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Mineralium Deposita

, Volume 22, Issue 1, pp 1–10 | Cite as

Chromite deposits in the northern Oman ophiolite: Mineralogical constraints

  • T. Augé
Article

Abstract

Chromite deposits in the northern Oman ophiolitic complex occur in three structural contexts, i.e., (1) at the base of the cumulate series, (2) in the top kilometer of the mantle sequence, and (3) in the deeper parts of the mantle. Types 1 and 2 are characterized by the diversity of interstitial silicates where in decreasing order of abundance olivine, clinopyroxene, orthopyroxene, plagioclase, and amphibole occur, as opposed to type 3 which contains only olivine. They differ however in ore texture. Similar silicates also occur as euhedral inclusions in chromite crystals, but their proportions are reversed. The composition of the interstitial silicates is comparable to that found in early cumulates. Type-1 and type-2 chromite deposits crystallized from a magma similar to that from which the basal cumulates formed (Al2O3, 15.1–16.1 wt%; FeO/MgO, 0.55–0.60). The type-3 chromites were derived from a magma of much lower Al2O3 content (12.5 wt%). It is considered that they belong to an older episode in the magmatic evolution of the complex.

Keywords

Oman Al2O3 Content Magmatic Evolution Ophiolitic Complex Lower Al2O3 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • T. Augé
    • 1
  1. 1.Groupement d'Intérêt Scientifique BRGM-CNRSOrléans, Cedex 02France

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