TY - JOUR

T1 - Геохимия и петрология палеопротерозойских мафических вулканических комплексов Карелии I. Ятулийский трапповый комплекс.

AU - Malashin, M. V.

AU - Golubev, A. I.

AU - Ivanikov, V. V.

AU - Philippov, N. B.

PY - 2003/12/1

Y1 - 2003/12/1

N2 - Palaeoproterozoic Jatulian volcanic rocks occupied huge areas of the Fennoscandian shield and their major occurrences situated in Karelia. In terms of geological and geochemical features Jatulian igneous rocks very similar to Phanerozoic continental flood basalts. This fact is emphasized with theirs intimate likeness with trapps from deep core in Norilsk area. Consideration of the geochemical data presented here allows determining the main factors had controlled the composition of Jatulian basalts and subvolcanic intrusive gabbro-dolerites as such as partial melting, fractionalcrystallization and crustal contamination. The Lower Jatulian basalts are characterized by the enrichments of HFS elements, LREE and by strongly fractionated REE patterns. The Middle Jatulian rocks have less fractionated REE patterns and relatively low content of incompatible elements in comparison with the Lower Jatulian ones. REE patterns of the upper Jatulian basalts and intrusive gabbro-dolerites are very similar to that of the Middle Jatulian volcanic rocks. At the same time the former are distinguished by the highest content of all REE and incompatible elements. The Jatulian volcanic rocks are characterized by the Fenner tendency of fractionation with Fe and Ti enrichment. Some geochemical signatures of the Jatulian igneous rocks attribute them to contamination with continental crust. According to model calculations parental magma of early Jatulian volcanic stage was formed with 10% melting of garnet peridotite and assimilated ∼ 20% of Archaean crust. The Middle and latter Jatulian parental magmas were generated with 30-35% melting of the source area in the field of spinel stability. Ratio of crust contamination in this case compiled ∼ 10%. The revealed regularities of Jatulian volcanic complex magmatic evolution are adequate to the model of polystage adiabatic melting of plume at decreasing of the depth of magma generation.

AB - Palaeoproterozoic Jatulian volcanic rocks occupied huge areas of the Fennoscandian shield and their major occurrences situated in Karelia. In terms of geological and geochemical features Jatulian igneous rocks very similar to Phanerozoic continental flood basalts. This fact is emphasized with theirs intimate likeness with trapps from deep core in Norilsk area. Consideration of the geochemical data presented here allows determining the main factors had controlled the composition of Jatulian basalts and subvolcanic intrusive gabbro-dolerites as such as partial melting, fractionalcrystallization and crustal contamination. The Lower Jatulian basalts are characterized by the enrichments of HFS elements, LREE and by strongly fractionated REE patterns. The Middle Jatulian rocks have less fractionated REE patterns and relatively low content of incompatible elements in comparison with the Lower Jatulian ones. REE patterns of the upper Jatulian basalts and intrusive gabbro-dolerites are very similar to that of the Middle Jatulian volcanic rocks. At the same time the former are distinguished by the highest content of all REE and incompatible elements. The Jatulian volcanic rocks are characterized by the Fenner tendency of fractionation with Fe and Ti enrichment. Some geochemical signatures of the Jatulian igneous rocks attribute them to contamination with continental crust. According to model calculations parental magma of early Jatulian volcanic stage was formed with 10% melting of garnet peridotite and assimilated ∼ 20% of Archaean crust. The Middle and latter Jatulian parental magmas were generated with 30-35% melting of the source area in the field of spinel stability. Ratio of crust contamination in this case compiled ∼ 10%. The revealed regularities of Jatulian volcanic complex magmatic evolution are adequate to the model of polystage adiabatic melting of plume at decreasing of the depth of magma generation.

UR - http://www.scopus.com/inward/record.url?scp=18344362256&partnerID=8YFLogxK

M3 - статья

AN - SCOPUS:18344362256

VL - 2003

SP - 3

EP - 32

JO - Вестник Санкт-Петербургского университета. Науки о Земле

JF - Вестник Санкт-Петербургского университета. Науки о Земле

SN - 2541-9668

IS - 1

ER -