Lithofacies, succession, and their genetic interpretation of lacustrine gravel beach-bars

Based on the elaborate dissection of profile sections parallel and vertical with the shoreline and the forming beach-bars, the unique sedimentary succession of gravel beach-bars, "ABC" sequence, has been found, and their lithofacies and origin have been explained. The A interval is composed of poorly sorted sand and gravel, formed in the wave asymmetric zone. The B interval is composed of well-sorted gravel, formed in the breaker zone. The C interval is composed of normally graded sand, formed in the surfing zone. In the actual gravel beach-bars, three intervals are often presented in a variety of combinations, such as "ABCABC," "BCBCBC," "ABABAB," and others. These findings provide an important basis for the identification and distribution prediction of beach-bar reservoirs in the ancient continental lake basins.