Research output: Contribution to journal › Article › peer-review
Comparison of Diamonds from the Rassolninskaya Depression and Modern Alluvial Placers of the Krasnovishersky District (Ural Region). / Klepikov, I. V.; Васильев, Евгений; Лукьянова, Людмила .
In: Geology of Ore Deposits, Vol. 61, No. 7, 01.12.2019, p. 598-605.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Comparison of Diamonds from the Rassolninskaya Depression and Modern Alluvial Placers of the Krasnovishersky District (Ural Region)
AU - Klepikov, I. V.
AU - Васильев, Евгений
AU - Лукьянова, Людмила
N1 - Publisher Copyright: © 2019, Pleiades Publishing, Ltd.
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Abstract: Three hundred thirty-six diamonds from deposits of the Rassolninskaya depression and 144 crystals from recent alluvial placers of the Krasnovishersky district were studied by IR absorption and photoluminescence spectroscopy. It is shown that crystals from the Rassolninskaya depression have a close-to-normal distribution for the nitrogen concentration. The average nitrogen content is 725 ppm, and no nitrogen-free crystals were detected. A sampling from recent alluvial placers contains 25% crystals with a nitrogen concentration smaller than 150 ppm; 3% of them are nitrogen-free. Among crystals from the Rassolninskaya depression, 12% are octahedral, 80% rhombododecahedral, and only one crystal has relicts of cubic faces. The collection from recent placers contains 3% cubic crystals, 10% individuals with relicts of cubic faces, 16% octahedroids, and 66% dodecahedra. Alluvial diamonds are often encountered with crescent-shaped cracks; however, they were observed only on a single crystal from the Rassolninskaya depression. It has been revealed that among alluvial placer diamonds, up to 95% of crystals contain nitrogen in the form of B1 defects. Thus, first, in morphological and structural-mineralogical features, diamonds from the Rassolninskaya depression differ from crystals of the nearest recent alluvial placers; second, they may belong to primary deposits based on the set of their characteristics.
AB - Abstract: Three hundred thirty-six diamonds from deposits of the Rassolninskaya depression and 144 crystals from recent alluvial placers of the Krasnovishersky district were studied by IR absorption and photoluminescence spectroscopy. It is shown that crystals from the Rassolninskaya depression have a close-to-normal distribution for the nitrogen concentration. The average nitrogen content is 725 ppm, and no nitrogen-free crystals were detected. A sampling from recent alluvial placers contains 25% crystals with a nitrogen concentration smaller than 150 ppm; 3% of them are nitrogen-free. Among crystals from the Rassolninskaya depression, 12% are octahedral, 80% rhombododecahedral, and only one crystal has relicts of cubic faces. The collection from recent placers contains 3% cubic crystals, 10% individuals with relicts of cubic faces, 16% octahedroids, and 66% dodecahedra. Alluvial diamonds are often encountered with crescent-shaped cracks; however, they were observed only on a single crystal from the Rassolninskaya depression. It has been revealed that among alluvial placer diamonds, up to 95% of crystals contain nitrogen in the form of B1 defects. Thus, first, in morphological and structural-mineralogical features, diamonds from the Rassolninskaya depression differ from crystals of the nearest recent alluvial placers; second, they may belong to primary deposits based on the set of their characteristics.
KW - diamonds
KW - FTIR
KW - morphology
KW - photoluminescence
KW - placer
KW - Rassolninskaya depression
KW - Urals
UR - http://www.scopus.com/inward/record.url?scp=85079193352&partnerID=8YFLogxK
U2 - 10.1134/S1075701519070134
DO - 10.1134/S1075701519070134
M3 - Article
AN - SCOPUS:85079193352
VL - 61
SP - 598
EP - 605
JO - Geology of Ore Deposits
JF - Geology of Ore Deposits
SN - 1075-7015
IS - 7
ER -
ID: 86253817