Provenance and tectonic setting of the Paleoproterozoic metasedimentary rocks from the Liaohe Group, Jiao-Liao-Ji Belt, North China Craton: Insights from detrital zircon U-Pb geochronology, whole-rock Sm-Nd isotopes, and geochemistry

摘要

Geochronological, geochemical and isotopic studies were carried out on the Paleoproterozoic metasedimentary rocks from the Jiao-Liao-Ji Belt, North China Craton, to constrain their provenance and tectonic setting, as well as to evaluate the effects of weathering and sedimentary processes on the source rock signature. U-Pb isotopic dating using the LA-ICP-MS method on zircons from the Paleoproterozoic metasedimentary rocks reveals that the depositional age can be constrained in the period between 1.98 and 1.9 Ga. Geochemical data reveal low-intermediate degrees of weathering of the source, compositionally immature and poorly sorted. Detailed analysis of detrital zircon U-Pb geochronology, whole-rock Sm-Nd isotope, and geochemistry show that these metasedimentary rocks are derived from a mixed provenance. The predominant derivation is from metavolcanic rocks of the Liaohe Group and Paleoproterozoic gneissic granitoids. There is also an input of Archean continental crust. The metasedimentary rocks were probably deposited in a back-arc basin within an arc system, thus supporting the Paleoproterozoic arc-continent collision model as already proposed by some authors. (C) 2015 Elsevier Ltd. All rights reserved.