Gakkel Ridge

[[File:Arctic Ocean bathymetric features.png|thumb|350px|Main bathymetric/topographic features of the Arctic Ocean]] The '''Gakkel Ridge''' (formerly known as the '''Nansen Cordillera''' and '''Arctic Mid-Ocean Ridge''') is a [[mid-oceanic ridge]], a divergent [[tectonics|tectonic]] plate boundary between the [[North American Plate]] and the [[Eurasian Plate]]. It is located in the [[Arctic Ocean]] between [[Greenland]] and [[Siberia]], and has a length of about 1,800 kilometers. Geologically, it connects the northern end of the [[Mid-Atlantic Ridge]] with the [[Laptev Sea Rift]]. The existence and approximate location of the Gakkel Ridge were predicted by [[Soviet Union|Soviet]] polar explorer [[Yakov Yakovlevich Gakkel]], and confirmed on Soviet expeditions in the Arctic around 1950. The Ridge is named after him, and the name was recognized in April 1987 by [[SCUFN]] (under that body's old name, the Sub-Committee on Geographical Names and Nomenclature of Ocean Bottom Features). The ridge is the slowest known spreading ridge on earth, with a rate of less than one centimeter per year. Until 1999, it was believed to be non-volcanic; that year, scientists operating from a nuclear submarine discovered active [[volcano]]s along it. In 2001 two research icebreakers, the German ''[[RV Polarstern|Polarstern]]'' and the American ''[[USCGC Healy|Healy]]'', with several groups of scientists, cruised to the Gakkel Ridge to explore it and collect petrological samples. Among other discoveries, this expedition found evidence of [[hydrothermal vent]]s. In 2007, [[Woods Hole Oceanographic Institution]] conducted the "Arctic Gakkel Vents Expedition" (AGAVE), which made some unanticipated discoveries, including the unconsolidated fragmented [[pyroclastic]] volcanic deposits that cover the axial valley of the ridge (whose area is greater than 10 km²). These suggest volatile substances in concentrations ten times those in the magmas of normal mid-ocean ridges. The AGAVE expedition also discovered on the Gakkel ridge, using "free-swimming" [[submersible#ROVs|robotic submersible]]s, what they called "bizarre 'mats' of microbial communities containing a half dozen or more new species". ==External links== * [http://polardiscovery.whoi.edu/expedition2/index.html Polar Discovery: Gakkel Ridge] *http://diotima.mpch-mainz.mpg.de/~geo/Arctic/index.html *http://www.geolsoc.org.uk/template.cfm?name=Gakkel *http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v421/n6920/abs/nature01351_r.html *http://www.noaanews.noaa.gov/stories/s1081.htm *http://news.yahoo.com/s/ap/20070622/ap_on_sc/arctic_new_life {{mid-ocean ridges}} {{coord missing}}