Composition-volume changes during metasomatic alteration of pan African andesitic volcanic rocks at gable El Dokhan Area, Northeastern Desert, Egypt
Other Title(s)
التغير الحجمي و التركيبي خلال تغير و تحول صخور الأنديزيت البركانية في منطقة جبل الدخان، شمال الصحراء الشرقية، مصر
Author
Khalaf, Izz al-Din Abd al-Hakim
Source
Journal of King Abdulaziz University : Earth Sciences
Issue
Vol. 11, Issue 1 (31 Dec. 1999), pp.177-206, 30 p.
Publisher
King Abdulaziz University Scientific Publishing Center
Publication Date
1999-12-31
Country of Publication
Saudi Arabia
No. of Pages
30
Main Subjects
Earth Sciences, Water and Environment
Topics
Abstract EN
Metasomatic alterations of the Late Proterozoic andesites at Gabal El Dokhan area display obvious change in mineralogical and chemical composition, if compared with the least altered andesitic rock types (assumed protoliths).
These altered andesitic rocks have been metamorphosed to lower-middle greenschist facies typified by biotite-actinolite-chlorite-albite-epidote-quartz-opaque minerals/sphene assemblages.
Five alteration facies have been recognized : 1) Biotitization- silicification, 2) Sericitization-silicification, 3) Albitizationsilicification, 4) Epidotization-silicification, and 5) Chloritization.
The biotitized-silicified rock types are enriched in K-Rb-Ba-FTSM and depleted in LREE relative to the least altered rock.
The sericitized-silicified rock types are significantly enriched in K-Rb-Ba and depleted in FTSM and LREE.
The albitized-silicified rock types are strongly enriched in Na and depleted in LILE and LREE relative to the least altered rock types.
The epidotized-silicified rock types are enriched in Ca-Cu-Pb and depleted in LILE and LREE.
The chloritized rock types exhibit relative enrichment in Mg, FTSM, Zn-As-Pb and depletion in LILE and LREE.
The behavior of the Ti, Al, Fet, P, and most HFS elements during biotitization, sericitization, albitization, epidotization and chloritization suggests that they were inert during metasomatic modification of the andesites.
Mass balance calculations suggest that volume change was restricted between zero and up to + 20 % for the altered upper andesites and 25 and up to +25 % for the altered lower andesites during the different types of metasomatic facies.
Elemental mobilities are interpreted in terms of the controlling mineral phases and the possible nature of the various metasomatising fluids.
American Psychological Association (APA)
Khalaf, Izz al-Din Abd al-Hakim. 1999. Composition-volume changes during metasomatic alteration of pan African andesitic volcanic rocks at gable El Dokhan Area, Northeastern Desert, Egypt. Journal of King Abdulaziz University : Earth Sciences،Vol. 11, no. 1, pp.177-206.
https://search.emarefa.net/detail/BIM-387361
Modern Language Association (MLA)
Khalaf, Izz al-Din Abd al-Hakim. Composition-volume changes during metasomatic alteration of pan African andesitic volcanic rocks at gable El Dokhan Area, Northeastern Desert, Egypt. Journal of King Abdulaziz University : Earth Sciences Vol. 11, no. 1 (1999), pp.177-206.
https://search.emarefa.net/detail/BIM-387361
American Medical Association (AMA)
Khalaf, Izz al-Din Abd al-Hakim. Composition-volume changes during metasomatic alteration of pan African andesitic volcanic rocks at gable El Dokhan Area, Northeastern Desert, Egypt. Journal of King Abdulaziz University : Earth Sciences. 1999. Vol. 11, no. 1, pp.177-206.
https://search.emarefa.net/detail/BIM-387361
Data Type
Journal Articles
Language
English
Notes
Includes appendix : p. 203-204
Record ID
BIM-387361