georefid:2008-004653SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1186/1467-4866-7-7<gco:CharacterString>Alkaline fluid circulation in ultramafic rocks and formation of nucleotide constituents; a hypothesis</gco:CharacterString>2006-01-01publicationgeorefid:2008-004653issn:1467-4866doi:10.1186/1467-4866-7-7Holm, Nils G.Stockholm University, Department of Geology and Geochemistry, Stockholm, SwedenauthorDumont, MarionauthorIvarsson, MagnusauthorKonn, CecileauthorBioMed Central, London, United KingdompublisherdocumentDigitalGeochemical Transactions7 (7)1467-4866Seawater is constantly circulating through oceanic basement as a low-temperature hydrothermal fluid (<150 degrees C). In cases when ultramafic rocks are exposed to the fluids, for instance during the initial phase of subduction, ferromagnesian minerals are altered in contact with the water, leading to high pH and formation of secondary magnesium hydroxide, among other--brucite, that may scavenge borate and phosphate from seawater. The high pH may promote abiotic formation of pentoses, particularly ribose. Pentoses are stabilized by borate, since cyclic pentoses form a less reactive complex with borate. Analyses have shown that borate occupies the 2' and 3' positions of ribose, thus leaving the 5' position available for reactions like phosphorylation. The purine coding elements (adenine, in particular) of RNA may be formed in the same general hydrothermal environments of the seafloor.completedGeochemistry of rocks, soils, and sedimentsalkalic compositionbiogenic processesbruciteferromanganese compositionfluid phasegeochemistryhydrothermal conditionshydroxidesigneous rocksLeg 201Mariana IslandsMariana TrenchMicronesiaNorth PacificNorthwest Pacificnucleic acidsOcean Drilling Programocean floorsOceaniaorganic compoundsoxidesPacific OceanpHplutonic rocksproteinspurinesRNAsea waterultramaficsWest Pacificurn:org.iodp:exp:201urnlargerWorkCitationcampaignEnglishgeoscientificInformation-110.3500149.0000-12.050022.3000Mariana IslandsMariana TrenchAccessed on May 29, 2007application/pdfunknownSEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContacthttp://www.geochemicaltransactions.com/content/pdf/1467-4866-7-7.pdfdownload