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Methane clathrate (CH4·5.75H2O) or (8CH4·46H2O), also called methane hydrate, hydromethane, methane ice, fire ice, natural gas hydrate, or gas hydrate, is a solid clathrate compound (more specifically, a clathrate hydrate) in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice. Originally thought to occur only in the outer regions of the Solar System, where temperatures are low and water ice is common, significant deposits of methane clathrate have been found under sediments on the ocean floors of the Earth. Methane hydrate is formed when hydrogen-bonded water and methane gas come into contact at high pressures and low temperatures in oceans.
Clathrate hydrates, or gas hydrates, clathrates, hydrates, etc., are crystalline water-based solids physically resembling ice, in which small non-polar molecules or polar molecules with large hydrophobic moieties are trapped inside "cages" of hydrogen bonded, frozen water molecules. In other words, clathrate hydrates are clathrate compounds in which the host molecule is water and the guest molecule is typically a gas or liquid. Without the support of the trapped molecules, the lattice structure of hydrate clathrates would collapse into conventional ice crystal structure or liquid water. Most low molecular weight gases, including O2, H2, N2, CO2, CH4, H2S, Ar, Kr, and Xe, as well as some higher hydrocarbons and freons, will form hydrates at suitable temperatures and pressures. Clathrate hydrates are not officially chemical compounds, as the enclathrated guest molecules are never bonded to the lattice. The formation and decomposition of clathrate hydrates are first order phase transitions, not chemical reactions. Their detailed formation and decomposition mechanisms on a molecular level are still not well understood. Clathrate hydrates were first documented in 1810 by Sir Humphry Davy who found that water was a primary component of what was earlier thought to be solidified chlorine.
The Paleocene–Eocene Thermal Maximum (PETM), alternatively "Eocene thermal maximum 1" (ETM1), and formerly known as the "Initial Eocene" or "Late Paleocene Thermal Maximum", was a time period with a more than 5–8 °C global average temperature rise across the event. This climate event occurred at the time boundary of the Paleocene and Eocene geological epochs. The exact age and duration of the event is uncertain but it is estimated to have occurred around 55.5 million years ago.
A cold seep is an area of the ocean floor where hydrogen sulfide, methane and other hydrocarbon-rich fluid seepage occurs, often in the form of a brine pool. Cold does not mean that the temperature of the seepage is lower than that of the surrounding sea water. On the contrary, its temperature is often slightly higher. The "cold" is relative to the very warm conditions of a hydrothermal vent. Cold seeps constitute a biome supporting several endemic species.
A mud volcano or mud dome is a landform created by the eruption of mud or slurries, water and gases. Several geological processes may cause the formation of mud volcanoes. Mud volcanoes are not true igneous volcanoes as they do not produce lava and are not necessarily driven by magmatic activity. Mud volcanoes may range in size from merely 1 or 2 meters high and 1 or 2 meters wide, to 700 meters high and 10 kilometers wide. Smaller mud exudations are sometimes referred to as mud-pots.
In geotechnical engineering, drilling fluid, also called drilling mud, is used to aid the drilling of boreholes into the earth. Often used while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are also used for much simpler boreholes, such as water wells. One of the functions of drilling mud is to carry cuttings out of the hole.
The National Institute of Ocean Technology (NIOT) was established in November 1993 as an autonomous society under the Ministry of Earth Sciences, Government of India. NIOT is managed by a Governing Council and the Director is the head of the Institute. The institute is based in Chennai.
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The clathrate gun hypothesis is a proposed explanation for the periods of rapid warming during the Quaternary. The idea is that changes in fluxes in upper intermediate waters in the ocean caused temperature fluctuations that alternately accumulated and occasionally released methane clathrate on upper continental slopes, these events would have caused the Bond Cycles and individual interstadial events, such as the Dansgaard–Oeschger interstadials.
Carbon dioxide hydrate or carbon dioxide clathrate is a snow-like crystalline substance composed of water ice and carbon dioxide. It normally is a Type I gas clathrate. There has also been some experimental evidence for the development of a metastable Type II phase at A temperature near the ice melting point. The clathrate can exist below 283K (10 °C) at a range of pressures of carbon dioxide. CO2 hydrates are widely studied around the world due to its promising prospects of carbon dioxide capture from flue gas and fuel gas streams relevant to post-combustion and pre-combustion capture. It is also quite likely to be important on Mars due to the presence of carbon dioxide and ice at low temperatures.
