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Hindawi Publishing CorporationJournal of Geological ResearchVolume 2013 Article ID 207031 11 pageshttpdxdoiorg1011552013207031

Review ArticleFormation of Gas Hydrates at Deep Interior of the Earth andTheir Dissipation to Near Surface Horizon

Ramachandran Ramasamy Subramanian Subramanianand Ranganathan Sundaravadivelu

Department of Ocean Engineering Indian Institute of Technology Madras Chennai 600036 India

Correspondence should be addressed to Ramachandran Ramasamy drrramyymailcom

Received 11 July 2013 Accepted 7 October 2013

Academic Editor Michela Giustiniani

Copyright copy 2013 Ramachandran Ramasamy et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Methane hydrates occur in diverse geological settings and their origin is puzzling owing to package of more than 160 times ofequivalent volume of methane in ice cage at standard temperature pressure indicating formation at high pressure state At the coremantle boundary of the Earth high dense supercritical fluids of Fe with significant amount of O Ti Nb C H and other elementsexist Geophysical studies reveal that at the core mantle boundary of the Earth at 2900 km depth temperature exceeds 4000∘Cpressure ranges around 135GPa and the material present possesses high molar volume 88 gmcm3 Sudden release of pressurecauses opening of vents and supercritical fluidplasma phase of CH

4

exsolves as finely divided plasma bubbles and rapidly rises upthroughweak planesThe potential energy of these bubbles is so high the velocity of ascending bubbles steadily increases with superadiabatic state with minimum frictional energy loss The rapidly ascending CH

4

plasma bubbles quench with outer skins of H2

orH2

O while passing through the permafrost or near surface horizons Again some bubbles burst into numerous tiny droplets ofdense methane into cold seawater near seafloor The water layer surrounding the tiny bubble is formed as ice-cage on hydrophobicmethane by absorbing or releasing sufficient latent heat energy from freezing water for endothermic formation ofmethane hydrateThe water envelops as ice cage around CH

4

near surface conditions at ambient temperature and pressure conditions Numericalanalyses of specific heats Jmole for CH

4

and H2

O reveal that such plasma bubbles could form even from upper mantle horizonssim100 km depth but with less potentiality The charged particles inside the plasma bubble are highly influenced by magnetic andelectric fields Hencemost bubbles drive through deep interconnecting fractures towards continental margins of polar region whereearthrsquos electromagnetic and gravity intensities are relatively high

1 Methane Hydrate

Huge reserves ofmethane hydrate (MH) are discovered in thecontinental shelves of Arctic Ocean MH deposits estimatedfrom different places amount to 2500Gt [1] These reservesmay be sufficient for energy resource for more than 300yearsMH is stable under fairly thermodynamic conditions ofhigh pressure (01MPa to over 120MPa) and low temperaturebetween minus2∘C and 24∘C [2 3] Growth rate of MH isdominated by solubility and adsorption of methane (CH

4)

gas filled water cages and CH4concentrated at solid liquid

interface [4] MH has a clathrate structure water moleculesform linked cages that enclose individual molecules oflow molecular weight gas (eg CH

4 CO2 H2S and C

2H6)

It appears that CH4and ice are separate phases in the

methane hydrate (MH) Chemical composition MH I is(CH4)8(H2O)46 It is composed of H 1306 C 1004 and

O 7690 [5] TheMH I has water 8659wt and methane isonly 1341 wt It is stable at 4 to 5∘Cand 50 bars Its structuralformula is 2(S) 6(L) 46(H

2O) where S represents CH

4 N2

H2S and L for CH

4 H2S and CO

2TheMH II usually found

in pore fluids locked up in sediments has the composition ofH 1313 C 1304 and O 7383 and its structural formulais 16(S) 8(L) 136 (H

2O) where S represents CH

4and H

2S

and L includes CH4 H2S CO

2 and C

2H6[6] The latter is

composed of 8313 (wt) ofwater and only 1687ofmethanelike gases The structural formula of MH is CH

4 and the

principal component of natural gas and water is present in

2 Journal of Geological Research

higher proportions than CH4 The presence of traces of H

2S

andN2indicates that the hydrates were formed at deep seated

source A large amount of CH4gas is trapped within a crystal

structure of waterice It is composed of onemole of CH4and

575 moles of water It has a density around 09 gcm3 TheoriginMH is puzzling owing to package of more than 168m3of equivalent volume of CH

4in its unit volume at STP

MH is tightly packed with CH4and surrounded by

H2O as separate phase CH

4and H

2O respectively have

critical temperatures 1904∘K and 6471∘K critical pressures46MPa and 2206MPa and critical densities of 0162 and0322 gcm3 CH

4has molar volume 1604 density 06556 gL

melting point minus182∘C and boiling point minus161∘C while theseproperties respectively for water are 18015 gcm3 1 kgL0∘C and 100∘C CH

4is the third lightest gas after H and

He in the Universe CH4being the simplest hydrocarbon

produces more heat per mass unit (357 J Kminus1molminus1) thanother complex hydrocarbons Therefore it has has higherdiffusivity than water Pure H

2O bearing fluid inclusions in

minerals behave perfectly as diathermal isochloric isoplethicsystems [7] H

2O exists as a supercritical fluid above its criti-

cal temperature of 300∘C inwide range of pressure conditionsfrom 300MPa to 300GPa [8] Experimental studies showCH4and H

2O attain solid states of MH at low temperatures

and high pressures [3 4 8] Solid CH4is produced at low

temperatures down to 21∘K and pressure up to 60 k barsat the Van der Walls Laboratory [9] Solid CH

4structure is

stable in the pressure range 10ndash90GPa The electronic bandstructure and density of states show that this structure hasnot metalized until 90GPa [9] Under high pressure CH

4

becomes unstable and it transforms to ethaneC2O6at 95GPa

butane C4H10

at 158GPa and further carbon and hydrogenabove 287GPa at zero temperature [10] In this paper anattempt is made on the possibility of formation of MH fromthe sources derived from deep interior of the Earth but alongthe continental margins of higher latitudes by the influencesof electromagnetic and gravity forces of the Earth

2 Mode of Occurrence

Themode of occurrences ofMH in diverse geological settings[11] is the major problem facing the study of origin of gashydrate deposits Recent bottom simulating reflector (BSR)explorations of hydrocarbon reveal that huge quantities of gashydrates occur in the following geological settings

(i) under the cover of permafrost [12](ii) continental shelves of high latitudes around Polar

Regions [12](iii) mid Oceanic Ridges [13](iv) ceep-sea hydrothermal vents [13 14](v) island arcs subduction zones and active continental

margins of China Taiwan-Luzon Island arcs [15](vi) passive continental margins [11 16](vii) CH

4plumes at Hydrate Ridge-Monterey Bay [17]

(viii) emissions of disc like CH4bubbles from the Abraham

Lake Alberto Canada [18 19]

(ix) active methane discharge on Hydrate Ridge on theCascadian accretionary margin Oregon [20] gas andfluid venting at the Makran accretionary wedge ofPakistan [21]

(x) seep gas composition similar to that of gassequestered in gas hydrates [22]

(xi) CH4ebullition sites that occur throughout the Arctic

region [17](xii) at some marine seeps massive relatively pure gas

hydrate occurs in seafloor mounds and in shallowsub-seafloor layers occurring at upper continentalslope depths

(xiii) seepage along fault planes of the continental slope inthe northwest Gulf of Mexico

(xiv) sublacustrine mud-volcanoes seeping out MH fromfreshwater Lake Baikal [23]

(xv) along the continental margins of India particularlythe Krishna-Godavari offshore basin [11 24]

(xvi) seeps of MH bubbles create carbonate rock formationand reefs by reaction between methane and seawater[25]

(xvii) CH4like gases migrates upward through networks

of fractures with elevated pore-fluid salinities intodeep offshore oceans near Korea along the activecontinental margins [26]

(xviii) migration of CH4from depth along geological faults

followed by precipitation or crystallization on con-tact of the rising gas stream with cold sea water [27]

(xix) hydrothermal venting of methane gas bubbles frommantle horizon to the Arctic seafloor is entrappedinto the growing ice-bergs and form as permafrostduring the course of several decades of duration [13]

(xx) thermohaline circulation promoted by differences indensity temperature and salinity of the Arctic Oceanwaters [13]

(xxi) microbial CH4can be formed where labile organic

carbon is available in onshore and offshore continen-tal margins [11]

Warm and cold currents have a major impact on forma-tion and dissipation of gas hydrates In the process of freezingthe salt in seawater is expelled as brine Approximatelyone-third of the Arctic Ocean is underlain by continentalshelf which includes a broad shelf north of Eurasia and thenarrower shelves of North America and Greenland

