| 18541 |
Creator |
4989dd10527e94ef140e45e8c9fb07e6 |
| 18541 |
Creator |
dcc9fa18f5550ef68ad869008376ba1a |
| 18541 |
Creator |
ff9a2101f76c86104fa99356120ecc41 |
| 18541 |
Creator |
aea1b3c384096d62b90f04433e2c6268 |
| 18541 |
Creator |
ext-e44cd9d49a773ea97975c4eddf7875be |
| 18541 |
Creator |
e5ace70794f6a796f86423580d77dcee |
| 18541 |
Date |
2010-01 |
| 18541 |
Is Part Of |
p00167037 |
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Is Part Of |
repository |
| 18541 |
abstract |
Spinel lherzolite xenoliths from Mont Briançon, French Massif Central, retain evidence
for multiple episodes of melt depletion and melt / fluid infiltration (metasomatism).
Evidence for primary melt depletion is still preserved in the co-variation of bulk-rock
major elements (MgO 38.7 - 46.1 weight%; CaO 0.9 - 3.6 weight%), and many samples
yield unradiogenic bulk-rock Os isotope ratios (<sup>187</sup>Os/<sup>188</sup>Os
= 0.11541-0.12626). However, many individual xenoliths contain interstitial glasses
and melt inclusions that are not in equilibrium with the major primary minerals. Incompatible
trace element mass balance calculations demonstrate that metasomatic components comprise
a significant proportion of the bulk-rock budget for these elements in some rocks,
ranging to as much as 25% of Nd and 40% of Sr Critically, for Re-Os geochronology,
melt / fluid infiltration is accompanied by the mobilisation of sulfide. Consequently,
bulk-rock isotope measurements, whether using lithophile (e.g. Rb-Sr, Sm-Nd) or siderophile
(Re-Os) based isotope systems, may only yield a perturbed and / or homogenised average
of these multiple events.
Osmium mass balance calculations demonstrate that bulk-rock Os in peridotite is dominated
by contributions from 2 populations of sulfide grain: (i) interstitial, metasomatic
sulfide with low [Os] and radiogenic <sup>187</sup>Os/<sup>188</sup>Os, and (ii) primary
sulfides with high [Os] and unradiogenic <sup>187</sup>Os/<sup>188</sup>Os, which
have been preserved within host silicate grains and shielded from interaction with
transient melts and fluid. The latter can account for > 97% of bulk rock Os and preserve
geochronological information of the melt from which they originally precipitated as
an immiscible liquid. The Re-depletion model ages of individual primary sulfide grains
preserve evidence for melt depletion beneath the Massif Central from at least 1.8
Gyr ago despite the more recent metasomatic event(s). |
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authorList |
authors |
| 18541 |
issue |
1 |
| 18541 |
status |
peerReviewed |
| 18541 |
uri |
http://data.open.ac.uk/oro/document/16041 |
| 18541 |
uri |
http://data.open.ac.uk/oro/document/18616 |
| 18541 |
uri |
http://data.open.ac.uk/oro/document/3442 |
| 18541 |
uri |
http://data.open.ac.uk/oro/document/9668 |
| 18541 |
volume |
74 |
| 18541 |
type |
AcademicArticle |
| 18541 |
type |
Article |
| 18541 |
label |
Harvey, J. ; Gannoun, A. ; Burton, K. W. ; Schiano, P.; Rogers, N. W. and Alard,
O. (2010). Unravelling the effects of melt depletion and secondary infiltration
on mantle re-os isotopes beneath the french Massif Central. Geochimica et Cosmochimica
Acta, 74(1) pp. 293–320. |
| 18541 |
label |
Harvey, J. ; Gannoun, A. ; Burton, K. W. ; Schiano, P.; Rogers, N. W. and Alard,
O. (2010). Unravelling the effects of melt depletion and secondary infiltration
on mantle re-os isotopes beneath the french Massif Central. Geochimica et Cosmochimica
Acta, 74(1) pp. 293–320. |
| 18541 |
sameAs |
j.gca.2009.09.031 |
| 18541 |
Title |
Unravelling the effects of melt depletion and secondary infiltration on mantle re-os
isotopes beneath the french Massif Central |
| 18541 |
in dataset |
oro |