Rock magnetic properties as proxy indicators of characteristic periodicities in Holocene aeolian sediments (Arturo Dune, Tierra del Fuego, Argentina)

ORGEIRA, M.J.; ACHAGA, R.; CAPPELLOTTO, L.; GOGORZA, C.; CORONATO, A.; PONCE, J.F.; VELASCO HERRERA, V.M.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2022

0895-9811

The objective of this contributionis to distinguish characteristic wind speed periodicities from a roughly 19m-thick profile of Arturo Dune (Tierra del Fuego, Argentina), which containseight interbedded paleosoils. The results include different magnetic propertiesand ratios measured in 29 aeolian sediment samples. These properties are coerciveforce (HC), saturation magnetization (MS), low-frequency (470 Hz) magneticsusceptibilities (kLF), anhysteretic remanent magnetization (ARM), amongothers. The statistical analysis of the variations in the magnetic propertiesof detrital minerals over time could indirectly indicate prevailingperiodicities of the wind rate during the studied interval. The power spectralanalysis was done using wavelets and multiple cross wavelets. The analysis bywavelets made it possible to distinguish periodicities in the variations ofclimatic parameters. A main periodicity of 2824 years was obtained in thedifferent wavelet and multiple cross wavelet analyses of the magneticparameters. By adding theδ18Oseries from the deep South Atlantic Ocean to thespectral power analysis, a periodicity of around 3000 years was also obtained.These periodicities could be related to a fundamental solar mode, with aperiodicity of 2300 years (Hallstattzeit cycle). Still, they are not conclusiveas solid empirical evidence to support sun-climate relationships on a series ofmillennial suborbital time scales.