Atmospheric dust dynamics in southern South America: A 14-year modern dust record in the loessic Pampean region

COSENTINO, N. J.; GAIERO, D. M.; TORRE, G.; PASQUINI, A. I.; COPPO, R.; ARCE, J. M.; VÉLEZ, G.

HOLOCENE (SEVENOAKS)

SAGE PUBLICATIONS LTD

Año: 2020

0959-6836

Mineral aerosols profoundly impact globalclimate. Modeling of the dust cycle is the main tool used to gauge this effect.However, the scarcity of in situ modern dust flux measurements is the mainreason why validation of existing models is hampered. We present the firstlong-term (14 yr) record of dust flux in the Pampas, southern South America,home to the largest loess deposit in the Southern Hemisphere. Measured 14-yearmean deposition (40 g m-2 yr-1) and horizontal (362 g m-2yr-1) fluxes imply that current models underestimate the power ofthe central Pampas as a dust sink. Based on cross-spectral analysis, both wetand, to a lesser extent, dry deposition are found to play significant roles inatmospheric dust extraction. Dust is sourced regionally from the South AmericanArid Diagonal and from the shores of Mar Chiquita lake (~260 km), which we find to be the main contributor ofdust particles >30 mm.Cross-spectral and satellite image analyses show that surface wind speed andprecipitation at the Puna-Altiplano Plateau are controlling factors forhorizontal dust flux in the Pampas. El Niño Southern Oscillation probably playsa role in controlling inter-annual horizontal dust flux periodicities. Finally,preliminary comparisons between modern vertical dust fluxes and loessaccumulation rates point to the Pampas as a more powerful dust sink during thelast deglaciation and Antarctic Cold Reversal (18-12.5 ka). ()<!-- /* Font Definitions */ @font-face{font-family:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:roman;mso-font-pitch:variable;mso-font-signature:-536870145 1107305727 0 0 415 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin:0cm;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:12.0pt;font-family:"Times New Roman",serif;mso-fareast-font-family:"Times New Roman";}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-family:"Calibri",sans-serif;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}@page WordSection1{size:612.0pt 792.0pt;margin:72.0pt 72.0pt 72.0pt 72.0pt;mso-header-margin:36.0pt;mso-footer-margin:36.0pt;mso-paper-source:0;}div.WordSection1{page:WordSection1;}-->