TY - JOUR
T1 - High-pressure ultramafics in the lower crustal rocks of the Pekul'ney complex, central Chukchi Peninsula. 2. Internal structure of blocks and ultramafic bodies, geologic and geodynamic setting of rock formation
AU - Bazylev, B. A.
AU - Ledneva, G. V.
AU - Ishiwatari, A.
N1 - Funding Information:
We are grateful to G.E. Nekrasov (Geological Institute, Russian Academy of Sciences) for consider able help during the field studies of 1987, as well as Y. Hayasaka (Hiroshima University, Japan), K. Koizumi (Kanazawa University, Japan), S.A. Palandzhyan (Geo logical Institute, Russian Academy of Sciences), O.L. Morozov (Aerogeologiya), and V.D. Shcherba kov (Moscow State University), who participated in the fieldwork of 2006. The authors thank V.V. Lebedev (FGUGP Georegion, Anadyr) for his help in the organization of field studies, V.A. Komel’kov and other citizens of the town of Anadyr for their technical assistance. Thanks are due to I.S. Puchtel and two anonymous reviewers for comments to the early vari ants of the manuscript. The fieldwork of 2006 and ana lytical investigations were financially supported by joint Japan–Russian grant no. 05 05 66947 YaF_a of the Russian Foundation for Basic Research and Japan Society for Promotion of Science; grants for the state support of leading scientific schools NSh 741.2012.5 (supervised by A.V. Sobolev) and NSh 51772012.5 (supervised by Yu.M. Pushcharovskii); and the Rus sian Foundation for Basic Research, project no. 11 05 01042.
Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.
PY - 2013
Y1 - 2013
N2 - The detailed mapping of the blocks of the Pekul'ney complex revealed that cumulate ultramafics occur as separate tabular bodies among metamorphic rocks and are only fragmentarily observed in some of the blocks. Within these bodies, different types of ultramafics are regularly and multiply intercalated, forming banded structures, which supports their assignment to a single cumulate series. The tabular ultramafic bodies investigated in different blocks of the Pekul'ney complex are from 350 to 1100 m thick, and their internal structure is made up of intercalated regular rhythms of dunites-peridotites and olivine pyroxenites-olivine-free ultramafics (garnet, ceylonite, and clinozoisite clinopyroxenites, websterites, and hornblendites) and units of irregularly interlayered dunites, peridotites, and olivine pyroxenites. The thickness of individual regular rhythms ranges from 50 to 410 m. The cumulate ultramafics of the Pekul'ney complex were derived from a water-rich highly magnesian primary melt, which was equilibrated with mantle harzburgites, within a wide temperature range at pressures of 11-13 kbar in the geodynamic setting of the base of an ensialic arc. The Pekul'ney complex can be considered as a reference object for the petrological and geochemical investigation of the evolution of suprasubduction mantle melts during their high-pressure fractionation.
AB - The detailed mapping of the blocks of the Pekul'ney complex revealed that cumulate ultramafics occur as separate tabular bodies among metamorphic rocks and are only fragmentarily observed in some of the blocks. Within these bodies, different types of ultramafics are regularly and multiply intercalated, forming banded structures, which supports their assignment to a single cumulate series. The tabular ultramafic bodies investigated in different blocks of the Pekul'ney complex are from 350 to 1100 m thick, and their internal structure is made up of intercalated regular rhythms of dunites-peridotites and olivine pyroxenites-olivine-free ultramafics (garnet, ceylonite, and clinozoisite clinopyroxenites, websterites, and hornblendites) and units of irregularly interlayered dunites, peridotites, and olivine pyroxenites. The thickness of individual regular rhythms ranges from 50 to 410 m. The cumulate ultramafics of the Pekul'ney complex were derived from a water-rich highly magnesian primary melt, which was equilibrated with mantle harzburgites, within a wide temperature range at pressures of 11-13 kbar in the geodynamic setting of the base of an ensialic arc. The Pekul'ney complex can be considered as a reference object for the petrological and geochemical investigation of the evolution of suprasubduction mantle melts during their high-pressure fractionation.
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U2 - 10.1134/S0869591113040024
DO - 10.1134/S0869591113040024
M3 - Article
AN - SCOPUS:84880493413
VL - 21
SP - 336
EP - 350
JO - Petrology
JF - Petrology
SN - 0869-5911
IS - 4
ER -