TY - JOUR

T1 - Petrogenesis of dike rocks in the western part of the verkhoyansk-kolyma fold area, Northeast Russia

AU - Iakovleva, K. Yu

AU - Fridovsky, V. Yu

AU - Vernikovskaya, A. E.

N1 - Funding Information: This research was supported by the Diamond and Precious Metals Geology Institute, Siberian Branch of the Russian Academy of Sciences, and was partially funded by the Russian Foundation for Basic Research (grants 18-45-140040 r_a). Publisher Copyright: © 2020 International Multidisciplinary Scientific Geoconference. All rights reserved. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2020

Y1 - 2020

N2 - The dike rocks under study are localized in Mesozoic (T3-J2) clastic rocks in the western part of Verkhoyansk-Kolyma fold area. Studying the nature of the dikes and geodynamic setting of their formation is of great interest now in view of the controversy surrounding their assignment to definite magmatic complexes of the Verkhoyansk-Kolyma fold area and the uncertain origin of mineralization in the Yana-Kolyma gold belt. Major elements were determined using the silicate analysis of magmatic rocks. The mineral compositions of dike rocks were studied using a Tescan MIRA 3 LMU scanning electron microscope. Studies of REE and other trace elements were performed with the use of mass spectrometers - quadrupolar Agilent7500ce (Japan) and high-resolution Element2 (Germany). Their petrologic compositions vary widely including basanite, trachybasalt, andesite, trachyandesite, dacite and granodiorite. The rocks are spatially associated with gold mineralization of the Yana-Kolyma gold belt. Intense secondary alteration of the dikes includes carbonatization, chloritization, pelitization, sericitization, saussuritization, and epidotization. The SiO2 content in the sampled rocks varies from 46.8 to 70.5 wt. %, while the total amount of Na2O+K2O ranges from 2.69 to 7.59 wt. %. The dike rocks belong to the low- and high-K calc-alkaline and the shoshonite magmatic series. They exhibit a uniform REE distribution pattern intermediate between those of OIB and E-MORB. The flat HREE trend is close to that of MORB. The Eu anomaly is absent (0.9-1.0). Positive Ba, K and negative Ti, Ta, and Nb anomalies are observed. Trace element trends are much like those established for mafic rocks from dikes at the Malo-Tarynskoe and Tin-Yuryuete gold deposits in the western part of the Verkhoyansk-Kolyma fold area. The dikes could have formed from mixed enriched and depleted mantle sources, possibly with the involvement of a subduction-related component.

AB - The dike rocks under study are localized in Mesozoic (T3-J2) clastic rocks in the western part of Verkhoyansk-Kolyma fold area. Studying the nature of the dikes and geodynamic setting of their formation is of great interest now in view of the controversy surrounding their assignment to definite magmatic complexes of the Verkhoyansk-Kolyma fold area and the uncertain origin of mineralization in the Yana-Kolyma gold belt. Major elements were determined using the silicate analysis of magmatic rocks. The mineral compositions of dike rocks were studied using a Tescan MIRA 3 LMU scanning electron microscope. Studies of REE and other trace elements were performed with the use of mass spectrometers - quadrupolar Agilent7500ce (Japan) and high-resolution Element2 (Germany). Their petrologic compositions vary widely including basanite, trachybasalt, andesite, trachyandesite, dacite and granodiorite. The rocks are spatially associated with gold mineralization of the Yana-Kolyma gold belt. Intense secondary alteration of the dikes includes carbonatization, chloritization, pelitization, sericitization, saussuritization, and epidotization. The SiO2 content in the sampled rocks varies from 46.8 to 70.5 wt. %, while the total amount of Na2O+K2O ranges from 2.69 to 7.59 wt. %. The dike rocks belong to the low- and high-K calc-alkaline and the shoshonite magmatic series. They exhibit a uniform REE distribution pattern intermediate between those of OIB and E-MORB. The flat HREE trend is close to that of MORB. The Eu anomaly is absent (0.9-1.0). Positive Ba, K and negative Ti, Ta, and Nb anomalies are observed. Trace element trends are much like those established for mafic rocks from dikes at the Malo-Tarynskoe and Tin-Yuryuete gold deposits in the western part of the Verkhoyansk-Kolyma fold area. The dikes could have formed from mixed enriched and depleted mantle sources, possibly with the involvement of a subduction-related component.

KW - Dike magmatism

KW - Northeast Asia

KW - Subduction-related component

KW - Verkhoyansk-Kolyma fold area

UR - http://www.scopus.com/inward/record.url?scp=85099769572&partnerID=8YFLogxK

U2 - 10.5593/sgem2020/1.1/s01.028

DO - 10.5593/sgem2020/1.1/s01.028

M3 - Conference article

AN - SCOPUS:85099769572

VL - 2020-August

SP - 221

EP - 227

JO - International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM

JF - International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM

SN - 1314-2704

IS - 1.1

T2 - 20th International Multidisciplinary Scientific Geoconference: Science and Technologies in Geology, Exploration and Mining, SGEM 2020

Y2 - 18 August 2020 through 24 August 2020

ER -