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Topic: Methane clathrate


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In the News (Mon 22 Jul 19)

  
  Methane - New World Encyclopedia Preview
Methane is the simplest hydrocarbon, with the chemical formula CH In chemical terms, it is classified as an alkane.
In methane, the carbon-hydrogen covalent bond is among the strongest in all hydrocarbons.
Methane in the Earth's atmosphere is an important "greenhouse gas" that contributes to the "greenhouse effect." The Earth absorbs some of the Sun's energy and then emits energy at longer wavelengths.
www.newworldencyclopedia.org /preview/Methane   (1902 words)

  
  Methane clathrate - Wikipedia, the free encyclopedia
Methane clathrates remain stable at temperatures up to 18 °C. The average methane clathrate hydrate composition is 1 mole of methane for every 5.75 moles of water, though this is dependent on how many methane molecules "fit" into the various cage structures of the water lattice.
Methane clathrates in continental rocks are trapped in beds of sandstone or siltstone at depths of less than 800m.
Because methane is a powerful greenhouse gas, ten times as effective as carbon dioxide, the sudden release of large amounts of natural gas from methane clathrate deposits has been hypothesized as a cause of past and possibly future climate changes.
en.wikipedia.org /wiki/Methane_clathrate   (1587 words)

  
 Clathrate compound - Wikipedia, the free encyclopedia
A clathrate or clathrate compound or cage compound is a chemical substance consisting of a lattice of one type of molecule trapping and containing a second type of molecule.
Clathrate complex used to refer only to the inclusion complex of hydroquinone, but recently it has been adopted for many complexes which consist of a host molecule (forming the basic frame) and a guest molecule (set in the host molecule by interaction).
The clathrate complexes are various and include, for example, strong interaction via chemical bonds between host molecules and guest molecules, or guest molecules set in the geometrical space of host molecules by weak intermolecular force.
en.wikipedia.org /wiki/Clathrate   (458 words)

  
 ipedia.com: Methane Article   (Site not responding. Last check: 2007-10-12)
CO The strength of the carbon-hydrogen covalent bond in methane is among the strongest in all hydrocarbons, and thus its use as a chemical feedstock is limited.
Pure methane is odorless, but when used as a fuel is usually mixed with small quantities of strongly-smelling sulfur compounds such as ethyl mercaptan to enable the detection of leaks.
Methane is a greenhouse gas with a global warming potential of 21 (meaning that it has 21 times the warming ability of carbon dioxide).
www.ipedia.com /methane.html   (432 words)

  
 Clathrate compound Summary
Methane hydrate is an ice-like compound in which methane molecules are enclosed in cavities formed by water molecules.
A clathrate or clathrate compound or cage compound is a chemical substance consisting of a lattice of one type of molecule trapping and containing a second type of molecule.
Clathrate complex used to refer only to the inclusion complex of hydroquinone, but recently it has been adopted for many complexes which consist of a host molecule (forming the basic frame) and a guest molecule (set in the host molecule by interaction).
www.bookrags.com /Clathrate_compound   (703 words)

  
 Hydrates store immense amounts of methane, with major implications for energy resources and climate, but the natural ...   (Site not responding. Last check: 2007-10-12)
Methane hydrate is stable in ocean floor sediments at water depths greater than 300 meters, and where it occurs, it is known to cement loose sediments in a surface layer several hundred meters thick.
Methane hydrate is a crystalline solid consisting of methane gas molecules, each surrounded by a cage of water molecules.
Methane released as a result of landslides caused by a sea-level fall would warm the Earth, as would methane released from methane hydrate in Arctic sediments as they become warmed during a sea-level rise.
www.ndsu.nodak.edu /instruct/ashworth/webpages/g491/2001presentations/methane_hydrate/introduction.htm   (376 words)

  
 Methane clathrate - Cassiopedia, The True Encyclopedia
Methane hydrates are believed to form by migration of gas from depth along geological faults, followed by precipitation, or crystallization, on contact of the rising gas stream with cold sea water.
Methane clathrates remain stable at temperatures up to 18 °C. The average methane clathrate hydrate composition is 1 mole of methane for every 5.75 moles of water, though this is dependent on how many methane molecules "fit" into the various cage structures of the water lattice.
Methane clathrates in continental rocks are trapped in beds of sandstone or siltstone at depths of less than 800m.
www.cassiopedia.org /wiki/index.php?title=Methane_clathrate   (1656 words)

  
 biology - Methane
CH → CO Methane is a greenhouse gas with a global warming potential of 21.
The strength of the carbon-hydrogen covalent bond in methane is among the strongest in all hydrocarbons, and thus its use as a chemical feedstock is limited.
Methane is a greenhouse gas with a global warming potential of 21.
www.biologydaily.com /biology/Methane   (617 words)

  
 Methane hydrates
Methane hydrates, a promising natural gas resource, are believed to reside throughout the globe in sea-floor sediments and permafrost.
A clathrate is simply a structure in which water molecules under certain conditions bond to form an ice-like cage that encapsulates a gas molecule, known as a guest molecule.
Methane hydrates, which form at low temperature and high pressure, are found in sea-floor sediments and the arctic permafrost.
www.ornl.gov /info/reporter/no16/methane.htm   (800 words)

