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| Titel |
Mantle reservoirs (EM-1, OIB, E-MORB and N-MORB), long duration and polystages history for PGE-bearing paleoproterozoic layered intrusions in the N-E part of Fennoscandian Shield. |
| VerfasserIn |
Tamara Bayanova, Ludmila Nerovich, Pavel Serov, Evgeniy Kunakkuzin, Dmitriy Elizarov |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101331
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| Publikation (Nr.) |
 EGU/EGU2015-449.pdf |
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| Zusammenfassung |
| Paleoproterozoic layered PGE –bearing intrusions located in the N-E part of the
Fennoscandian Shield and have a total are about 2000 km2. Long multidisciplinary studies
using isotope Nd-Sr, U-Pb and 3He/4He systematics permit create a big bank of geochemistry
data for different part of the intrusions: barren and main Cu-Ni-Cr-Ti-V and PGE phases,
dykes complexes and host rocks. Based on U-Pb isotope data (on baddeleyite and zircon) and
Sm-Nd mineral isochrones (on rock-forming and sulphides minerals) there is distinguished
long magmatic duration from 2.53 to 2.40 Ga. Using precise U-Pb and Sm-Nd data for
different part of the intrusions there are established four main impulses: 2.53, 2.50, 2.45, and
2.40 Ga of magmatic (LIP) activities for gabbronorite, anothosite et.set. rocks. The
primary reservoir for all precious and multimetal massifs are considered as enriched
mantle EM-1 using ÉNd- ISr system with negative ÉNd values and low ISr data for
whole rocks of the intrusions. Dyke complexes are presented as three groups: high
Ti-ferrodolerites, low Ti and low Fe-gabbronorites. Complex isotope (U-Pb, Sm-Nd)
and geochemistry (REE, ÉNd, ISr) data investigations reflect OIB, E-MORB and
N-MORB reservoirs for its origin (Nerovich et all., 2014). Isotope 3He/4He and
3He concentrations for accessory minerals ( ilmenite, magnetite et. set ) from the
layered paleoproterozoic intrusions reflect significant lower mantle component
and upper mantle contribution. According to the model of binary mixing (Jahn et
all, 2000) there were calculated mantle and core component into plume magmatic
reservoir connected with the origin of the PGE paleoproterozoic intrusions. The
mantle contributions lie in the interval from 85 to 93% and core component are very
less.
All investigations are devoted to memory of academician RAS, professor F.Mitrofanov
(Russia), he was a leader of scientific school for geology, geochemistry and metallogenesis of
ore deposits.
The studies are contribution by RFBR OFI-M 13-05-12055, 13-05-00493, Department of
Earth Sciences RAS (programs 2 and 4) and IGCP-SIDA 599. |
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