TY - JOUR

T1 - Prospects of search for diamondiferous kimberlites in the northeastern Siberian Platform

AU - Sobolev, N. V.

AU - Sobolev, A. V.

AU - Tomilenko, A. A.

AU - Kuz'min, D. V.

AU - Grakhanov, S. A.

AU - Batanova, V. G.

AU - Logvinova, A. M.

AU - Bul'bak, T. A.

AU - Kostrovitskii, S. I.

AU - Yakovlev, D. A.

AU - Fedorova, E. N.

AU - Anastasenko, G. F.

AU - Nikolenko, E. I.

AU - Tolstov, A. V.

AU - Reutskii, V. N.

PY - 2018/10/1

Y1 - 2018/10/1

N2 - The objects of study are Triassic hypabyssal diamondiferous kimberlites with an age of 220-245 Ma, containing macrocrysts of unaltered olivine. The latter are close in the time of formation to the main stage of intrusion of the Siberian Trap Province (252 Ma), which lasted less than 1 Myr. A comparative high-precision analytical study of the Ti, Ca, Cr, and Al impurity patterns in about 1000 olivine macrocryst samples with a forsterite content Fo = (100Mg/(Mg + Fe)) of 78 to 93 has demonstrated the effect of traps on the lithospheric composition. A comprehensive comparative study of diamonds from northern placers and Triassic kimberlites, including determination of their carbon isotope composition, was performed. Chromatography-mass-spectroscopic analysis of submicron fluid inclusions in diamonds from northern placers and kimberlites has shown predominant hydrocarbons of a wide range of compositions and subordinate contents of N2, H2O, and CO2. These findings, together with the results of previous studies of subcalcic Cr-pyropes and diamonds found in the Lower Carboniferous gritstones of the Kyutyungde graben, lead to the conclusion that the Toluopka kimberlite field is promising for Paleozoic kimberlites. The results of comprehensive studies of diamonds and indicator minerals and U/Pb isotope dating of numerous detrital zircon samples from the basal horizon of the Carnian Stage (Upper Triassic) of the Bulkur site in the lower reaches of the Lena River suggest the presence of diamondiferous kimberlites within the northeastern Siberian Platform. The age of the probable primary diamond sources in the study area can be evaluated by an integrated U/Pb isotope dating of zircons, perovskites, and rutiles from the developed diamond placers and the basal horizon of the Carnian Stage.

AB - The objects of study are Triassic hypabyssal diamondiferous kimberlites with an age of 220-245 Ma, containing macrocrysts of unaltered olivine. The latter are close in the time of formation to the main stage of intrusion of the Siberian Trap Province (252 Ma), which lasted less than 1 Myr. A comparative high-precision analytical study of the Ti, Ca, Cr, and Al impurity patterns in about 1000 olivine macrocryst samples with a forsterite content Fo = (100Mg/(Mg + Fe)) of 78 to 93 has demonstrated the effect of traps on the lithospheric composition. A comprehensive comparative study of diamonds from northern placers and Triassic kimberlites, including determination of their carbon isotope composition, was performed. Chromatography-mass-spectroscopic analysis of submicron fluid inclusions in diamonds from northern placers and kimberlites has shown predominant hydrocarbons of a wide range of compositions and subordinate contents of N2, H2O, and CO2. These findings, together with the results of previous studies of subcalcic Cr-pyropes and diamonds found in the Lower Carboniferous gritstones of the Kyutyungde graben, lead to the conclusion that the Toluopka kimberlite field is promising for Paleozoic kimberlites. The results of comprehensive studies of diamonds and indicator minerals and U/Pb isotope dating of numerous detrital zircon samples from the basal horizon of the Carnian Stage (Upper Triassic) of the Bulkur site in the lower reaches of the Lena River suggest the presence of diamondiferous kimberlites within the northeastern Siberian Platform. The age of the probable primary diamond sources in the study area can be evaluated by an integrated U/Pb isotope dating of zircons, perovskites, and rutiles from the developed diamond placers and the basal horizon of the Carnian Stage.

KW - diamond

KW - hypabyssal kimberlite

KW - lithospheric mantle

KW - Mesozoic

KW - olivine

KW - perovskite

KW - rutile

KW - Siberian Platform

KW - U/Pb isotope dating

KW - zircon

KW - GARNETS

KW - INCLUSIONS

KW - LITHOSPHERIC MANTLE

KW - INFRARED-ABSORPTION

KW - U-PB

KW - HYPABYSSAL KIMBERLITES

KW - PHASE-COMPOSITION

KW - KOKCHETAV MASSIF

KW - DIAMONDS

KW - OLIVINE

UR - http://www.scopus.com/inward/record.url?scp=85054924904&partnerID=8YFLogxK

U2 - 10.1016/j.rgg.2018.09.012

DO - 10.1016/j.rgg.2018.09.012

M3 - Article

AN - SCOPUS:85054924904

VL - 59

SP - 1365

EP - 1379

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 10

ER -