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Title: Strontium isotopes in the rocks of the ophiolite complex in the Khan-Tayshiri Range (Western Mongolia)

Journal Article · · Int. Geol. Rev.; (United States)

The distribution of strontium isotopes has been examined in a section through the ophiolite complex of the Khan-Tayshiri Range (Western Mongolia). The basal parts of the complex consist of apo-dunites (/sup 87/Sr//sup 86/Sr = 0.7118 - 0.7124), and higher up in the section there are pyroxenites (0.7064 - 0.7095) and gabbros (0.7034-0.7065). The upper parts of the complex consist of pillow lavas (0.7068-0.7071), the conduits for which were a series of laminar dikes (0.7057-0.7087). An analysis of petrological and geochemical information with a selection of isotope data suggests that during the formation of the rocks of the Khan-Tayshiri Complex, three components, different in nature and chemical composition, were involved: the remains of the Earth's protolithosphere in the form of apo-dunites, a mantle quartz-tholeiite magma, and seawater. Variations in the /sup 87/Sr//sup 86/Sr ratio are associated both with the isotope composition of the original magma, and also with the conditions of its emplacement. The ultrabasic rocks are regarded as relicts of the ancient ultrabasic layer or protolithosphere of the Earth.

Research Organization:
Inst. of Geochemistry, Moscow, USSR
OSTI ID:
6682077
Journal Information:
Int. Geol. Rev.; (United States), Vol. 22:8; Other Information: Translated from Izv. Akad. Nauk SSR, Ser. Geol., No. 7, 36-45(1979)
Country of Publication:
United States
Language:
English