Please use this identifier to cite or link to this item: http://hdl.handle.net/10553/30030
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dc.contributor.authorDíaz-Hernández, J. L.en_US
dc.contributor.authorSánchez-Navas, A.en_US
dc.contributor.authorDelgado, A.en_US
dc.contributor.authorYepes, J.en_US
dc.contributor.authorGarcia-Casco, A.en_US
dc.date.accessioned2018-02-20T10:41:44Z-
dc.date.available2018-02-20T10:41:44Z-
dc.date.issued2018en_US
dc.identifier.issn0016-7037en_US
dc.identifier.urihttp://hdl.handle.net/10553/30030-
dc.description.abstractModels for evaluating the terrestrial carbon cycle must take into account not only soil organic carbon, represented by a mixture of plant and animal remains, but also soil inorganic carbon, contained in minerals, mainly in calcite and dolomite. Thick soil caliches derived from weathering of mafic and ultramafic rocks must be considered as sinks for carbon storage in soils. The formation of calcite and dolomite from pedogenic alteration of volcanic tephras under an aridic moisture regime is studied in an unusually thick 3-m soil profile on Gran Canaria island (Canary Islands, Spain). The biological activity of the pedogenic environment (soil respiration) releases CO 2 incorporated as dissolved inorganic carbon (DIC) in waters. It drives the formation of low-magnesian calcite and calcian dolomite over basaltic substrates, with a δ 13 C negative signature (−8 to −6‰ vs. V-PDB). Precipitation of authigenic carbonates in the soil is accompanied by the formation of Mg-rich clay minerals and quartz after the weathering of basalts. Mineralogical, textural, compositional, and isotopic variations throughout the soil profile studied indicate that dolomite formed at greater depths and earlier than the calcite. The isotopic signatures of the surficial calcite and deeper dolomite crusts are primary and resulted from the dissolution-precipitation cycles that led to the formation of both types of caliches under different physicochemical conditions. Dolomite formed within a clay-rich matrix through diffusive transport of reactants. It is precipitated from water with more negative δ 18 O values (−1.5 to −3.5‰ vs. V-SMOW) in the subsoil compared to those of water in equilibrium with surficial calcite. Thus, calcite precipitated after dolomite, and directly from percolating solutions in equilibrium with vadose water enriched in δ 18 O (−0.5 to +1.5‰) due to the evaporation processes. The accumulation of inorganic carbon reaches 586.1 kg m −2 in the soil studied, which means that the carbon sequestration capacity of mafic rocks must be taken into account for certain terrestrial settings. Dolomite together with calcite should be assessed when quantifying carbon stored in arid-semiarid soils as a result of the natural weathering processes.en_US
dc.languageengen_US
dc.relation.ispartofGeochimica et Cosmochimica Actaen_US
dc.sourceGeochimica et Cosmochimica Acta[ISSN 0016-7037],v. 222, p. 485-507en_US
dc.subject2506 Geologíaen_US
dc.subject.otherC and O isotopesen_US
dc.subject.otherC stocksen_US
dc.subject.otherCalichesen_US
dc.subject.otherPedogenic dolomiteen_US
dc.subject.otherVolcanic soilsen_US
dc.titleTextural and isotopic evidence for Ca-Mg carbonate pedogenesisen_US
dc.typeinfo:eu-repo/semantics/Articlees
dc.typeArticleen_US
dc.identifier.doi10.1016/j.gca.2017.11.006
dc.identifier.scopus85035035533
dc.identifier.isi000424972200028
dc.identifier.urlhttp://api.elsevier.com/content/abstract/scopus_id/85035035533-
dc.contributor.orcid#NODATA#en
dc.contributor.orcid#NODATA#en
dc.contributor.orcid#NODATA#en
dc.contributor.orcid#NODATA#en
dc.contributor.orcid#NODATA#en
dc.contributor.authorscopusid36947525700
dc.contributor.authorscopusid55664564300
dc.contributor.authorscopusid14015420100
dc.contributor.authorscopusid16314521900
dc.contributor.authorscopusid6602948015
dc.description.lastpage507-
dc.description.firstpage485-
dc.relation.volume222-
dc.investigacionCienciasen_US
dc.source.typearen
dc.type2Artículoen_US
dc.contributor.daisngid2254916
dc.contributor.daisngid10175947
dc.contributor.daisngid504449
dc.contributor.daisngid2313783
dc.contributor.daisngid424750
dc.contributor.wosstandardWOS:Diaz-Hernandez, JL
dc.contributor.wosstandardWOS:Sanchez-Navas, A
dc.contributor.wosstandardWOS:Delgado, A
dc.contributor.wosstandardWOS:Yepes, J
dc.contributor.wosstandardWOS:Garcia-Casco, A
dc.date.coverdateFebrero 2018
item.fulltextSin texto completo-
item.grantfulltextnone-
crisitem.author.deptDepartamento de Ingeniería Civil-
crisitem.author.deptIOCAG:Geología Aplicada y Regional-
crisitem.author.deptIU de Oceanografía y Cambio Global-
crisitem.author.orcid0000-0001-5039-1482-
crisitem.author.parentorgIU de Oceanografía y Cambio Global-
crisitem.author.fullNameYepes Temiño, Jorge-
crisitem.author.departamentoIngeniería Civil-
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