Study of the varve record from Erlongwan maar lake, NE China, over the last 13 ka BP

In a sediment sequence from Erlongwan maar lake that spans the last 13 ka BP, two main varve types can be recognized: biogenic varves (from the present to ∼11.2 ka BP, 0–632 cm) and clastic varves (from ∼11.2 to ∼12.7 ka BP, 632–700 cm). Based on the dominant types of algae contained in the sediment, the biogenic varves can be classified into dinocyst-biogenic varves (0–63 cm) and mixed (dinocyst and diatom)-biogenic varves (214–632 cm). In this paper, the formation process and components of the varve are described, the possible reason for the types of varve changing throughout the record is discussed and a high-resolution varve chronology is established spanning the last 13 ka BP. Although further varve counting and error assessment are needed, the results presented here represent a solid foundation for studying the palaeoclimate record of Erlongwan maar lake. Supported by CAS Key Project (Grant No. KZCX3-SW-145) and the National Natural Science Foundation of China (Grant No. 4032014043)