AGU Fall Meeting 2007 Abstracts - AGU - Over 90 Years of ...
More than 300 mud volcanoes have already been recognized here onshore or offshore, 220 of which lie within an area of 16,000 km2. Many of these mud volcanoes are ...
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Volcanology, Geochemistry, and Petrology [V]
V22C MW:2005 Tuesday
Mud Volcanoes and Their Eruption Dynamics II
Presiding: A Mazzini, PGP, University of Oslo; S Planke, Volcanic Basin Petroleum Research
V22C-01
Mud Volcanoes Formation And Occurrence
* Guliyev, I S (iguliyev@gia.az), Azerbaijan National academy of Sciences, H.Javid av., 29A, Baku, Az1143, Azerbaijan
Mud volcanoes are natural phenomena, which occur throughout the globe. They are found at a greater or lesser scale in Azerbaijan, Turkmenistan, Georgia, on the Kerch and Taman peninsulas, on Sakhalin Island, in West Kuban, Italy, Romania, Iran, Pakistan, India, Burma, China, Japan, Indonesia, Malaysia, New Zealand, Mexico, Colombia, Trinidad and Tobago, Venezuela and Ecuador. Mud volcanoes are most well-developed in Eastern Azerbaijan, where more than 30% of all the volcanoes in the world are concentrated.
More than 300 mud volcanoes have already been recognized here onshore or offshore, 220 of which lie within an area of 16,000 km2. Many of these mud volcanoes are particularly large (up to 400 m high).
The volcanoes of the South Caspian form permanent or temporary islands, and numerous submarine banks. Many hypotheses have been developed regarding the origin of mud volcanoes.
Some of those hypotheses will be examined in the present paper. Model of spontaneous excitation-decompaction (proposed by Ivanov and Guliev, 1988, 2002). It is supposed that one of major factors of the movement of sedimentary masses and formation of hydrocarbon deposits are phase transitions in sedimentary basin.
At phase transitions there are abnormal changes of physical and chemical parameters of rocks. Abnormal (high and negative) pressure takes place. This process is called as excitation of the underground environment with periodicity from several tens to several hundreds, or thousand years. The relationship between mud volcanism and the generation of hydrocarbons, particularly methane, is considered to be a critical factor in mud volcano formation.
At high flow rates the gas and sediment develops into a pseudo-liquid state and as flow increases the mass reaches the "so-called hover velocity" where mass transport begins.
The mass of fluid moves as a quasi-uniform viscous mass through the sediment pile in a piston like manner until expelled from the surface as a "catastrophic eruption". Model of buoyancy drive (by Brown, 1990).
Brown's basic hypothesis is similar to Ivanov and Guliev and may be summarized briefly as follows: -in situations where rapid sedimentation is occurring mud may be driven to the surface by buoyancy forces due to bulk density contrasts between mud and overlying sediment cover.
Such density contrasts may be simply the result of compaction -disequilibrium, but more importantly may be related to gas expansion when fluids are transported to shallower depths with lower pressure and temperature conditions. Synthetic model had been proposed by I.Lerche, E.Bagirov, I.Guliyev (1997).
The model includes the following studies: The starting point of the mud volcanoes begins with the formation of a zone of decompaction as a consequence of a high rate of gas generation.
The mud body starts to rise under buoyancy. The excess pressure inside the mud intrusion is less than in surrounding formation. As a result, fluid flow toward the body of mud volcanoes.
The body of the mud volcanoes then grows, increasing the buoyancy forces, with further drive the mud. If the rate of gas generation more than gas flow, causing exsolving of gas to free-phase gas.
If there are open faults and fractures which cross the body of mud volcanoes, then gas and mud can penetrate through the faults, and so from gryphons and salses on the surface.
A mud volcanoes can be consider as a huge accumulation of gas, where as the oil is concentrated on the flanks of the mud body.
V22C-02
Cyclic Activity of Mud Volcanoes: Evidences from Trinidad (SE Caribbean)
* Deville, E (eric.deville@ifp.fr), IFP, 1-4, av. Bois-Préau, Rueil-Malmaison, 92852, France
Fluid and solid transfer in mud volcanoes show different phases of activity, including catastrophic events followed by periods of relative quiescence characterized by moderate activity.
