scholarly journals Late Quaternary Climate and Hydrology of Tropical South America Inferred from an Isotopic and Chemical Model of Lake Titicaca, Bolivia and Peru

2001 ◽  
Vol 56 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Scott L. Cross ◽  
Paul A. Baker ◽  
Geoffrey O. Seltzer ◽  
Sherilyn C. Fritz ◽  
Robert B. Dunbar
Keyword(s):  
Late Quaternary ◽  
Early Holocene ◽  
Balance Model ◽  
South American ◽  
Lake Titicaca ◽  
Quaternary Climate ◽  
Pleistocene Climate ◽  
Precipitation Decrease ◽  
Simple Mass ◽  
Lake Waters

AbstractA simple mass balance model provides insight into the hydrologic, isotopic, and chemical responses of Lake Titicaca to past climatic changes. Latest Pleistocene climate of the Altiplano is assumed to have been 20% wetter and 5°C colder than today, based on previous modeling. Our simulation of lacustrine change since 15,000 cal yr B.P. is forced by these modeled climate changes. The latest Pleistocene Lake Titicaca was deep, fresh, and overflowing. The latest Pleistocene riverine discharge from the lake was about 8 times greater than the modern average, sufficient to allow the expansion of the great paleolake Tauca on the central Altiplano. The lake δ18O value averaged about −13‰ SMOW (the modern value is about −4.2‰). The early Holocene decrease in precipitation caused Lake Titicaca to fall below its outlet and contributed to a rapid desiccation of paleolake Tauca. Continued evaporation caused the 100-m drop in lake level, but only a slight (1–2‰) increase (relative to modern) in δ18O of early Holocene lake waters. This Holocene lowstand level of nearly 100 m was most likely produced by a precipitation decrease, relative to modern, of about 40%. The lake was saline as recently as 2000 cal yr B.P. The timing of these hydrologic changes is in general agreement with calculated changes of insolation forcing of the South American summer monsoon.

scholarly journals Late Glacial–Holocene climatic transition record at the Argentinian Andean piedmont between 33 and 34° S

2014 ◽  
Vol 10 (2) ◽  
pp. 863-875 ◽  
Author(s):  
A. E. Mehl ◽  
M. A. Zárate
Keyword(s):  
Late Pleistocene ◽  
Late Quaternary ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Early Holocene ◽  
South American ◽  
Aeolian Deposits ◽  
The Andes ◽  
Climatic Transition ◽  
Flooding Events

Abstract. The Arroyo La Estacada (~ 33°28' S, 69°02' W), eastern Andean piedmont of Argentina, cuts through an extensive piedmont aggradational unit composed of a dominant Late Pleistocene–early Holocene (LP–EH) alluvial sequence that includes several paleosols. One of these paleosols developed affecting the topmost part of likely Late Glacial aeolian deposits aggraded into a floodplain environment by the end of the Late Pleistocene. The paleosol shows variable grade of development along the arroyo outcrops. Organic matter humification, carbonate accumulation and redox processes were the dominant processes associated with paleosol formation. By the early Holocene, when the formation of the paleosol ended, renewed alluvial aggradation and high magnitude flooding events affected the arroyo's floodplain environment. Accordignly, a period of relative landscape stability in the Arroyo La Estacada basin is inferred from the paleosol developed by the LP–EH transition in response to the climatic conditions in the Andes cordillera piedmont after the Late Glacial arid conditions. The analyzed Late Glacial–Holocene alluvial record of the Andean piedmont constitutes a suitable record of the LP–EH climatic transition in the extra-Andean region of Argentina. It is in agreement with regional paleoclimatic evidence along the southern tip of the South American continent, where other pedosedimentary sequences record similar late Quaternary paleoenvironmental changes over both fluvial and interfluvial areas.

scholarly journals Late Glacial-Holocene climatic transition record at the Argentinian Andean piedmont between 33–34° S

