitigation in the region. This paper focuses on utilizing surface geological mapping data and Interferometric Synthetic Aperture Radar (InSAR) data to analyze the relationship between fault creep and overpressure manifestations in Grobogan, Central Java. While continuous research on fault creep has been conducted since the 1960s on the San Andreas fault in the United States, there has been a lack of continuous research on onshore fault creep in the Northeast Java Basin or Kendeng Basin, particularly in the Grobogan area. This region, known for its abundance of active mud volcano manifestations, is predominantly characterized by marl and clay lithology. It represents a warm basin environment that is prone to overpressure and ideal for fault creep occurrences.To investigate further, fluid, gas, and mud samples were collected from the mud volcanoes, along with rock samples from the surrounding area, for comprehensive laboratory analysis. The integration of these sample analyses aimed to determine the correlation between the activity of the Kendeng thrust fault creep and the subsurface overpressure conditions. While this study observed several indications of creeping in the vicinity of InSAR anomalies, the exact location of the creeping fault plane could not be definitively determined. The Kendeng thrust fault exhibits the three main factors necessary for initiating fault creeping. The fault segment’s extremely slow creeping may be linked to the activity of the mud volcanoes, as indicated by the results of fluid, gas, and rock sample analysis. The findings of this research hold potential for informing the development of oil and gas fields, as well as enhancing the mitigation of natural disasters associated with oil and gas exploration and earthquakes in the region.

Origins of sediments and fluids in submarine mud volcanoes off Tanegashima Island, northern Ryukyu Trench, Japan

Mud volcanoes are topographic features through which over-pressurized sediments are intruded upward and erupted, transporting fluids and sediments from the deep subsurface to the surface/seafloor. To understand material and biogeochemical cycling through mud volcanoes, we investigated the origins of sediments and fluids erupted by four submarine mud volcanoes off Tanegashima Island, along the northern Ryukyu Trench: MV#1–3 and MV#14. We estimated the ages of the source sequences of the mud volcano sediments to be middle to late Miocene based on nannofossils and 10Be ages. The sediments were characteristically enriched in illite. The similar mineral compositions and vitrinite reflectance values (0.42%–0.45%) of sediments erupted by the mud volcanoes strongly suggest that each is rooted in the same source sequence. Pore waters had Cl− concentrations ∼40% that of seawater and were proportionally enriched in 18O and depleted in D, indicating the addition of freshwater from the dehydration of clay minerals. However, the smectite and illite contents (<40%) in the clay size fraction ruled out in situ smectite dewatering as the cause of the pore water Cl− dilution. Thus, fluids derived from clay dewatering must have originated from deeper than the source sequence of the mud volcano sediments. Vertical Cl− profiles indicate that the upward fluid advection rate and eruption frequency decrease from MV#3 to MV#2, MV#1, and MV#14 (MV#14 being dormant). At the active mud volcanoes, the C1/C2 ratios (<100) and methane δ13C values (−56‰ to −42‰) indicate that hydrocarbon gases are mostly derived from the thermal decomposition of organic matter in deep sediments where the in situ temperature exceeds 80°C. At the dormant MV#14, high C1/C2 ratios (700–4,000) and low methane δ13C values (ca. −75‰) suggest the limited supply of thermogenic methane and the subsequent shallow methanogenesis. Because vitrinite reflectance values indicate that the source sediments are too immature to produce thermogenic hydrocarbons, the hydrocarbon gases, like the fluids derived from clay dewatering, were probably supplied from deeper than the source strata. The supply of deep fluids into the source sequence might be a universal phenomenon in subduction zones, and may play an important role in mud volcanism and associated biogeochemical cycling.