3 Mineral Phase Transitions at Interior ofthe Earth

Temperature and confining pressure increase with depth Inthe upper mantle along the subduction zones serpentiniza-tion of ultrabasic rocks [28] is reported At the tempera-ture around 900∘K and pressure corresponding to 600 kmCH4bearing serpentinized zones are recognized by acoustic

Journal of Geological Research 3

emissions which are absent in unaltered ultrabasic rocks[28 29] Temperature difference near phase boundary resultsin density anomaly Dissociation of carbonates particularlysiderite would release methane in significant amount [30] atthe pressure range between 5 and 11 GPa and temperaturebetween 500 and 1500∘C at depths ranging between 150 and400 km Upper mantle consist mostly of olivine pyroxenespinel-structure minerals and garnet [31] typical rock typesare thought to be peridotite dunite and eclogite Betweensim400 km and 650 km depth olivine is not stable and it isreplaced by high pressure polymorph is wadslevite and orringwoodite Below this depth of about 650 km all of theminerals of the upper mantle begin to become unstable Themost abundant silicate perovskite mineral have structureslike those of the oxide mineral perovskite followed bythe magnesiumiron oxide or ferro-periclase [32] In thelower mantle post perovskite phase modification results withrelease of FeO down to the core The perovskite is expectedto react with liquid iron to produce metallic alloys (FeO andFeSi) with nonmetallic stishovite (SiO

2) and perovskite at

the pressure 140GPa [33] High density of reaction productsrelative to lower mantle (particularly in D10158401015840 layer) movesdownward to liquid CMB layer Such changes in mineralogymay influence in density changes and they may absorb orrelease latent heat as well as depress or elevate the depth ofthe polymorphic phase transitions for regions of differenttemperaturesThe slow and steady formation of high pressurepolymorphs creates vacant sites in the lower and uppermantle by changing the rheology of the mantle material Thisleads to structural deformation in themantle horizon leadingto fault movements and earthquakes Increasing temperatureand pressure from surface to down to the Earth states ofmaterials in the mantle widely vary though they representlayered structures Heterogeneity in themantlemay be due topartial melting of mantle andmagma generations Ascendingand upwelling of volatile materials of light elements frommagma also cause depletion of these elements from themantle The rock in the upper mantle has a relatively lowviscosityThe lowermantle is under tremendous pressure andtherefore has a higher viscosity than the upper mantle Atelevated temperatures and pressures conditions that permitsome minerals to behave like soft plastic that if they arestretched or squeezed they become flattened or elongatewithout breaking as ductile material Under high confiningpressures coordination numbers of minerals increase byreducing vacant sites in the lattices of minerals This phe-nomenon induces void spaces within mantle At an optimumlevel residual stress accumulates in the mantle and the stressis released as creep and faults It is inferred that these cracksand faults discontinuously extend from crust to top of CMBSuch types of paleo-faults or creeps are filled with viscoelasticmantle materials These fault planes are weak planes as theyare frequently reactivated repeatedly by the tectonic forcesinduced by phase transitions of mantle minerals with releaseof huge quantities of heat energy from the CMB Suddenrelease of pressure due to creeping and faulting void spacesare developed and at the state of 4000∘C at CMBwith releaseof pressure from 135GPa to lt1MPa vapourization of volatilelight materials such as H He CH

4and H

2Omay be released

from the liquid phase at CMB A high pressure carbonbearing phase is formed by recombination of CO

2with other

oxides at P-T conditions close to the lower mantle geothermThis behavior might be due to a strong thermodynamicstability of the new carbon bearing phase An increase inthe ionic character of CndashO bonds at high pressures andtemperatures indicate presence of carbonate carbon di oxide(i-CO

2) near the Earthrsquos core-mantle boundary conditions

provides insights into both the deep carbon cycle and thetransport of atmospheric CO

2to anhydrous silicates in the

mantle and iron core [34]

20 (Mg025

Fe10158401015840075

)CO3= 20Mg

025

Fe101584010158401015840030

(C3O9)

0233

+3Fe3O4+ 6CO or 3 (C + CO

2)

(1)

A large amount of iron concentrates as a result of intracrys-talline reaction between iron and carbonate producinghigh pressure polymorph of carbonate Further increase ofpressure magnetite and nanodiamonds crystallize [34] Thedevelopments high dense mineral polymorphs in the lowermantle induce cracks creeps and faults in the lower mantleResidual stress accumulated by the phase transition andcontraction of lower mantle and d10158401015840 horizon may be causedfor the change of state of certain zone of weak planes fromviscoelastic to brittleductile state Along these weak planesdue to sudden release of pressure creepsmay be induced [35]

4 Creep

As rock is heated its ability to deform elastically is graduallylost It can deform plastically at lower stresses Rocks atdeeper levels tend to deform plastically rather than elasticallyduring tectonic movements But over longer periods theycan deform plastically (creeping) At deeper depths rocksretain permanent strains when they deform plastically Suchrocks tend to deformplastically once the temperature exceeds70 of the melting temperature Highly competent layersembedded in lower competent material will form bucklefolds and can tend to creep Lower competent rock-types candistort more easily so commonly pick out a rock cleavageDue to variations in temperatures and confining pressuressome rocks attain strain softening and others attain strainhardening and these processes lead to creep During thecourse of younger deformations it is easier to deform alongpreexisting creep than to deform the surrounding rocks Itis a weak zone that nucleates further deformation At highpressure and temperature the rocks at the lower mantle byphase transitions begin to yield creep The failure processinvolves some shearing mechanism If stresses induce creepthe creep produces heat A temperature increase often occursand contributes to strain softening Solid-solid phase transi-tion occurs preferentially along the plane of maximum shearstresses and if this transition occurs suddenly it is likely toradiate to produce acoustic emission As pressure and tem-perature increase brittle materials sequentially transformedinto ductile elastic and viscoelastic state and finally attainfluid stage depending upon prevailing differential pressure


and temperature Faultcreep controls on concentration anddispersion of chemical elements due to deformation of rocksand mineral grains Along the creep planes Si and Fe oftenincrease due to bleeding of K and Na The stable order ofelements from compressional creep to shear plane is Si-Fe-Mg-Ca-Al-K-Na in accordance with the order of ionic radiusfrom small to large Generally CMB remains in a reducedstate owing to presence of H He and CH

4 Extensional creep

is generally in the oxidation environment due to extensionand dilatancy the porosity and permeability enhance So H

2

He2 CH4like gases stores along these planes Primordial H

and He were trapped and stored in the Earthrsquos interior as HandHe-solutions and compounds stable only under ultrahighPT conditions [36] The explosive chain reactions of H Heand their compounds are triggered by decompression withinfault zones [36] Water is a catalyst accelerating explosivereactions thousand fold Volcanoes spewed H CO and CH

4

into the atmosphere because their magma source from thevicinity of upper mantle was much reduced [37]

5 Primordial Methane

Formation of the carbon atomic nucleus requires a nearlysimultaneous triple collision of alpha particles (4He nuclei)at very high pressure and temperature conditions withinthe core of the Earth Further nuclear fusion reactions of4He with 1H produce 5Li and 8Be are produced by nuclearfusion of 4He with 4He at required temperature and pressureconditions [38] However in this triple alpha process theelements formed 5Li 8Be and 11B are rarely stable and decayalmost instantly and back to elements of smaller nucleiPresence of intense H CO and CH

4keeps the CMB in a

reduced state Primordial CH4in the Earthrsquos core is reported

by Gold [39] Both CH4and H

2O are greatly soluble in

the materials present in CMB till they reach the state oftheir critical densities Hence they dissolve in the CMBmaterials till they attain a state of equilibrium possibly allavailable CH

4and H

2O Solvent power of supercritical fluid

of CH4and H

2O increases with increasing temperature to

the extent of a given density of 88 gcm3 at CMB Furthermole factions of CH

4and H

2O from the materials of CMB

having 88 gcm3 are also increased at this equilibrium statewith CH

4and H

2O On the basis of the density of Fe

7C3

at inner core conditions Mookerjee et al predicted that themaximumpossible carbon content of the inner core is around15 wt [40] Carbon in the Earthrsquos core can generate largeperturbations by the flux of lighter elements from the CMB[41] Presence of significant amount of C in the inner corecreates electromagnetic fields in the Earth [42] At elevatedtemperatures carbon reacts with oxygen to form CO andwill reduce such metal oxides as iron oxide to the metalHigh temperature plasmaHwill diffuse into iron carbide andcombine with carbon to form tiny pockets of CH

