Eolian depositional phases during the past 50 ka and inferred climate variability for the Pampean Sand Sea, western Pampas, Argentina

Tripaldi, Alfonsina; Forman, Steven L.

doi:10.1016/j.quascirev.2016.03.007

Cited by 24 publications

(22 citation statements)

References 91 publications

(160 reference statements)

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“…Glaciers advanced between ~26-20 ka contemporaneous with lake level highstands recorded in the Uyuni (Baker et al, 2001) and Poopo Basin (paleolake Sajsi 24-20.5 ka, Placzek et al, 2006Placzek et al, , 2011 in response to increased precipitation by an intensified SASM. Humid conditions were also reported for this period off shore Chile, 33°S (Lamy, 1999), in Laguna Tagua Tagua (Chile, 34°30´S, Valero Garcés et al, 2005) and in eolian sequences in Argentina (34°S, Tripaldi and Forman, 2016). Maximum austral summer insolation at 30°S (Berger and Loutre, 1991) favoured a southward position of the ITCZ and was conducive for an intensification of the SASM and the upper tropospheric easterlies, so that a combination of globally lower temperatures and insolation minima and more humid conditions seem to have been responsible for glacial advances during the gLGM between 22° and 39°S.…”

Section: Discussionsupporting

confidence: 67%

Timing and extent of late pleistocene glaciation in the arid Central Andes of Argentina and Chile (22°-41°S)

Zech¹,

Terrizzano²,

Veit³

et al. 2017

CIG

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Section: Discussionsupporting

confidence: 67%

Timing and extent of late pleistocene glaciation in the arid Central Andes of Argentina and Chile (22°-41°S)

Zech¹,

Terrizzano²,

Veit³

et al. 2017

CIG

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“…Eolian deposition spans most of the Holocene to ca. 400 years ago, associated with an inferred mean annual precipitation of 100-450 mm and drier conditions compared to the late 20th century (Tripaldi and Forman, 2016). Holocene eolian events along the Andean foreland are well constrained with OSL geochronology and have occurred over 4.3-4, 2.1, and 0.6-0.4 ka ( Figure 8A; Tripaldi and Forman, 2007).…”

Section: Aridification Drives Orogen Parallel Eolian Activitymentioning

confidence: 98%

“…expressed as a decrease in fluvial sedimentation and erosion rates, without preservation of eolian strata (Amidon et al, 2017;Stevens Goddard and Carrapa, 2018). Preserved Oligocene-Miocene eolian strata along the southern Central Andes (Tripaldi and Limarino, 2005;Levina et al, 2014;Fosdick et al, 2017) suggest a protracted history of fluctuating arid conditions in this region throughout the Cenozoic. Moreover, a thorough understanding of processes operating in eolian systems is important for predicting how these regions will continue to evolve as anthropogenic warming and increased agricultural development continues to shape the Earth's landscape, resource management, and human land use (Munson et al, 2011;Sickmann et al, 2019).…”

Section: Aridification Drives Orogen Parallel Eolian Activitymentioning

confidence: 98%

“…Precipitation in western Argentina is associated with monsoon-type circulation that is generated by humid air masses from the Atlantic anticyclone, and is concentrated (>70%) during October to March. Precipitation decreases from east to west; from 90 to 100 cm/year in the northeastern Pampas to <25-30 cm/year in the Andean piedmont study area (Compagnucci et al, 2002;Tripaldi and Forman, 2016). Regionally, wind conditions are controlled by the subtropical high-pressure cells (Pacific and Atlantic anticyclones), which modulates the Westerlies and Polar advection wind activity.…”

Section: Holocene Andean Foreland Eolian Dune Fieldsmentioning

confidence: 99%

“…The central foreland basin is dominated by a >10,000 km 2 north-trending zone of eolian landforms, including the southern Medanos Telteca and northern Medanos Grande eolian dune fields ( Figure 2B). Both Medanos Telteca and Grande systems have been estimated to be last active during the Holocene, exhibiting high-relief (50 m) parallel ridges of dominantly longitudinal (seif) dunes and asymmetric transverse dunes, and litharenite to feldspathic litharenite sand composition (Iriondo, 1999;Zárate, 2003;Zárate and Tripaldi, 2012;Tripaldi et al, 2013;Tripaldi and Forman, 2016;Tripaldi and Zárate, 2016). Detailed optically stimulated luminescence (OSL) geochronology has been established across the major eolian provinces of central Argentina, providing a framework to analyze sediment transport across the sediment routing system during the Holocene Forman, 2007, 2016;Latrubesse and Ramonell, 2010).…”

