Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Geochemical evidence for the fractionation of iridium group elements at the early stages of crystallization of the Dovyren Magmas (northern Baikal area, Russia)

A. A. Ariskin, G. S. Nikolaev, L. V. Danyushevsky, M. Fiorentini, E. V. Kislov and I. V. Pshenitsyn
Geochemical evidence for the fractionation of iridium group elements at the early stages of crystallization of the Dovyren Magmas (northern Baikal area, Russia)
Russian Geology and Geophysics (May 2018) 59 (5): 459-471

Abstract

We have first generalized geochemical and mineralogical data indicating the important role of crystallization of Os-Ir-Ru phases and fractionation of refractory iridium subgroup of PGE (IPGE) at the early stages of the evolution of parental magmas and primitive cumulates from the Yoko-Dovyren layered massif (northern Baikal area, Russia). The object of study was two types of plagioclase peridotites from the lower part of the intrusion, differing in the porosity of primary olivine cumulates: less melanocratic (but more primitive) type I and more melanocratic type II. Inclusions of refractory IPGE (Os, Ir, and Ru) discovered during LA-ICP-MS studies of aluminochromite from type I rocks are the first evidence for the presence of Os-Ir-Ru phases. Subsequent electron microscopy examinations revealed more than 25 grains of laurite and Ir-containing osmium in aluminochromite from plagioperidotites of both types. Attention is focused on the importance of the Ru/Cr (sub 2) O (sub 3) and Ir/Cr (sub 2) O (sub 3) ratios in rocks for the separation of IPGE at early and late fractionation stages. The conclusion is drawn that the higher Ru/Cr (sub 2) O (sub 3) and Ir/Cr (sub 2) O (sub 3) ratios in type I plagioperidotites indicate higher enrichment of aluminochromite in inclusions of refractory IPGE minerals. This is consistent with the fact that these rocks are assigned to the most primitive high-temperature ultramafites genetically related to the parental magma, which was in equilibrium with olivine Fo (sub 88) at approximately 1290 degrees C. We have established that the parental Dovyren magma was already depleted in IPGE and rhodium before its entrance into a chamber. No signs of early sulfide-silicate immiscibility have been detected. Copyright 2018, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.


ISSN: 1068-7971
Serial Title: Russian Geology and Geophysics
Serial Volume: 59
Serial Issue: 5
Title: Geochemical evidence for the fractionation of iridium group elements at the early stages of crystallization of the Dovyren Magmas (northern Baikal area, Russia)
Affiliation: Lomonosov Moscow State University, Moscow, Russian Federation
Pages: 459-471
Published: 201805
Text Language: English
Publisher: Allerton Press, New York, NY, United States
References: 28
Accession Number: 2022-003767
Categories: Geochemistry of rocks, soils, and sedimentsIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 5 tables
N51°00'00" - N61°00'00", E104°00'00" - E118°30'00"
Secondary Affiliation: Vernadsky Institute of Geochemistry and Analytical Chemistry, RUS, Russian FederationUniversity of Tasmania, AUS, AustraliaUniversity of Western Australia, AUS, AustraliaSiberian Branch of the Russian Academy of Sciences, RUS, Russian Federation
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2022
Close Modal

or Create an Account

Close Modal
Close Modal