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| Titel |
Thermodynamic modelling of Sol Hamed serpentinite, South Eastern Desert of Egypt: implication for two serpentinization stages in the Arabian-Nubian Shield ophiolites |
| VerfasserIn |
T. Abu-Alam, M. Hamdy |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250066137
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| Zusammenfassung |
| The Arabian-Nubian Shield is the largest tract of juvenile continental crust of Neoproterozoic
age on Earth. This crust was generated due to arc-arc collision associated with the
closing of the Mozambique Ocean. Distribution of ophiolitic rocks marks fossils
suture zones in the shield. Petrological, mineral chemistry, whole-rock chemistry
and thermodynamic studies are carried out to examine the serpentinite component
of Sol Hamed ophiolite in south Eastern Desert of Egypt. The protolith mantle
was harzburgite and formed in subduction zone of forearc setting. Serpentinization
occurred in two stages. The first by intrusion of high concentrated CO2 fluid released
from carbonate-bearing sediments and altered basalt at the subduction zone. The
serpentinization achieved during isobaric cooling path at pressure of 1 kbar and
before the emplacement. The minimum temperature limit of the serpentinization
is above the breakdown of lizardite to antigorite and brucite (170 ºC). The fluid
composition during the isobaric cooling path was buffered by the metamorphic
reactions. The second stage of serpentinization took place through prograde path
which led to formation of chrysotile after lizardite. The increasing in the pressure
during this stage occurred as a result of extensive duplex array and thrusting of
oceanic crust. The crust in the forearc basin was overloaded by 28 km of obducted
and thrusted oceanic crust from both mid-oceanic and forearc basins, respectively. |
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