Late-stage B-bearing fluid circulation in the Kavala pluton: Evidence from mineralogical, spectroscopic and geochemical data in tourmaline-rich fault-related rocks

Postgraduate Thesis uoadl:2626104 595 Read counter

Unit:
Κατεύθυνση Μεταπτυχιακό Δίπλωμα
Library of the School of Science
Deposit date:
2018-01-21
Year:
2018
Author:
Stamatios Xydous
Supervisors info:
Δρ. Παναγιώτης Πομώνης, Επίκουρος Καθηγητής, Τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Original Title:
M.Sc. Thesis Late-stage B-bearing fluid circulation in the Kavala pluton: Evidence from mineralogical, spectroscopic and geochemical data in tourmaline-rich fault-related rocks
Languages:
English
Translated title:
Late-stage B-bearing fluid circulation in the Kavala pluton: Evidence from mineralogical, spectroscopic and geochemical data in tourmaline-rich fault-related rocks
Summary:
The tourmaline-rich rocks in Kavala are the products of juvenile late B-rich hydrothermal fluids exsolved from a granitic magma. In other words, this granitic magma that generated after anatectic processes in a thickened crust, during its emplacement in an ascending core-complex margin was fractionated leading to the exsolution through boiling of an immiscible volatile B-rich phase. The boiling pressure of the fluid exceeded the relatively low lithostatic pressure as it happened in a brittle setting of upper tectonic floors. Hydraulic, almost vertical, fracturing of various degrees and in dispersed places occurred, which mostly located along the NE-SW axial planes of the foliated and folded granitic pluton. This process may have occurred at least two times after further magmatic fractionation and exsolution. Hydrothermal fluid infiltration, triggered metasomatic alteration of the host granodiotite, resulting in the formation of tourmaline-rich rocks. Tourmalinites, in which tourmaline exceeded 50% vol, were formed at high fluid/rock ratios, while tourmaline breccias formed at lower ones. The latter, which comprise abundant angular to sub-rounded clasts of country rock infilled mostly by cryptocrystalline tourmaline, prevailed, indicating that the process was of high temperature and salinity.Progressive enrichment in Boron and other oxides compatible in tourmaline, coupled with depletion in REE’s produced a geochemical signature of typical toyrmalinization, suggesting an acidic pH, for the overall procces, which is maybe a dominat factor for the absence of sulfide mineralization within the breccias.
Main subject category:
Science
Keywords:
Tourmaline,Tourmalinites,Hydrothermal,Kavala,Granodiorite
Index:
Yes
Number of index pages:
1
Contains images:
Yes
Number of references:
149
Number of pages:
86
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