2013 ◽  
Vol 9 (5) ◽  
pp. 6125-6160
Author(s):  
A. E. Mehl ◽  
M. A. Zárate
Keyword(s):  
Late Pleistocene ◽  
Late Quaternary ◽  
Late Glacial ◽  
Early Holocene ◽  
South American ◽  
The South ◽  
Sedimentary Sequences ◽  
Aeolian Deposits ◽  
Climatic Transition ◽  
Flooding Events

Abstract. The Arroyo La Estacada (~33°28' S, 69°02' W), eastern Andean piedmont of Argentina, cuts through an extensive piedmont aggradational unit composed of a dominant late Pleistocene–early Holocene (LP–EH) alluvial sequence including several paleosols. The arroyo sedimentary record exhibits a paleosol developed affecting the topmost part of likely Lateglacial aeolian deposits aggraded into a floodplain environment by the end of the late Pleistocene. The paleosol shows variable grade of development in the outcrops along the arroyo probably in relation to fluvial valley paleotopography. Organic matter humification, carbonate accumulation and redox processes were the dominant processes associated with paleosol formation. By the early Holocene, when the formation of the paleosol ended, alluvial aggradation renewed and a higher frequency of flooding events could have affected the arroyo's floodplain environment. A period of relative landscape stability in the Arroyo La Estacada basin is inferred from the paleosol developed by the LP–EH transition in response to a climatic amelioration in the Andes cordillera piedmont after the Late Glacial arid conditions. The renewal of early Holocene alluvial aggradation was probably influenced by the South American Monsoon and resulted in a change in the sedimentary dynamics of the arroyo. The analyzed Late Glacial-Holocene alluvial record of the Andean piedmont constitutes a suitable record of the LP–EH climatic transition at the extra Andean region of Argentina. It is in agreement with regional paleoclimatic evidence along the southern tip of the South American continent, where other sedimentary sequences record similar late Quaternary paleoenvironmental changes over both fluvial and interfluvial areas.

scholarly journals Millennial-Scale Response of a Western Mediterranean River to Late Quaternary Climate Changes: A View from the Deep Sea

2014 ◽  
Vol 122 (6) ◽  
pp. 687-703 ◽  
Author(s):  
Lucile Bonneau ◽  
Stéphan J. Jorry ◽  
Samuel Toucanne ◽  
Ricardo Silva Jacinto ◽  
Laurent Emmanuel
Keyword(s):  
Deep Sea ◽  
Climate Changes ◽  
Late Quaternary ◽  
Western Mediterranean ◽  
Mediterranean River ◽  
Quaternary Climate ◽  
Scale Response ◽  
Quaternary Climate Changes ◽  
Millennial Scale

scholarly journals Phytogeographical patterns of dry forests sensu stricto in northern Minas Gerais State, Brazil

2013 ◽  
Vol 85 (2) ◽  
pp. 623-634 ◽  
Author(s):  
DANIEL M. ARRUDA ◽  
WALNIR G. FERREIRA-JUNIOR ◽  
REINALDO DUQUE-BRASIL ◽  
CARLOS E.R. SCHAEFER
Keyword(s):  
Late Quaternary ◽  
Sensu Stricto ◽  
Minas Gerais ◽  
Dry Forest ◽  
Floristic Similarity ◽  
Humid Forest ◽  
Quaternary Climate ◽  
Dominant Soil ◽  
Minas Gerais State ◽  
Semi Arid

