Palaeoreconstruction of the Amazon River freshwater and sediment discharge using sediments recovered at Site 942 on the Amazon Fan

Maslin, Mark; Durham, Emma; Burns, Stephen J.; Platzman, Ellen; Grootes, P. M.; Greig, S. E. J.; Nadeau, Marie‐Josée; Schleicher, Markus; Pflaumann, Uwe; Lomax, Becky; Rimington, Nicola

doi:10.1002/1099-1417(200005)15:4<419::aid-jqs541>3.0.co;2-l

Cited by 40 publications

(26 citation statements)

References 60 publications

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“…In the northern part of South America, Van der Hammen and Hooghiemstra (1995) and Rull et al (2010) describe a cool and dry YD in the Colombian and Venezuelan Andes respectively and there is reduced continental runoff recorded in the Cariaco Basin. In a record from the Amazon Fan Maslin et al (2000) also report a dry YD, but with a short lived major peak in Amazon discharge around 11,400 BP, which the authors associate with Termination 1B. In contrast, the Botuvera stalagmite record and lake records from the Bolivian Altiplano (Baker et al, 2001) show wet conditions.…”

Section: Discussionmentioning

confidence: 99%

Hydrology and climatology at Laguna La Gaiba, lowland Bolivia: complex responses to climatic forcings over the last 25 000 years

Metcalfe

Whitney

Fitzpatrick

et al. 2014

J Quaternary Science

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Diatom, geochemical and isotopic data provide a record of environmental change in Laguna La Gaiba, lowland Bolivia, over the last ca. 25,000 years. High-resolution diatom analysis around the last glacial -interglacial transition provides new insights into this period of change. The full and late glacial lake was generally quite shallow, but with evidence of periodic flooding. At about 13,100 cal a BP, just prior to the start of the Younger Dryas chronozone, the diatoms indicate shallower water conditions, but there is a marked change at about 12,200 cal a BP indicating the onset of a period of high variability, with rising water levels punctuated by periodic drying. From ca. 11,800 to 10,000 cal a BP stable, deeper water conditions persisted. There is clear evidence for drying in the early to mid Holocene, but not as pronounced as that reported from elsewhere in the southern hemisphere tropics of South America. This was followed by the onset of wetter conditions in the late Holocene consistent with insolation forcing. Conditions very similar to present were 2 established about 2,100 cal a BP. A complex response to both insolation forcing and millennial scale events originating in the North Atlantic is noted.

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Section: Discussionmentioning

confidence: 99%

Hydrology and climatology at Laguna La Gaiba, lowland Bolivia: complex responses to climatic forcings over the last 25 000 years

Metcalfe

Whitney

Fitzpatrick

et al. 2014

J Quaternary Science

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show abstract

“…During deglaciation, the climate changed and studies support evidence for a significant Amazon River discharge event at the end of the Younger Dryas (Showers and Bevis, 1988;Maslin et al and Mikkelsen, 1997;Maslin et al 2000). During this discharge event, there was an increase in deposition on the Amazon Fan of sediment originating from the Andes, coeval with the first melting of the Andean Ice sheet (Thompson et al, 1995;Arz et al, 1998;Maslin et al, 2000) (Fig. 10).…”

Section: Controls On Channels and Lobes Constructionmentioning

confidence: 99%

Channel-mouth lobe complex of the recent Amazon Fan: The missing piece

et al. 2008

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“…CLIMAP, 1976;Ganopolski et al, 1998;Kutzbach et al, 1998;Hostetler and Mix, 1999;Maslin et al, 2000). Although these models differ in the amount of reduction in paleoprecipitation, ranging from 1 mm per day to 5 mm per day in DJF, they all suggest that DJF-the wet season over much of Amazonia-was drier than modern.…”

Section: Palaeoprecipitation and Forest Extentmentioning

confidence: 99%

“…Cerveny, 1999;Fritz et al, 2001). Most recent models of palaeoclimatic change have used cloud location to infer the position of the ITCZ, and some show the ITCZ extending more than 20 S (Martin et al, 1997;Maslin et al, 2000;. However, we believe that this definition of the ITCZ obscures the underlying causes of the southern hemispheric wet season and, more importantly, masks factors important to past climate reconstructions.…”

Section: Introductionmentioning

confidence: 99%

Observations on Late Pleistocene cooling and precipitation in the lowland Neotropics

Bush

Silman

2004

J Quaternary Science

103

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Although accurate reconstructions of Amazonian palaeoclimates are central to understanding the distribution and history of Neotropical biodiversity, current reconstructions based on proxy data are discordant and subject to intense debate. We review some current thinking in Amazonian climatology and incorporate some new ideas in an attempt to explain the apparently contradictory records of palaeoprecipitation from across the Amazon Basin. We suggest that palaeoecologists need to recognise that organised convective radiation, the process that induces most wet season rainfall in Amazonia, should be treated as a phenomenon related to, but separate from, the passage of the inter-tropical convergence zone (ITCZ). Decoupling ITCZ migration from larger convective activity provides a mechanism to account for observed palaeoclimatic heterogeneity. Patterns of observed precipitation change are consistent with the long-term persistence of closed forest across much of Amazonia, indicating that the greatest changes in precipitation during the last glacial maximum came during the wet season, which would have little negative impact on forest extent. Neotropical cooling at the last glacial maximum (LGM) is widely accepted, although the estimates of that cooling range between 1 C and > 5 C. In answering the basic question 'What is meant by cooling?' we observe that interhemispheric ice mass asymmetry may have caused cooling to be manifested differently according to location. A terrestrial cooling of ca. 5 C, as well as radiative cooling and event-based cooling combined to induce vegetation change. Probably, both absolute temperature and mean monthly minima were reduced by polar air incursions in the northern Neotropics. However, in the southern Neotropics, mean monthly minima were reduced by more frequent incursions of Patagonian air masses, but absolute minima may have been largely unchanged.

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Palaeoreconstruction of the Amazon River freshwater and sediment discharge using sediments recovered at Site 942 on the Amazon Fan

Cited by 40 publications

References 60 publications

Hydrology and climatology at Laguna La Gaiba, lowland Bolivia: complex responses to climatic forcings over the last 25 000 years

Hydrology and climatology at Laguna La Gaiba, lowland Bolivia: complex responses to climatic forcings over the last 25 000 years

Channel-mouth lobe complex of the recent Amazon Fan: The missing piece

Observations on Late Pleistocene cooling and precipitation in the lowland Neotropics

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