TY - JOUR

T1 - Crystal morphological evolution of growth and dissolution of curve-faced cubic diamonds from placers of the Anabar diamondiferous region

AU - Pavlushin, A. D.

AU - Zedgenizov, D. A.

AU - Pirogovskaya, K. L.

N1 - Publisher Copyright: © 2017, Pleiades Publishing, Ltd.

PY - 2017/12/1

Y1 - 2017/12/1

N2 - In this paper, we consider an ontogenic model for the formation of morphological types of growth and dissolution of cubic diamonds of variety II by Yu.L. Orlov from placers of the Anabar diamondiferous region. The following ontogenic domains of crystals and corresponding evolutionary stages of growth accompanying a general decrease in supersaturation in the crystallization medium were distinguished: microblock mosaic cuboids with defects produced by the mechanism of rotational plastic deformation–cuboids with linear translation deformations–cuboids and antiskeletal growth forms of cuboids composed of octahedral growth layers–pseudocubic growth forms of a flat-faced octahedron. The crystal morphological evolution of cuboids during the bulk dissolution of individuals in fluid-bearing melt transporting them to the surface was traced. The investigation of transitional forms of cuboid diamond dissolution showed that the final form of diamond dissolution is a rounded tetrahexahedroid independent of the combination of cuboid faces with subordinate faces of octahedron, rhombododecahedron, and tetrahexahedron observed on resorbed crystals of cubic habit. It was found that the final stages of cuboid dissolution produced disk-shaped microrelief features on the diamond surface in the form of randomly distributed ideal rounded etch pits resulting from interaction with microscopic cavitation gas bubbles released during the decompression of ascending kimberlite melt.

AB - In this paper, we consider an ontogenic model for the formation of morphological types of growth and dissolution of cubic diamonds of variety II by Yu.L. Orlov from placers of the Anabar diamondiferous region. The following ontogenic domains of crystals and corresponding evolutionary stages of growth accompanying a general decrease in supersaturation in the crystallization medium were distinguished: microblock mosaic cuboids with defects produced by the mechanism of rotational plastic deformation–cuboids with linear translation deformations–cuboids and antiskeletal growth forms of cuboids composed of octahedral growth layers–pseudocubic growth forms of a flat-faced octahedron. The crystal morphological evolution of cuboids during the bulk dissolution of individuals in fluid-bearing melt transporting them to the surface was traced. The investigation of transitional forms of cuboid diamond dissolution showed that the final form of diamond dissolution is a rounded tetrahexahedroid independent of the combination of cuboid faces with subordinate faces of octahedron, rhombododecahedron, and tetrahexahedron observed on resorbed crystals of cubic habit. It was found that the final stages of cuboid dissolution produced disk-shaped microrelief features on the diamond surface in the form of randomly distributed ideal rounded etch pits resulting from interaction with microscopic cavitation gas bubbles released during the decompression of ascending kimberlite melt.

KW - cuboid

KW - diamond

KW - dissolution evolution

KW - growth evolution

KW - microrelief

KW - morphology

KW - rounded crystals

KW - Siberian platform

UR - http://www.scopus.com/inward/record.url?scp=85038412906&partnerID=8YFLogxK

U2 - 10.1134/S0016702917090051

DO - 10.1134/S0016702917090051

M3 - Article

AN - SCOPUS:85038412906

VL - 55

SP - 1193

EP - 1203

JO - Geochemistry International

JF - Geochemistry International

SN - 0016-7029

IS - 12

ER -