  
 Clathrates - little known components of the global carbon cycle
Clathrates occur wherever the conditions within the sediments are in the methane-clathrate stability field, and where methane and water are available (Fig.
Methane is greenhouse gas, and discharge of large amounts of methane into the atmosphere would cause global warming.
Overall decreasing methane hydrate reservoirs (e.g., as a result of fluctuating sea levels during glacial -interglacial alternation) thus lead to a secular trend towards a lighter carbon isotopic signature of the ocean-atmosphere reservoir.
ethomas.web.wesleyan.edu /ees123/clathrate.htm   (2582 words)

  
 The Canadian National Newspaper: Methane threatens to bake humanity like Turkeys in an Oven
Methane is 60 times more powerful than CO2 as a greenhouse gas but only remains in the atmosphere for about ten years and so looses it's greenhouse effect quickly compared to CO2 which remains in the atmosphere for 100 years.
Methane can also be trapped by permafrost layers which over-lay lower unfrozen layers of vegetable material that is decaying and producing methane which remains trapped by the frozen permafrost on top.
As the atmosphere warmed different types of methane deposits would start to be released and so a cycle of methane release leading to increased warming leading to more methane release from other areas of methane deposits elsewhere in the world would become established as global warming effected different areas of the world.
www.agoracosmopolitan.com /home/Frontpage/2007/01/16/01314.html   (3025 words)

  
 Crystallography News No.86 September 2003   (Site not responding. Last check: 2007-10-12)
Calculations suggest methane clathrate hydrate becomes unstable with respect to ice and methane at 1.2 GPa and so just prior to overturn, all of the methane in the rock-ice core is assumed to have been in the form of free methane.
The pulse of methane cannot have been injected directly into the atmosphere because the rate of removal by photo-dissociation is such that all methane would be lost in a timescale much shorter than the life of the Solar System.
From neutron diffraction patterns of methane hydrate collected on increasing pressure at room temperature, it is found that at ~0.9 GPa, methane clathrate hydrate transforms to a new form, methane hydrate II (MH-II) and ice VI appears — indicating that MH-II is richer in methane than its parent phase.
bca.cryst.bbk.ac.uk /bca/on-line/2003/cn86tite.htm   (1309 words)

  
 [No title]
Methane escaping from the sea floor to the atmosphere has been a popular suspect for causing rapid climate changes during and at the end of the last ice age.
These clathrates are stable only within a certain range of temperatures and pressures; when brought to the surface, they melt rapidly and release burnable gas to the air.
Methane from clathrates contains more deuterium (the heavy form of hydrogen) than methane from land-based sources, thanks in part to the bacteria that create the gas on the sea floor, and the material they consume.
www.climateark.org /shared/reader/welcome.aspx?linkid=52198   (816 words)

  
 Global Warming: Methane Could Be Far Worse Than Carbon Dioxide - Health Supreme
Methane gas, abundantly trapped as a half frozen slush in the northern hemisphere's tundra permafrost regions and at the bottom of the sea may well be a ticking time bomb, says geologist John Atcheson in an article published by the Baltimore Sun in December last year.
Methane is about twenty times stronger as a greenhouse gas than carbon dioxide.
Ruskin believes that methane may have been the driving force in previous catastrophic changes of the earth's climate, where 95 percent of marine species and 70 percent of land species were lost in - geologically speaking - the blink of an eye.
www.newmediaexplorer.org /sepp/2005/02/01/global_warming_methane_could_be_far_worse_than_carbon_dioxide.htm   (5571 words)

  
 EIA Energy Kids Page
A gas hydrate, such as methane hydrate, is a crystalline solid known as a clathrate.
The word clathrate has its origins in the Latin word meaning “to enclose with bars.” It follows then that clathrates are a class of chemical substances made of two unique materials, one of which encloses the other in an open, lattice-like cage.
Methane hydrate is formed when water molecules freeze around a molecule of methane gas.
www.eia.doe.gov /kids/classactivities/methanehydrates_sec.html   (608 words)

  
 USGS Fact sheet: Gas (Methane) Hydrates -- A New Frontier
Methane trapped in marine sediments as a hydrate represents such an immense carbon reservoir that it must be considered a dominant factor in estimating unconventional energy resources; the role of methane as a 'greenhouse' gas also must be carefully assessed.
Hydrates store immense amounts of methane, with major implications for energy resources and climate, but the natural controls on hydrates and their impacts on the environment are very poorly understood.
Methane released as a result of landslides caused by a sea-level fall would warm the Earth, as would methane released from gas hydrates in Arctic sediments as they become warmed during a sea-level rise.
marine.usgs.gov /fact-sheets/gas-hydrates/title.html   (989 words)

