TY - JOUR

T1 - Alkaline volcanism of the initial phase of Paleozoic tectono-magmatic reactivation in northeastern Fennoscandia

T2 - Geochemical features and petrologic consequences

AU - Arzamastsev, A. A.

AU - Arzamastseva, L. V.

AU - Belyatskii, B. V.

PY - 1998/5/1

Y1 - 1998/5/1

N2 - This paper presents the results of studying the Paleozoic volcanic series of the Kola Province, widespread in the areas of the Lovozero and Khibina massifs, the Kontozero caldera, and the Ivanovka volcano-plutonic complex. A distinctive feature of the volcanics is the presence of moderately alkaline basanites along with silica-undersaturated alkaline rock associations. All of the rocks are significantly enriched in incompatible elements: the contents of Rb, Ba, Sr, Nb, Zr, and Y in the volcanics of the Lovozero and Kontozero formations are considerably higher than those in the alkaline basalts of continental associations from various provinces. The Sm-Nd and Rb-Sr data suggest that the volcanics of the study area were derived from two different mantle sources: (1) superdepleted mantle material resulted from the multistage crustal growth over Archean and Proterozoic time in the Kola-White Sea rift-collision zone and (2) a source that had properties of moderately enriched EMI-type mantle. It is shown that the emplacement of the volcanics preceded the main phase of alkaline magmatism in the region and can be referred to as the initial phase of the Paleozoic tectono-magmatic reactivation. According to geochronological data, the alkaline volcanic rocks were emplaced at least 20-30 m.y. before the intrusion of the alkaline plutonic rocks. The Early Paleozoic volcanism of the Kola alkaline province was coeval with the peak of tectonic activity at the northwestern boundary of the Fennoscandian Shield in the North Atlantic belt of Caledonides and can be correlated with the collision maximum associated with the closure of the Iapetus Ocean.

AB - This paper presents the results of studying the Paleozoic volcanic series of the Kola Province, widespread in the areas of the Lovozero and Khibina massifs, the Kontozero caldera, and the Ivanovka volcano-plutonic complex. A distinctive feature of the volcanics is the presence of moderately alkaline basanites along with silica-undersaturated alkaline rock associations. All of the rocks are significantly enriched in incompatible elements: the contents of Rb, Ba, Sr, Nb, Zr, and Y in the volcanics of the Lovozero and Kontozero formations are considerably higher than those in the alkaline basalts of continental associations from various provinces. The Sm-Nd and Rb-Sr data suggest that the volcanics of the study area were derived from two different mantle sources: (1) superdepleted mantle material resulted from the multistage crustal growth over Archean and Proterozoic time in the Kola-White Sea rift-collision zone and (2) a source that had properties of moderately enriched EMI-type mantle. It is shown that the emplacement of the volcanics preceded the main phase of alkaline magmatism in the region and can be referred to as the initial phase of the Paleozoic tectono-magmatic reactivation. According to geochronological data, the alkaline volcanic rocks were emplaced at least 20-30 m.y. before the intrusion of the alkaline plutonic rocks. The Early Paleozoic volcanism of the Kola alkaline province was coeval with the peak of tectonic activity at the northwestern boundary of the Fennoscandian Shield in the North Atlantic belt of Caledonides and can be correlated with the collision maximum associated with the closure of the Iapetus Ocean.

UR - http://www.scopus.com/inward/record.url?scp=22544463559&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:22544463559

VL - 6

SP - 293

EP - 312

JO - Petrology

JF - Petrology

SN - 0869-5911

IS - 3

ER -