Humid Medieval Warm Period recorded by magnetic characteristics of sediments from Gonghai Lake, Shanxi, North China

• Published in: Chinese science bulletin Vol. 56; no. 23; pp. 2464 - 2474
• Main Authors: Liu, JianBao, Chen, FaHu, Chen, JianHui, Xia, DunSheng, Xu, QingHai, Wang, ZongLi, Li, YueCong
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer-Verlag 01.08.2011; SP Science China Press
• Subjects: Chemistry/Food Science; Earth Sciences; Engineering; environmental factors; Freshwater; Humanities and Social Sciences; humid zones; isotopes; lacustrine sediments; lakes; Life Sciences; magnetic properties; magnetite; mineral content; monsoon season; multidisciplinary; oxygen; paleoclimatology; paleoecology; Physics; pollen; Science; Science (multidisciplinary); soil analysis; soil formation; soil minerals; summer; watersheds; 中世纪暖期; 中国北方; 季风强度; 山西; 湖泊沉积物; 潮湿; 特征记录; 磁性矿物; China; China, People's Rep; Gonghai Lake; lacustrine sediments; magnetic parameter; humid climate; Medieval Warm Period
• ISSN: 1001-6538; 1861-9541
• DOI: 10.1007/s11434-011-4592-y

Variations in monsoon strength, moisture or precipitation in eastern China during the MWP reflected by differenl climatic records have shown apparent discrepancies. Here, detailed environmental magnetic investigations and mineralogical analyses were con- ducted on lacustrine sediments of Core GH09B1 （2.8 m long） from Gonghai Lake, Shanxi, North China, concerning the monsoon history during the MWP. The results demonstrate that the main magnetic mineral is magnetite. The sediments with relatively high magnetic mineral concentrations were characterized by relatively fine magnetic grain sizes, which were formed in a period of relatively strong pedogenesis and high precipitation. In contrast, the sediments with low magnetic mineral concentrations reflected an opposite process. The variations of magnetic parameters in Gonghai Lake sediments were mainly controlled by the degree of pedogenesis in the lake drainage basin, which further indicated the strength of the Asian summer monsoon. The variations in the X and S-300 parameters of the core clearly reveal the Asian summer monsoon history over the last 1200 years in the study area, sug- gesting generally abundant precipitation and a strong summer monsoon during the Medieval Warm Period （MWP, AD 910-1220） which is supported by pollen evidence. Furthermore, this 3-6-year resolution environmental magnetic record indicates a dry event around AD 980-1050, interrupting the generally humid MWP. The summer monsoon evolution over the last millennium recorded by magnetic parameters in sediments from Gonghai Lake correlates well with historical documentation （North China） and spele-othem oxygen isotopes （Wanxiang Cave）, as well as precipitation modeling results （extratropical East Asia）, which all indicate a generally humid MWP within which centennial-scale moisture variability existed. It is thus demonstrated that environmental magnetic parameters could be used as an effective proxy for monsoon climate variations in high-resolution lacustrine sediments.