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Plagioclase archives of depleted melts in the oceanic crust

David A. Neave and Olivier Namur
Plagioclase archives of depleted melts in the oceanic crust
Geology (Boulder) (April 2022) 50 (7): 848-852


Mid-ocean ridge and ocean-island basalts provide vital but incomplete insights into mantle chemistry. For example, high-anorthite plagioclase is generally too refractory and incompatible-element depleted to have crystallized from the melts that carry it to the surface. Moreover, erupted basalts rarely preserve the extreme isotopic and incompatible-element depletions found in some primitive melt inclusions and residual abyssal peridotites. By integrating experimental observations with analyses of natural crystals and glasses, we infer that high-anorthite plagioclase grows from high-degree melts of refractory but otherwise unexotic mantle sources with depleted incompatible-element compositions. The widespread occurrence of high-anorthite plagioclase in oceanic basalts and the oceanic crust hence indicates that refractory melts pervade the uppermost mantle and lower crust. We thus suggest that refractory melts play much a greater role in crustal accretion than typically recognized and that refractory and feasibly depleted peridotite is more prevalent in the upper mantle than previously thought.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 50
Serial Issue: 7
Title: Plagioclase archives of depleted melts in the oceanic crust
Affiliation: University of Manchester, Department of Earth and Environmental Sciences, Manchester, United Kingdom
Pages: 848-852
Published: 20220426
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 35
Accession Number: 2022-046337
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
N63°40'00" - N66°30'00", W24°45'00" - W13°30'00"
S50°00'00" - S48°00'00", E68°00'00" - E71°00'00"
S21°25'00" - S20°49'60", E55°00'00" - E56°00'00"
S01°30'00" - N01°00'00", W92°00'00" - W89°00'00"
Secondary Affiliation: Katholieke Universiteit Leuven, BEL, Belgium
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 202235
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