WAVELET ANALYSIS IN ROCK MAGNETIC PROPERTIES IN HOLOCENE AEOLIAN SEDIMENTS OF ARTURO DUNE, TIERRA DEL FUEGO, ARGENTINA

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

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Congreso; 6th PAGES Open Science Meeting; 2022

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">We performed a wavelet analysis in time series of magnetic properties obtained from a19 m-thick profile of Arturo Dune, in the northern region of Isla Grande of Tierra delFuego, Argentina (53° 43' 28'' S, 68° 18' 51'' W). The profile comprises a succession ofaeolian units interdigitated with paleosoil levels.Considering the 14C datings from organic matter in the paleosoil levels presented byCoronato et al. (2021), an age model was created taking a continuous sedimentation rateto date the aeolian deposits. According to this model, the profile was developed along theHolocene, covering an age range from 832 to 12086 years BP.The results include different magnetic properties and ratios, such as coercive force (Hc),saturation magnetization (Ms), low-frequency (470 Hz) magnetic susceptibilities (kLF),anhysteretic remanent magnetization (ARM), among others, measured in aeoliansediment samples. These properties and ratios are widely used to study magneticmineralogy, concentration, and magnetic grain size in sediment samples. Rock magneticresults indicate stable magnetic mineralogy in the aeolian deposits (magnetite ortitanomagnetite, with low content of Ti), showing that the variations in the concentrationand magnetic grain size parameters could be related to wind variations.The wavelet analysis has been relevant to distinguishing common and consistentperiodicities in time series. Velasco Herrera et al. (2017) created a new algorithm toanalyze spectral covariance for multiple-time series that can be applied to geophysicalrecords. The statistical analysis of the magnetic parameters in the profile could indirectlyindicate any prevailing periodicity of the wind variations over time recorded in thedeposit. The results obtained through the wavelet and multiple cross wavelet analyses ofthe magnetic parameters suggested a periodicity of around 2800 years. By adding theSouth Atlantic Ocean paleotemperatures in the analysis, a periodicity of about 3000 yearswas obtained.The results that emerge from this wavelet analysis are similar to recurrent cycles thatappear in other wavelet analyses of different records that identify fundamental solarmodes (Soon et al. 2014). However, they are not conclusive about the sun-climaterelationship on a series of millennial suborbital time scales, and more studies should beperformed.