This can be notably shown by historical data onshore Trinidad. Several authors have evoked a possible link between the frequencies of eruption of some mud volcanoes and seismic activity, but in Trinidad there is no direct correlation between mud eruptions and seisms.
It appears that each eruptive mud volcano has its own period of catastrophic activity, and this period is highly variable from one volcano to another. The frequency of activity of mud volcanoes seems essentially controlled by local pressure regime within the sedimentary pile.
At the most, a seism can, in some cases, activate an eruption close to its term. The dynamics of expulsion of the mud volcanoes during the quiescence phases has been studied notably from temperature measurements within the mud conduits.
The mud temperature is concurrently controlled by, either, the gas flux (endothermic gas depressurizing induces a cooling effect), or by the mud flux (mud is a vector for convective heat transfer). Complex temperature distribution was observed in large conduits and pools.
Indeed, especially in the bigger pools, the temperature distribution characterizes convective cells with an upward displacement of mud above the deep outlet, and ring-shaped rolls associated with the burial of the mud on the flanks of the pools. In simple, tube-like shaped, narrow conduits, the temperature is more regular, but we observed different types of profiles, with either downward increasing or decreasing temperatures.
If the upward flow of mud would be regular, we should expect increasing temperatures and progressively decreasing gradient with depth within the conduits. However, the variable measured profiles from one place to another, as well as time-variable measured temperatures within the conduits and especially, at the base of the conduits, shows that the fluid flow expelled by the studied mud volcanoes is not constant but highly variable through short time-periods.
We notably observed very short time-period cyclic variations with a frequency of about 10 minutes. These high frequencies temperature changes could be related to the dynamics of two-phase flows (gas and mud) through the mud volcano conduits. We also observed locally a significant daily changes of the temperature of the expelled mud which shows also that the mud flux is changing very rapidly from one day to another.
V22C-03
Did an Earthquake Trigger the Eruption of the Sidoarjo (Lusi) Mud Volcano?
* Brumm, M (mbrumm@berkeley.edu), Department of Earth and Planetary Science, University of California, Berkeley, 307 McCone Hall UC Berkeley, Berkeley, CA 94720, United States Manga, M (manga@seismo.berkeley.edu), Department of Earth and Planetary Science, University of California, Berkeley, 307 McCone Hall UC Berkeley, Berkeley, CA 94720, United States Davies, R J), Centre for Research into Earth Energy Systems (CeREES), Department of Earth Sciences University of Durham Science Labs, Durham, DH1 3LE, United Kingdom
On May 29th 2006, a mud volcano started to erupt in the Porong District of Sidoarjo. The volcano, now known as "Lusi", has displaced tens of thousands of people. It also offers a unique opportunity to observe the processes that initiate and sustain mud volcano eruptions.
Three trigger mechanisms have been proposed, (a) the May 27th 2006 Yogyakarta earthquake, (b) well drilling operations in progress near the initial eruption site at the time of the eruption, and (c) a combination of earthquake and drilling operations. Here we consider possibility (a).
We compare the distance and magnitude of the Yogyakarta earthquake to the relationship between distance and magnitude of historical earthquakes that caused liquefaction and triggered the eruption of mud volcanoes elsewhere.
We also evaluate the static stress changes caused by the Yogyakarta earthquake, and compare the strength of ground shaking with that caused by other regional earthquakes.
We find that (1) the Yogyakarta earthquake was smaller and farther away than earthquakes that have been observed to trigger liquefaction in other settings, (2) the static stress changes caused by the Yogyakarta earthquake was much smaller than changes in stress caused by tides or barometric pressure changes, (3) in the past 35 years, tens to hundreds of other earthquakes caused stronger ground shaking at the site of the eruption but did not trigger an eruption, and (4) the period immediately preceding the eruption was seismically quieter than average, suggesting that previous earthquakes did not bring the subsurface into a critical state. Based on these results, we conclude that the Yogyakarta earthquake, by itself, was not sufficient to trigger an eruption.
