Geochemistry of Precambrian volcanosedimentary rocks of the Karsakpai Group in southern Ulutau (Central Kazakhstan)

• Published in: Russian geology and geophysics Vol. 58; no. 8; pp. 935 - 948
• Main Authors: Dmitrieva, N.V., Letnikova, E.F., Vishnevskaya, I.A., Serov, P.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2017; Allerton Press
• Subjects: absolute age; Asia; banded iron formations; Central Asia; Central Kazakhstan; chemical composition; chemically precipitated rocks; Commonwealth of Independent States; ferruginous quartzite; Geochemistry; igneous rocks; iron formations; isotope ratios; isotopes; Karsakpay Group; Kazakhstan; Late Precambrian; mafic composition; major elements; Mesoproterozoic; metals; metamorphic rocks; Nd-144/Nd-143; neodymium; plate tectonics; Precambrian; Proterozoic; quartzites; rare earths; rift volcanics; rifting; schists; sedimentary rocks; sedimentary rocks of iron formation; Sm-Nd isotope composition; Sm/Nd; stable isotopes; trace elements; Ulu-Tau; upper Precambrian; volcanic rocks; volcanosedimentary rocks; rift volcanics; Central Kazakhstan; volcanosedimentary rocks; sedimentary rocks of iron formation; Late Precambrian; Sm-Nd isotope composition
• ISSN: 1068-7971; 1878-030X
• DOI: 10.1016/j.rgg.2017.07.004

We have analyzed the isotope-geochemical features of volcanosedimentary rocks of the Karsakpai Group in southern Ulutau (Central Kazakhstan): mafic volcanics, siliceous and siliceous-ferruginous sediments, and quartz-sericite-chlorite schists. The close association of ferruginous quartzites with intraplate volcanics indicates that they formed in a tectonically active basin. The Nd isotope composition of ferruginous quartzites was governed by synchronous underwater volcanism, whereas the 143Nd/144Nd value of schists was additionally controlled by the Nd isotope composition of older sources. The Mesoproterozoic Nd model ages and positive εNd(t) values of the metaterrigenous rocks of the Karsakpai Group indicate the presence of Mesoproterozoic juvenile material in the provenance. The minimum Nd model ages suggest the lower boundary of sedimentation of 1.3 Ga.