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Syncollisional gabbro in the Irtysh shear zone, Eastern Kazakhstan : Compositions, geochronology, and geodynamic implications. / Khromykh, Sergey V.; Izokh, Andrey E.; Gurova, Alexandra V. и др.
в: Lithos, Том 346-347, 105144, 15.11.2019.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Syncollisional gabbro in the Irtysh shear zone, Eastern Kazakhstan
T2 - Compositions, geochronology, and geodynamic implications
AU - Khromykh, Sergey V.
AU - Izokh, Andrey E.
AU - Gurova, Alexandra V.
AU - Cherdantseva, Maria V.
AU - Savinsky, Ilya A.
AU - Vishnevsky, Andrey V.
N1 - Publisher Copyright: © 2019 Elsevier B.V. Copyright: Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/11/15
Y1 - 2019/11/15
N2 - New data of petrography, mineralogy, and geochemistry from the Irtysh shear zone in Eastern Kazakhstan reveal three types of gabbro: (1) dolerite and gabbrodolerite, (2) biotite-bearing gabbronorite and gabbrodiorite, and (3) layered peridotite-gabbro intrusions. Rocks of types 1 and 2 occur mainly as small bodies and share similarity in major- and trace-element compositions. Layered gabbro (type 3) forms the largest intrusion in the area and has a different composition: higher CaO and Al2O3 but lower K2O, TiO2, P2O5, Zr, Nb, REE. Correspondingly, the gabbro of two first types may result from differentiation of the same tholeiite magma, whereas the layered gabbro rather derived from a magma intermediate between tholeiite and calc-alkaline series. According to geochemical and isotopic signatures, both types of primary magma originated from the same sublithospheric depleted mantle by low- and high-degree partial melting of spinel lherzolite. The obtained 317–313 Ma U-Pb and Ar-Ar ages of the gabbro fall within the time of collisional events in the area. The suggested model explains the origin of syncollisional gabbro as intrusion of ascending mafic melts from a mantle wedge at the transform boundary of colliding plates along the Irtysh shear zone where strike-slip faulting produced slab windows open to inputs of hot asthenospheric material.
AB - New data of petrography, mineralogy, and geochemistry from the Irtysh shear zone in Eastern Kazakhstan reveal three types of gabbro: (1) dolerite and gabbrodolerite, (2) biotite-bearing gabbronorite and gabbrodiorite, and (3) layered peridotite-gabbro intrusions. Rocks of types 1 and 2 occur mainly as small bodies and share similarity in major- and trace-element compositions. Layered gabbro (type 3) forms the largest intrusion in the area and has a different composition: higher CaO and Al2O3 but lower K2O, TiO2, P2O5, Zr, Nb, REE. Correspondingly, the gabbro of two first types may result from differentiation of the same tholeiite magma, whereas the layered gabbro rather derived from a magma intermediate between tholeiite and calc-alkaline series. According to geochemical and isotopic signatures, both types of primary magma originated from the same sublithospheric depleted mantle by low- and high-degree partial melting of spinel lherzolite. The obtained 317–313 Ma U-Pb and Ar-Ar ages of the gabbro fall within the time of collisional events in the area. The suggested model explains the origin of syncollisional gabbro as intrusion of ascending mafic melts from a mantle wedge at the transform boundary of colliding plates along the Irtysh shear zone where strike-slip faulting produced slab windows open to inputs of hot asthenospheric material.
KW - Gabbro
KW - Irtysh shear zone
KW - Layered gabbro
KW - Slab windows
KW - Syncollisional magmatism
KW - MANTLE-CRUST INTERACTION
KW - OLKHON REGION
KW - BELT IMPLICATIONS
KW - CONTINENTAL-CRUST
KW - HERCYNIAN POSTCOLLISIONAL MAGMATISM
KW - WESTERN PART
KW - GRANITOID MAGMATISM
KW - CHINGIZ RANGE
KW - TECTONIC EVOLUTION
KW - OROGENIC BELT
UR - http://www.scopus.com/inward/record.url?scp=85070624717&partnerID=8YFLogxK
U2 - 10.1016/j.lithos.2019.07.011
DO - 10.1016/j.lithos.2019.07.011
M3 - Article
AN - SCOPUS:85070624717
VL - 346-347
JO - Lithos
JF - Lithos
SN - 0024-4937
M1 - 105144
ER -
ID: 21255544