Paleosecular variations since ~ 9000 yr BP as recorded by sediments from maar lake Shuangchiling, Hainan, South China

Abstract

High-resolution paleosecular variation (PSV) can play an important role in sediment dating and for understanding the temporal characteristics of the geodynamo of the Earth's magnetic field. In this article, based on magnetic susceptibility correlation, a composite sediment profile has been compiled from a ~ 16 m long core (HN-2) and a ~ 8 m deep well (HN-3) in Shuangchiling maar lake, a crater basin located on Hainan Island, Southern China. Fine and homogeneous silty clay corroborates with a stable, continuous and undisturbed deposition. A U-channel-based paleomagnetic study, constrained by AMS 14C chronology derived from leaves, plant debris and woods, and supported by rock magnetic data, indicates that the lake sediments document a reliable paleosecular variation (PSV) record since ~ 9000 cal. year BP. Comparison of our PSV features with other records from lakes Biwa (Japan), Erhai (China), Baikal (Russia) as well as archaeomagnetic records demonstrate that the inclination pattern is generally synchronous within chronological uncertainties, suggesting further PSV dating may be valuable for stratigraphic correlation on a regional scale.