V22C-04 INVITED
Sources and Rates of Fluid Flow at Mud Volcanoes - Examples from the Gulf of Cadiz
* Haeckel, M (mhaeckel@ifm-geomar.de), IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany Liebetrau, V (vliebetrau@ifm-geomar.de), IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany Linke, P (plinke@ifm-geomar.de), IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany Reitz, A (areitz@ifm-geomar.de), IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany Schneider v. Deimling, J (jschneider@ifm-geomar.de), IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany Schönfeld, J (jschoenfeld@ifm-geomar.de), IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany Vanneste, H (hlaev105@soton.ac.uk), NOC, European Way, Southampton, SO14 3ZH, United Kingdom
Mud volcanism is a widespread phenomenon in the Gulf of Cadiz (GoC) and provides a window into deep structural and diagenetic processes. Pore fluids from the Mercator mud volcano (MMV), located in the El Arraiche mud volcano field offshore Morocco, are highly enriched in Cl (5.3 M). Na/Cl ratios are close to 1 indicating halite dissolution by the rising fluid.
This is corroborated by 3D seismic data that shows ongoing localized uplift creating an anticline below the eastern flank of the MMV, which can only be explained by a rising salt diapir. Triassic evaporites are known on the Moroccan margin 500 km further south as well as on land in Spain.In addition, the fluids are highly enriched in Li (5.3 mM) and B (12 mM) indicating a deep fluid source from mineral dewatering at T>150° C.
The porewater d18O vs dD relation shows a negative correlation typical for clay mineral dehydration (smectite-illite transformation). A deep fluid source is also supported by a radiogenic 87Sr/86Sr porewater signal of 0.7106. The emitted gas contains mainly methane of thermogenic origin (d13C = -30 to -40 ‰ vPDB).
The morphology of quartz crystals found in the mud suggests transport from large depths. In contrast, gypsum crystals also found in the mud, exhibit the same radiogenic Sr signature as the porewater suggesting secondary precipitation.Applying a 1-D transport-reaction model using conservative porewater compounds constrains the fluid advection rates to be 6 cm/a at the summit, decreasing to 0.3 cm/a towards the rim.
The advection rates correlate well with T and S data recorded with a CTD mounted to a video sled system. Combining the CTD track data across the MMV and the model results allows to calculate spatial budgets for water and methane release as well as the heat flow of the MMV.
V22C-05
Seismic Imaging of Mud Volcanoes on the Calabrian Arc Accretionary Prism, Central Mediterranean Sea
* Ceramicola, S (sceramicola@ogs.trieste.it), Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42/c, Sgonico, Trieste, 34010, Italy Praeg, D (dpraeg@ogs.trieste.it), Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42/c, Sgonico, Trieste, 34010, Italy Wardell, N (nwardell@ogs.trieste.it), Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42/c, Sgonico, Trieste, 34010, Italy Unnithan, V (v.unnithan@jacobs-university.de), Jacobs University Bremen, School of Engineering and Science, P.O. Box 750 561, Bremen, 28725, Germany
A new province of mud volcanoes was discovered on the Calabrian Arc during the HERMES-HYDRAMED IONIO 2005 campaign of the Italian research vessel OGS Explora.
Short-offset (600 m) 2D & 3D seismic reflection data were acquired from a feature referred to as the Madonna dello Ionio, which lies on the inner Arc, c. 40 km from the Calabrian coast, in water depths of 1650-1850 m.
The Madonna comprises an elongate fault-bounded seabed depression containing three circular extrusive features, including a pair of cones, each up to 150 m high and 1.5 km wide. The latter were the targets of the 3D seismic survey, involving the acquisition of 109 closely-spaced (c. 25 m) short-offset profiles; CMPs were assigned to 25 m bins to obtain an average data fold of 84 over a 2.8 x 5.9 km area, then migrated (2-pass finite difference) using velocities available for the upper second sub-seabed.
The 2D & 3D data together provide information on the extrusive cones and their shallow (<1 km) rooting structure.
The 3D imagery reveal the seabed cones to be underlain by offset buried cones that interfinger with the upper 300 ms of flanking Plio-Quaternary strata, indicating extrusive activity over a long period (perhaps more than 1 million years).
Cross-cutting reflections beneath the mud volcanoes suggest the presence of fluids and gas (including possible hydrates) within the structure.
