Petrography and geochemistry of clastic sedimentary rocks as evidence for the provenance of the Jurassic stratum in the Daqingshan area

Abstract

The Daqingshan area is located in the Khondalite belt in the northern margin of the North China Craton. It has the best-preserved Mesozoic basin and is an ideal area for research on Jurassic strata. Sandstones mainly contain quartz and feldspar, with significantly less debris content. In addition, petrography and geochemical classifications have revealed the presence of arkose and wacke. Chondrite-normalized rare earth element patterns of samples are characterized by the enrichment of light rare elements and the flat trend toward heavy rare earth elements. Petrography and source rock discrimination diagrams of geochemical data suggest the presence of felsic rock and Precambrian basement in the northern and southern parts of the basin, which are crucial source areas; however, few mafic materials occur in the Wudanggou Formation. Tectonic discrimination diagrams of geochemical data show that the source materials were deposited on an active continental margin and/or continental island arc. Petrological and geochemical data from the Wudanggou Formation and Changhangou Formation samples suggest that the Yanshan movement influenced the formation of the Changhangou Formation.

Keywords

• khondalite belt
• daqingshan area
• jurassic strata
• geochemical
• provenance
• tectonic setting