TY - JOUR

T1 - Mineralogical, geochemical, and age characteristics of the rocks of the Inagli dunite-clinopyroxenite-shonkinite massif with platinum-chromite and Cr-diopside mineralization (Aldan Shield)

AU - Okrugin, A. V.

AU - Borisenko, A. S.

AU - Zhuravlev, A. I.

AU - Travin, A. V.

PY - 2018/10

Y1 - 2018/10

N2 - We consider the mineralogical and geochemical features of the rocks of the Inagli dunite-clinopyroxenite-shonkinite massif with platinum-chromite and unique jewelry Cr-diopside mineralization, which is a reference object of concentric zonal complexes. The massif rocks, from dunites to pulaskites, including peridotites, clinopyroxenites, shonkinites, and melanocratic alkali syenites, form a single continuous comagmatic series. This is confirmed by a clear dependence of the compositions of olivine, pyroxene, phlogopites, and Cr-spinels on the MgO content of the rocks and on the behavior of trace elements in them. The similar compositions of pyroxenes and trace-element patterns of clinopyroxenite rocks and Cr-diopsidite veins indicate a genetic similarity of these rocks. The age and mineralogical and geochemical compositions of the rocks and the geologic and morphological features of the intrusion prove that the Inagli massif formed from high-K picritoid melts, which underwent gradual decompression solidification during the ascent and formed a cylindrical diapir-like body at the subsurface level in the Early Cretaceous. The new portions of differentiates supplied from the lower horizons of the magma column determined the complex composition of the massif: It has a concentric zonal structure cut by numerous radial-circular vein bodies of pegmatites and pure anchimonomineral rocks (Cr-diopsidites), in places, of jewelry quality.

AB - We consider the mineralogical and geochemical features of the rocks of the Inagli dunite-clinopyroxenite-shonkinite massif with platinum-chromite and unique jewelry Cr-diopside mineralization, which is a reference object of concentric zonal complexes. The massif rocks, from dunites to pulaskites, including peridotites, clinopyroxenites, shonkinites, and melanocratic alkali syenites, form a single continuous comagmatic series. This is confirmed by a clear dependence of the compositions of olivine, pyroxene, phlogopites, and Cr-spinels on the MgO content of the rocks and on the behavior of trace elements in them. The similar compositions of pyroxenes and trace-element patterns of clinopyroxenite rocks and Cr-diopsidite veins indicate a genetic similarity of these rocks. The age and mineralogical and geochemical compositions of the rocks and the geologic and morphological features of the intrusion prove that the Inagli massif formed from high-K picritoid melts, which underwent gradual decompression solidification during the ascent and formed a cylindrical diapir-like body at the subsurface level in the Early Cretaceous. The new portions of differentiates supplied from the lower horizons of the magma column determined the complex composition of the massif: It has a concentric zonal structure cut by numerous radial-circular vein bodies of pegmatites and pure anchimonomineral rocks (Cr-diopsidites), in places, of jewelry quality.

KW - chromites

KW - diopsides

KW - dunites

KW - Inagli massif

KW - magma differentiation

KW - platinum

KW - shonkinites

KW - COMPLEX

KW - NUGGETS

KW - PLACER DEPOSIT

KW - ORIGIN

KW - RUSSIA

KW - UREYITE

UR - http://www.scopus.com/inward/record.url?scp=85054907143&partnerID=8YFLogxK

U2 - 10.1016/j.rgg.2018.09.008

DO - 10.1016/j.rgg.2018.09.008

M3 - Article

AN - SCOPUS:85054907143

VL - 59

SP - 1301

EP - 1317

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 10

ER -