Genesis of vein-quartz deposits in relation to uplift of the Serbo-Macedonian Zone, N. Greece: Evidence from fluid inclusion studies

Kilias, SP

dc.contributor.author	Kilias, SP	en
dc.date.accessioned	2014-03-01T01:51:09Z
dc.date.available	2014-03-01T01:51:09Z
dc.date.issued	2001	en
dc.identifier.issn	0009-2819	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/26238
dc.subject.classification	Geochemistry & Geophysics	en
dc.subject.other	CLATHRATE MELTING TEMPERATURES	en
dc.subject.other	LATE CENOZOIC EXTENSION	en
dc.subject.other	RE-EQUILIBRATION	en
dc.subject.other	NORTHEASTERN GREECE	en
dc.subject.other	CH4-CO2-H2O SYSTEM	en
dc.subject.other	CARBON-DIOXIDE	en
dc.subject.other	ALPINE SCHIST	en
dc.subject.other	X PROPERTIES	en
dc.subject.other	NEW-ZEALAND	en
dc.subject.other	EQUATION	en
dc.title	Genesis of vein-quartz deposits in relation to uplift of the Serbo-Macedonian Zone, N. Greece: Evidence from fluid inclusion studies	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	2001	en
heal.abstract	A major group of quartz veins occur in two-mica gneisses of the polymetamorphic Vertiskos Formation (VF) of the Permian or older Serbo-Macedonian Zone, The host rocks have been affected by five metamorphic (M-1-M-5) and deformation phases (D-1-D-5). Vein emplacement in the Kastri vein-quartz deposit, Thessaloniki district, occurred along axial planes of the D-3 regional folding event. Vein-quartz is characterized by an early episode of ductile deformation (quartz 1). local cata-clasis and dynamic recrystallization (quartz 2), overprinted by brittle fracturing. Fluid inclusion studies reveal five types of inclusions: (1) Type 1, carbonic CO2 (+/-H2O) inclusions with calculated densities of 0.85-0.98 g/cc; (2) Type II, low salinity (0.9-14.4 wt % eq. NaCl) aqueous-carbonic H2O-CO2-NaCl (+/- CH4-N-2) inclusions with highly variable aqueous: carbonic phase ratios, bubble - as well as clew-point T-h between 200 and 400 degreesC, and a wide range of calculated densities from 0.74 to 0.99 g/cc; (3) Type III, aqueous H2O-NaCl (+/- CO2) inclusions (T-h: 130-269 degreesC - salinity: 2.9 to 12.7 wt % NaCl equiv. - density: 0.85-0.95 g/cc); (4) Naturally decrepitated/leaked type IV inclusions, and, (5) Type V inclusions which occupy recrystallized-uns trained quartz 2 boundaries. Types 1, II, and IV occur together within quartz I grains either as isolated inclusions or groups, and are interpreted as coeval and most likely related to vein filling. Type III occur mainly in healed brittle fractures crosscutting both quartz I and 2 and are interpreted as post-vein filling hydrothermal fluids, whereas type V are very late. Natural decrepitation and leakage textures of type IV inclusions are attributed to internal overpressures, and linked to post-D-3 regional decompressive uplift of the VF. Uplift from mid-crustal depths is also supported by deformation microstructures in quartz which indicate that the vein was forced through the ductile-brittle transition resulting in the overprinting of ductile strain textures by brittle fractures. Wide ranges in aqueous-carbonic inclusion compositions, densities, and P-T conditions of entrapment may have been derived by a combination of various processes accompanying decompression, such as post-entrapment re-equilibration, syn- to postmetamorphic fluid evolution and immiscibility. In the absence of independent constraints on the P-T-X conditions of vein mineralization and a solid relative chronology of inclusion types I, II, and IV, a choice among alternative interpretations for variable fluid iclusion properties is difficult. However, each process may have been dependent on decompresssion and uplift. Type III late inclusions may have been trapped late along the uplift path during ongoing decompression. Uplift of VF may be related to the Late Cenozoic evolution of the region characterized by extensional tectonics.	en
heal.publisher	URBAN & FISCHER VERLAG	en
heal.journalName	CHEMIE DER ERDE-GEOCHEMISTRY	en
dc.identifier.isi	ISI:000171704400003	en
dc.identifier.volume	61	en
dc.identifier.issue	2	en
dc.identifier.spage	117	en
dc.identifier.epage	139	en