4at internal

surfaces like grain boundaries and voids The CH4collects in

the voids at high pressure and initiates creeps and cracks inthe iron carbide present at the lower mantle or at the innercore Iron carbide is present in significant proportion at theinner core of the Earth The plasmatic hydrogen is diffused

into the iron carbide and combines with carbon to form tinypockets of CH

4at internal surfaces like grain boundaries and

voids At high pressures CH4stored in the voids and grain

boundaries of iron carbide The explosive chain reaction ofH and He compounds triggered by decompression withinfault zones and upward moving microplumes of CH

4will be

accompanied by additional release of energy This will alsocause decomposition of H and He compounds and releaseof fugitive elements such as H O C N Cl and F Furtherdetonation-induced synthesis of H

2O CO

2 CH4 H2S HCl

and other compounds [36] methane plasma behaves like afluid with zero viscosity High pressured mantle gases andsupercritical fluids or plasmatic bubbles inflate and weakenany accessible faults reducing static friction across theirwalls Frequent triggering of earth quake tremors initiatecracks in the iron carbide and release methane from thevoids and intergranular boundaries of iron carbides Thereleased methane forms as plasma bubble which ascendsrapidly because of its light weight supercritical fluidplasmastate with zero viscosity Primordial H and He accumulatedthe excess energy during Earthrsquos accretion by endothermalformation of solutions in solids and liquids Concentratedflux of hotter than mantle and He from the core will generateliquid magma by the process of volatile flux melting andwarm the wall rocks producing heat focusing effect H andHe do not cool adiabatically under decompression The localincreases in discharge of energy and heat together with thefluxing and decompressing action of volatile componentswould cause local fusion at seismic discontinuities UltrahighPT conditions during accretion enhance the progress ofendothermic reactions of formation of H andHe compoundsand solid solutions which provide efficient cooling andproduce more compact components than the re-actives [36]

6 Methane Plasma Bubbles

Suddenly released CH4-plasma bubble has electron and

proton which are not bound together resulting in veryhigh electrical conductivity and high emissivity The chargedparticles are highly influenced bymagnetic and electric fieldsThe ionized gas could then become plasma if the proper con-ditions for density temperature and characteristic length aremet (quasineutrality collective behaviour) As an interpene-trating CH

4plasma fluid its solubility at CMB increases with

increasing density of CH4to 88 molar volumecm3 at the

existing confining pressure over 135GPa and the temperatureabove 4000∘C CH

4plasma may pass through solids in the

lower mantle d10158401015840 layer [43 44] It may diffuse faster in asolid matrix than a liquid yet possess a solvent strength toextract the solute from the solid matrix [10] Molar volumeof methane decreases with increase of pressure Under ultrahigh pressure at 200GPa the molar volume of methanedecreases to one third of its volume [10] Before generation ofMH it appears to be remained as supercritical fluids of CH

4

and H2O Due to the large compressibility of supercritical

fluid small changes in pressure can produce very substantialchanges in density which in turn affect phase equilibriumboundary shifts and at favourable environment MH forms


Table 1 Increase of specific heat energy Jmole in the interior of theearth

GPa 119879

∘C H He CH4 H2O0 300 8652 12480 10707 2261103 500 14420 20800 17845 3768534 1800 51912 74880 64242 13566618 2000 57680 83200 71380 15074040 2500 72100 104000 89225 18842588 3500 100940 145600 124915 263795160 5500 158620 228800 196295 414535238 5800 167272 241280 207002 437146321 6000 173040 249600 214140 452220358 6200 178808 257920 221278 467294

as compressed supercritical CH4locked in an icy crystal

lattice of water Hydrogen bonding in water is so strongthat it actually forces the crystal structure of the ice to takeup a larger volume than the same amount of liquid wateroccupies It prevents leakage of highly compressed CH

4from

the structure of MH Table 1 represents specific heat energyJmole calculated for the elements of H He CH

4and H

2O

for the temperature listed in the columnT∘C [36]The specificheat energies (Jmole) increase as the temperature increases(Tables 1 and 2) Figure 1 shows relative specific energypotential of H He CH

4 and H

2O from the ground surface

to inner core temperature and with corresponding pressurecondition Owing to sudden drop of pressure from 358GPato lt1MPa the differential energy potential is calculatedto corresponding temperature without any changes In theFigure 2 the specific energy potentials of CH

4and H

2O are

calculated for the corresponding temperatures when suddendrop of molar volume (density) of CH

4and H

2O suddenly

decreased to their critical densities (molar volume at criticaltemperature and pressure) when these components attainingthe state of supercritical fluid stage Were Figure 3 showsthe calculation of specific heat energy at their differencesbetween maximum confined pressure at CMB 88 gmcm3and critical density state CH

4and H

2O respectively of 0162

and 0322 gcm3 Then the excess energy is converted toexcessive temperature rise by dividing their specific heatenergyJ moleThe results show that the temperature at 100mdeep in the earth is sufficient to make plasma bubbles of CH

4

and H2O

However plasma bubbles derived from deep seatedsources especially from CMB has more potential for rapidascent with dense packing of CH

4with water cages Com-

pared to CH4plasma H

2O have more specific energy poten-

tial to higher level ascent from deep seated source HoweverCH4has lower molar volume and the initial formation of

CH4plasma bubble is surrounded by H

2O Further the latter

has higher solubility than CH4 CH4has lower solubility

hence it is released earlier than H2O plume CMB increases

both by increase of temperature and density referred to asmolar volume gcm3 At CMB both temperature and densityof CH

4are respectively 4000∘C and 88 gcm3 while critical

density is 0162 gcm3 and critical temperature is only 48∘C

50

40

30

20

10

00 2000 4000 6000 8000

times104

Spec

ific e

nerg

y (J

mol

e)

HHe

CH4

H2O

Temperature (∘C)

Figure 1 Relative specific energy potential for emission of plasmabubbles at various temperatures conditions from interior of theEarth Components of relative lower solubility potential H CH

4

arediffused out initially from the CMB

40

30

20

10

0

times105

0 2000 4000 6000 8000

Spec

ific e

nerg

y (J

mol

e)

minus10

CH4

H2O

Temperature (∘C)

Figure 2 CH4

plasma bubble is released out initially relative to itslower solubility and is molar volume in the CMB materials thoughplasmatic H

2

O has higher specific energy potential per mole andhaving higher solubility factor than CH

4

at the deep interiors ofthe Earth Plasma is an ionized gas comprised of ions and freefloating electrons that can create and respond to magnetic andelectromagnetic fields

Therefore CH4has very high kinetic energy for upward

movement H He and CH4gases do not cool upon adiabatic

expansion Such high pressured gases inflate and weaken anyaccessible creep or fault and reduce static friction across itswalls Continuous tremendous degassing of primordial HHe and CH

4from Earthrsquos interior According to Gold that

CH4is one of the primordial gases prevailed at the interior

of the Earth and outgassing largely through faults [39]Whenquantity of heat energy is balanced with by the products ofspecific energy of the substance and temperature differences

119876 = 119862119898Δ119879 (2)

for constant molar volume


Table 2 Transformation of specific heat energy Jmole from plasmatic ions of CH4 andH2O to supercritical fluids in the interior of the Earthowing to sudden drop of pressure (Jules Thompson effect)

GPa 119879∘C CH4 CH4 H2O H2O CH4 H2OCH4exJm H2Oex Jm 119879

∘C + CH4 119879∘C + H2O

0 300 2212 120133 minus1797 minus49207 117921 minus47407 115709 minus45610 3242 minus60503 500 3368 182947 3060 83615 179579 80460 176211 77400 4937 102634 1800 10884 591241 34627 969826 580356 911592 569472 876966 15956 11629I8 2000 12041 654055 39483 1079038 642014 1039459 629974 999976 17651 1326040 2500 14931 811091 22939 1410845 796159 1359125 781228 1336187 21889 1771988 3500 20713 1125163 75906 2074460 1104450 1998458 1083736 1922552 30365 25494160 5500 32277 1753307 124471 3401690 1721030 3277123 1688753 3152652 47317 41806238 5800 34011 1847529 131756 3600775 1813517 3468923 1779506 3337168 49860 44253321 6000 35168 1910343 136612 3733498 1875175 3596790 1840008 3460178 51555 45884358 6200 36324 1973157 141469 3866221 1936833 3724656 1900509 3583188 53250 47516

0 40000 6000020000

times105

Exce

ss sp

ecifi

c ene

rgy

(Jm

ole)

40

30

20

10

0

minus10

minus20000

CH4

H2O

Excess T (∘C)

Figure 3 The excessive specific energy (Jmole) potential may beexpended for keeping the methane bubble in plasmatic state duringascent to higher levels from CMB However the rate ascending sorapid the bubble will maintain its plasmatic state till it reaches thenear surface condition with very limited loss of heat energy

The formula is restated when mass is transformed criticaldensity releasing heat specific energy into as