The rooting structure is seen to comprise a relatively narrow (<1 km) central conduit surrounded by a broad zone (3-4 km) of sediment that is complexly structured (low reflection continuity), which may have been disturbed in situ or emplaced beneath the mud volcanoes.
The seabed cones are flanked by on one side by normal faults with seabed expression, recording recent movement that may be in part due to subsidence induced by the extruded material, but that is inferred to be linked to an underlying fault that has localised the activity of the mud volcanoes in space (and perhaps over time, in response to compressional episodes on the Calabrian Arc).
V22C-06
Gas-Charged Sediments Within the Hyblean Plateu Seismo-Stratigraphic Sequence and Associated Likely Shallow Mud-Volacanoes Seafloor Features Offshore Southern Sicily (Sicily Channel � Mediterranean Sea)
* Savini, A (alessandra.savini@unimib.it), Dept. of Geological Sciences and Geotechnologies - Milano Bicocca University, P.za della Scienza, 4, Milano, 20126, Italy Tessarolo, C (chiara tessarolo@unimib.it), Dept. of Geological Sciences and Geotechnologies - Milano Bicocca University, P.za della Scienza, 4, Milano, 20126, Italy Corselli, C (cesare.corselli@unimib.it), Dept. of Geological Sciences and Geotechnologies - Milano Bicocca University, P.za della Scienza, 4, Milano, 20126, Italy
A shallow province of small-scale likely mud-volcanoes (MVs) seafloor features was recently discovered few miles offshore south-eastern Sicily (Holland et al., 2003) over the Hyblean-Malta plateau (Sicily-channel � Mediterranean sea), on an area whose surface might be over 100 square km and in a bathymetric range comprised between -100 and -200m.
Such discovery promoted the National multidisciplinary programm MESC (Mud volcanoes Ecosystem study � Sicily Channel) aimed to provide a detailed acoustic mapping of the area (Savini et al., 2006) and focused water and sediment samples to study the ecosystem response to such geological phenomena.
The main data set thus collected, during three different cruises carried out by the Italian R/V UNIVERSITATIS by mean of acoustic survey techniques, including new multibeam bathymetric data, side- scan sonar mosaics, a dense network of chirp-sonar profiles and focused multi-tip sparker profiles, is here presented.
The detailed seafloor topography and the side scan sonar mosaic well show the occurrence of a field of more than 100 small scale conical and sub-conical seabed features, few meters high. Their morphologies, their strong acoustic scattering and the presence over them of distinct gas plumes, are foremost distinctive proprieties that liken them to MVs.
Such filed consists of single and composite MVs arranged on the seafloor in two main different styles: 1) several conical features 50 - 200m in diameter, preferentially aligned along the isobaths 2) numerous close-set small cones no more than 10m in diameter, settled within well defined, flat, elongated areas (the largest one reaches 2000m in its long axis and 500m in its short axis) rising up to 10m from the seafloor. The acoustic character of the sediments in the chirp and sparker records indicates that such features are gas charged, because of the presence of numerous acoustic anomalies (i.e.: acoustic turbidity zones, wipe outs, gas pockets, enhanced reflectors�).
In particular, the identified gas-related seafloor features are associated to sub- surface structures formed within a gas accumulative horizon covered by a variable thickness of sediments. This gas accumulative horizon has been found in association to a marked unconformity resembles the last trasgressive surface at the boundary between the Holocene and the Pleistocene sediments.
Such gas-charged horizon has been used to map the depth of the free gas within the seafloor sediments. The depth of this "gas- front" is variable and domes up to the seafloor where MVs morphologies are found at the surface, often showing gas plumes (up to 20m high) at their top.
V22C-07
Mineralogy And Geochemistry Of Mud From Andaman Mud Volcanoes And Its Potential As A Hydrocarbon Source
* Datta, S (saugata.datta@gcsu.edu), Georgia College and State University, Department of Biological and Environmental Sciences, Campus Box 081, Milledgeville, GA 31061, United States Bhattacharyya, C R (crbcgeology@yahoo.com), University of Calcutta, Department of Geology, 35 Ballygunj Circular Road, Kolkata, WB 700019, India
Mud volcanoes are a common feature, reported by several workers, in the Baratang Island of Middle Andamans, India.