Multidisciplinary Study of Mud Emissions Following the 2016 Norcia Earthquake

We report composition, grain size, and rheological data related to the mud emitted as a consequence of the maximum moment magnitude (Mw max = 6.5) on 30 October 2016, commonly referred to as the Norcia earthquake (central Italy), and on the activity of pre-existent mud volcanoes affected by the central Italy seismic sequence started on 24 August 2016. The emission sites were located at Monteleone di Fermo and Santa Vittoria in Matenano, two municipalities near the town of Fermo (Marche Region, Italy). We sampled, measured, and analyzed the products of mud emissions 3 days after the mainshock to characterize the mud by geochemical, mineralogical, and rheological analyses. The muds’ geochemical composition and low electrical conductivity suggest a continental origin, likely belonging to the Colombacci Formation. The collected muds are silt–sand–water-rich suspensions characterized by a Bigham rheology with viscosity values between 6.3∙107 and 6.9∙105 Pa∙s. The calculated minimum fluidization velocity of the mud suspensions is between 0.05 m/s (grain size of 2 μm) and 0.74 m/s (grain size of 8 μm). Water-rich mud suspensions flowing on a slope move faster as the water content increases up to 30 wt.%. At higher values, the velocity remains almost constant due to the disaggregation of bonds among the solid particles in the mixtures.

Tracing Water–Rock–Gas Reactions in Shallow Productive Mud Chambers of Active Mud Volcanoes in the Caspian Sea Region (Azerbaijan)

We present geochemical and mineralogical datasets for five new mud volcanoes in continental Azerbaijan (Hamamdagh and Bendovan) and the adjacent Caspian Sea (Khara-Zire, Garasu and Sangi-Mughan). The fluid ejects have a Na–Cl-type composition and are generated by the mixing of evaporated Caspian seawater and low- to high-salinity pore waters, as indicated by Br–B and Cl–B systematics and Na–K and SiO2 geo-thermometers. The fluids contain high concentrations of As, Ba, Cu, Si, Li, Sr and Zn (60 to 26,300 ppm), which are caused by surface evaporation, pyrite oxidation, ion exchange reactions and hydrocarbon maturation in Oligocene-Miocene ‘Maykop’ shales. The solid ejects comprise liquid, oily and brecciated mud, mud/claystones and sandstones. The mud heterogeneity of the volcanoes is related to the geological age and different sedimentological strata of the host rocks that the mud volcanoes pass through during their ascent. All ejects show evidence of chemical alterations via water–rock–gas reactions, such as feldspar weathering, smectite illitization and the precipitation of Fe-(hydr)oxides, calcite, calcian dolomite, kaolinite and smectite. The studied localities have petrographic similarities to northern extending mud volcano systems located on Bahar and Zenbil islands, which suggests that mud volcanoes in the Caspian Sea region are sourced from giant shallow mud chambers (~1–4 km depth) located in Productive Series strata. Our results document the complex architecture of the South Caspian Basin—the most prolific hydrocarbon region in the world.

Deformation Signals at Mud Volcano in Kambing Island Detected by L-band InSAR

Abstract – Mud volcanoes are generated by fluid and solid material extrusion from their mud reservoir and are predominantly found at convergent plate margins. Kambing Island is a small island in Eastern Timor, Indonesia, where the Australian continental plate collides with the Banda Sea plate. The previous geological study identified active mud volcano on this island, but it is still unclear whether and to what extent they are active. In this work, we attempt to detect surface deformation due to the mud volcanoes activism in Kambing island using the Advanced Land Observing Satellite/ Phased Array Type L-band Synthetic Aperture Radar (ALOS/PALSAR) Interferometry Synthetic Aperture Radar (InSAR). The ALOS/PALSAR datasets consist of 12 ascending and 5 descending Synthetic Aperture Radar (SAR) data from 2006 to 2011. Although the results indicate surface deformation signals are hardly detected in the interferogram pairs due to lost coherence and atmospheric noise, we could highlight the episodic occurrence of surface deformation signals between April and November 2008 reaches 6.4 cm moving away from the satellite line of sight. In the future, to back up our findings, further field surveys or long-term InSAR are needed. Keywords: mud volcano, InSAR, deformation.