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The Nankai Trough is a submarine trough located south of the Nankaidō region of Japan's island of Honshū, extending approximately 900 km (559 mi) offshore. The underlying fault, the Nankai megathrust, is the source of the devastating Nankai megathrust earthquakes, while the trough itself is potentially a major source of hydrocarbon fuel, in the form of methane clathrate.
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Mount Elbert Methane Hydrate Site
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Ocean Networks Canada is a University of Victoria initiative that operates the NEPTUNE and VENUS cabled ocean observatories in the northeast Pacific Ocean and the Salish Sea. Additionally, Ocean Networks Canada operates smaller community-based observatories offshore from Cambridge Bay, Nunavut., Campbell River, Kitamaat Village and Digby Island. These observatories collect data on physical, chemical, biological, and geological aspects of the ocean over long time periods. As with other ocean observatories such as ESONET, Ocean Observatories Initiative, MACHO and DONET, scientific instruments connected to Ocean Networks Canada are operated remotely and provide continuous streams of freely available data to researchers and the public. Over 200 gigabytes of data are collected every day.
Gas hydrate stability zone, abbreviated GHSZ, also referred to as methane hydrate stability zone (MHSZ) or hydrate stability zone (HSZ), refers to a zone and depth of the marine environment at which methane clathrates naturally exist in the Earth's crust.
References
- ↑ Wunsch, C.; D. E. Gunn (2003). "A densely sampled core and climate variable aliasing". Geo-Marine Letters. 23 (1): 64–71. Bibcode:2003GML....23...64W. doi:10.1007/s00367-003-0125-2. S2CID 12475897.
- ↑ Bloemendal, J.; X. M. Liu; T. C. Rolph (1995). "Correlation of the magnetic susceptibility stratigraphy of Chinese loess and the marine oxygen isotope record: chronological and palaeoclimatic implications". Earth and Planetary Science Letters. 131 (3–4): 371–380. Bibcode:1995E&PSL.131..371B. doi:10.1016/0012-821X(95)00016-6.
- ↑ Robinson, Simon G.; Mark A. Maslin; I. Nicholas McCave (1995). "Magnetic susceptibility variations in Upper Pleistocene deep-sea sediments of the NE Atlantic: Implications for ice rafting and paleocirculation at the Last Glacial Maximum". Paleoceanography. 10 (2): 221–250. Bibcode:1995PalOc..10..221R. doi:10.1029/94PA02683.
- ↑ Offshore-SEA
- ↑ Schultheiss, Peter J.; Timothy J. G. Francis; Melanie Holland; John A. Roberts; H. Amann; Thjunjoto; R. John Parkes; Derek Martin; Martin Rothfuss; Floris Tyunder; Peter D. Jackson (2006). "Pressure coring, logging and subsampling with the HYACINTH system". New Techniques in sediment core analysis. Special Publication. Vol. 267. London: Geological Society. pp. 151–163.
- ↑ Holland, Melanie; Peter J. Schultheiss; John A. Roberts; Matthew J. Druce (2008). "Observed gas hydrate morphologies in marine sediments". Proceedings of the 6th International Conference on Gas Hydrates. 6th International Conference on Gas Hydrates. Vancouver, British Columbia. hdl:2429/1201.
- ↑ Schultheiss, Peter J.; Melanie E. Holland; Gary D. Humphrey (2008). Borehole pressure coring and laboratory pressure core analysis for gas hydrate investigations. Offshore Technology Conference. Houston.
- ↑ Schultheiss, Peter J.; Melanie Holland; John A. Roberts; Gary D. Humphrey (2008). "Pressure core analysis: The keystone of a gas hydrate investigation". Proceedings of the 6th International Conference on Gas Hydrates. 6th International Conference on Gas Hydrates. Vancouver, British Columbia. hdl:2429/1200.
- ↑ "Archived copy". Archived from the original on 2016-11-16. Retrieved 2012-08-25.
{{cite web}}: CS1 maint: archived copy as title (link) - ↑ Weaver, P. P. E.; Peter J. Schultheiss (1990). "Current methods for obtaining, logging and splitting marine sediment cores". In Ernest A. Hailwood; Robert B. Kidd (eds.). Marine geological surveying and sampling. Dordrecht: Kluwer. pp. 85–101. ISBN 978-0-7923-0788-4.