@article{fdi:010055943,
  title = {{P}hillipsite formation in nephelinitic rocks in response to hydrothermal alteration at {M}ount {E}tinde, {C}ameroon},
  author = {{E}tame, {J}. and {S}uh, {C}. {E}. and {G}{\'e}rard, {M}artine and {B}ilong, {P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{F}resh nephelinitic rocks and hydrothermally altered rocks at {M}ount {E}tinde ({C}ameroon {V}olcanic {L}ine, {W}est {A}frica) have been studied by combined whole rock geochemistry ({ICP}-{MS}), mineralogy and mineral chemistry ({SEM}-{EDS}, {WDS}, {XRD}) techniques. {T}he nephelinites have feldspathoids, clinopyroxene, perovskite and titanomagnetite as the principal minerals in the mode with subsidiary apatite and sphene. {T}he mineralogy of their hydrothermally altered counterparts includes phillipsite, calcite and analcime which are secondary phases developed in response to hydrothermal fluid events. {C}orrespondingly, the bulk rock geochemical data show elevated {S}i{O}2, {C}a{O}, {N}a2{O} and {K}2{O} concentrations with increasing alteration and {A}l2{O}3 and {F}e2{O}3 depletion while {M}g{O}, {M}n{O} and {T}i{O}2 concentrations are largely unaffected. {T}he nephelinites also have high concentrations of {LILLE}, {HFSE} and {REE} and upon hydrothermal alteration they show an enrichment of {LREE} and {MREE} over {HREE}. {P}hillipsite is the principal alteration mineral in the rocks and it occurs along cracks, vesicles and also forms alteromorphs after feldspathoids. {T}he {C}e content of these categories of phillipsite varies. {P}hillipsite along cracks is richer in {C}e while phillipsite associated with calcite has lower {C}e concentration and the phillipsite alteromorphs very little or no {C}e. {V}arious stages of fluid circulation are proposed hereby to explain the variations in phillipsite generation and composition.},
  keywords = {{N}ephelinite ; {H}ydrothermal alteration ; {P}hillipsite ; {REE}},
  booktitle = {},
  journal = {{C}hemie der {E}rde-{G}eochemistry},
  volume = {72},
  numero = {1},
  pages = {31--37},
  ISSN = {0009-2819},
  year = {2012},
  DOI = {10.1016/j.chemer.2011.08.002},
  URL = {https://www.documentation.ird.fr/hor/fdi:010055943},
}