The association of methane gas and adsorbed hydrocarbons in the mud has been cited well by scientists working in Andamans and also by others working on other eruption areas around the world.
Our intended work centres around delineating the nature of such mud volcanoes in the above terrain, their chemical composition with special reference to the clay minerals formed under this sedimentary volcanism environment and exploiting such volcanic deposits towards potential hydrocarbon reserves (if any).
The analysis so far suggests that, at any instant of time, gas vents at variable rates in different gas channels at the same site, and that the compositional differences in these vent gases are nearly as large as can be produced by hydrate crystallization.
Our hypothesis is compatible with geologic generalizations that venting evolves from fast (mud volcano), to intermediate (hydrate crystallization), to slow (carbonate precipitation) if venting organized into more discrete vents with time.
The most realistic agent that explains the observed effects is a rapid local emission of mud and/or water. Powder XRD of bulk mud samples enable identification of the complete suite of minerals, in addition to the clay minerals.
Variability in modal mineralogy is tracked using Rietveld Method of crystal structure refinement. In addition, micro- XRD of sample cores in situ provide mineral identification as well as textural information such as grain size and distribution (e.g. fine-grained polycrystalline versus larger crystals) as well as preferred orientation (e.g. due to flow layering or strain).
Stable isotopes of the separated clay minerals (smectite- and illite-rich extruded mud) from the mud volcanoes will be utilized towards the knowledge of nature of volcanism in the Andaman areas. The most likely mechanism believed is re-hydration of shales by both hydrocarbons and a geochemically mature fluid from greater depth within the wedge.
Trace element and REE studies of the muds will be conducted to attest to the above hypothesis. The overall results attest active local flow of geochemically different fluids along deep- seated faults penetrating the wedge, with the waters as well as the gases coming from below.
V22C-08
Simulations of the Explosive Venting of Supercritical Fluids through Porous Media
* Gisler, G R (galen.gisler@fys.uio.no), Physics of Geological Processes, University of Oslo PO Box 1048 Blindern, Oslo, 0316, Norway Svensen, H (henrik.svensen@matnat.uio.no), Physics of Geological Processes, University of Oslo PO Box 1048 Blindern, Oslo, 0316, Norway Mazzini, A (adriano.mazzini@fys.uio.no), Physics of Geological Processes, University of Oslo PO Box 1048 Blindern, Oslo, 0316, Norway Polteau, S (stephane.polteau@fys.uio.no), Physics of Geological Processes, University of Oslo PO Box 1048 Blindern, Oslo, 0316, Norway Planke, S (planke@vbpr.no), Volcanic Basin Petroleum Research, Oslo Innovation Park, Oslo, 0349, Norway
Superheated or overpressured water and other fluids at depth can cause surface disturbances in the form of vents, seafloor pockmarks, or mud volcanoes. In sedimentary basins, magmatic intrusive events are a source of heating of included fluids.
Metamorphic reactions triggered by heating can release more volatiles. Confined by impermeable clays or metamorphic rocks, the fluid is thus heated and pressurized.
If confinement is breached in such a way that the superheated or overpressured fluid has access to porous sediments, a violent eruption of a mixture of fluid and sediment may result. Manifestations of this include both hydrothermal vents (as in the Karoo Basin of South Africa and the North Sea off the Norwegian coast) and mud volcanoes.
Because these are widespread on Earth, they are likely to exist on other terrestrial planets where water or other volatiles are present. The search for such features is therefore relevant as a diagnosis for water, and hence life, on other planets.
We have performed simulations with the Sage hydrocode (from Los Alamos and Science Applications International) of supercritical venting in a variety of geometries and configurations relevant to both Earth and Mars.
The simulations show several different patterns of propagation and fracturing in porous or otherwise weakened overburden, dependent on depth, source conditions (fluid availability, temperature, and pressure), and manner of confinement breach. Because of the lower surface gravity and atmospheric pressure on Mars, such features should produce greater surface disturbances in the form of larger vent craters and more extensive aureoles than on Earth.
Author(s) (2007), Title, Eos Trans. AGU, 8