TY - JOUR

T1 - High-Grade Metamorphism and Anatexis in the Teletskoe-Chulyshman Belt (Gorny Altai)

T2 - U-Pb Geochronology, P-T Estimates, and Thermal Tectonic Model

AU - Polyansky, O. P.

AU - Kargopolov, S. A.

AU - Babichev, A.

AU - Reverdatto, V. V.

PY - 2019/12

Y1 - 2019/12

N2 - A model of the formation of the Teletskoe-Chulyshman metamorphic belt (TCMB) in Gorny Altai has been elaborated. The estimated pressure (not exceeding 3-4 kbar) and temperature (about 740 ºС) indicate an increased regional crustal thermal gradient equal to 60-90 ºС/km during the formation of the metamorphic belt. The age of migmatites of the Chulyshman complex has been evaluated at 483.9 ± 5.7 Ma (Early Ordovician) by U/Pb (SHRIMP) zircon dating. The paleogeodynamic setting of the TCMB formation and the protolith nature are identified based on the geochemical and petrochemical parameters of the metamorphic rocks. Structural parameters and numerical modeling show that the Chulyshman migmatite-gneiss complex is an apical part of the thermal-dome structure formed under the thermal impact of a magmatic basic heat source in the base of the crust and displaced to the relevant depths via thrusts and crustal extrusion during the Early Ordovician accretion-collision event. Matching the metamorphism parameters and the numerical-modeling results for the crustal thermal regime, we determined the rate of the anatectic front displacement along the thrust to be at least 6 cm/yr.

AB - A model of the formation of the Teletskoe-Chulyshman metamorphic belt (TCMB) in Gorny Altai has been elaborated. The estimated pressure (not exceeding 3-4 kbar) and temperature (about 740 ºС) indicate an increased regional crustal thermal gradient equal to 60-90 ºС/km during the formation of the metamorphic belt. The age of migmatites of the Chulyshman complex has been evaluated at 483.9 ± 5.7 Ma (Early Ordovician) by U/Pb (SHRIMP) zircon dating. The paleogeodynamic setting of the TCMB formation and the protolith nature are identified based on the geochemical and petrochemical parameters of the metamorphic rocks. Structural parameters and numerical modeling show that the Chulyshman migmatite-gneiss complex is an apical part of the thermal-dome structure formed under the thermal impact of a magmatic basic heat source in the base of the crust and displaced to the relevant depths via thrusts and crustal extrusion during the Early Ordovician accretion-collision event. Matching the metamorphism parameters and the numerical-modeling results for the crustal thermal regime, we determined the rate of the anatectic front displacement along the thrust to be at least 6 cm/yr.

KW - P-T parameters

KW - thermal tectonic model

KW - U/Pb age

KW - high-temperature/low-pressure metamorphism

KW - Teletskoe-Chulyshman metamorphic belt

KW - Gorny Altai

KW - META-SEDIMENTARY ROCKS

KW - EVOLUTION

KW - CRUSTAL

KW - GEODYNAMICS

KW - GRANITE

KW - MANTLE

KW - REGION

KW - CONSTRAINTS

KW - PROVENANCE

KW - SAYAN

KW - Thermal tectonic model

KW - High-temperature/low-pressure metamorphism

UR - http://www.scopus.com/inward/record.url?scp=85089101795&partnerID=8YFLogxK

U2 - 10.15372/RGG2019108

DO - 10.15372/RGG2019108

M3 - Article

VL - 60

SP - 1425

EP - 1443

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 12

ER -