119876 = 119862Δ119898119879 (3)

keeping 119879 and 119875 at critical states where119876 = quantity of heat119862 = Specific heat of the substance Jmole119898 =mass Δ119879 is thetemperature variation between the two states and Δ119898 = themass difference between the two states

Under sudden release of pressure adiabatic temperaturerises to attain an equilibrium state with its potential heatenergy numerous tiny plasmatic bubbles of CH

4are frac-

tionated from the prevailing liquid at the CMB Outer skinof plasmatic CH

4bubble is quenched generally double walls

and outer wall are filled with H2as layer and sometimes

the outer shell may be filled with H2O as layer A small

decrease in pressure causes a large decrease in the density ofthe super critical phase of methane and water The flexible

thin outer wall is pulling in while the CH4plasma inside

of it is pushing out Sphere shaped bubble takes up a verylittle space and hold a lot of methane in the plasma Undersudden decrease of pressure and rise of temperature withexisting heat capacity numerous tiny plasmatic methanebubbles are released Methane is released out in the form ofdense supercritical fluid emulsion from CMB due to suddenthermal turbulence Numerous bubbles of CH

4rapidly rise

with high velocity at the rate of 100 to 200ms without anysignificant loss of heat energy as that in the case of mostvolcanic eruptions fromdeep-seated sourceThe outer skin ofthe plasma bubble becomes flexible elastic and hydrophobicand it can hold the shape of a bubble of H

2OorH

2when CH

4

is blown into it The stretchable skin is made up of plasmaticfluid of H

2or H2O formed by oxidation of CH

4The thin wall

skin of the bubble is pulling-in while the CH4inside of it is

pushing-out

7 Ascending of Plasma Bubbles

Since plasmatic CH4dissolved in the liquidmaterials at CMB

has a low degree of thermal turbulence in the upper horizonof CMB numerous CH

4plasma bubbles are fractionated

Frequent earth quake tremors less than the intensity of 3 inRichterrsquos scale might have induced fractionation of pure CH

4

bubblesThe quenched elastic bubble wall of H2surrounding

the CH4core is more impervious to CH

4and prevents the

escape of dense CH4 The oxidation of H

2during upward

ascent causes formation of H2O skin which is hydrophobic

to CH4present at the core of the bubble The rapidly upward

ascending plasmatic CH4plasma bubble with zero viscosity

and insignificant loss of frictional energy makes its contin-uous path by widening and interconnecting discontinuouscreeps (Figures 4(a) and 4(b)) A plume generally maintainssame diameter till its eruption at the surface [45] Adiabaticprocesses can occur in an extremely short time so that thereis no opportunity for significant heat exchange Adiabaticchanges in temperature occur due to changes in pressureof CH

4H2 and H

2O while not adding or subtracting any

heat The rapid ascent of bubbles widens the conduit to a


Sea

Creep

Viscoelastic

(a)

Ice cage

Ice cageSea

CH4

CH4

CH4

CH4

CH4

CH4 CH4

CH4

1 m

1 km

2900 km

Brittle

Plasma

Plasma

Plasma

CMB Liquid layer

Plastic

Viscoelastic

Pockmark

Elastic

High dense

Sudden ductile creep

Viscoelastic horizon

Very high dense

(H2O bubble

H2 2

H2

O

wall)Dense CH4

(b)

Figure 4 (a) Development of discontinuous creep from lower mantle to ground surface mainly due to mineral phase transformationsand release of energy during earthquakes and tectonic movements Rapidly ascending of micro-plumes and CH

4

plasma bubbles create acontinuous conduit path by interconnecting discontinuous creeps and fractures on their way (b)The plasma bubble is thermally insulated byH2

Pressure suddenly drops from 135GPa to lt1MPa at about 4000∘C from the state of CMB Plasma bubble enlarges its size occupying entirewidth of the narrow conduit The outer skin of H

2

shell surrounding the CH4

plasma is oxidized to H2

O at higher levels The hydrophobicCH4

is protected by quenched H2

O After entry of seafloor sediments H2

O shell is get freeze slowly and form ice cage Surrounding en-masseof coldwater and sediments at low temperature prevents escape of trapped CH

4

inside the MH Disc like CH4

rises up from the pockmarkowing to confining pressure of water column

limited extent and the most of energy is expended for rapidupward movement The plasma bubble reaching near thesurfaceH

2shell is oxidized toH

2Oshell which is hydrophobic

to CH4thus preventing the escape of dense CH

4packed

inside the bubble Reaching impervious sediment layer belowthe seafloor though the conduit of a pockmark the outershell of water surrounding the plasma bubble gets freezeThe high temperature bubble slowly cools owing to thesurrounding en-masse of cold water at 4∘C or less than minus2∘Cor at ambient temperature and pressure conditions for theformation of MH The bubble always tries to take up thesmallest amount of space and hold the most of CH

4that it

possibly can The dense supercritical tiny CH4bubble burst

into the en-masse of cold water ice-cage forms around thehydrophobic CH

4by absorbing or releasing sufficient latent

heat energy from the surrounding coldwater layer tomaintainits ambient pressure temperature conditions Larger surfaceareas of the tiny bubbles are provided far more nucleation

points enabling a much faster formation of MH The lens-shape of the bubble is the best way to take up a little space andhold a lot of CH

4 while passing through a narrow conduit

produced by the creep Further the bubble wall becomesflexible and elastic and it will be flattened in the form ofdiscs very similar to the CH

4bubbles ejected in the Abraham

Lake Alberta Canada [18 19] Disc-shaped methane bubblesoften observed in marine sediments result from growth in amedium that elastically resists expansion of the bubbles andyields by fracture Discoid bubbles that grow in sedimentsthat obey LEFM grow much faster than spherical bubbles(two- to fourfold faster for the times and conditions testedhere) and become more eccentric with time (aspect ratiosfalling from 03 to 003 over 8 d of growth) In addition theirgrowth is not continuous but punctuated by fracture eventsFurthermore under some conditions LEFM predicts thatbubble growth can become arrested which is not possiblefor a bubble in a nonresistant medium even for nonspherical


bubbles Cessation of growth occurs when the dissolved gasconcentration gradient near the bubble surface disappearsas a result of the increase in bubble gas pressure neededto overcome sediment elasticity [46] Owing to increase ofpressure deep in the Earth denser mineral phase transitiontakes place Formations of such denser minerals voids aredeveloped at the interiors where residual stress energiesare stored Sudden release of such energies by earthquakesfollowed by numerous aftershocks causes release of numerousbubbles and plumes of CH

4at CMB Ascending numerous

plumes within a day or two large MH deposits may formin the regions of high latitudes The latent heat emitted orabsorbed during the course of freezing or melting of iceturbidity salinity volume of waterice wind speed warmand cold currents and atmospheric pressure play criticalrole in the formation of MH entrapped into ice cages [13]MH can dissociate rapidly due to expulsion of warm fluidsfrom the seafloor warming of overlying waters or possiblypressure perturbations For exploration and exploitation ofthe resources it is essential to know the physical propertiesof MH with its origin and mode of occurrences

8 Lava Tubes and Bubbles

In Tamil Nadu India lava tubes and bubbles of compositionof basaltic materials erupted at many places [47] SimilarlyFe Ti and Nb bearing lava tubes were also erupted in severalplaces as bubbles lava flows without any feeder dykes [48]From these evidences lava tubes and bubbles may be directlyfrom deep-seated source The gas trapped in bubble has arelatively thin glassy outer crust Inner portion of the bubblewall is coated with glassy exotic material of limu o pele[49] The Fe-Ti-Nb lava flows scattered at some places ofTamil Nadu indicate that they were directly erupted from theCMB horizon indicating that some fractures continuouslyextend up to CMB of 2900 km deep into the Earth Thesebasaltic bubbles that erupted on the surface have no rootsor feeder dykes The roots hardly extend less than a meterdeep and then vanish Lava bubble formation is very similarto the formation of CH

4plasma bubbles with similar bubble

tectonic mode The origin of MH is very similar to theeruption of alkali-basaltic basaltic eruptions that took placefrom the 1996 to 2004 at several places of Tamil Nadu Theholes and pits of various sizes are probably formed by lavaerupting onto the seafloor so quickly it traps water beneathit forming bubbles of steam that eventually collapse as thewater cools The hardened crust then breaks forming pockmarks and glassy black plates of ocean crust with stalactiteson their underside [49]

9 Continental Margins

Continental margins are genetically related to plate marginsPerhaps they appear to be one and the same Though thereare 6 continents Eurasia Africa Australia Antarctica NorthAmerica and South America their margins are marked byeither deep fractures ending with edges of mid oceanic ridgesor active subduction zones comprised of shallow fractures

