Аннотация:Chemical composition of the Chiney mafic-ultramafic
layered intrusion was studied in two main sections and
from other rock types in the eastern part. All rocks, except
norite, are enriched in Fe and Ti. The MgO and TiO2 variations
demonstrate a rhythmic structure of the Chiney
pluton. Distribution of rare elements in rocks is similar to
the distribution in typical crustal rocks with negative
Ta-Nb and positive Pb anomalies. Techniques of geochemical
thermometry with the use of the COMAGMAT
computer program allowed to estimate the phase and
chemical composition of the parental magma. The Chiney
magma was represented by differentiated suspension of
olivine, plagioclase, and magnetite crystals in ferrobasaltic
melt at a temperature of approximately 1130 °C. The
gravitational separation of these phases in the melt before
its emplacement into the chamber and during the subsequent
emplacement of various portions of the initial
magma into the modern chamber predetermined the heterogeneity
of the pluton.