SOURCES OF THE PALEOZOIC SEDIMENTARY ROCKS IN THE NORA-SUKHOTINO TERRANE: RESULTS OF Sm-Nd ISOTOPIC-GEOCHEMICAL STUDIES

Abstract

The paper presents the first results on Sm-Nd isotopic-geochemical studies of the Paleozoic sedimentary rocks in the Nora-Sukhotino terrane at the northeastern flank of the South Mongolia-Khingan orogenic belt.According to the studies, the sedimentary rocks of the Zeya-Selemdzha and Amur fragments of the Nora-Sukhotino terrane are characterized by the two-stage Mesoproterozoic Nd-model age (TNd(DM2)=1.62–1.08 Ga) at negative εNd(0)=–9.5…–3.0 and εNd(T)=–5.8...–0.2. Based on previous geochemical and isotopic (U-Pb, Lu-Hf) studies of sedimentary rocks of the Nora-Sukhotino terrane, as well as on the available models for the formation of the South Mongolia-Khingan orogenic belt, it can be assumed that most of the Paleozoic sediments of the Nora-Sukhotino terrane were carried from the Mamyn terrane of the Argun superterrane with the participation of the island arc formations.

Keywords

• south mongolia-khingan orogenic belt
• paleozoic
• sedimentary rocks
• sm-nd data