Section: Holocene Andean Foreland Eolian Dune Fieldsmentioning

confidence: 99%

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Fluvial and Eolian Sediment Mixing During Changing Climate Conditions Recorded in Holocene Andean Foreland Deposits From Argentina (31–33°S)

et al. 2019

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Continental drainage systems archive complex records of rock uplift, source area relief, precipitation, glaciation, and carbon cyclicity driven largely by tectonics and climate. Significant progress has been made in linking such external environmental forcings to the geomorphic expression of landscapes and the stratigraphic record of depositional basins in coastal and offshore areas. However, there are large uncertainties in the degree to which sediment dispersal processes can modify signals between the erosional sources and the depositional sinks. We investigate a Holocene sediment transfer zone with contrasting fluvial and eolian sediment transport mechanisms to understand how river and wind processes impact the propagation of environmental signals in continentalscale drainage systems. To quantify these processes, we employ sediment fingerprinting methods for unconsolidated sand samples (detrital zircon U-Pb geochronology), incorporate sediment mixing models, and correlate the findings with the regional geologic and geomorphic framework. Three contrasting source regions deliver sediment to the Andean foreland: volcanic rocks of the Frontal Cordillera, sedimentary rocks of the Precordillera, and metamorphic basement of the Sierras Pampeanas. Although all samples of Holocene eolian dunes accurately record sediment input from three fluvial source regions, spatial variations in U-Pb results are consistent with north-directed paleowinds, whereby river sediments from Frontal Cordillera sources are transported northward and progressively mixed with river sediments from Precordillera and Sierras Pampeanas sources. In contrast, samples of modern rivers show progressive southward (downstream) mixing along a large axial fluvial system. Sediment mixing induced by eolian transport and reworking of various sources is likely a critical, climate-modulated process in the propagation of environmental signals, potentially involving the aliasing of tectonic signals, local storage and recycling of synorogenic river sediment, and cyclical patterns of sediment starvation and delivery to distal zones of accumulation.

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Plants versus streams: Their groundwater‐mediated competition at “El Morro,” a developing catchment in the dry plains of Argentina

Jobbágy

Lorenzo

Buono

et al. 2021

Hydrological Processes

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Our understanding of how groundwater mediates evapotranspiration/streamflow partitioning is still fragmented and catchment studies under changing vegetation conditions can provide a useful frame for integration. We explored this partition in a flat sedimentary dry catchment in central Argentina in which the replacement of native vegetation with rainfed crops was accompanied by the abrupt formation of groundwater-fed streams by subsurface erosion (i.e., sapping) episodes. Historical records indicated widespread water table rises ($0.3 m y À1 on average). Groundwater level and stream baseflow fluctuated seasonally with minima in the warm rainy season, indicating that evaporative discharge rather than rainfall shapes saturated flows. Diurnal groundwater level fluctuations showed that plant uptake was widespread where water tables are shallow (<3 m) but restricted to deep-rooted Prosopis forests where they are deep (7-10 m). MODIS and LANDSAT NDVI revealed a longterm greening for native vegetation, new wetlands included, but not for croplands, suggesting more limited evapotranspiration-groundwater level regulation under agriculture. Close to the deepest (20 m) and most active incisions, groundwater level and greenness declined and stream baseflow showed no seasonal fluctuations, hinting decoupling from evapotranspiration. Intense ecological and geomorphological transformations in this catchment exposed the interplay of five mechanisms governing evapotranspiration/streamflow partition including (a) unsaturated uptake and both (b) riparian and (c) distributed uptake from the saturated zone by plants, as well as (d) deepening incisions and (e) sediment deposits over riparian zones by streams.Acknowledging the complex interplay of these mechanisms with groundwater is crucial to predict and manage future hydrological changes in the dry plains of South America.

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Eolian depositional phases during the past 50 ka and inferred climate variability for the Pampean Sand Sea, western Pampas, Argentina

Cited by 24 publications

References 91 publications

Timing and extent of late pleistocene glaciation in the arid Central Andes of Argentina and Chile (22°-41°S)

Timing and extent of late pleistocene glaciation in the arid Central Andes of Argentina and Chile (22°-41°S)

Fluvial and Eolian Sediment Mixing During Changing Climate Conditions Recorded in Holocene Andean Foreland Deposits From Argentina (31–33°S)

Plants versus streams: Their groundwater‐mediated competition at “El Morro,” a developing catchment in the dry plains of Argentina

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