Based on this concept of continental drift plate tectonicmodels are conceived The lithosphere is broken up into 7or 8 major plates and many minor plates The major platesbounded as edges of major continents The African plateenclosed with mid oceanic ridges of Atlantic AustralianIndian and Red sea mid oceanic ridges except northernpart whch is a fault bounded Alpine-Himalayan region Theeastern margin of Eurasian plate is marked by subductionzone and its western margin ended with the eastern edges ofAtlantic mid those of ocean ridges These features are verysimilar to the North American South American plates andPacific plates There exist some genetic relationships betweenplate margins and continental margins Tectonic plates arecomposed of thin oceanic crust and thick continental crustGlobal earth quake epicenters are concentrated along activemargins Active margins are commonly the sites of tectonicactivity earthquakes volcanoes mountain building and theformation of new igneous rock Because of the mountainousterrain most of the rivers are fairly short and the continentalshelf is narrow to non-existent dropping off quickly intothe depths of the subduction trench The passive continentalmargin is the transition between oceanic and adjoiningcontinental crust It is constructed by sedimentation abovean ancient rift Continental rifting creates new ocean basinsMajor portion of continental margins are surrounded bydeeply faulted and rifted volcanic and subducted activevolcanic continental margins Isostasy controls the uplift ordownwarp of rifted blocks The continental crust is stretchedand thinned due to plate movements Active margins are thesites of tectonic activity with narrow continental shelves Thecontinental margins of the two antipodal large low shear-velocity provinces (LLSVPs) under Africa and the Pacificare favourable locations for the episodic initiation of largethermal upwelling (mantle plume) Mantle plumes fromthe edges of stable areas with low seismic shear velocityabove the core-mantle boundary can explain the surfacedistribution of most hotspots LIPs and kimberlites [50]Because of isostatic compensation the continental regions donot correlate with topographic features Many hydrocarbonreservoirs occur with temporal and spatial relationships inpassive margins The spatial and temporal formation of MHfrom plasmatic state from deep interior of the earth is moreplausible than microbial or thermal dissociation of carbona-ceous materials into MH CH

4plasmatic bubbles attracted

by electromagnetic and gravity fields such bubbles movethrough interconnecting fractures towards polar regionMostsubduction zones trending N-S directions lying along theeastern peripheral portions of Eurasia and America arecaptured and concentrated towards polar region SimilarlyN-S trending Mid Oceanic Ridges and their interconnectingtransform faults guide these bubbles towards polar region

10 Cooling Earth

The huge quantities of energy released during the course ofearthquakes melting of rock at depth tectonic and orogenicmovements and volcanic and magmatic activities might havebeen derived by cooling of the Earth ever since its formation


estimated about 4500ma Earth evolution and dynamicsare determined by interior heat production and the heattransport towards the surface While the core heat is mostlytransported outwards by mantle plumes the sinking of coldsubducted plate material is balanced by a pervasive warmcounter flow transporting the mantle-generated radiogenicheat Hot lithosphere is generated at the oceanic spreadingridges and efficiently cooled by hydrothermal circulation inthe fractured ridge crust Subduction of oceanic lithosphereis the main cooling agent of the mantle The highest rates ofmagma production takes place along divergent plate marginsatmidocean ridges which are also the locus ofmost ofmantledegassing The ultrahigh PT-conditions during accretionenhance progress of endothermic reactions of formationof H and He-compounds which provide efficient coolingand produce end products more compact than the reactive[36]When Pacific plate undergoing subduction the oceanicplate absorbs huge quantity of heat from the mantle andcore Such type of cooling generates downstreams of coldmaterial that cross outer core and freeze onto the inner coreConvection currents move warm mantle to the surface andsend cool mantle back to the core Blobs of light elementsare being constantly released from the CMB The heat givenoff as the core cools flows from the core to the mantle toEarthrsquos crust Earth has an outer silicate solid crust a highlyviscous mantle a liquid outer core that is much less viscousthan the mantle and a solid inner core The blobs of lightelements will rise through this layer before they stir theoverlying outer core The dense LLSVP and ULVZ reservoirscould have remained largely isolated for most of the Earthrsquoshistory and stabilized antipodal near the equator by Earthrsquosrotation [50] Ocean floor sinking into the mantle due totectonic processes can lead to cooling in the mantle Theinner core of Earth is simultaneously melting and freezingdue to circulation of heat in the overlying rocky mantleDuring oceanic plate undergoing subduction the oceanicplate absorbs huge quantity of heat from the mantle and coreDownstreams of cold materials those cross outer core andfreeze onto the inner core and convection currents movewarm mantle to the surface and send cool mantle back tothe core Blobs of light elements are being constantly releasedfrom the CMB Over millions of years Earth has cooled fromthe inside out causing the CMB to partly freeze and solidifyThe inner core has subsequently freeze and for a solid mass[51]

11 Global Warming

When heat energy is dissipated out from the core to landsurface it is warmed up The release of methane likegreen house gases by natural dissociation also causes globalwarming Global warming causes thermal expansion of theEarthrsquos crust In areas prone to seismic activity this cancause submarine earthquakes and landslides Shockwaves candisturb methane hydrates that are already more vulnerabledue to temperature rises of the ocean During the last 5000years the Earth on average cooled about 072∘C until the last100 years when it warmed about 072∘C [52]

12 Conclusion

Research is going on the plasma state of a matter Heat energyis stored or released in a matter when transition from onephase to another is subjected to considerable debate Atsuper critical plasmatic state ions of different combinationsand dissociations could release or absorb various amounts ofenergy potentials to form new material In addition to pres-sure temperature and storage of potential energy in a matterspace time and the external or internal forces impacting onthe matter play a critical role in the dynamic changes or evo-lution of the matter into different many numbers forms CH

4

bearing fluid inclusions in minerals [53] are direct evidencesfor formation of MH bubbles During estimation of PTXcondition of in the trapping of fluid inclusions in mineralsseveral unknown factors are not considered Therefore onlyvery approximate results are obtained The occurrences ofrootless lava-tubes of alkali basalts Fe-Ti-Nb oxides lavatubes and carbonatite lava occurrences in various parts ofTamil Nadu might be other of evidence for such formationof MH bubbles from deep interior of the Earth Methaneplasma bubbles may be captured by electromagnetic fieldsand gravitational forces along N-S trending normal faultplanes of mid oceanic ridges of passive continental marginsand similarly along N-S trending faulted edges of activecontinental margins towards polar region where ambientconditions are available for the formation ofmethane hydrateHowever N-S trending passive margins comprised of deepnormal faults favour higher concentrations of accumulationof MH as larger deposit than that of active margins A largedeposit of methane hydrate may be formed in a day or twowhen earthquakes are associated with numerous foreshocksand aftershocks by releasing residual stresses stored by phasetransformation of minerals in the deep interior of the Earth

References

[1] F Pearce ldquoArctic-meltdown is a threat to humanityrdquo NewScientist Reed Business InformationArchived from the originalon 29th March 2009

[2] W Borg ldquoGraphic developed based on data from physicalchemical characteristics of natural gas hydraterdquo in EconomicGeology of Natural Gas Hydrate vol 9 of Coastal Systems andContinental Margins 2010

[3] R Sun and Z Duan ldquoAn accurate model to predict thethermodynamic stability of methane hydrate and methanesolubility in marine environmentsrdquo Chemical Geology vol 244no 1-2 pp 248ndash262 2007

[4] Y-T Tung L-J Chen Y-P Chen and S-T Lin ldquoThe growthof structure i methane hydrate from molecular dynamicssimulationsrdquo Journal of Physical Chemistry B vol 114 no 33pp 10804ndash10813 2010

[5] Methane hydrate-I Mineral Data 2013 httpwebmineralcomAlphabetical ListingshtmlUno9rlf8J9C

[6] Methane hydrate-II Mineral Data 2013 httpwebmineralcomAlphabetical ListingshtmlUno9 1f8J9B

[7] L W Diamond ldquoSystematics of H2

O inclusions Ch3

rdquo in FluidInclusions Analysis and Interpretation I Samson A Andersonand D Marshall Eds vol 32 of Mineralogical Association ofCanada Short Course Series 2003


[8] R J Hemley A P Jephcoat H K Mao C S Zha L W Fingerand D E Cox ldquoStatic compression of H

2

O-ice to 128GPa (128Mbar)rdquo Nature vol 330 no 6150 pp 737ndash740 1987

[9] N J Trappeniers ldquoPhase transitions in solid methane at highpressuresrdquo in Ices in the Solar System J Klinger D BenestA Dollfus and R Smoluchowski Eds pp 49ndash58 D ReidelPublishing Company 1985

[10] G Gao A R Oganov Y Ma et al ldquoDissociation of methaneunder high pressurerdquo The Journal of Chemical Physics vol 133no 14 Article ID 144508 2010

