Mud volcano

Note:See the volcano article for information on magmatic volcanoes such as Mount St. Helens or Kilauea.

The term mud volcano or mud dome is used to refer to formations created by geologically excreted liquids and gases, although there are several different processes which may cause such activity. Temperatures are much cooler than igneous processes. The largest structures are 10 km in diameter and reach 700 metres in height.

About 86% of released gases are methane, with much less carbon dioxide and nitrogen emitted. Ejected materials often are a slurry of fine solids suspended in liquids which may include water (frequently acidic or salty) and hydrocarbon fluids.

In Azerbaijan, eruptions are driven from a deep mud reservoir which is connected to the surface even during dormant periods, when seeping water still shows a deep origin. Seeps have temperatures up to 2–3 °C above the ambient temperature.^{Gulf of Mexico sea bottom.}

A mud volcano may be the result of a piercement structure created by a pressurized mud diapir which breaches the Earth's surface or ocean bottom. Temperatures may be as low as the freezing point of ejected materials, particularly when venting is associated with the creation of hydrocarbon clathrate hydrate deposits.

Mud volcanoes are often associated with petroleum deposits and tectonic subduction zones and orogenic belts. Hydrocarbon gases often are erupted.

Contents

1 Features

2 Emissions

3 Locations

3.1 Europe and Asia
3.2 North and South America

3.2.1 Yellowstone's Mud Volcano

3.3 Other parts of the world

4 See also

5 References

6 External links

Features

gryphon: steep-sided cone shorter than 3m. Extrude mud.
mud cones: high cones shorter than 10m. Extrude mud and rock fragments.
scoria cones: formed by heating of mud deposits during fires.
hydrocarbon deposits.
salses: water-dominated pools with gas seeps.
springs: water-dominated outlets smaller than 0.5 m.
burning fires

Emissions

Most liquid and solid material is released during eruptions, but various seeps occur during dormant periods.

First order estimates of mud volcano emissions have been recently made. How much of the powerful greenhouse gas methane reaches the atmosphere from submarine volcanoes is not known.

2002: L.I. Dimitrov estimated that 10.2–12.6 Tg/yr of methane is released from onshore and shallow offshore mud volcanoes.

2002: Etiope and Klusman in 2002 estimated at least 1–2 and as much as 10–20 Tg/yr of methane may be emitted from onshore mud volcanoes.

2003: Etiope, in an estimate based on 120 mud volcanoes: "The emission results to be conservatively between 5 and 9 Tg/yr, that is 3–6 % of the natural methane sources officially considered in the atmospheric methane budget. The total geologic source, including MVs (this work), seepage from seafloor (Kvenvolden et al., 2001), microseepage in hydrocarbon-prone areas and geothermal sources (Etiope and Klusman, 2002), would amount to 35–45 Tg/yr." ^{2003: Milkov et al's analysis suggests that the global gas flux may be as high as 33 Tg/yr (15.9 Tg/yr during quiescent periods plus 17.1 Tg/yr during eruptions). 6 Tg/yr of greenhouse gases from onshore and shallow offshore mud volcanoes. Deep-water sources may emit 27 Tg/yr. Total may be 9% of fossil CH₄ missing in the modern atmospheric CH₄ budget, and 12% in the preindustrial budget. ^{2003: Alexei Milkov estimated approximately 30.5 Tg/yr of gases (mainly methane and CO₂) may escape from mud volcanoes to the atmosphere and the ocean. ^{2003: Achim J. Kopf estimated 1.97 × 10¹¹ to 1.23 × 10¹⁴ m³ of methane is released by all mud volcanoes per year, of which of which 4.66 × 10⁷ to 3.28 × 10¹¹ m³ is from surface volcanoes.^{Tg/yr from all mud volcanoes, of which 0.033–235 Tg is from surface volcanoes.}}}}

Locations

Missing image
Gas_hydrates_1996.jpg

Hydrate-bearing sediments, which often are associated with mud volcano activity.
Source: USGS, 1996.

Europe and Asia

Mud volcanoes are generally few in Europe, but dozens can be found on the Kerch Peninsula of southeastern Ukraine.

