Cooling rates in the lower crust of the Oman Ophiolite; Ca in olivine, revisited

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doi: 10.1016/j.epsl.2007.11.034
Authors:VanTongeren, Jill A.; Kelemen, Peter B.; Hanghoj, Karen
Author Affiliations:Primary:
Lamont-Doherty Earth Observatory, Department of Earth and Environmental Sciences, Palisades, NY, United States
Volume Title:Earth and Planetary Science Letters
Source:Earth and Planetary Science Letters, 267(1-2), p.69-82. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X
Publication Date:2008
Note:In English. Supplemental information/data is available in the online version of this article. 82 refs.; illus., incl. 1 table, geol. sketch map
Summary:Debate over the mechanism of accretion of the lower oceanic crust has centered around the gabbro glacier and the sheeted sills models. The thermal profile of the crust, specifically the roles of hydrothermal circulation and cooling rate, is a key component in distinguishing between these two models. Results of this study show no systematic variation of cooling rate with depth in the lower crust of the Khafifah section in the Wadi Tayin massif of the Oman ophiolite. Additionally, very high rates recorded near the base of the crust suggest that hydrothermal circulation plays an important role in the removal of heat throughout the crust. While the conclusions presented here do not rule out the possibility of accretion by gabbro glacier, they do contradict the initial tenet of the gabbro glacier model - convective heat loss by hydrothermal circulation can penetrate to Moho depths and crystallization is not, by necessity, constrained to the upper crust. On the basis of these results it can be concluded that the sheeted sills model is a thermally viable mechanism for accretion of oceanic lower crust. [G.L.B.]
Sections:Mineral data
Subsections:Oceanic petrology
Mineral Groups:Ortho-and ring silicates
Subjects:Accretion; Alkaline earth metals; Calcium; Circulation; Convection; Cooling; Crust; Diffusivity; Dikes; Electron probe data; Gabbros; Grain size; Hydrothermal alteration; Igneous rocks; Intrusions; Lower crust; Mechanism; Metals; Metasomatism; Models; Nesosilicates; Oceanic crust; Olivine; Olivine group; Orthosilicates; Plutonic rocks; Semail Ophiolite; Sheeted dikes; Silicates; Size distribution; Thermal history; Arabian Peninsula; Asia; Oman; Gabbro glacier model; Khafifah Oman; Sheeted sill model; Wadi Tayin Massif
Coordinates:N223000 N233000 E0590000 E0573000
Abstract Numbers:08M/1209
Record ID:2008109547
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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