[11] C D Ruppel ldquoMethane hydrates and contemporary climatechangerdquo Nature EducationKnowledge vol 3 no 10 p 29 2011

[12] N Shakhova I Semiletov A Salyuk andD Kosmach ldquoAnoma-lies ofmethane in the atmosphere over the East Siberian shelf isthere any sign ofmethane leakage from shallow shelf hydratesrdquoEGU General Assembly Geophysical Research Abstracts vol10 EGU2008-A-01526 2008

[13] R Ramasamy S P Subramanian and R SundaravadiveluldquoStructure and tectonics of Lomonosov Ridge in Arctic Oceanad their significance on exploration and exploitation of Gashydratesrdquo in Proceedings of the 2nd nternational Conference onDrilling Technology IITM Chennai India December 2012

[14] CSSF ldquoMid Ocean Rides and volcanoes Prospective UsersrdquoCanadian Scientific Submersible Facility 2008

[15] H Deng P Yan H Liu and W Lou ldquoSeismic data processingand the characterization of a gas hydrate bearing zone offshoreof southwestern Taiwanrdquo Terrestrial Atmospheric and OceanicSciences vol 17 no 4 pp 781ndash797 2006

[16] U Tinivella M Giustiniani Xuewei Liu and I Pecher ldquoGashydrate on continental marginsrdquo Journal of Geological Researchvol 2012 Article ID 781429 2 pages 2012

[17] K Schmidt ldquoGas hydrate and methane plumes at HydrateRidge-Monerey BayrdquoMBARI College ofWilliam andMary pp1ndash13 2004

[18] K M Walter L C Smith and F S Chapin III ldquoMethanebubbling from northern lakes present and future contributionsto the global methane budgetrdquo Philosophical Transactions of theRoyal Society A vol 365 no 1856 pp 1657ndash1676 2007

[19] M V Ramana T Ramprasad K A Kamesh Raju andM DesaldquoOccurrence of gas hydrates along the continental marginsof India particularly the Krishna-Godavari offshore basinrdquoInternational Journal of Environmental Studies vol 64 pp 675ndash693 2007

[20] M E Torres A C Mix K Kinports et al ldquoIs methane ventingat the seafloor recorded by 12057513C of benthic foraminifera shellsrdquoPaleoceanography vol 18 no 3 p 1062 2003

[21] N Fechner P Linke A Luckge et al ldquoGas and fluid ventingat the Makran accretionary wedge off Pakistanrdquo Geo-MarineLetters vol 20 no 1 pp 10ndash19 2000

[22] R G Bowen S R Dallimore M Goe J F Wright and TG Lorenson ldquoGeomorphology and gas release from pock-mark features in the Mackenzie Delta Northwest TerritoriesCanadardquo in Proceedings of the 9th International Conference onPermafrost D L Kane K M Hinkel and A K Fairbanks Edspp 171ndash176 Institute of Northern Engineering 2008

[23] P van Rensbergen M de Batist J Klerkx et al ldquoSublacustrinemud volcanoes andmethane seeps caused by dissociation of gashydrates in Lake Baikalrdquo Geology vol 30 no 7 pp 631ndash6342002

[24] M V Ramana T Ramprasad K A K Raju and M DesaldquoOccurrence of gas hydrates along the continental margins

of India particularly the Krishna-Godavari offshore basinrdquoInternational Journal of Environmental Studies vol 64 no 6 pp675ndash693 2007

[25] K Fujikura T Okutani and T Maruyama Sensui Chosasenga Mita Shinkai Seibutsu Shinkai Seibutsu kenkyu no Genzai(Deep-Sea Life Biological Observations Using Research Sub-mersibles) Tokai University Press 2008

[26] R R Haacke R D Hyndman K-P Park D-G Yoo I Stoianand U Schmidt ldquoMigration and venting of deep gases intothe ocean through hydrate-choked chimneys offshore KoreardquoGeology vol 37 no 6 pp 531ndash534 2009

[27] G R Dickens C K Paull and PWallace ldquoDirect measurementof in situ methane quantities in a large gas-hydrate reservoirrdquoNature vol 385 no 6615 pp 426ndash428 1997

[28] A Rajan J Mienert S Bunz and S Chand ldquoPotential serpen-tinization degassing and gas hydrate formation at a young (lt20Ma) sedimented ocean crust of the Arctic Ocean ridge systemrdquoJournal of Geophysical Research B vol 117 no 3 Article IDB03102 2012

[29] D Andrault M Munoz N Bolfan-Casanova et al ldquoExperi-mental evidence for perovskite and post-perovskite coexistencethroughout the whole D1015840 regionrdquo Earth and Planetary ScienceLetters vol 293 no 1-2 pp 90ndash96 2010

[30] H P Scott R J Hemleym H-K Mao et al ldquoGenerationof methane in the earthrsquos mantle of carbonate reductionrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 101 no 39 pp 14023ndash14026 2004

[31] B R GeorgeMineralogical Applications of Crystal FieldTheoryCambridge University Press 1993

[32] D L AndersonNewTheory of the Earth Cambridge UniversityPress 2007

[33] E Knittle and R Jeanloz ldquoEarthrsquos core-mantle boundary resultsof experiments at high pressures and temperaturesrdquo Science vol251 no 5000 pp 1438ndash1443 1991

[34] C-S Yoo A Sengupta and M Kim ldquoCarbon dioxide carbon-ates in the earthrsquosmantle implications to the deep carbon cyclerdquoAngewandte ChemiemdashInternational Edition vol 50 no 47 pp11219ndash11222 2011

[35] E Boulard A Gloter A Cirgne et al ldquoNew host for carbon inthe deep Earthrdquo Proceedings of the National Academy of Sciencesof the United States of America vol 108 no 13 pp 5184ndash51872011 httpwwwpnasorgcontent108135184

[36] A Gilat and A Vol ldquoPrimordial hydrogen-helium degassingan overlooked major energy source for internal terrestrialprocessesrdquo HAIT Journal of Science and Engineering vol 2 no1-2 pp 125ndash167 2005

[37] Terradaily ldquoDeep mantle volcanic plumes cause of atmosphericoxygenationrdquo SpaceDaily November 2000

[38] G Audi O Bersillon J Blachot and A H Wapstra ldquoTheNUBASE evaluation of nuclear and decay propertiesrdquo NuclearPhysics A vol 624 no 1 pp 1ndash124 1997

[39] T Gold ldquoTerrestrial sources of carbon and earthquake out-gassingrdquo Journal of PetroleumGeology vol 1 no 3 pp 3ndash191979

[40] MMookherjee Y Nakajima G Steinle-Neumann et al ldquoHigh-pressure behavior of iron carbide (Fe

7

C3

) at inner core condi-tionsrdquo Journal of Geophysical Research B vol 116 no 4 ArticleID B04201 2011

[41] M Satish-Kumar H So T Yoshino M Kato and Y HiroildquoExperimental determination of carbon isotope fractionationbetween iron carbide melt and carbon 12C-enriched carbon in


the Earthrsquos corerdquo Earth and Planetary Science Letters vol 310no 3-4 pp 340ndash348 2011

[42] B J Wood ldquoCarbon in the corerdquo Earth and Planetary ScienceLetters vol 117 no 3-4 pp 593ndash607 1993

[43] ldquoSupercritical fluids-Fundamentals and applicationsrdquo httpchemengiiscernetingiridharrecthtml

[44] N J English and J M D MacElroy ldquoTheoretical studies ofthe kinetics of methane hydrate crystallization in externalelectromagnetic fieldsrdquoThe Journal of Chemical Physics vol 120no 21 pp 10247ndash10256 2004

[45] A A Kirdyashkin N L Dobretsov A G Kirdyashkin I NGladkov and N V Surkov ldquoHydrodynamic processes associ-ated with plume rise and conditions for eruption conduit for-mationrdquo Russian Geology Geologiya and Geophysics i Geofizikavol 46 no 9 pp 891ndash907 2005

[46] B S Gardiner B P Boudreau and B D Johnson ldquoGrowth ofdisk-shaped bubbles in sedimentsrdquo Geochimica et Cosmochim-ica Acta vol 67 no 8 pp 1485ndash1494 2003

[47] R Ramasamy ldquoMolten rock extrusionsrdquo Journal of the Geologi-cal Society of India vol 55 pp 337ndash338 2000

[48] R Ramasamy ldquoPetrographic observations on lava-tube injec-tions and eruptions and spray of volcanic beads in TamilNadu and evolution of plume tectonics of Indian Platerdquo inProceedings of the Workshop on Plume Tectonics pp 32ndash33NGRI Hyderabad India March 2000

[49] D A Clague A S Davis J L Bischoff J E Dixon andR Geyer ldquoLava bubble-wall fragments formed by submarinehydrovolcanic explosions on Lorsquoihi Seamount and KilaueaVolcanordquo Bulletin of Volcanology vol 61 no 7 pp 437ndash4492000

