ISOTOPIC INHOMOGENEITY OF SOURCES OF LATE PALEOZOIC INTRAPLATE MAGMATISM IN CENTRAL-ASIA (BASED ON SR AND ND ISOTOPE DATA FOR BASALIS OF BIMODAL ASSOCIATIONS)
Vv. Yarmolyuk et al., ISOTOPIC INHOMOGENEITY OF SOURCES OF LATE PALEOZOIC INTRAPLATE MAGMATISM IN CENTRAL-ASIA (BASED ON SR AND ND ISOTOPE DATA FOR BASALIS OF BIMODAL ASSOCIATIONS), Geologia i geofizika, 38(6), 1997, pp. 1142-1147
Study is given to isotope composition (Sr, Nd) of basalts of bimodal a
ssociations of the Late Paleozoic rift system in Central Asia. It has
been established that this composition is relatively stable in the str
ike of separate rift zones and in significantly different zones. Varia
tions of isotope compositions are estimated in the context of mixing o
f two isotope sources with drastically different isotope parameters in
chambers of magma generation. It is shown that the regional crust cou
ld not influence changes of isotope composition, Therefore, it is supp
osed that the melt source was the MORB-type depleted mantle and the EM
-II-type mantle enriched mainly in Sr-87.