Diamantes en cromititas ofiolíticas
- J. Farré-de-Pablo 1
- J.A. Proenza 1
- J.M. González-Jiménez 2
- A. García-Casco 2
- V. Colás 3
- J. Roqué-Rosell 1
- A. Camprubí 3
- A. Sánchez-Navas 2
- X. Llovet 4
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1
Universitat de Barcelona
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2
Universidad de Granada
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- 3 Instituto de Geología. Universidad Nacional Autónoma de México
- 4 Centres Científics i Tecnològics de la Universitat de Barcelona
ISSN: 1576-5172
Year of publication: 2021
Issue Title: X Congreso Geológico de España
Issue: 18
Pages: 1052
Type: Article
More publications in: Geotemas (Madrid)
Abstract
Chromitite deposits are a common feature of many mantle portions of ophiolites. Classic formation models of these depo- sits systematically assume low-pressure processes in the mantle (<30 km). However, in recent years, these models have been challenged by the discovery of minerals typically associated to ultra-high pressure (UHP) and super-reducing (SuR) environments found as inclusions in the ophiolitic chromitites and their hosting peridotites. This is the case for diamond. In order to explain these findings, several authors proposed geodynamic models implying the formation and/or recycling of the ophiolitic chromitites and hosting peridotites near the mantle transition zone (410-600 km), where they would incorporate the diamonds. However, detailed studies of in situ diamonds in sealed fractures in the Tehuitzingo chromitites (Southern Mexico) showed that they formed at low pressure and temperature. In this scenario, metastable diamonds would crystallize from C-O-H fluids in super-reducing micro-environments during the first stages of alteration (serpentinization) of the spatially associated rocks. Therefore, a detailed study of the diamond inclusions and their parageneses is necessary before conside- ring a complex geodynamic history at UHP environments for the formation/evolution of their hosting ophiolitic chromitites and peridotites.