[50] ldquoCentre for Earth Evolution and Dynamics Deep Earth Mate-rials structure and dynamics UiOrdquoThe Faculty of Mathematicsand Natural Sciences CEED 2013

[51] S A Marcott J D Shaku P U Clark and A C Mix ldquoAReconstruction of regional and global temperature for the past11300 yearsrdquo Science vol 339 no 6124 pp 1198ndash1201 2013

[52] Trans Canada ldquoRate of Global warming is 50 times faster thanrate of cooling in last 5000 yearsrdquo Posted by gettingonmysoap-box on March 2013

[53] R B Larsen C K Brooks and D K Bird ldquoMethane-bearingaqueous saline solutions in the Skaergaard intrusion eastGreenlandrdquo Contributions to Mineralogy and Petrology vol 112no 2-3 pp 428ndash437 1992

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

EcologyInternational Journal of


EarthquakesJournal of


Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Mining


Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics

OceanographyInternational Journal of


Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering


GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Atmospheric SciencesInternational Journal of


OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in


MineralogyInternational Journal of


MeteorologyAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Geological ResearchJournal of


Geology Advances in


higher proportions than CH4 The presence of traces of H

2S

andN2indicates that the hydrates were formed at deep seated

source A large amount of CH4gas is trapped within a crystal

structure of waterice It is composed of onemole of CH4and

575 moles of water It has a density around 09 gcm3 TheoriginMH is puzzling owing to package of more than 168m3of equivalent volume of CH

4in its unit volume at STP

MH is tightly packed with CH4and surrounded by

H2O as separate phase CH

4and H

2O respectively have

critical temperatures 1904∘K and 6471∘K critical pressures46MPa and 2206MPa and critical densities of 0162 and0322 gcm3 CH

4has molar volume 1604 density 06556 gL

melting point minus182∘C and boiling point minus161∘C while theseproperties respectively for water are 18015 gcm3 1 kgL0∘C and 100∘C CH

4is the third lightest gas after H and

He in the Universe CH4being the simplest hydrocarbon

produces more heat per mass unit (357 J Kminus1molminus1) thanother complex hydrocarbons Therefore it has has higherdiffusivity than water Pure H

2O bearing fluid inclusions in

minerals behave perfectly as diathermal isochloric isoplethicsystems [7] H

2O exists as a supercritical fluid above its criti-

cal temperature of 300∘C inwide range of pressure conditionsfrom 300MPa to 300GPa [8] Experimental studies showCH4and H

2O attain solid states of MH at low temperatures

and high pressures [3 4 8] Solid CH4is produced at low

temperatures down to 21∘K and pressure up to 60 k barsat the Van der Walls Laboratory [9] Solid CH

4structure is

stable in the pressure range 10ndash90GPa The electronic bandstructure and density of states show that this structure hasnot metalized until 90GPa [9] Under high pressure CH

4

becomes unstable and it transforms to ethaneC2O6at 95GPa

butane C4H10

at 158GPa and further carbon and hydrogenabove 287GPa at zero temperature [10] In this paper anattempt is made on the possibility of formation of MH fromthe sources derived from deep interior of the Earth but alongthe continental margins of higher latitudes by the influencesof electromagnetic and gravity forces of the Earth

2 Mode of Occurrence

Themode of occurrences ofMH in diverse geological settings[11] is the major problem facing the study of origin of gashydrate deposits Recent bottom simulating reflector (BSR)explorations of hydrocarbon reveal that huge quantities of gashydrates occur in the following geological settings

(i) under the cover of permafrost [12](ii) continental shelves of high latitudes around Polar

Regions [12](iii) mid Oceanic Ridges [13](iv) ceep-sea hydrothermal vents [13 14](v) island arcs subduction zones and active continental

margins of China Taiwan-Luzon Island arcs [15](vi) passive continental margins [11 16](vii) CH

4plumes at Hydrate Ridge-Monterey Bay [17]

(viii) emissions of disc like CH4bubbles from the Abraham

Lake Alberto Canada [18 19]

(ix) active methane discharge on Hydrate Ridge on theCascadian accretionary margin Oregon [20] gas andfluid venting at the Makran accretionary wedge ofPakistan [21]

(x) seep gas composition similar to that of gassequestered in gas hydrates [22]

(xi) CH4ebullition sites that occur throughout the Arctic

region [17](xii) at some marine seeps massive relatively pure gas

hydrate occurs in seafloor mounds and in shallowsub-seafloor layers occurring at upper continentalslope depths

(xiii) seepage along fault planes of the continental slope inthe northwest Gulf of Mexico

(xiv) sublacustrine mud-volcanoes seeping out MH fromfreshwater Lake Baikal [23]

(xv) along the continental margins of India particularlythe Krishna-Godavari offshore basin [11 24]

(xvi) seeps of MH bubbles create carbonate rock formationand reefs by reaction between methane and seawater[25]

(xvii) CH4like gases migrates upward through networks

of fractures with elevated pore-fluid salinities intodeep offshore oceans near Korea along the activecontinental margins [26]

(xviii) migration of CH4from depth along geological faults

followed by precipitation or crystallization on con-tact of the rising gas stream with cold sea water [27]

(xix) hydrothermal venting of methane gas bubbles frommantle horizon to the Arctic seafloor is entrappedinto the growing ice-bergs and form as permafrostduring the course of several decades of duration [13]

(xx) thermohaline circulation promoted by differences indensity temperature and salinity of the Arctic Oceanwaters [13]

(xxi) microbial CH4can be formed where labile organic

carbon is available in onshore and offshore continen-tal margins [11]

Warm and cold currents have a major impact on forma-tion and dissipation of gas hydrates In the process of freezingthe salt in seawater is expelled as brine Approximatelyone-third of the Arctic Ocean is underlain by continentalshelf which includes a broad shelf north of Eurasia and thenarrower shelves of North America and Greenland

3 Mineral Phase Transitions at Interior ofthe Earth

Temperature and confining pressure increase with depth Inthe upper mantle along the subduction zones serpentiniza-tion of ultrabasic rocks [28] is reported At the tempera-ture around 900∘K and pressure corresponding to 600 kmCH4bearing serpentinized zones are recognized by acoustic





4and H

2Omay be released


2with other






20 (Mg025

Fe10158401015840075

)CO3= 20Mg

025

Fe101584010158401015840030

(C3O9)

0233


2)

(1)


4 Creep




4 Extensional creep


2



4




4keeps the CMB in a





4and H


of CH4and H



4and H



4and H


7C3


4at internal







4will be


2O CO

2 CH4 H2S HCl










4





GPa 119879

∘C H He CH4 H2O0 300 8652 12480 10707 2261103 500 14420 20800 17845 3768534 1800 51912 74880 64242 13566618 2000 57680 83200 71380 15074040 2500 72100 104000 89225 18842588 3500 100940 145600 124915 263795160 5500 158620 228800 196295 414535238 5800 167272 241280 207002 437146321 6000 173040 249600 214140 452220358 6200 178808 257920 221278 467294



4from


4and H

2O


4 and H



4and H

2O are


4and H

2O suddenly


4and H



4

and H2O













50

40

30

20

10

00 2000 4000 6000 8000

times104

Spec

ific e

nerg

y (J

mol

e)

HHe

CH4

H2O

Temperature (∘C)


4


40

30

20

10

0

times105

0 2000 4000 6000 8000

Spec

ific e

nerg

y (J

mol

e)

minus10

CH4

H2O

Temperature (∘C)

Figure 2 CH4


2


4








119876 = 119862119898Δ119879 (2)





∘C + CH4 119879∘C + H2O


0 40000 6000020000

times105

Exce

ss sp

ecifi

c ene

rgy

(Jm

ole)

40

30

20

10

0

minus10

minus20000

CH4

H2O

Excess T (∘C)



119876 = 119862Δ119898119879 (3)



4are frac-








4rapidly rise


2OorH

2when CH

4



4The thin wall


pushing-out






4



4and prevents the


2during upward





4H2 and H




Sea

Creep

Viscoelastic

(a)

Ice cage

Ice cageSea

CH4

CH4

CH4

CH4

CH4

CH4 CH4

CH4

1 m

1 km

2900 km

Brittle

Plasma

Plasma

Plasma

CMB Liquid layer

Plastic

Viscoelastic

Pockmark

Elastic

High dense



Very high dense

(H2O bubble

H2 2

H2

O

wall)Dense CH4

(b)


4



2







4







4packed


4that it























10 Cooling Earth




11 Global Warming


12 Conclusion


4


References








O inclusions Ch3




2



































7

C3


























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in





4and H

2Omay be released


2with other






20 (Mg025

Fe10158401015840075

)CO3= 20Mg

025

Fe101584010158401015840030

(C3O9)

