Facies and geochemistry of non-marine gypsum, EMISAL, Egypt
Ali-Bik, M. W. (National Research Centre. Geological Sciences Department(Egipte))
Metwally, H. I. M. (National Research Centre. Geological Sciences Department (Egipte))
Wali, A. M. A. (Cairo University (Egipte). Geology Department)
Kamel, M. G. (Academy of Scientific Research and Technology (Egipte))

Date:	2013
Abstract:	Diverse gypsum facies in terms of crystal size and morphology are deposited in a shallow, non-marine, sulfate-enriched, semi-closed, perennial evaporite basin. These gypsum facies were deposited in intimate association with cyanobacterial mats. Facies analyses and geochemistry revealed two distinct primary facies, based on gypsum fabric; massive selenite, and laminated gypsum varieties. The massive selenite facies is composed of clusters of single and twinned crystals along (100), with upward pointing re-entrant angle. The laminated gypsum varies from rhythmically laminated grass-like selenite to gypsum microbialite (stromatolite). The change from massive selenite to laminated gypsum facies implies fluctuation in lateral and vertical salinity profiles, seasonal brine concentrations and wind action. Post-depositional changes in the form of dissolution, slight to moderate crystal deformation and recrystallization to anhydrite are evaluated. We develop a qualitative model for the depositional basin and facies distribution in order to simulate ancient analogues.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Gypsum ; Lithofacies ; Non-marine ; Geochemistry
Published in:	Geologica acta, Vol. 11, Núm. 4 (December 2013) , p. 409-420, ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/271209
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/105.000002051
DOI: 10.1344/105.000002051

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