Revisiting the chronology and environmental conditions for the accretion of late Pleistocene-early Holocene Pampean loess (Argentina)

Atmospheric Dust Variations in the Ili Basin, Northwest China, During the Last Glacial Period as Revealed by a High Mountain Loess‐Paleosol Sequence

“…The lifetime of atmospheric fine particles is primarily constrained by wet deposition (Lambert et al, ). In reality, changes of dust fluxes in the polar ice cores are a consequence of increasing atmospheric transport efficiency and/or source intensity changes (e.g., Torre et al, ). As described above, an improved hydrological cycle during early MIS3 leads to shorter lifetime for atmospheric dust particles thus reducing their transport efficiency to distal sites due to increased scavenging on the route, that is, wet deposition mechanisms (Lambert et al, ).…”

New insights on sources contributing dust to the loess record of the western edge of the Pampean Plain during the transition from the late MIS 2 to the early Holocene

“…At Lozada, a 9.3-m vertical section is exposed along an abandoned road excavation on an extensive plain. Here, we choose a 1-m section based on previously published data indicating that the OSL age located at 2.4 m from the top surface of the profile corresponds to the LGM period (Kemp et al, 2006; Torre et al, 2019). However, new OSL ages indicate that this 1-m loess profile is in normal stratigraphic order and that it was deposited during the transition from the late Marine Isotope Stage (MIS 2) to the early Holocene (i.e.…”

“…Loess deposits are excellent continental records of past environmental conditions that permitted the aeolian sediment accumulation, as well as of climatic variability occurring over dust source areas (Torre et al, 2019). In southern South America (SSA), loess records are extended over a vast area covering ~10 6 km 2 , with thicknesses that vary between 20 and 50 m. The Pampean loess is thought to be linked to dust source areas located to the west along the so-called ‘Arid Diagonal’ of SSA (Gili et al, 2017; Torre et al, 2019). These arid and semi-arid terrains are intersected by two important zonal wind belts: the Southern Westerlies Winds System (SWW) and the Subtropical Jet Stream (STJ).…”

“…The proximal deposit of dust forming the Pampean loess mantle provides a unique long-term terrestrial archive for reconstructing the history of palaeoclimatic changes and wind patterns in the continental interior, close to the source areas of aeolian sediments. Recent evidence indicates that the grain-size composition of the Pampean loess has a systematic bimodal distribution, pointing out that the fine and coarse components are derived from different source areas, probably transported by different atmospheric mechanisms (Gaiero et al, 2013; Torre et al, 2019). Previous geochemical studies of SSA loess refined the previous ideas about the provenance of the Pampean aeolian sediments.…”

“…For example, in the southern Pampas, the origin of loess seems to be linked to relatively proximal sediments derived from rocks of northern Patagonia (Sayago, 1995; Teruggi, 1957; Zárate and Blasi, 1993) and/or to sediments from the Andes piedmont of Mendoza (Clapperton, 1993; Iriondo, 1990; Iriondo and Kröhling, 1996; Zárate, 2003). Also, it is suggested that during the past interglacial cycles, dust from the more distal PAP was transported to the Pampas through high-altitude subtropical westerly jet streams (Gili et al, 2017; Milana and Kröhling, 2017; Torre et al, 2019). Up to now, others even closer dust source areas were less considered as potential suppliers of sediments for provenance studies, as, for example, the aeolian particles derived from metamorphic and igneous rocks forming the Pampean Ranges (Cantú, 1992; Cantú and Degiovanni, 1984; González Bonorino, 1965; Kröhling, 1999; Morrás, 1999), or the shores of the Mar Chiquita Lake seasonally exposed to wind erosion (Bucher and Stein, 2016).…”