  
 NASA GISS: Research Features: Methane: A Scientific Journey from Obscurity to Climate Super-Stardom   (Site not responding. Last check: 2007-10-12)
As shown by a chemistry "ball and stick" model, a methane molecule is composed of one atom of carbon surrounded by four atoms of hydrogen.
Clathrates are a class of compound that consist of a cage of molecules that can trap gases, such as methane, in a solid form.
There is a small increase in methane concentrations from about 5000 years ago, and the conventional wisdom attributes this to the development of boreal wetlands and the major river deltas (at the mouths of the Nile, Mississippi, Niger and Amazon rivers, for instance) once sea level had basically stabilised after the deglaciation.
www.giss.nasa.gov /research/features/methane   (3278 words)

  
 BBC NEWS | Science/Nature | Search for life signal on Titan
Methane is constantly destroyed by UV light so there must be a source within Titan to replenish the atmosphere.
Methane can also be released from a trapped form called clathrate and produced by a geological process called "serpentinisation".
Another possibility is that methane molecules are trapped in a water-ice matrix called clathrate (or methane hydrate).
news.bbc.co.uk /2/hi/science/nature/4196261.stm   (620 words)

  
 Science News Online (11/9/96): The Mother Lode of Natural Gas
Methane below the hydrate layer remains in gaseous form because the temperatures there are too high to support freezing.
Because methane is a powerful greenhouse gas--about 10 times as strong as carbon dioxide--massive melting of hydrates and the ensuing release of methane gas could raise Earth's surface temperature.
Because methane has a distinctive isotopic fingerprint that matches the shifts, Kennett suggests that large volumes of methane must have poured into the ocean at these times.
www.sciencenews.org /pages/sn_arch/11_9_96/bob1.htm   (1970 words)

  
 section1.htm
The methane clathrate remained a laboratory oddity until in the early 1980’s the Russians became aware of just how much of this material was present in Northern Siberia and started to develop methods of extracting it.
Methane hydrate is a crystalline clathrate compound in which methane gas molecules are trapped in water cages which form part of a distorted ice matrix.
Methane hydrate has a cubic crystal structure consisting of two types of dodecahedral water cages: a small cage which has twelve pentagonal faces and a large cage having twelve pentagonal and two hexagonal faces.
www.ijvs.com /volume6/edition1/section1.html   (5777 words)

  
 MainlyMartian: Where have we got to?
If the methane is made in the atmosphere, it might be more concentrated at altitude than near the surface, and observations might be able to say whether this is true or not.
There are lots of methane clathrates on the earth, and there's no reason to think they couldn't form on Mars, if there was some methane and the right conditions.
One is that methane leaks out all the time and that it has been doing so for millions of years, which implies that there is a truly colossal reservoir in the clathrates.
mainlymartian.blogs.com /semijournal/2004/04/where_have_we_g.html   (1815 words)

  
 Does Titan's methane originate from underground?
The Cassini-Huygens mission also showed that there is not after all a lot of liquid methane remaining on the moon's surface, and so it is not clear where the atmospheric methane gas comes from.
"As methane is broken down by light-induced chemical reactions over a timescale of tens of millions of years, it can't just be a remnant of the atmosphere present when Titan itself was formed, and it must be replenished quite regularly," said Tobie.
"According to our model, during the last outgassing episode, the dissociation of the methane clathrate and hence release of methane are induced by thermal anomalies within the icy crust, which are generated by crystallisation in the internal ocean," said Tobie.
www.eurekalert.org /pub_releases/2006-03/esa-dtm030206.php   (588 words)

  
 Janda Lab
One example of clathrate hydrate is a propane clathrate hydrate (here is a movie illustrating a burning of a propane hydrate prepared in an undergraduate laboratory we have developed for UCI students).
Some gas clathrate hydrates can be stable almost up to a room temperature at 1 atm, for example Cl hydrate, others require a higher pressure and/or a lower temperature as, for example, methane hydrate.
Although the mechanism for forming these large deposits is not yet understood in detail, it is clear that methane in sediments combine with the water when the pressure and temperature are within the stability region.
chem.ps.uci.edu /~kcjanda/index.htm   (715 words)

  
 SEMP: Evidence-based disaster management: preparedness, response, recovery, and mitigation.
Methane is a small molecule made up of a single carbon atom surrounded by four hydrogen atoms, which exists in an ice-like form variously called “methane hydrate”, “methane ice” or “methane clathrate”.
Clathrate means “cage”, which describes the structure of methane ice: a cage of water molecules around methane gas molecules, allowing high methane concentrations.
Methane ices can break down at certain temperatures and pressures, permitting the gas in the clathrate cages to be released.
www.semp.us /publications/biot_reader.php?BiotID=301   (1045 words)

  
 Methane Hydrates May Solve Energy Woes — Or Not
Methane hydrate (aka methane clathrate) is formed when methane migrates upward from undersea organic sediments and bonds with water under specific conditions of temperature and pressure to form a crystal structure similar to ice.
The methane would then be collected in much the same way as natural gas is extracted today, using pipes set into the deposit from drilling rigs.
Methane is a very effective greenhouse gas (It traps 21 times the heat of CO2.), and the development of methane hydrate raises serious issues related to global warming.
gnn.tv /threads/24993/Methane_Hydrates_May_Solve_Energy_Woes_Or_Not   (1016 words)

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