TY - JOUR

T1 - Fe-Ti oxide assemblages from the contact- metamorphosed mafic-ultramafic rocks of the sedova zaimka intrusion (Western Siberia, Russia)

T2 - The tracking of metamorphic transformations

AU - Svetlitskaya, Tatyana V.

AU - Nevolko, Peter A.

AU - Fominykh, Pavel A.

N1 - Publisher Copyright: © 2020 by the authors. Licensee MDPI, Basel, Switzerland. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/3

Y1 - 2020/3

N2 - Studies that track and compiled transformations of ilmenite and magnetite under conditions of different metamorphic grades are still very limited. The Sedova Zaimka intrusion in Western Siberia (Russia) is a good example to examine the effect of contact metamorphism from greenschist to low-amphibolite facies on magmatic Fe-Ti oxide minerals, as this small mafic-ultramafic body is located within contact metamorphic aureole of a large granite pluton. In the Sedova Zaimka, ilmenite with little to no magnetite is present as an accessory dissemination throughout metamorphosed rocks. Ilmenite is variably enriched in MnO (1 to 13.3 wt%) and depleted in MgO (less than 0.3 wt%), suggesting that its primary magmatic composition has been unevenly modified by diffusion re-equilibrium with coexisting metamorphic silicates. The elevated content of ZnO (up to 0.5 wt%) and NiO (up to 0.4 wt%) in ilmenite suggests that both ZnO and NiO, like MnO, must be strongly partitioned into ilmenite relatively to silicate minerals under the reducing contact metamorphic conditions, if chromite is absent. The textural observations of ilmenite–sulfide and ilmenite–titanite–sulfide relationships indicate that Ti-magnetite, in contrast to ilmenite, is an unstable phase in the presence of sulfur-rich reduced metamorphic fluids and is completely replaced by sulfides, with the development of specific “octahedral meshes” of ilmenite in sulfides.

AB - Studies that track and compiled transformations of ilmenite and magnetite under conditions of different metamorphic grades are still very limited. The Sedova Zaimka intrusion in Western Siberia (Russia) is a good example to examine the effect of contact metamorphism from greenschist to low-amphibolite facies on magmatic Fe-Ti oxide minerals, as this small mafic-ultramafic body is located within contact metamorphic aureole of a large granite pluton. In the Sedova Zaimka, ilmenite with little to no magnetite is present as an accessory dissemination throughout metamorphosed rocks. Ilmenite is variably enriched in MnO (1 to 13.3 wt%) and depleted in MgO (less than 0.3 wt%), suggesting that its primary magmatic composition has been unevenly modified by diffusion re-equilibrium with coexisting metamorphic silicates. The elevated content of ZnO (up to 0.5 wt%) and NiO (up to 0.4 wt%) in ilmenite suggests that both ZnO and NiO, like MnO, must be strongly partitioned into ilmenite relatively to silicate minerals under the reducing contact metamorphic conditions, if chromite is absent. The textural observations of ilmenite–sulfide and ilmenite–titanite–sulfide relationships indicate that Ti-magnetite, in contrast to ilmenite, is an unstable phase in the presence of sulfur-rich reduced metamorphic fluids and is completely replaced by sulfides, with the development of specific “octahedral meshes” of ilmenite in sulfides.

KW - Contact metamorphism

KW - Ilmenite

KW - Kolyvan zone

KW - Magnetite

KW - Metagabbro

KW - Russia

KW - Sedova Zaimka

KW - Titanite

KW - Tom’

KW - MANGANOAN ILMENITE

KW - ORE-DEPOSITS

KW - contact metamorphism

KW - Tom'-Kolyvan zone

KW - metagabbro

KW - KUHMO GREENSTONE-BELT

KW - ORIGIN

KW - ilmenite

KW - GEOTHERMOMETRY

KW - PYROPHANITE

KW - magnetite

KW - OXYGEN FUGACITY

KW - IRON-TITANIUM OXIDES

KW - SOLID-SOLUTIONS

KW - LAMELLAR MAGNETISM

KW - titanite

UR - http://www.scopus.com/inward/record.url?scp=85081611673&partnerID=8YFLogxK

U2 - 10.3390/min10030253

DO - 10.3390/min10030253

M3 - Article

AN - SCOPUS:85081611673

VL - 10

JO - Minerals

JF - Minerals

SN - 2075-163X

IS - 3

M1 - 253

ER -