Petrogenesis of basalts from the project FAMOUS area: experimental study from 0 to 15 kbars

Details Petrogenesis of basalts from the project FAMOUS area: experimental study from 0 to 15 kbars Petrogenesis of basalts from the project FAMOUS area: experimental study from 0 to 15 kbars

Nov 1978

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1978e%26psl..41..277b&link_type=abstract

Earth and Planetary Science Letters, Volume 41, Issue 3, p. 277-302.

Computer Science

96

Scientific paper

Tholeiitic basalt glasses from the FAMOUS area of the Mid-Atlantic Ridge are among the most primitive basaltic liquids reported from the ocean basins. One of the more primitive of these [Mg/(Mg + Fe2+) = 0.68; Ni = 232 ppm; TiO2 = 0.61] glasses (572-1-1) was selected for an experimental investigation. This study found olivine to be the liquidus phase from 1 atm to 10.5 kbar where it is replaced by clinopyroxene. The sequence of appearance of phases at 1 atm pressure is olivine (1268°C), plagioclase (1235°C) and clinopyroxene (1135°C). The sample is multiply saturated at 10.5 kbar with olivine (Fo88), clinopyroxene (Wo32En60Fs9), and orthopyroxene (Wo5En83Fs12). From the 1-atm data we have measured (FeO/MgO) olivine/(FeO*/MgO) liquid (K'D) for olivine-melt pairs equilibrated at 12 temperatures in the range 1268-1205°C. K'D varies from 0.30 at 1205°C to 0.27 at 1268°C. Analysis of high-pressure olivine melt pairs indicates a systematic increase in K'D with pressure. Evaluation of the 1-atm experiments reveals that fractionation of olivine followed by olivine + plagioclase can generate much of the variation in major element chemistry observed in the FAMOUS basalt glasses. However, it cannot account for the entire spectrum of glass compositions - particularly with respect to TiO2 and Na2O. The variations in these components are such as to require different primary liquids. Comparison of clinopyroxene microphenocrysts/xenocrysts found in oceanic tholeiites with experimental clinopyroxenes reveal that the majority of those in the tholeiites may have crystallized from the magma at pressures greater than ~ 10 kbar and are not accidental xenocrysts. Clinopyroxene fractionation at high pressures may be a viable mechanism for fractionating basaltic magmas. The major and minor element mineral/melt K'd's from our experiments have been used to model the source region residual mineralogy for given percentages of partial melting. These data suggest that ~20% partial melting of a lherzolite source containing 0-10% clinopyroxene can generate the major and minor element concentrations in the parental magmas of the Project FAMOUS basalt glasses.

Affiliated with

Also associated with

No associations

Rating

Petrogenesis of basalts from the project FAMOUS area: experimental study from 0 to 15 kbars 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 Petrogenesis of basalts from the project FAMOUS area: experimental study from 0 to 15 kbars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Petrogenesis of basalts from the project FAMOUS area: experimental study from 0 to 15 kbars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1067145