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Causes of variations in morphology and impurities of diamonds from the Udachnaya Pipe eclogite

Citation

Stepanov, AS and Shatsky, VS and Zedgenizov, DA and Sobolev, NV, Causes of variations in morphology and impurities of diamonds from the Udachnaya Pipe eclogite, Russian Geology and Geophysics, 48, (9) pp. 758-769. ISSN 1068-7971 (2007) [Refereed Article]

Copyright Statement

Copyright 2007 Elsevier

DOI: doi:10.1016/j.rgg.2007.01.003

Abstract

A unique xenolith of eclogite, 231711 cm in size and 8 kg in weight, was found in the Udachnaya kimberlite pipe. One hundred twenty-four diamond crystals recovered from it were analyzed by a number of methods. The diamonds differ in morphology, internal structure, color, size, and composition of defects and impurities. The xenolith contains diamonds of octahedral and cubooctahedral habits. In cathodoluminescence, the octahedral crystals have a brightly glowing core with octahedral zones of growth and a weakly glowing rim. In the cores of these crystals the N impurity is mostly present in the B1 form (30 to 60%). At the same time, N in the rim is chiefly in the A form. The cubooctahedral crystals show a weak luminescence. The content of nitrogen and degree of its aggregation are close to those in the rim of octahedral crystals. The diversity of morphology and impurity composition of diamonds from the xenolith can be explained by their formation in two stages. At the first stage, the diamonds formed which became the cores of octahedra. After a long-time interruption, at the second stage of diamond formation crystals of cubooctahedral habit appeared and the octahedral crystals were overgrown. Wide variations in nitrogen contents in the xenolith crystals allowed their use to estimate the kinetics of aggregated nitrogen. The data obtained show that the aggregation of A centers into B1 centers in the diamonds is described by a kinetic reaction of an order of 1.5.

Item Details

Item Type:Refereed Article
Keywords:diamond, mantle, eclogite, defects of crystal structure
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Inorganic Geochemistry
Objective Division:Mineral Resources (excl. Energy Resources)
Objective Group:Mineral Exploration
Objective Field:Diamond Exploration
Author:Stepanov, AS (Mr Sasha Stepanov)
ID Code:95759
Year Published:2007
Web of Science® Times Cited:15
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2014-10-08
Last Modified:2014-11-11
Downloads:0

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