Влияние космических факторов на грязевулканическую деятельность Земли

In this work, the influence of various cosmic factors (gravitational influence of the Moon and the Sun, solar activity, the Earth’s rotation) on mud volcanic activity was analyzed for the first time. The analysis was carried out mainly on the example of mud volcanoes in Azerbaijan, for which there is the largest and most complete catalog of eruptions (431 events over almost 210 years). It has been found that the activity of mud volcanoes can increase after syzygial tides, when the Earth is in line with the Moon and the Sun (their tidal forces are summed up in this case). The response of mud volcanoes to the tidal influence of the Moon is delayed by 5–10 days. It is also found that the number of mud volcanic eruptions is distributed unevenly throughout the year with maximums in March–June and September–October. The presence of these maximums may be due to a change in the distance between the Sun and the Earth and variations in solar tidal forces during the periods of perihelion and aphelion. At the same time, the response of mud volcanoes to the tidal influence of the Sun is delayed by several months and is quite strongly extended in time. It was revealed that there are fluctuations in mud volcanic activity with a period of 14–20 years, which do not coincide with the cycles of solar activity (with periods of 11 and 22 years), although some researchers talk about a connection between solar and mud volcanic activity. It is possible that the indicated fluctuations in mud volcanic activity are related to the main harmonic of the Earth’s nutation (18.6 years). It is shown that the maximum number of mud volcanoes on the Earth falls on the latitudinal belts of 30–45° N and 10–15° N (about 22 and 46 % of the total number of volcanoes, respectively). In the southern hemisphere, the largest number of volcanoes (about 3 % of their total number) is located within the boundaries of 5–10° S.

Thermal structure and sediment bulk density of the MV420 mud volcano on the continental slope of the Canadian Beaufort Sea and its implications for the plumbing system

The shallow migration path of mudflow of the mud volcano MV420 on the continental slope of the Canadian Beaufort Sea is investigated in terms of thermal and geotechnical characteristics. MV420 is a nearly flat topped active mud volcano that emits methane and fluidized mud. Its top is at a depth of water of 420 m, within the gas hydrate stability zone. During the summer 2017 IBRV Araon expedition, several measurements of marine heat flow were conducted in the area of juvenile mud mound/pond morphologies identified by multibeam bathymetry and backscatter intensity images obtained by the Monterey Bay Aquarium Research Institute’s autonomous underwater vehicle. The heat probe (a gravity corer with temperature, pressure, and tilt sensors) appeared to penetrate to a depth of >70 m below the seafloor. The sediment bulk density in the mudflow migration path of MV420, estimated by pressure change with controlled stretches of a winch cable, was 1.56 g/cm3. The subsurface temperature reaches up to 18°C and profiles show that the maximum local temperature occurs from 20 to 40 m below the seafloor, implying substantial vertical variability of geothermal gradients. Our finding of large positive and small negative geothermal gradients above and below the depth of the local temperature maximum may represent stagnant hot mud along the mudflow migration path, indicating a pulsative eruption of the mudflow. Gas hydrate is stable only within a few meter thick layer near the seafloor above the path because of the cold bottom water (0.4°C) covering the top of the mud volcano. Furthermore, the thermal conductivity of 0.939 W/m/K and the marine heat flow of 22.5 mW/m2 at a control site outside MV420 is estimated as the background heat flow in the slope, for which little data exists.

