TY - JOUR

T1 - Geodynamic Formation Conditions and Age of Granitoids from Small Intrusions in the West of the Yana–Kolyma Gold Belt (Northeast Asia)

AU - Fridovsky, V. Yu

AU - Vernikovskaya, A. E.

AU - Yakovleva, K. Yu

AU - Rodionov, N. V.

AU - Travin, A. V.

AU - Matushkin, N. Yu

AU - Kadilnikov, P. I.

N1 - Funding Information: This study was financially supported by the fundamental research program of the Diamond and Precious Metal Geology Institute (Yakutsk). Publisher Copyright: Russian Geology and Geophysics © 2022, Novosibirsk State University.

PY - 2022/4

Y1 - 2022/4

N2 - We report results of geological, mineralogical-petrographic, geochemical, isotope-geochemical (Sm–Nd, Rb–Sr), and geo-chronological (U–Pb,40Ar/39Ar) studies of acid and intermediate intrusive rocks (granodiorites, leucocratic granites, subalkaline granites, and subalkaline leucocratic granites, diorites, and quartz diorites) of the Bukeschen and Samyr small plutons in the western part of the Yana–Kolyma gold belt (northeast Asia). These rocks are combined with Late Jurassic (151–145 Ma) dikes of basic, intermediate, and acid compositions into a single complex of small intrusions. They intrude the Upper Triassic–Middle Jurassic terrigenous deposits of continental margin blocks in the eastern part of the Verkhoyansk–Kolyma folded area. Our new U–Pb data for zircon (SHRIMP-II) indicate that the Bukeschen and Samyr pluton granitoids formed in the Berriasian, at 144.5 and 143 Ma, respectively. The small-intrusion granitoids have geochemical and isotope (Sm–Nd and Rb–Sr) characteristics similar to those of Late Jurassic dikes of varying composition. Therefore, they can be united into a single complex of small intrusions generated from a mixed source with the participation of mantle (OIB-and E-MORB type), lower crust, and subduction components and with Paleoproterozoic–Mesoproterozoic Sm–Nd model age estimates for the magma sources. Late Jurassic–Early Cretaceous magmatic and postmagmatic events and cooling of the intrusions played an important role in the processes of gold localization in the western part of the Yana–Kolyma gold belt. This is reflected in two tectonothermal stages (accounting for closing temperatures of the U–Pb,40Ar/39Ar, and Re–Os isotope systems for different minerals) estimated at 151–141 and 138–137 Ma. These results for the small-intrusion complex agree with the tectonic model of the evolution of an active continental margin (northeastern Siberia) in the Mesozoic era, whose final development stage in the Berriasian age saw the formation of mostly small granitoid plutons.

AB - We report results of geological, mineralogical-petrographic, geochemical, isotope-geochemical (Sm–Nd, Rb–Sr), and geo-chronological (U–Pb,40Ar/39Ar) studies of acid and intermediate intrusive rocks (granodiorites, leucocratic granites, subalkaline granites, and subalkaline leucocratic granites, diorites, and quartz diorites) of the Bukeschen and Samyr small plutons in the western part of the Yana–Kolyma gold belt (northeast Asia). These rocks are combined with Late Jurassic (151–145 Ma) dikes of basic, intermediate, and acid compositions into a single complex of small intrusions. They intrude the Upper Triassic–Middle Jurassic terrigenous deposits of continental margin blocks in the eastern part of the Verkhoyansk–Kolyma folded area. Our new U–Pb data for zircon (SHRIMP-II) indicate that the Bukeschen and Samyr pluton granitoids formed in the Berriasian, at 144.5 and 143 Ma, respectively. The small-intrusion granitoids have geochemical and isotope (Sm–Nd and Rb–Sr) characteristics similar to those of Late Jurassic dikes of varying composition. Therefore, they can be united into a single complex of small intrusions generated from a mixed source with the participation of mantle (OIB-and E-MORB type), lower crust, and subduction components and with Paleoproterozoic–Mesoproterozoic Sm–Nd model age estimates for the magma sources. Late Jurassic–Early Cretaceous magmatic and postmagmatic events and cooling of the intrusions played an important role in the processes of gold localization in the western part of the Yana–Kolyma gold belt. This is reflected in two tectonothermal stages (accounting for closing temperatures of the U–Pb,40Ar/39Ar, and Re–Os isotope systems for different minerals) estimated at 151–141 and 138–137 Ma. These results for the small-intrusion complex agree with the tectonic model of the evolution of an active continental margin (northeastern Siberia) in the Mesozoic era, whose final development stage in the Berriasian age saw the formation of mostly small granitoid plutons.

KW - Ar/Ar

KW - active continental margin

KW - granitoids

KW - northeast Asia

KW - Sm–Nd and Rb–Sr isotope data

KW - U–Pb

KW - Yana–Kolyma gold belt

KW - 40Ar/39Ar

UR - http://www.scopus.com/inward/record.url?scp=85140432028&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/a28d9543-0d12-3a7f-9ca3-0c2d671de326/

U2 - 10.2113/RGG20214442

DO - 10.2113/RGG20214442

M3 - Article

AN - SCOPUS:85140432028

VL - 63

SP - 483

EP - 502

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 4

ER -