The Middle-Late Devonian Liuling Group in Shanyang region,Shaanxi Province, located in between the Shang-Dan Fault and Shanyang Fault of the Qinling orogenic belt. Determination of nature of the Liuling Group sediments and basin tectonic setting could offer important information for processes of tectonic evolution in the Qinling area due to the special spatio-temporal distribution of the Liuling Group in geological evolution since Paleozoic. Analyses of rock geochemistry showed that high contents of SiO2 and K2O among the oxides of major elements of the Liuling Group sandstones were mainly characterized and reflected generally higher chemical maturity of sandstones, whose clastics derived from relative stable continent provenance or older recycled sedimentary rocks. The average LREE/HREE value was 5.27 and average Eu/Eu* ratio (0.77) was a depleted type in the sandstones from the group, which was approximately consistent with the Eu evolution feature of post-Archean sedimentary rocks. According to multi-analysis of oxides of major elements, rare earth elements and trace elements in plot diagrams and parameters, the results showed that the sediments of the Liuling Group were not representative as accumulation of a foreland basin. The clastic rocks of the Liuling Group were regarded as deposited products of a Middle-Late Devonian passive continental margin based on discriminations of tectonic setting and provenance from sandstones geochemistry, synthesized with the researches on sedimentary succession and petrology.
He Zhengjun,Niu Baogui,Ren Jishun. TECTONIC DISCRIMINATIONS OF SANDSTONES GEOCHEMISTRY FROM THE MIDDLELATE DEVONIAN LIULING GROUP IN SHANYANG AREA, SOUTHERN SHAANXI[J]. Chinese Journal of Geology, 2005, (4): 594-607.