Research output: Contribution to journal › Article › peer-review
Regional, Contact Metamorphism, and Autometamorphism of the Olkhon Terrane (West Baikal Area). / Sklyarov, E. V.; Lavrenchuk, A. V.; Fedorovsky, V. S. et al.
In: Petrology, Vol. 28, No. 1, 01.2020, p. 47-61.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Regional, Contact Metamorphism, and Autometamorphism of the Olkhon Terrane (West Baikal Area)
AU - Sklyarov, E. V.
AU - Lavrenchuk, A. V.
AU - Fedorovsky, V. S.
AU - Gladkochub, D. P.
AU - Donskaya, T. V.
AU - Kotov, A. B.
AU - Mazukabzov, A. M.
AU - Starikova, A. E.
PY - 2020/1
Y1 - 2020/1
N2 - The rocks of the Olkhon terrane experienced high-grade regional metamorphism reaching granulite facies. In addition to regional metamorphism, they were subjected to contact metamorphism and autometamorphism (mafic dikes). Three types of regional metamorphism have been distinguished. A terrane collage north of the Orso Zone revealed two stages of regional metamorphism: early-stage granulite metamorphism (Т = 750–900°С, Р = 8–9 kbar, around 500 Ma) and late-stage amphibolite and low–amphibolite facies (Т = 550–710°С, Р = 4–6 kbar, 460–470 Ma). The Orso microterrane separating the Krestovsky island-arc subterrane from a collage of other microterranes contains high-pressure mineral assemblages (up to 10 kbar), which are characterized by the presence of high-calcium garnet in metapelites. The Orso microterrane and Krestovsky subterrane are characterized by relatively high-pressure path of metamorphism. An extended zone of contact high-temperature metamorphism related to the emplacement of gabbro of the second phase of the Ustkrestovsky Complex has been mapped in the Krestovsky subterrane. The temperature of formation of two-pyroxene hornfels after metaporphyrites of the Birkhin volcanoplutonic association is estimated at 750–850°С. Beerbachites were formed by autometamorphism of subvolcanic mafic bodies, which compose the northern part of the Tazheran composite massif (syenite, Ne-syenite, subalkaline gabbro), dikes in the Birkhin gabbro massif, as well as dikes and separate blocks in marble mélange. The temperature of autometamorphism during formation of beerbachites is estimated from two-pyroxene geothermometer as 700–1000°С.
AB - The rocks of the Olkhon terrane experienced high-grade regional metamorphism reaching granulite facies. In addition to regional metamorphism, they were subjected to contact metamorphism and autometamorphism (mafic dikes). Three types of regional metamorphism have been distinguished. A terrane collage north of the Orso Zone revealed two stages of regional metamorphism: early-stage granulite metamorphism (Т = 750–900°С, Р = 8–9 kbar, around 500 Ma) and late-stage amphibolite and low–amphibolite facies (Т = 550–710°С, Р = 4–6 kbar, 460–470 Ma). The Orso microterrane separating the Krestovsky island-arc subterrane from a collage of other microterranes contains high-pressure mineral assemblages (up to 10 kbar), which are characterized by the presence of high-calcium garnet in metapelites. The Orso microterrane and Krestovsky subterrane are characterized by relatively high-pressure path of metamorphism. An extended zone of contact high-temperature metamorphism related to the emplacement of gabbro of the second phase of the Ustkrestovsky Complex has been mapped in the Krestovsky subterrane. The temperature of formation of two-pyroxene hornfels after metaporphyrites of the Birkhin volcanoplutonic association is estimated at 750–850°С. Beerbachites were formed by autometamorphism of subvolcanic mafic bodies, which compose the northern part of the Tazheran composite massif (syenite, Ne-syenite, subalkaline gabbro), dikes in the Birkhin gabbro massif, as well as dikes and separate blocks in marble mélange. The temperature of autometamorphism during formation of beerbachites is estimated from two-pyroxene geothermometer as 700–1000°С.
KW - beerbachite
KW - hornfels
KW - metamorphism
KW - Olkhon terrane
KW - West Baikal Area
KW - ORTHO-PYROXENE
KW - THERMOMETRY
KW - MARGIN
KW - MA
KW - ROCKS
KW - LAKE BAIKAL
KW - PARAMETERS
UR - http://www.scopus.com/inward/record.url?scp=85083247409&partnerID=8YFLogxK
U2 - 10.1134/S0869591120010051
DO - 10.1134/S0869591120010051
M3 - Article
AN - SCOPUS:85083247409
VL - 28
SP - 47
EP - 61
JO - Petrology
JF - Petrology
SN - 0869-5911
IS - 1
ER -
ID: 24012539