Journal/NDM54 2021 eng

New Data on Minerals, Volume 55, 2021

DEADLINES FOR ARTICLES

Issue 1 - March 31, 2021
Issue 2 - May 31, 2021
Issue 3 - August 31, 2021
Issue 4 - November 30, 2021

Editorial Board

Editor in Chief:
Plechov P.Yu. - Doctor of Geology and Mineralogy, Professor
Members of Editorial Board:
Pekov I.V. - Corresponding Member of the Russian Academy of Sciences
Garanin V.K. - Doctor of Geology and Mineralogy, Professor
Novgorodova M.I. - Doctor of Geology and Mineralogy, Professor
Borutsky B.E. - Doctor of Geology and Mineralogy
Spiridonov B.E. - Doctor of Geology and Mineralogy
Kamenetsky V.S. - Professor (University of Tasmania)
Nenasheva S.N. - PhD in Geology and Mineralogy
Matvienko E.N. - PhD in Geology and Mineralogy
Generalov M.E. - PhD in Geology and Mineralogy
Pautov L.A. - Senior Researcher
Layout Designer
Kronrod E.V. - PhD in Chemistry

Content

Issue 1

Kutyrev A.V., Kamenetskiy V.S., Nekrylov N.A. Silicate inclusions in minerals of the Os-Ir-Ru system of the Adamsfield placer (Western Tasmania), p. 5-13

The collection of the native osmium grains from the Adamsfield placer (Western Tasmania) was studied. The majority of these grains and compositionally homogeneous (average composition of native osmium – 52.9 wt.% of Os, 41.2 wt.% of Ir, and 6.4 wt.% of Ru), while other minerals (native iridium, isoferroplatinum, native ruthenium, and arsenides of platinum) are rare. The chromitites from the ultramafic ophiolites of the Adamsfield complex are likely the source of the placer. Polymineralic inclusions consisting of olivine, orthopyroxene, chromium spinel, hornblende, low-Ca amphiboles (cummingtonite and anthophyllite), quartz, anorthite, and micas were found within the native osmium grains. These inclusions typically have a hexagonal shape exhibiting the habit of a negative crystal. Their origin can hardly be explained by the model suggested in previous studies (direct crystallization of the native osmium from the boninitic melt), and they rather support the modern view on the origin of chromitite and platinum mineralization in ophiolites as a result of a reaction of harzburgites with slab-derived fluids and melts. A number of morphological and compositional features of minerals hosted by these inclusions suggest the extreme heterogeneity of the mineral-forming environment, as well as the crucial role of metamorphic and metasomatic processes in the origin of studied mineral association.
Keywords: PGM, osmium, inclusions, metamorphism, subduction.
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