Deposition of Yanchang Formation deep-water sandstone under the control of tectonic events in the Ordos Basin

A large area of deep-water sandstone was formed under the combined action of delta and gravity flow in the central Ordos Basin during the depositional period of the Ch6 and Ch7 oil-bearing formations of the Yanchang Formation. According to U-Pb dating of zircons by the method of LA-ICP-MS, the ages of the tuff layers at the base and upper parts of the Ch7 oil-bearing formation are 228.2±6.0 Ma and 222.2±2.0 Ma, respectively. Based on the ages of...