Many mud volcanoes exist on the shores of the Black Sea and Caspian Sea. Tectonic forces and large sedimentary deposits around the latter have created several fields of mud volcanoes, many of them emitting methane and other hydrocarbons. Features over 200 meters high exist in Azerbaijan, with large eruptions sometimes producing flames of similar scale. Iran and Pakistan also possess mud volcanoes in the Makran range of mountains in the south of the two countries. China has a number of mud volcanoes in Xinjiang province.

North and South America

Mud volcanoes of the North American continent include:

Shrub and Klawasi mud volcanoes in the Copper River basin by the Wrangell Mountains, Alaska, USA. Emissions are mostly CO₂ and nitrogen; the volcanoes are associated with magmatic processes.
An unnamed mud volcano 30 m high and with a top about 100 m wide, 24 km off Redondo Beach, California, and 800 m under the surface of the Pacific Ocean.
Smooth Ridge mud volcano in 1,000 m of water near Monterey Canyon, California.
Kaglulik mud volcano, 43 m under the surface of the Beaufort Sea, near the northern boundary of Alaska and Canada. Petroleum deposits are believed to exist in the area.
There are many mud volcanoes in Trinidad and Tobago in the Caribbean, near oil reserves in southern parts of the island of Trinidad. These include:
- the Devils Woodyard mud volcano near Hindustan
- the Moruga Bouffe mud volcano near Moruga
- the Piparo mud volcano
- the Chatham mud volcano located underwater in the Columbus Channel; this mud volcano periodically produces a short-lived island.

South American mud volcanoes include:

El Totumo, near Cartagena, Colombia.

Yellowstone's Mud Volcano

Missing image
Yellowstone_mud_volcano_17894.jpg

Yellowstone's Mud Volcano feature. (NPS,Peaco,1998)

The name of Yellowstone National Park's Mud Volcano feature and the surrounding area is misleading; it consists of hot springs, mud pots and fumaroles rather than a true mud volcano. The feature is much less active than in its first recorded description, although the area is quite dynamic. Yellowstone is an active geothermal area with a magma chamber near the surface, and active gases tend to be steam, carbon dioxide, and hydrogen sulfide.^{Andaman Islands in the Indian Ocean.}

References

^ S. Planke, H. Svensen, M. Hovland, D. A. Banks, B. Jamtveit (December 2003). "Mud and fluid migration in active mud volcanoes in Azerbaijan". Geo-Marine Letters 23 (3-4): 258-268. DOI:10.1007/s00367-003-0152-z
^ Etiope, Giuseppe. (2003). "A NEW ESTIMATE OF GLOBAL METHANE FLUX TO THE ATMOSPHERE FROM ONSHORE AND SHALLOW SUBMARINE MUD VOLCANOES". Geological Society of America Abstracts with Programs, 115. "A NEW ESTIMATE OF GLOBAL METHANE FLUX TO THE ATMOSPHERE FROM ONSHORE AND SHALLOW SUBMARINE MUD VOLCANOES." XVI INQUA Congress. Accessed on April 20, 2005.
^ Milkov, A. V., R. Sassen, T. V. Apanasovich, and F. G. Dadashev (2003). "Global gas flux from mud volcanoes: A significant source of fossil methane in the atmosphere and the ocean". Geophys. Res. Lett. 30 (2): 1037. DOI:10.1029/2002GL016358
^ "Global Distribution and Significance of Mud Volcanoes." AAPG Annual Meeting 2003: Energy - Our Monumental Task. Accessed on April 20, 2005.
^ Achim J. Kopf (2003). "Global methane emission through mud volcanoes and its past and present impact on the Earths climate". International Journal of Earth Sciences 92 (5): 806-816. DOI:10.1007/s00531-003-0341-z ISSN 1437-3254 (Paper) ISSN 1437-3262 (Online)
^ "Mud volcano." USGS Photo glossary of volcano terms. Accessed on April 20, 2005.

External links

Gaia's Breath—Methane and the Future of Natural Gas - USGS, June 2003
Azeri mud volcano flares - October 29 2001 BBC report
Redondo Beach mud volcano with methane hydrate deposits
Hydrocarbons Associated with Fluid Venting Process in Monterey Bay, California
Hydrothermal Activity and Carbon-Dioxide Discharge at Shrub and Upper Klawasi Mud Volcanoes, Wrangell Mountains, Alaska - U.S. Geological Survey Water-Resources Investigations Report 00-4207
Mud Volcano Eruption at Baratang, Middle Andamans