Sedimentary succession and recognition marks of lacustrine gravel beach-bars, a case study from the Qinghai Lake, China

Abstract

Abstract The present is the key to the past. Based on the dissection of modern beach-bars in the Qinghai Lake, Qinghai-Tibet Plateau, China, including two profiles parallelly to the shoreline, two profiles vertically to the shoreline and one plane-view profile, the sedimentary succession and recognition marks of lacustrine gravel beach-bars have been summarized. Vertically, the lacustrine gravel beach-bars develop with the “ABC” succession. The A interval, the B interval, and the C interval respectively correspond with the gravelly sand facies, the well-sorted gravel facies, and the graded sand facies. The lacustrine gravel beach-bars is composed of several combinations of the “ABC” succession, such as “ABAB”, “ABCABC”, “BCBC”. The main recognition marks of lacustrine gravel beach-bars is the following: the bottom contact is distinct and with the “ABC” succession; and the lacustrine beach-bars develop the swash bedding and sheet-like parallelly to the lakeshore. These viewpoints have significant contributions to the reconstruction of paleoenvironments and paleoshorelines and to the reservoir interpretation within lacustrine beach-bar clastic bodies.