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| Titel |
Mineralogical and Geochemical Characterization of the Kimmeria
Intrusion-Related Deposit, Xanthi, NE Greece |
| VerfasserIn |
Stella Theodoridou, Vasilios Melfos, Panagiotis Voudouris, Aleksandar Miskovic |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250128894
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| Publikation (Nr.) |
 EGU/EGU2016-8933.pdf |
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| Zusammenfassung |
| Although intrusion-related systems have not been previously recognized in the European
segment of the Tethyan Metallogenic Belt, the Rhodope metallogenic province of SE Balkan
peninsula hosts numerous such occurrences.
The Kimmeria hydrothermal system incorporates two styles of ore mineralization: i) a
massive Au-bearing magnetite-pyrrhotite skarn and ii) a Mo-Cu-Bi-W quartz vein-hosted
mineralization, both of which are related to the Oligocene Xanthi pluton (25.5±1.2 to
30±1 My, K-Ar in hornblende and biotite). The Xanthi pluton, consisting of I-type
gabbros, monzonites and amphibole-biotite granodiorites, intrudes the basement
gneisses, mica schists, amphibolites and marbles of the Southern Rhodope Core
Complex; a dome that has gradually exhumed from Paleocene/mid Eocene to Miocene
(starting between 65 and >42 to 10 My). The Xanthi pluton emplacement and the
magmatically derived hydrothermal fluid circulation were controlled by two major regional
structures: the low-angle Kavala-Xanthi-Komotini detachment fault and the Nestos thrust
fault.
The Kimmeria Au-Cu-Fe skarn mineralization features a well-preserved aureole
at the contact between the granodiorite and the surrounding marbles. It consists
of two paragenetic stages comprising magnetite and pyrrhotite-rich assemblages.
Alteration minerals comprise chlorite and sericite. Bulk chemical analyses of the skarn
mineralization revealed relatively high concentration of Cu (1 wt.%), Pb (288 ppm) and
Zn (0.74 wt.%). The mineralization is also enriched in As (< 75.8 ppm), W (<
82.1 ppm), Bi (<10.1 ppm), Sb (<331.9 ppm), Ag (< 15.9 ppm), and Sn (< 50
ppm). Te and Au are found in low concentrations of less than 2 ppm and 0.4 ppm,
respectively.
The Kimmeria Mo-Cu-Bi-W vein-type mineralization comprises a system of
cross-cutting and sheeted quartz veins within the granodiorite, with pyrite, chalcopyrite and
molybdenite as dominant sulfides. Minor sphalerite, tetrahedrite-tennantite, galena
and rutile are also present, while sericite and chlorite as the alteration minerals.
The Cu and Mo content of the vein type mineralization exceed 1.0 and 0.2 wt.%
respectively, along with < 2.7 ppm Au, 1.3 to 79.5 ppm W and 0.6 to 456 ppm
Bi.
A first approach fluid study has revealed small variations in δ34S values of sulfides (0 -
2.3 ‰ VCDT) from both types of mineralization suggesting a magmatic source
of sulfur. Silicate δ18O values of quartz show a narrow range between 10.3 and
11.2 ‰ (VSMOW) suggesting similar quartz formation for both mineralization
types, at relatively low temperatures and probably from the same fluid. Oxygen
isotopes values in calcite from the unmineralized marbles and ore specimens are
scattered over a wide range from 12.1 to 41.7 ‰ (V-SMOW). They have relatively
low carbon isotopic values (-4.8 to 2.1 ‰ V-PDB), indicative of a magmatic δ13C
signature and a restricted isotopic exchange with hydrothermal fluids. Primary fluid
inclusion studies have revealed the presence of CO2 in the ore fluid, which might have
played an important role during the ore genesis irrespective of the mineralization
style.
This work was financially supported by the Western Tethyan Metallogeny Project
(MDRU – The University of British Columbia). |
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