Methane HydratesMethane HydratesJake Ross and Yuliana Proenza Jake Ross and Yuliana ProenzaThe Three QuestionsThe Three QuestionsWhat is a Gas Hydrate? What is a Gas Hydrate?What is their potential as an energy resource? What is their potential as an energy resource?What role do they play in global climateWhat role do they play in global climate change? change?What is a Gas Hydrate?What is a Gas Hydrate?A gas hydrate is a crystalline solid; its building blocks consist o a gas molecule surrounded by a cage o !ater molecules"#t is similar to ice$ e%cept that the crystalline structure is stabilized by the guest gas molecule !ithin the cage o !ater molecules" &uitable gases are' carbon dio%ide$ hydrogen sulide$ and se(eral lo!)carbon)number hydrocarbons" *ost gas hydrates $ ho!e(er are *ethane Hydrates"

Hydrate SamplesHydrate SamplesGas hydrates in sea)loor moundsHere methane gas is acti(ely dissociating rom a hydrate mound"Gas hydrate can occur as nodules$ laminae$ or (eins !ithin sediment" CHCH4 4 Hydrate StabilityHydrate StabilityWhere are Methane Hydrates Where are Methane Hydrates located?located?

Found in 4 major location typesFound in 4 major location types&ubduction zones +e"g"$ ,ankai -rough Japan$ .ascadia /asin0 &ubduction zones +e"g"$ ,ankai -rough Japan$ .ascadia /asin0Passi(e *argins +e"g"$ /lake Ridge on the southeast cost o the 1&0 Passi(e *argins +e"g"$ /lake Ridge on the southeast cost o the 1&02)shore hydrocarbon +e"g"$ Gul o *e%ico$ ,orth &lope Alaska0 2)shore hydrocarbon +e"g"$ Gul o *e%ico$ ,orth &lope Alaska02n)shore Arctic Permarost +e"g"$ *ackenzie 3elta$ Arctic Russia$2n)shore Arctic Permarost +e"g"$ *ackenzie 3elta$ Arctic Russia$ Arctic Alaska0Arctic Alaska0 Where are Methane Hydrates Where are Methane Hydrates located?located?

Methane hydrate occurs in a zone referred to as theMethane hydrate occurs in a zone referred to as the hydrate stability zone. hydrate stability zone.The zone lies roughly parallel to the land or seafloorThe zone lies roughly parallel to the land or seafloor surface. surface.ermafrost regions!ermafrost regions! depths about "#$ % &$$$ m belo' the surface. depths about "#$ % &$$$ m belo' the surface.(n oceanic sediment(n oceanic sediment ocean is at least )$$ m deep!ocean is at least )$$ m deep! depths of $ % "!"$$ m belo' the seafloor. depths of $ % "!"$$ m belo' the seafloor.Where are Methane Hydrates Where are Methane Hydrates located?located?Hydrate concentration occurs at depocentersWhere there is a rapid accumulation o organic detritus +rom !hichbacteria generate methane0" .arbon isotope analyses indicate most o the methane in hydrates is microbial$ ho!e(er thermogenic sources ha(e been identiied in the Gul o *e%icoWhere there is a rapid accumulation o sediments +!hich protect detritus rom o%idation0"What is the potential of What is the potential of CHCH44 Hydrates as an energy resourceHydrates as an energy resource

Why are CHWhy are CH44 Hydrates a good energy Hydrates a good energy resourceresource-he gas is held in a crystal structure$ thereore gas molecules are-he gas is held in a crystal structure$ thereore gas molecules are more densely packed than in con(entional or other uncon(entionalmore densely packed than in con(entional or other uncon(entional gas traps"gas traps" Hydrate orms as cement in the pore spaces o sediment and has theHydrate orms as cement in the pore spaces o sediment and has the capacity to ill sediment pore space and reduce permeability"capacity to ill sediment pore space and reduce permeability" .H .H4 4 )) hydrate)cemented strata thereby act as seals or trapped ree gas hydrate)cemented strata thereby act as seals or trapped ree gasProduction o gas rom hydrate)sealed traps may be an easy !ay toProduction o gas rom hydrate)sealed traps may be an easy !ay to e%tract hydrate gas because the reduction o pressure caused bye%tract hydrate gas because the reduction o pressure caused by production can initiate a breakdo!n o hydrates and a recharging oproduction can initiate a breakdo!n o hydrates and a recharging o the trap !ith gas the trap !ith gas CHCH44 Hydrates and Climate ChangeHydrates and Climate Change*ethane is a (ery eecti(e greenhouse gas"#t is ten times more*ethane is a (ery eecti(e greenhouse gas"#t is ten times more potent than carbon dio%ide" potent than carbon dio%ide" -here is increasing e(idence that points to the periodic massi(e-here is increasing e(idence that points to the periodic massi(e release o methane into the atmosphere o(er geological timescales" release o methane into the atmosphere o(er geological timescales"Are these enormous releases o methane a cause or an eect o globalAre these enormous releases o methane a cause or an eect o global climate change? climate change?*Global !arming may cause hydrate destabilization through a rise in oceanGlobal !arming may cause hydrate destabilization through a rise in ocean bottom !ater temperatures"-he increased methane content in thebottom !ater temperatures"-he increased methane content in the atmosphere in turn !ould be e%pected to accelerate !arming$ causingatmosphere in turn !ould be e%pected to accelerate !arming$ causing urther dissociation$ potentially resulting in run a!ay global !arming"urther dissociation$ potentially resulting in run a!ay global !arming" *&ea le(el rise$ ho!e(er$ during !arm periods may act to stabilize hydrates&ea le(el rise$ ho!e(er$ during !arm periods may act to stabilize hydrates by increasing hydrostatic pressure$ thereby acting as a check on !arming"by increasing hydrostatic pressure$ thereby acting as a check on !arming" *Hydrate dissociation may act as a check on glaciations$ !hereby reducedHydrate dissociation may act as a check on glaciations$ !hereby reduced sea le(els may cause sealoor hydrate dissociation$ releasing methane andsea le(els may cause sealoor hydrate dissociation$ releasing methane and !arming the climate !arming the climate. .-his diagram illustrates the aect sea le(el change has on the stability o hydrates.