@article{fdi:010046242,
  title = {{U}nderstanding the genesis of ultramafic soils and catena dynamics in {N}iquelandia, {B}razil},
  author = {{G}arnier, {J}. and {Q}uantin, {C}. and {G}uimaraes, {E}. and {G}arg, {V}. {K}. and {M}artins, {E}. {S}. and {B}ecquer, {T}hierry},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his study focuses on the fate of chromium during ultramafic weathering under tropical conditions. {T}hree soils were studied along a characteristic catena on the ultramafic outcrop of {N}iquelandia, {B}razil. {I}n these soils, the {C}r-bearing minerals are inherited chromites (15.4-26.8 wt% {C}r) and magnetites (0.4-4.8 wt.% {C}r) and secondary minerals such as iron oxides (0-2 wt.% {C}r) or {N}i-smectites (0-6.8 wt.% {C}r). {I}ndeed, during weathering, {C}r liberated from primary minerals can first be incorporated into {N}i-smectites (garnierite) or {F}e oxides. {A}s the weathering continues, smectites become unstable and {C}r liberated into the soil solution, and incorporates in {F}e oxides. {I}n this oxidized environment, {F}e and {M}n are oxidized and oxides can incorporate elements like {C}r, {N}i and {A}l. {T}wo types of chromites were distinguished, i.e. a vein type ({VC}) and a rock type ({RC}) according to their composition. {C}hromites could be used as tracer of pedogenesis processes due to the distinct composition of {VC} and {RC} types. {T}hey allow us to show that the upper part of some soil profile results exclusively from colluvial processes, and the lower part of the profile results from the ultramafic bedrock weathering. {T}he chromite tracer allows us to propose a model of the catena evolution.},
  keywords = {{U}ltramafic soil ; {P}edogenesis ; {M}ineralogy ; {C}hromium ; {C}hromite ; {N}i-bearing smectites},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {151},
  numero = {3-4},
  pages = {204--214},
  ISSN = {0016-7061},
  year = {2009},
  DOI = {10.1016/j.geoderma.2009.04.020},
  URL = {https://www.documentation.ird.fr/hor/fdi:010046242},
}