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Title: Compositions of melts coexisting with plagioclase, augite, and olivine,or low-calcium pyroxene, at anhydrous and hydrous conditions and pressures from 1 atm. to 8 kbar: application to the petrogenesis of Aleutian and Mariana Island arc rocks and Columbia River basalts

Abstract

Anhydrous and hydrous, 2% water in the melt, experiments have been performed on a suite of high-alumina basalts and andesites from the Aleutian and Mariana island arcs. Compositions of experimentally produced melts coexisting with plagioclase (plag), augite (aug), and olivine (ol), or low-calcium pyroxene (lpx) have been used to construct liquid lines of multiple saturation (LLMS's) on pseudoternary diagrams. Anhydrous LLMS's at 1 atm. and 8 kbar and hydrous LLMS's at 2 and 5 kbar were determined. At 1 atm. and under hydrous conditions orthopyroxene (opx) is the stable lpx; at 8 kbar pigeonite (pig) is the stable lpx. Comparison of the plotted positions of the LLMS's and the compositions of rocks from the Aleutians suggest that basaltic andesites and andesites were produced by crystal fractionation of plag+aug+ol or plag+aug+opx from basaltic magmas with less than 2% water content at pressure between 2 and 5 kbar. Comparison of the LLMS's with the compositions of Columbia River Basalts indicates that crystal fractionation of plag+aug+ol (or lpx) in magma chambers at Moho depths cannot alone account for the observed compositional trend; instead the trend is probably due to some combination of polybaric fractionation, contamination, and possibly mixing of magmas between deep andmore » shallow magma chambers.« less

Authors:
;
Publication Date:
Research Org.:
Smithsonian Institution, Washington, DC (USA)
OSTI Identifier:
6898740
Alternate Identifier(s):
OSTI ID: 6898740
Report Number(s):
CONF-8510489-
Journal ID: CODEN: GAAPB
Resource Type:
Conference
Journal Name:
Geol. Soc. Am., Abstr. Programs; (United States)
Additional Journal Information:
Journal Volume: 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 54 ENVIRONMENTAL SCIENCES; ALEUTIAN ISLANDS; ANDESITES; BASALT; MINERALOGY; PETROCHEMISTRY; PETROGENESIS; MARIANA ISLANDS; ANORTHOSITES; CHEMICAL COMPOSITION; COMPARATIVE EVALUATIONS; MAGMATISM; OLIVINE; PRESSURE EFFECTS; PYROXENES; ALKALINE EARTH METAL COMPOUNDS; GABBROS; IGNEOUS ROCKS; IRON COMPOUNDS; IRON SILICATES; ISLANDS; MAGNESIUM COMPOUNDS; MAGNESIUM SILICATES; MINERALS; NORTH AMERICA; OXYGEN COMPOUNDS; PLUTONIC ROCKS; ROCKS; SILICATE MINERALS; SILICATES; SILICON COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; TRUST TERRITORY OF THE PACIFIC ISLANDS; USA; VOLCANIC ROCKS 052002* -- Nuclear Fuels-- Waste Disposal & Storage; 520200 -- Environment, Aquatic-- Chemicals Monitoring & Transport-- (-1989); 520300 -- Environment, Aquatic-- Radioactive Materials Monitoring & Transport-- (1989)

Citation Formats

Baker, D.R., and Eggler, D.H. Compositions of melts coexisting with plagioclase, augite, and olivine,or low-calcium pyroxene, at anhydrous and hydrous conditions and pressures from 1 atm. to 8 kbar: application to the petrogenesis of Aleutian and Mariana Island arc rocks and Columbia River basalts. United States: N. p., 1985. Web.
Baker, D.R., & Eggler, D.H. Compositions of melts coexisting with plagioclase, augite, and olivine,or low-calcium pyroxene, at anhydrous and hydrous conditions and pressures from 1 atm. to 8 kbar: application to the petrogenesis of Aleutian and Mariana Island arc rocks and Columbia River basalts. United States.
Baker, D.R., and Eggler, D.H. Tue . "Compositions of melts coexisting with plagioclase, augite, and olivine,or low-calcium pyroxene, at anhydrous and hydrous conditions and pressures from 1 atm. to 8 kbar: application to the petrogenesis of Aleutian and Mariana Island arc rocks and Columbia River basalts". United States.
@article{osti_6898740,
title = {Compositions of melts coexisting with plagioclase, augite, and olivine,or low-calcium pyroxene, at anhydrous and hydrous conditions and pressures from 1 atm. to 8 kbar: application to the petrogenesis of Aleutian and Mariana Island arc rocks and Columbia River basalts},
author = {Baker, D.R. and Eggler, D.H.},
abstractNote = {Anhydrous and hydrous, 2% water in the melt, experiments have been performed on a suite of high-alumina basalts and andesites from the Aleutian and Mariana island arcs. Compositions of experimentally produced melts coexisting with plagioclase (plag), augite (aug), and olivine (ol), or low-calcium pyroxene (lpx) have been used to construct liquid lines of multiple saturation (LLMS's) on pseudoternary diagrams. Anhydrous LLMS's at 1 atm. and 8 kbar and hydrous LLMS's at 2 and 5 kbar were determined. At 1 atm. and under hydrous conditions orthopyroxene (opx) is the stable lpx; at 8 kbar pigeonite (pig) is the stable lpx. Comparison of the plotted positions of the LLMS's and the compositions of rocks from the Aleutians suggest that basaltic andesites and andesites were produced by crystal fractionation of plag+aug+ol or plag+aug+opx from basaltic magmas with less than 2% water content at pressure between 2 and 5 kbar. Comparison of the LLMS's with the compositions of Columbia River Basalts indicates that crystal fractionation of plag+aug+ol (or lpx) in magma chambers at Moho depths cannot alone account for the observed compositional trend; instead the trend is probably due to some combination of polybaric fractionation, contamination, and possibly mixing of magmas between deep and shallow magma chambers.},
doi = {},
journal = {Geol. Soc. Am., Abstr. Programs; (United States)},
number = ,
volume = 17,
place = {United States},
year = {1985},
month = {1}
}

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