title: Holocene ENSO-related cyclic storms recorded by magnetic minerals in speleothems of central China.
abstract: Extreme hydrologic events such as storms and floods have the potential to severely impact modern human society. However, the frequency of storms and their underlying mechanisms are limited by a paucity of suitable proxies, especially in inland areas. Here we present a record of speleothem magnetic minerals to reconstruct paleoprecipitation, including storms, in the eastern Asian monsoon area over the last 8.6 ky. The geophysical parameter IRMsoft-fluxrepresents the flux of soil-derived magnetic minerals preserved in stalagmite HS4, which we correlate with rainfall amount and intensity. IRMsoft-fluxexhibits relatively higher values before 6.7 ky and after 3.4 ky and lower values in the intervening period, consistent with regional hydrological changes observed in independent records. Abrupt enhancements in the flux of pedogenic magnetite in the stalagmite agree well with the timing of known regional paleofloods and with equatorial El Niño-Southern Oscillation (ENSO) patterns, documenting the occurrence of ENSO-related storms in the Holocene. Spectral power analyses reveal that the storms occur on a significant 500-y cycle, coincident with periodic solar activity and ENSO variance, showing that reinforced (subdued) storms in central China correspond to reduced (increased) solar activity and amplified (damped) ENSO. Thus, the magnetic minerals in speleothem HS4 preserve a record of the cyclic storms controlled by the coupled atmosphere-oceanic circulation driven by solar activity.
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China; zhumin@cug.edu.cn.|Institute for Rock Magnetism, University of Minnesota, Minneapolis, MN 55455.
authors.forename: Zongmin
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Institute for Rock Magnetism, University of Minnesota, Minneapolis, MN 55455.
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Feinberg
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China.
authors.forename: Shucheng
authors.initials: S
authors.lastname: Xie
authors.affiliation: Institute for Rock Magnetism, University of Minnesota, Minneapolis, MN 55455.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Bourne
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China.
authors.forename: Chunju
authors.initials: C
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China.
authors.forename: Chaoyong
authors.initials: C
authors.lastname: Hu
authors.affiliation: Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Cheng
keywords: environmental magnetism; paleoclimate; paleoprecipitation; speleothems; storms