H2O concentrations in primary melts from supra-subduction zones and mid-ocean ridges: Implications for H2O storage and recycling in the mantle

Physics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

88

Scientific paper

A total of 145 inclusions, trapped and isolated in Mg-rich olivine phenocrysts (Fo 0.87-0.94 ) from basalts and ultramafic lavas, and representing the most primitive mantle melts known, have been analysed by ion microprobe for their H 2 O contents. This approach allows us to conduct a general survey of the distribution of water in primary melts derived from the mantle beneath mid-ocean ridges and above subduction zones. The primitive melts included in MORB olivines have low H 2 O contents (mean at 0.12 wt% for N-MORB (14 samples), 0.17 wt% for T-MORB (9 samples) and 0.51 wt% for E-MORB (14 samples)). A strong decoupling between H 2 O and K 2 O has been found in some MORB primary melts which might well be explained by the presence of a H 2 O-bearing CO 2 -rich fluid. In contrast with mid-ocean ridges, primitive melts of subduction zones basalts are very rich in H 2 O (between 1.0 and 2.9 wt% (mean at 1.7 wt%, 84 samples) for boninites and between 1.2 and 2.5 wt% (mean at 1.6 wt%, 24 samples) for island arc tholeiites). In addition, most of these melts have high ratios which are consistent with a transfer of H 2 O as a fluid phase from the subducted slab to the mantle wedge. For boninites and island arc primary melts, the present H 2 O contents are 2.5 × higher than commonly assumed, which suggests that the amount of H 2 O released to the surface in arc magmatism has been previously underestimated.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

H2O concentrations in primary melts from supra-subduction zones and mid-ocean ridges: Implications for H2O storage and recycling in the mantle does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with H2O concentrations in primary melts from supra-subduction zones and mid-ocean ridges: Implications for H2O storage and recycling in the mantle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and H2O concentrations in primary melts from supra-subduction zones and mid-ocean ridges: Implications for H2O storage and recycling in the mantle will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-970246

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.