The Deciduous Complex that occurs in northern Minas Gerais State, Brazil, raises questions about the floristic affinities of these formations in relation to neighboring phytogeographical domains. Little is known about the identity of the seasonal forest formations that comprise this complex, or about its relationships to abiotic components, such as soils, topography and climate. This study aimed to recognize the patterns of floristic similarity of all studied fragments of dry forest of northern Minas Gerais with soil and climate attributes, based on the available database. Cluster analysis indicated the existence of two floristic groups that had clear associations with either the Koppen's BSh (semi-arid) or Aw (seasonal tropical) climates. Likewise, the subdivisions of these groups showed clear associations with the dominant soil classes in the region. The Red-Yellow Latosol is the dominant soil classes in the BSh climatic domain, seconded by alluvial areas associated with Fluvic Neosols. The Aw domain comprised a much varied set of soils: Nitosols, Argisols, Cambisols and Litholic Neosols, most derived from the Bambuí limestone/slate formation. The ecotonal nature of northern Minas Gerais State provides a complex interaction between the flora of neighboring phytogeographical domains. This, allied to pedogeomorphological factors, allowed a better understanding of the effects of late Quaternary climate changes for the Deciduous Complex evolution. We conclude that the Latosols under present-day semi-arid climates (BSh) are relicts of former wetter climates, during which humid forest (semideciduous) expansion took place. Later, these semideciduous forests were subjected to a much drier climate, when selection for deciduousness led to the present-days Deciduous Complex scenario.

scholarly journals Late Quaternary climate change in the north-eastern highlands of Ethiopia: A high resolution 15,600 year diatom and pigment record from Lake Hayk

2018 ◽  
Vol 202 ◽  
pp. 166-181 ◽  
Author(s):  
Katie L. Loakes ◽  
David B. Ryves ◽  
Henry F. Lamb ◽  
Frank Schäbitz ◽  
Michael Dee ◽  
...  
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Late Quaternary ◽  
The North ◽  
Quaternary Climate ◽  
North Eastern ◽  
Eastern Highlands

Late Pleistocene climate inferences from a water balance model of Jakes Valley, Nevada (USA)

2016 ◽  
Vol 56 (2-3) ◽  
pp. 109-122 ◽  
Author(s):  
Cornelia Barth ◽  
Douglas P. Boyle ◽  
Benjamin J. Hatchett ◽  
Scott D. Bassett ◽  
Christopher B. Garner ◽  
...  
Keyword(s):  
Water Balance ◽  
Late Pleistocene ◽  
Water Balance Model ◽  
Balance Model ◽  
Pleistocene Climate

scholarly journals Satellite- and ground-based CO total column observations over 2010 Russian fires: accuracy of top-down estimates based on thermal IR satellite data.

2011 ◽  
Vol 11 (4) ◽  
pp. 12207-12250 ◽  
Author(s):  
L. Yurganov ◽  
V. Rakitin ◽  
A. Dzhola ◽  
T. August ◽  
E. Fokeeva ◽  
...  
Keyword(s):  
Balance Model ◽  
Top Down ◽  
Fire Event ◽  
Mixing Ratios ◽  
Central Russia ◽  
Abstract Data ◽  
Simple Mass ◽  
Peat Fires ◽  
Total Column ◽  
Moscow Area

Abstract. Data are presented from three space sounders and two ground-based spectrometers in Moscow and its suburbs during the forest and peat fires that occurred in Central Russia in July–August 2010. The Moscow area was strongly impacted by the CO plume from these fires. Concurrent satellite- and ground-based observations were used to quantify the errors of CO top-down emission estimates. On certain days, CO total columns retrieved from the data of the space-based sounders were 2–3 times less than those obtained from the ground-based sun-tracking spectrometers. The depth of the polluted layer over Moscow was estimated using total column measurements compared with CO volume mixing ratios in the surface layer and on the TV tower and found to be between 180 and 360 m. The missing CO that is the average difference between the CO total column accurately determined by the ground spectrometer and that retrieved by MOPITT and AIRS, was determined for the Moscow area as ∼3 E18 molec cm−2. This value was extrapolated onto the entire plume; subsequently, the CO burden (total mass) over Russia during the fire event was corrected. A top-down estimate of the total emitted CO, obtained by a simple mass balance model increased by 80%–100% due to this correction (up to 40 Tg).

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