Geochemistry of the Oceanic Crust

Authored book
(Textbook)


Publication Details

Author(s): Haase K
Publisher: John Wiley and Sons
Publication year: 2011
Pages range: 61-83
ISBN: 9781405193382
Language: English


Abstract


The oceanic crust has an average thickness of 7 km and forms by decompression melting of peridotitic rocks of the upper mantle at divergent plate boundaries, so - called mid - ocean ridges. The oceanic crust consists of tholeiitic basalts and gabbros, typically with low concentrations of incompatible elements like K, U and the light rare - earth elements. Evolved rocks like rhyolites or andesites and their plutonic equivalents are rare in the oceanic crust. Variations in the composition of the mafi c rocks are due to variable degrees and depths of partial melting and chemical heterogeneities in the upper mantle. The chemical heterogeneities often contain higher concentrations of incompatible elements than the upper - mantle peridotites, and refl ect upwelling of relatively hot deep mantle plumes causing age - progressive volcanic chains next to the mid - ocean ridges. After crystallization of the magmas, the rocks of the upper part of the oceanic crust chemically react with seawater, leading to metamorphic processes and severe alteration of the uppermost kilometre of the crust. Intrusion and extrusion of intraplate magmas also change the composition of the oceanic crust after its generation at the mid - ocean ridge. ©2011 Blackwell Publishing Ltd. © 2011 Blackwell Publishing Ltd. All rights reserved.



FAU Authors / FAU Editors

Haase, Karsten Prof. Dr.
Lehrstuhl für Endogene Geodynamik


How to cite

APA:
Haase, K. (2011). Geochemistry of the Oceanic Crust. John Wiley and Sons.

MLA:
Haase, Karsten. Geochemistry of the Oceanic Crust. John Wiley and Sons, 2011.

BibTeX: 

Last updated on 2018-12-12 at 20:50