Mathematics – Logic
Scientific paper
Jul 1978
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1978e%26psl..40..203h&link_type=abstract
Earth and Planetary Science Letters, Volume 40, Issue 2, p. 203-219.
Mathematics
Logic
122
Scientific paper
Partitioning of Ni between olivine and silicate melt has been determined for compositions in the system Fo-Ab-An (1 atm) for temperatures ranging from 1250°C to 1450°C. Nickel concentrations were determined by electron microprobe; concentration levels in the liquids ranged from 0.1% to 0.5%. Platinum capsules or Pt wire loops were used as containers. Equilibrium was evaluated from kinetic considerations and by variation of run parameters; it was documented in one case by a bracketed reversal. No evidence was found for a dependence of the partition coefficient D (Ni in olivine/Ni in liquid) on Ni concentration. D is strongly dependent on melt composition, varying linearly with (1/MgO) at constant temperature. The intrinsic temperature dependence of D is small; the apparent temperature dependence reported in previous studies is largely related to the variation of melt composition with temperature. Our D values determined in the simple system Fo-An-Ab agree well with those reported by Leeman for natural (Fe-bearing) basalt systems. Overall variation of D in our system (and in natural basalts) can be expressed by the regression: D = (124/MgO) - 0.9 Our data are used to evaluate published Ni-MgO relationships in natural basalt series from Kilauea, Crozet, Cape Verde and Baffin Bay. A combination of olivine accumulation and fractional crystallization processes are sufficient to model these series. Using our data, unique ``parental'' liquids can be specified for each of these series; the MgO content of these liquids varies from 6% to 13%. Basalts with MgO contents greater than these ``parental'' liquids must be accumulative. The linear Ni-MgO trends, high absolute Ni concentrations, and large spread of Ni contents for the high-MgO basalts argue convincingly against their being ``primary'' liquids. Models such as those of O'Hara [6,13] and Clarke [24], based on the assertion of primary high-MgO liquids, must therefore be re-evaluated. Because of the high Si/O ratio and low MgO content of island arc andesites, the Ni partition coefficient D may be quite high. Therefore, the relatively low Ni content of such andesites may not be an argument against their derivation as direct partial melts of the mantle. Present address: Department of Geological Sciences, State University of New York, Albany, NY, U.S.A.
Davis Karleen E.
Hart Stanley R.
No associations
LandOfFree
Nickel partitioning between olivine and silicate melt 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 Nickel partitioning between olivine and silicate melt, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nickel partitioning between olivine and silicate melt will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1699273