The study looked at how different types of rocks from different areas influenced the formation of sediment in the northwest of Ordos basin. By analyzing rocks and minerals, they found that four main sources affected the area: Rujigou lobe from Alxa Ancient Land, Shigouyi lobe from Daluo Mountain, Otog Qi lobe, and Dingbian lobe from the northeast of Ordos basin. These sources have different types of rocks, like metamorphic and granite, which can help with oil and gas exploration in the region.