@article{fdi:010023061,
  title = {{C}hemical mass balance of calcrete genesis on the {T}oledo granite ({S}pain)},
  author = {{C}hiquet, {A}. and {C}olin, {F}abrice and {H}amelin, {B}. and {M}ichard, {A}. and {N}ahon, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he chemical mass balance of calcrete genesis is studied on typical sequence developed in granite, in the {T}oledo mountains, {C}entral {S}pain. {F}ield evidence and petrographic observations indicate that the texture and the bulk volume of the parent rock are strictly preserved all along the studied calcrete profile. {M}icroscopic observations indicate that the calcitization process starts within the saprolite, superimposed on the usual mechanisms of granite weathering : the fresh rock is first weathered to secondary clays, mainly smectites, which are then pseudomorphically replaced by calcite. {B}ased on this evidence, chemical mass transfers are calculated, assuming iso-volume transformation from the parent rock to the calcrete. {T}he mass balance results show the increasing loss of matter due to weathering of the primary phases, from the saprolite towards the calcrete layers higher in the sequence. {Z}r, {T}i or {T}h, which are classically considered as immobile during weathering, are also depleted along the profile, especially in the calcrete layer. {T}his results from the prevailing highly alkaline conditions, which could account for the simultaneous precipitation of {C}a{CO}3 and silicate dissolution. {T}he calculated budget suggests that the elements exported from the weathering profile are provided dominantly by the weathering of plagioclase and biotite. {W}e calculate that 8-42% of the original {C}a remains in granitic relics, while only 15% of the authigenic {C}a released by weathering is reincorporated in the calcite. {T}his suggests that 373 kg/m2 of calcium (i.e., three times the original amount) is imported into the calcrete from allochtonous sources, probably due to the aeolian transport from distant limestone formations. ({R}{\'e}sum{\'e} d'auteur)},
  keywords = {{CROUTE} {D}'{ALTERATION} ; {CROUTE} {CALCAIRE} ; {SOL} ; {CALCITE} ; {ALTERATION} ; {ROCHE} {MERE} {DU} {SOL} ; {GRANITE} ; {METHODE} {D}'{ANALYSE} ; {ANALYSE} {QUANTITATIVE} ; {ANALYSE} {CHIMIQUE} ; {BILAN} {DE} {MATIERE} ; {ANALYSE} {PETROGRAPHIQUE} ; {ETUDE} {REGIONALE} ; {ZONE} {SEMIARIDE} ; {ESPAGNE} ; {TOLEDE} {REGION}},
  booktitle = {},
  journal = {{C}hemical {G}eology},
  volume = {170},
  numero = {1-4},
  pages = {19--35},
  ISSN = {0009-2541},
  year = {2000},
  DOI = {10.1016/{S}0009-2541(99)00240-5},
  URL = {https://www.documentation.ird.fr/hor/fdi:010023061},
}