Data for: Oligocene-Miocene (28-13 Ma) climato-tectonic evolution of the northeastern Qinghai-Tibetan Plateau evidenced by mineralogical and geochemical records of the Xunhua Basin

A total of 541 samples were collected at quasi-regular intervals of 3 to 4 m over a continuous stratigraphic interval of 1400 m spanning all four units of the Yangquangou section. Sampled lithologies include conglomerate, medium-coarse sandstone, fine sandstone, siltstone, and mudstone. Partial samples were selected according to lithological characteristics of detrital composition, grain size, and color for X-ray diffraction (XRD) and trace-element concentration measurements.