A major Miocene deepwater mud canopy system: The North Sabah–Pagasa Wedge, northwestern Borneo

Abstract Three-dimensional seismic reflection data, well data, and analogues from areas with extensive shale tectonics indicate that the enigmatic deepwater “shale nappe or thrust sheet” region of northern offshore Sabah, Malaysia, now referred to as the North Sabah–Pagasa Wedge (NSPW), is actually a region of major mobile shale activity characterized by mini-basins and mud pipes, chambers, and volcanoes. A short burst of extensive mud volcano activity produced a submarine mud canopy complex composed of ~50 mud volcano centers (each probably composed of multiple mud volcanoes) that cover individual areas of between 4 and 80 km2. The total area of dense mud canopy development is ~1900 km2. During the middle Miocene, the post-collisional NSPW was composed predominantly of overpressured shales that were loaded by as much as 4 km thickness of clastics in a series of mini-basins. Following mini-basin development, there was a very important phase of mud volcanism, which built extensive mud canopies (coalesced mud flows) and vent complexes. The mud canopies affected deposition of the overlying and interfingering deposits, including late middle to early late Miocene deepwater turbidite sandstones, which are reservoirs in some fields (e.g., Rotan field). The presence of the extensive mud volcanoes indicates very large volumes of gas had to be generated within the NSPW to drive the mud volcanism. The Sabah example is only the second mud canopy system to be described in the literature and is the largest and most complex.

Studies on biodiversity and bioprospecting of active mud volcano associated bacteria and actinobacteria from Baratang, Andaman Islands, India

A total of 79 bacteria and 101 actinobacteria strains were isolated from the sediment samples of the different points of Baratang mud volcano viz., point of the eruption (M), middle of the volcano (MD), and the dried part of the mud volcano (E). Based on the biochemical and molecular characterization, the isolates were categorized under the phyla Proteobacteria, Firmicutes and Proteobacteria included representatives of Classes Alphaproteobacteria, Gammaproteobacteria and Deltaproteobacteria of 29 genera with 38 distinct ribotypes. Thirty-eight bacterial strains from four different regions of mud volcano revealed excellent activity for indole-3-acetic acid (IAA) production. Excellent antagonistic property, plant growth promoting properties such as IAA production, phosphate, potassium and zinc solubilization were identified in Bacillus megaterium NIOT_MV 31 strain of 38 studied isolates. In this study, we investigated the optimization of IAA production by B. megaterium NIOT_MV 31 and its formulation as a plant growth promoter to improve economic and agricultural development. Maximum IAA yield was achieved using optimal conditions (42.63 mg/mL) in the presence of optimized tryptophan after 4 days of incubation. Twofold increase in the plant growth parameters were observed to that of control plants. Optimization of culture conditions resulted in a fourfold increase in IAA production by B. megaterium NIOT_MV 31 cells. The results clearly demonstrated that, B. megaterium NIOT_MV 31 holds great potential as a source for IAA production and may be useful for commercial applications.

Isotopic composition of the products of the mud volcanoes activity in the South-Caspian Basin in connection with petroleum potential of the deeply burried sediments

Isotopic composition of the products of the mud volcanoes activity in the South-Caspian Basin in connection with petroleum potential of the deeply burried sediments

The role of mud volcanism in prediction of oil-gas bearing content in deep layers of Meso-Cenozoic sediment complex of South Caspian megabasin

While conducting exploration surveys for new hydrocarbon fields in oil-gas bearing basins of the world, the data on the mud volcanoes in the area and their explosion is widely used. As the stage of initial activity of mud volcanoes, the source of generation, the product of explosion etc. are associated with the deep layers (7–8 km) of the Earth, this process is an essential source of information for exploration surveys. One of the original aspects of the South Caspian basin is the great amount of mud volcanoes. The study of the composition of gas masses released into the atmosphere as a result of explosion of mud volcanoes enables to make objective forecast on the gas generation zones on the deposition cover of the area and the oil-gas bearing potential as well. By the distribution areal the mud volcanoes predominantly cover oil-gas bearing zones. Thus, there are mud volcanoes on sixty basins from existing 252 oil-gas bearing zones in sedimentation basin of the Earth. Although the generation source of a great deal of mud volcanoes in Azerbaijan is principally associated with Paleogen-Neogen sedimentation complexes, a specific part of volcanic gases is supposed to belong to the Cretaceous-Jurassic sedimentation complexes (8−10 km), which increases the probability of existence of formation sources for hydrocarbon in these complexes.