TY - JOUR

T1 - Rift-related explosive volcanism on the eve of the Cambrian ‘explosion’ on the Olenek Uplift (northeastern margin of Siberian Craton)

AU - Chayka, Ivan F.

AU - Izokh, Olga P.

AU - Rogov, Vladimir I.

AU - Vinogradov, Evgeny V.

AU - Vasyukova, Elena A.

AU - Lobastov, Boris M.

AU - Rudnev, Sergey N.

AU - Izokh, Andrey E.

AU - Grazhdankin, Dmitriy V.

N1 - ield work in the Arctic Siberia was conducted with financial contributions from the National Geographic Society’s Committee for Research and Exploration (grant NGS-372R-18 to D.V.G.) and the Russian Foundation for Basic Research (grant 18-05-70110 to D.V.G.). The final stage of manuscript preparation has been completed as part of the Gauß-Professorship Award (Akademie der Wissenschaften zu Göttingen) to D.V.G. Stratigraphic studies have been conducted under Government Contract FWZZ-2022-0002 (Fundamental Scientific Research Programme of the Russian Federation). I.F.C. was financially supported by ongoing Research program FMUF-2022-0004 of the D.S.Korzhinskii Institute of Experimental Mineralogy RAS. E.V.V. was financially supported by the Russian Science Foundation grant 24-17-00057. Adaptation of sample processing, measurement technique, and data treatment have been implemented as part of the Government Contract 122041400171-5. Integrative palaeobiological study of the Ediacaran–Cambrian boundary strata on the northwestern slope of the Olenek Uplift has been financially supported by the Russian Science Foundation grant 23-17-00202. Analysis of chemical composition was financed by the Russian Science Foundation grant 22-77-00026. We thank Konstantin Nagovitsin, Natalia Bykova, Dmitry Melnik, Olzhas Zharasbaev and Munko Dorzhiev for assistance in the field, Viktoria Danilovskaya and Mikhail Khlestov for assistance with the EPMA and SEM techniques.

PY - 2025/7/1

Y1 - 2025/7/1

N2 - Igneous occurrences comprising stratiform volcanic breccia, diatremes, basalt flows and feeders, and dolerite sills exhibit structural relationships with the Ediacaran–Cambrian boundary strata on the Olenek Uplift (northeastern Siberian Craton). A U-Pb date of 543.9 ± 0.24 Ma for zircons from the volcaniclastics (Bowring et al., 1993) had been considered as the age of the magmatic complex and used to constraint the Ediacaran-Cambrian boundary. We conducted a multifaceted study of this complex shedding additional light on its classification, petrology, tectonics and emplacement regime. We distinguish between basic and high-potassic rock varieties and attribute this diversity to a syn-emplacement overprint by K+-bearing sedimentary brines. All the rocks are co-magmatic, originated from a mantle-derived alkali-basaltic melt, and constitute a single event herein formally described as the Tas-Yuryakh complex. Its parental melt supposedly originated via 15–20 % melting of a garnet lherzolite at 65–70 km depth due to reaction of a plume with moderately enriched lithospheric mantle at the passive continental margin. These data combined with the geological evidence corroborate an earlier conclusion that the Tas-Yuryakh complex together with the adjacent Kharaulakh occurrence mark a rift structure that existed at ∼ 540 Ma in an ocean basin between Siberia and Baltica. The volcanic events took place over > 600 km2 in shallow-depth coastal settings over a drowned carstified carbonate platform. The reaction of the hot magma with seawater and underground brines could have released a substantial mass of halogen- and boron-bearing compounds into the water and atmosphere affecting local environment and biota.

AB - Igneous occurrences comprising stratiform volcanic breccia, diatremes, basalt flows and feeders, and dolerite sills exhibit structural relationships with the Ediacaran–Cambrian boundary strata on the Olenek Uplift (northeastern Siberian Craton). A U-Pb date of 543.9 ± 0.24 Ma for zircons from the volcaniclastics (Bowring et al., 1993) had been considered as the age of the magmatic complex and used to constraint the Ediacaran-Cambrian boundary. We conducted a multifaceted study of this complex shedding additional light on its classification, petrology, tectonics and emplacement regime. We distinguish between basic and high-potassic rock varieties and attribute this diversity to a syn-emplacement overprint by K+-bearing sedimentary brines. All the rocks are co-magmatic, originated from a mantle-derived alkali-basaltic melt, and constitute a single event herein formally described as the Tas-Yuryakh complex. Its parental melt supposedly originated via 15–20 % melting of a garnet lherzolite at 65–70 km depth due to reaction of a plume with moderately enriched lithospheric mantle at the passive continental margin. These data combined with the geological evidence corroborate an earlier conclusion that the Tas-Yuryakh complex together with the adjacent Kharaulakh occurrence mark a rift structure that existed at ∼ 540 Ma in an ocean basin between Siberia and Baltica. The volcanic events took place over > 600 km2 in shallow-depth coastal settings over a drowned carstified carbonate platform. The reaction of the hot magma with seawater and underground brines could have released a substantial mass of halogen- and boron-bearing compounds into the water and atmosphere affecting local environment and biota.

KW - Alkali basalt

KW - Cambrian

KW - Continental rifting

KW - Ediacaran

KW - Olenek Uplift

UR - https://www.mendeley.com/catalogue/0036169a-40fb-3fa7-8cdd-3a1089fcd475/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-105002339116&origin=inward&txGid=d76fd2a02ad7007ffd73f39615a31895

U2 - 10.1016/j.jseaes.2025.106592

DO - 10.1016/j.jseaes.2025.106592

M3 - Article

VL - 288

JO - Journal of Asian Earth Sciences

JF - Journal of Asian Earth Sciences

SN - 1367-9120

M1 - 106592

ER -