0233


2)

(1)


4 Creep




4 Extensional creep


2



4




4keeps the CMB in a





4and H


of CH4and H



4and H



4and H


7C3


4at internal







4will be


2O CO

2 CH4 H2S HCl










4





GPa 119879

∘C H He CH4 H2O0 300 8652 12480 10707 2261103 500 14420 20800 17845 3768534 1800 51912 74880 64242 13566618 2000 57680 83200 71380 15074040 2500 72100 104000 89225 18842588 3500 100940 145600 124915 263795160 5500 158620 228800 196295 414535238 5800 167272 241280 207002 437146321 6000 173040 249600 214140 452220358 6200 178808 257920 221278 467294



4from


4and H

2O


4 and H



4and H

2O are


4and H

2O suddenly


4and H



4

and H2O













50

40

30

20

10

00 2000 4000 6000 8000

times104

Spec

ific e

nerg

y (J

mol

e)

HHe

CH4

H2O

Temperature (∘C)


4


40

30

20

10

0

times105

0 2000 4000 6000 8000

Spec

ific e

nerg

y (J

mol

e)

minus10

CH4

H2O

Temperature (∘C)

Figure 2 CH4


2


4








119876 = 119862119898Δ119879 (2)





∘C + CH4 119879∘C + H2O


0 40000 6000020000

times105

Exce

ss sp

ecifi

c ene

rgy

(Jm

ole)

40

30

20

10

0

minus10

minus20000

CH4

H2O

Excess T (∘C)



119876 = 119862Δ119898119879 (3)



4are frac-








4rapidly rise


2OorH

2when CH

4



4The thin wall


pushing-out






4



4and prevents the


2during upward





4H2 and H




Sea

Creep

Viscoelastic

(a)

Ice cage

Ice cageSea

CH4

CH4

CH4

CH4

CH4

CH4 CH4

CH4

1 m

1 km

2900 km

Brittle

Plasma

Plasma

Plasma

CMB Liquid layer

Plastic

Viscoelastic

Pockmark

Elastic

High dense



Very high dense

(H2O bubble

H2 2

H2

O

wall)Dense CH4

(b)


4



2







4







4packed


4that it























10 Cooling Earth




11 Global Warming


12 Conclusion


4


References








O inclusions Ch3




2



































7

C3


























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in



4 Extensional creep


2



4




4keeps the CMB in a





4and H


of CH4and H



4and H



4and H


7C3


4at internal







4will be


2O CO

2 CH4 H2S HCl










4





GPa 119879

∘C H He CH4 H2O0 300 8652 12480 10707 2261103 500 14420 20800 17845 3768534 1800 51912 74880 64242 13566618 2000 57680 83200 71380 15074040 2500 72100 104000 89225 18842588 3500 100940 145600 124915 263795160 5500 158620 228800 196295 414535238 5800 167272 241280 207002 437146321 6000 173040 249600 214140 452220358 6200 178808 257920 221278 467294



4from


4and H

2O


4 and H



4and H

2O are


4and H

2O suddenly


4and H



4

and H2O













50

40

30

20

10

00 2000 4000 6000 8000

times104

Spec

ific e

nerg

y (J

mol

e)

HHe

CH4

H2O

Temperature (∘C)


4


40

30

20

10

0

times105

0 2000 4000 6000 8000

Spec

ific e

nerg

y (J

mol

e)

minus10

CH4

H2O

Temperature (∘C)

Figure 2 CH4


2


4








119876 = 119862119898Δ119879 (2)





∘C + CH4 119879∘C + H2O


0 40000 6000020000

times105

Exce

ss sp

ecifi

c ene

rgy

(Jm

ole)

40

30

20

10

0

minus10

minus20000

CH4

H2O

Excess T (∘C)



119876 = 119862Δ119898119879 (3)



4are frac-








4rapidly rise


2OorH

2when CH

4



4The thin wall


pushing-out






4



4and prevents the


2during upward





4H2 and H




Sea

Creep

Viscoelastic

(a)

Ice cage

Ice cageSea

CH4

CH4

CH4

CH4

CH4

CH4 CH4

CH4

1 m

1 km

2900 km

Brittle

Plasma

Plasma

Plasma

CMB Liquid layer

Plastic

Viscoelastic

Pockmark

Elastic

High dense



Very high dense

(H2O bubble

H2 2

H2

O

wall)Dense CH4

(b)


4



2







4







4packed


4that it























10 Cooling Earth




11 Global Warming


12 Conclusion


4


References








O inclusions Ch3




2



































7

C3


























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in



GPa 119879

∘C H He CH4 H2O0 300 8652 12480 10707 2261103 500 14420 20800 17845 3768534 1800 51912 74880 64242 13566618 2000 57680 83200 71380 15074040 2500 72100 104000 89225 18842588 3500 100940 145600 124915 263795160 5500 158620 228800 196295 414535238 5800 167272 241280 207002 437146321 6000 173040 249600 214140 452220358 6200 178808 257920 221278 467294



4from


4and H

2O


4 and H



4and H

2O are


4and H

2O suddenly


4and H



4

and H2O













50

40

30

20

10

00 2000 4000 6000 8000

times104

Spec

ific e

nerg

y (J

mol

e)

HHe

CH4

H2O

Temperature (∘C)


4


40

30

20

10

0

times105

0 2000 4000 6000 8000

Spec

ific e

nerg

y (J

mol

e)

minus10

CH4

H2O

Temperature (∘C)

Figure 2 CH4


2


4








119876 = 119862119898Δ119879 (2)





∘C + CH4 119879∘C + H2O


0 40000 6000020000

times105

Exce

ss sp

ecifi

c ene

rgy

(Jm

ole)

40

30

20

10

0

minus10

minus20000

CH4

H2O

Excess T (∘C)



119876 = 119862Δ119898119879 (3)



4are frac-








4rapidly rise


2OorH

2when CH

4



4The thin wall


pushing-out






4



4and prevents the


2during upward





4H2 and H




Sea

Creep

Viscoelastic

(a)

Ice cage

Ice cageSea

CH4

CH4

CH4

CH4

CH4

CH4 CH4

CH4

1 m

1 km

2900 km

Brittle

Plasma

Plasma

Plasma

CMB Liquid layer

Plastic

Viscoelastic

Pockmark

Elastic

High dense



Very high dense

(H2O bubble

H2 2

H2

O

wall)Dense CH4

(b)


4



2







4







4packed


4that it























10 Cooling Earth




11 Global Warming


12 Conclusion


4


References








O inclusions Ch3




2



































7

C3


























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in




∘C + CH4 119879∘C + H2O


0 40000 6000020000

times105

Exce

ss sp

ecifi

c ene

rgy

(Jm

ole)

40

30

20

10

0

minus10

minus20000

CH4

H2O

Excess T (∘C)



119876 = 119862Δ119898119879 (3)



4are frac-








4rapidly rise


2OorH

2when CH

4



4The thin wall


pushing-out






4



4and prevents the


2during upward





4H2 and H




Sea

Creep

Viscoelastic

(a)

Ice cage

Ice cageSea

CH4

CH4

CH4

CH4

CH4

CH4 CH4

CH4

1 m

1 km

2900 km

Brittle

Plasma

Plasma

Plasma

CMB Liquid layer

Plastic

Viscoelastic

Pockmark

Elastic

High dense



Very high dense

(H2O bubble

H2 2

H2

O

wall)Dense CH4

(b)


4



2







4







4packed


4that it























10 Cooling Earth




11 Global Warming


12 Conclusion


4


References








O inclusions Ch3




2



































7

C3


























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in


Sea

Creep

Viscoelastic

(a)

Ice cage

Ice cageSea

CH4

CH4

CH4

CH4

CH4

CH4 CH4

CH4

1 m

1 km

2900 km

Brittle

Plasma

Plasma

Plasma

CMB Liquid layer

Plastic

Viscoelastic

Pockmark

Elastic

High dense



Very high dense

(H2O bubble

H2 2

H2

O

wall)Dense CH4

(b)


4



2







4







4packed


4that it























10 Cooling Earth




11 Global Warming


12 Conclusion


4


References








O inclusions Ch3




2



































7

C3


























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in














10 Cooling Earth




11 Global Warming


12 Conclusion


4


References








O inclusions Ch3




2



































7

C3


























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in



11 Global Warming


12 Conclusion


4


References








O inclusions Ch3




2



































7

C3


























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in



2



































7

C3


























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in
























Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in










Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

Documents

Review Article Formation of Gas Hydrates at Deep …downloads.hindawi.com/journals/jgr/2013/207031.pdfHindawi Publishing Corporation Journal of Geological Research Volume , Article