Characteristics of sandstones in Shiqianfeng Formation at Majiatan area.Ordos basin

Located at the central thrust section of the southwestern Ordos Basin,Majiatan area has a promising oil-gas pros- pcct for its gas shows.In order to obtain the sedimentary context,provenance characteristics and the distribution pat- tern,on the basis of study on regional geology,tectonic se- quences of the indosinian cycle at the area are classified;the component characteristics of clastic particles and the litho- genesis in the formation are generalized;and the provenance of the set of clastic rocks are comprehensively analyzed.Re- sults indicate the sandstones in the formation are relatively low in the component maturity and the textural maturity, but have the material basis for high quantity reservoirs.The provenance of sandstones in Shiqianfeng formation most like- ly originated from the metamorphic crystalline rocks and granite of the Paleoproterozoic Erathem,and the volcanics of the lower Paleozoic Erathem.