Abstract
Atmospheric dust loadings play a crucial role in the global climate system. Southern South America is a key dust source, however, dust deposition rates remain poorly quantified since the last glacial termination (~17 kyr ago), an important timeframe to anticipate future climate changes. Here we use isotope and element geochemistry in a peat archive from Tierra del Fuego, to reconstruct atmospheric dust fluxes and associated environmental and westerly wind changes for the past 16.2 kyr. Dust depositions were elevated during the Antarctic Cold Reversal (ACR) and second half of the Younger Dryas (YD) stadial, originating from the glacial Beagle Channel valley. This increase was most probably associated with a strengthening of the westerlies during both periods as dust source areas were already available before the onset of the dust peaks and remained present throughout. Congruent with glacier advances across Patagonia, this dust record indicates an overall strengthening of the wind belt during the ACR. On the other hand, we argue that the YD dust peak is linked to strong and poleward shifted westerlies. The close interplay between dust fluxes and climatic changes demonstrates that atmospheric circulation was essential in generating and sustaining present-day interglacial conditions.
Highlights
Deposited on outwash plains, prone to mobilization[12]
This is slightly younger than earlier basal ages reported for this mire (17.8 cal kyr BP15), the latter indicating that Harberton was already ice-free by ~17.8 cal kyr BP as the result of deglaciation
With the onset of the deglaciation the glacier retreated westwards (Fig. 1c), allowing the development of terrestrial and lacustrine environments in the ice-free valley until ca. 11 cal kyr BP, when the Beagle Channel was flooded by the sea (Fig. 2c)[19]
Summary
Deposited on outwash plains, prone to mobilization[12]. To date, this hypothesis could not be verified because of a lack of paleodust records from Patagonia. To further trace the origin of the atmospheric dust, we determined the neodymium isotopic composition of a selection of peat samples across the intervals with increased ADD (Fig. 2a and Table 1).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
