FN Archimer Export Format
PT J
TI Pure forsterite in Nyiragongo lavas: evidence for subsolidus oxidation of volcanic rocks
BT 
AF Badriyo Agama, Innocent
   Chazot, Gilles
   Kamgang, Pierre
AS 1:1,3;2:2;3:1;
FF 1:;2:;3:;
C1 Département Des Sciences de la Terre, Faculté Des Sciences, Université de Yaoundé I, B.P. 812, Yaoundé, Cameroon
   Laboratoire Géosciences Océan, Institut Universitaire Européen de la Mer, Université de Brest (UBO), UMR 6538, Place Copernic, 29280, Plouzané, France
   Observatoire Volcanologique de Goma, B.P. 484, Goma, Nord-Kivu, Democratic Republic of the Congo
C2 UNIV YAOUNDE, CAMEROON
   UBO, FRANCE
   OBSERV VOLCANOL GOMA, REP CONGO
UM GEO-OCEAN
IN WOS Cotutelle UMR
   copubli-int-hors-europe
   copubli-sud
TC 0
UR https://archimer.ifremer.fr/doc/00746/85826/91023.pdf
LA English
DT Article
DE ;Nyiragongo;Olivine;Forsterite;Oxidation
AB Some volcanic rocks from Nyiragongo volcano in the Democratic Republic of Congo contain highly oxidized olivine crystals. These olivines crystals are made of two phases, dark olivine on backscattered electron images of pure forsterite composition and grey Mg-poor areas made of olivine and iron-rich oxides. Calculation of the initial composition confirms that they are primary olivine with late separation of two different olivine compositions. Pure forsterite is enriched in SiO2 but contains lower amounts of CaO than Fe-rich areas, in agreement with expected partitioning of these elements related to the composition of the olivine. Iron-rich oxides formed around or inside the olivine crystals during the separation process and confirm a highly oxidized environment during their evolution. We propose that this separation occurred during subsolidus recrystallization under high fO2 conditions of the olivine crystals after cooling of the volcanic rocks. It provides evidences for circulation of iron-rich fluids or gas inducing deuteritic processes occurring in the large volcanic cone of the Nyiragongo, in relation with the presence of a shallow magma chamber connected to a large and permanent lava lake 
PY 2022
PD FEB
SO Acta Geochimica
SN 2096-0956
PU Springer Science and Business Media LLC
VL 41
IS 1
UT 000740423200001
BP 12
EP 23
DI 10.1007/s11631-021-00513-y
ID 85826
ER

EF