Abstract:

In order to discuss the sedimentary environment,provenance and tectonic settings of Upper Carboniferous Suogedangtawu Formation of Keping area in northwestern margin of Tarim Basin, on the basis of geological investigation, we selected 12 samples to test and analyze trace and rare earth elements. Redox-sensitive elements combination and trace element characteristic parameters reflect that the finegrained detrital rocks form in weak reduction environment. Using Hf-La/Th, La/Sc-Co/Th and REE-La/Yb diagram, trace element ratios(La/Sc, Sc/Th, Cr/Th and Co/Th), combined with microscopic identification, we regard that the sources of sediments are mainly from upper continental crust with felsic rocks. By the contrast of characteristics of REE, combined with La-Th-Sc,Th-Sc-Zr/10,Th-Co-Zr/10 diagram, a conclusion can be drawn that the tectonic settings of the study area are continental island arc, active continental margin and passive continental margin.

Key words: Upper Carboniferous, REE, trace element, depositional environment, provenance, tectonic setting