FN Archimer Export Format
PT J
TI Nickel distribution and isotopic fractionation in a Brazilian lateritic regolith: coupling Ni isotopes and Ni K-edge XANES.
BT 
AF RATIE, G.
   GARNIER, J.
   CALMELS, D.
   VANTELON, D.
   GUIMARAES, E.
   MONVOISIN, G.
   NOUET, J.
   PONZEVERA, Emmanuel
   QUANTIN, C.
AS 1:1,2,3;2:2;3:1;4:5;5:2;6:1;7:1;8:4;9:1;
FF 1:;2:;3:;4:;5:;6:;7:;8:PDG-RBE-BE-LBCM;9:;
C1 Univ Paris Saclay, Univ Paris Sud, CNRS, UMR 8148,GEOPS, F-91405 Paris, France.
   Univ Brasilia, ICC Ctr, GMP, IG, Campus Univ Darcy Ribeiro, BR-70910970 Brasilia, DF, Brazil.
   Univ Brasilia, Inst Rech Dev, Brazil Lab Mixte Int, LMI,OCEuObserv Changements Environm, Campus Darcy Ribeiro, Brasilia, DF, Brazil.
   Synchrotron Soleil, Lorme Merisiers, BP 48, F-91192 Gif Sur Yvette, France.
   IFREMER, Ctr Brest, Unite Geosci Marines, F-29280 Plouzane, France.
C2 UNIV PARIS SACLAY, FRANCE
   UNIV BRASILIA, BRAZIL
   UNIV BRASILIA, BRAZIL
   SYNCHROTRON SOLEIL, FRANCE
   IFREMER, FRANCE
SI NANTES
SE PDG-RBE-BE-LBCM
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-univ-france
   copubli-int-hors-europe
   copubli-sud
IF 4.258
TC 30
UR https://archimer.ifremer.fr/doc/00436/54712/56149.pdf
LA English
DT Article
DE ;Nickel cycle;Lateritic regolith;Nickel isotopes;XANES;Ultramafic environment;Weathering
AB Ultramafic (UM) rocks are known to be nickel (Ni) rich and to weather quickly, which makes them a good candidate to look at the Ni isotope systematics during weathering processes at the Earth’s surface. The present study aims at identifying the Ni solid speciation and discussing the weathering processes that produce Ni isotope fractionation in two deep laterite profiles under tropical conditions (Barro Alto, Goiás State, Brazil). While phyllosilicates and to a lower extent goethite are the main Ni-bearing phases in the saprolitic part of the profile, iron (Fe) oxides dominate the Ni budget in the lateritic unit. Nickel isotopic composition (δ60Ni values) has been measured in each unit of the regolith, i.e., rock, saprock, saprolite and laterite (n=52). δ60Ni varies widely within the two laterite profiles, from -0.10 ± 0.05‰ to 1.43 ± 0.05‰, showing that significant Ni isotope fractionation occurs during the weathering of UM rocks. Overall, our results show that during weathering, the solid phase is depleted in heavy Ni isotopes due to the preferential sorption and incorporation of light Ni isotopes into Fe oxides; the same mechanisms likely apply to the incorporation of Ni into phyllosilicates (type 2:1). However, an isotopically heavy Ni pool is observed in the solid phase at the bottom of the saprolitic unit. This feature can be explained by two hypotheses that are not mutually exclusive: i) a depletion in light Ni isotopes during the first stage of weathering due to the preferential dissolution of light Ni-containing minerals, and ii) the sorption or incorporation of isotopically heavy Ni carried by percolating waters (groundwater samples have δ60Ni of 2.20 and 2.27‰), that were enriched in heavy Ni isotopes due to successive weathering processes in the overlying soil and laterite units. 
PY 2018
PD JUL
SO Geochimica Et Cosmochimica Acta
SN 0016-7037
PU Pergamon-elsevier Science Ltd
VL 230
UT 000430999100008
BP 137
EP 154
DI 10.1016/j.gca.2018.03.026
ID 54712
ER

EF