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

Cross, Scott; Baker, Paul A.; Seltzer, Geoffrey O.; Fritz, Sherilyn C.; Dunbar, Robert B.

doi:10.1006/qres.2001.2244

Cited by 102 publications

(55 citation statements)

References 31 publications

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“…The higher pollen influx probably reflects a closer pollen source as the lake contracted. These findings are entirely consistent with previous reports of a dry mid-Holocene at Titicaca (Baker et al, 2001b;Cross et al, 2001 andSeltzer et al, 1998).…”

Section: A Mid-holocene Dry Eventsupporting

confidence: 93%

A vegetation and fire history of Lake Titicaca since the Last Glacial Maximum

Paduano

Bush

Baker

et al. 2003

Palaeogeography, Palaeoclimatology, Palaeoecology

180

157

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Fine-resolution fossil pollen and charcoal analyses reconstruct a vegetation and fire history in the area surrounding Lake Titicaca (3810 m, Peru/Bolivia) since ca. 27,500 cal yr BP (hereafter BP). Time control was based on 26 accelerator mass spectrometer (AMS) radiocarbon dates. Seventeen AMS dates and 155 pollen and charcoal samples between ca. 17,500 BP and ca. 3,100 BP allow a centennial-scale reconstruction of deglacial and early-to mid-Holocene events. Local and regional fire signals were based on the separation of two charcoal size fractions, ≥180 μm and 179-65 μm. Charcoal abundance correlated closely with the proportion of woody taxa present in the pollen spectra. Little or no pollen was detected in the sedimentary record prior to ca. 21,000 BP. Very cold climatic conditions prevailed, with temperatures suggested to be at least 5-8°C cooler than present. Increases in pollen concentration suggest initial warming at ca. 21,000 BP with a more significant transition toward deglaciation ca. 17,700 BP. Between 17,700 BP and 13,700 BP, puna brava is progressively replaced by puna and sub-puna elements. The most significant changes between the Pleistocene and the Holocene floras were largely complete by 13,700 BP, providing an effective onset of near-modern conditions markedly earlier than in other Andean records. Fire first occurs in the catchment at ca. 17,700 BP and becomes progressively more important as fuel loads increase. No evidence is found of a rapid cooling and warming coincident with the Younger Dryas chron. A dry event between ca. 9,000 BP and 3,100 BP, with a peak between 6,000 and 4,000 BP, is inferred from changes in the composition of aquatics, and the marsh community as pollen of Cyperaceae is replaced by Poaceae, Apiaceae, Plantago and the shrub Polylepis. Human disturbance of the landscape is evident in the pollen spectra after ca. 3,100 BP with the appearance of weed species.

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Section: A Mid-holocene Dry Eventsupporting

confidence: 93%

A vegetation and fire history of Lake Titicaca since the Last Glacial Maximum

Paduano

Bush

Baker

et al. 2003

Palaeogeography, Palaeoclimatology, Palaeoecology

180

157

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“…This assumption is in accordance with a study by Cross et al (2001) where the input value represents a mean of measured inflow concentrations. Except for lakes A and C, modelled Cl -inflow concentrations match the measured concentrations in the groundwater samples, indicating inflow from local groundwater.…”

Section: Application Of Mina Trêssupporting

confidence: 87%

Estimating water balance components of tropical wetland lakes in the Pantanal dry season, Brazil

Schwerdtfeger

Weiler

Johnson

et al. 2014

Hydrological Sciences Journal

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Water balance studies with stable water isotopes have rarely been conducted in remote and tropical wetland areas. As such, little is known regarding the water balance and groundwater-surface water interaction in the Pantanal, one of the largest and most pristine wetlands in the world. We applied MINA TrêS, a water balance model utilizing stable water isotopes (δ 18 O, δ 2 H) and chloride (Cl -) to assess the dry-season hydrological processes controlling groundwater-surface water interactions and the water balance of six floodplain lakes in the northern Pantanal, Brazil. Qualitatively, all lakes exhibited similarity in hydrological controls. Quantitatively, they differed significantly due to morphological differences in controlling groundwater inflow and lake volume. Our approach is readily transferable to other remote and tropical wetland systems with minimal data input requirements, which is useful in regions with sparse hydrometric monitoring.Key words Pantanal; dry season; stable water isotopes; chloride; water balance; groundwater-surface water interactions Estimation des composantes du bilan hydrique en saison sèche des lacs des zones humides tropicales du Pantanal (Brésil) Résumé Les études sur le bilan hydrique utilisant des isotopes stables de l'eau ont rarement été menées dans les zones humides et tropicales reculées. En tant que tel, on connaît peu le bilan hydrique et les interactions entre eaux superficielles et souterraines dans le Pantanal, une des zones humides les plus importantes et les plus vierges du monde. Nous avons appliqué le modèle de bilan hydrique MINA Três, en utilisant des isotopes stables de l'eau (δ 18 O, δ 2 H) et les chlorures (Cl -), afin d'évaluer, en saison sèche, les processus hydrologiques contrôlant les interactions des eaux souterraines et superficielles et le bilan hydrologique de six lacs de la plaine d'inondation dans le Nord du Pantanal, au Brésil. Qualitativement, les contrôles hydrologiques de tous les lacs sont similaires. Quantitativement, ils diffèrent sensiblement en raison des différences morphologiques du contrôle de l'écoulement souterrain et du volume des lacs. Notre approche, qui ne demande que très peu de données, est facilement transférable à d'autres systèmes de zones humides tropicales reculées, ce qui est utile dans les régions où le suivi hydrométrique est rare.

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“…Middle Holocene precipitation on the Altiplano was perhaps 40% less than modern (Cross et al, 2001). This aridity caused the level of Lake Titicaca to drop as low as 85 m below its present level (Seltzer et al, 1998;Cross et al, 2000).…”

Section: Introductionmentioning

confidence: 94%

Fluvial history of the Rio Ilave valley, Peru, and its relationship to climate and human history

Rigsby

Baker

Aldenderfer

2003

Palaeogeography, Palaeoclimatology, Palaeoecology

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Fluvial strata and landforms in the Rio Ilave valley (Peru) document a history of Holocene aggradation and downcutting that is correlative with regional climatic events and provides an environmental context for human occupation of the river valley. Periods of aggradation correspond to periods of high (or rising) level in Lake Titicaca and elsewhere on the Altiplano, and increased sediment accumulation in the Rio Ilave valley. Downcutting episodes correspond to periods of low level in Lake Titicaca and low or rapidly decreasing sedimentation rates in the Ilave delta. There are five terrace tracts (T1 through T5) present in this southwestern Lake Titicaca tributary. These tracts occur as both paired and unpaired terraces and have average heights from 1.4 to 24.3 m above the valley floor. The major part of the fluvial sequence was deposited during the time period from prior to the Last Glacial Maximum until about 8300 calendar years Before Present (cal BP)^a period of generally high (but variable) precipitation on the Altiplano and high water level in Lake Titicaca. Initial deposition (aggradation) was followed by successive downcutting to the T4 and T3 terrace surfaces. Initial downcutting began immediately after precipitation, runoff, and sediment load decreased while base level dropped. It was followed by a period of episodic equilibrium and minor downcutting that included a prolonged period of soil formation between V8350 and 6780 cal BP. The major pulses of downcutting likely occurred between V6000 and 4500 cal BP and were coincident with periods of decreased precipitation on the Altiplano and decreasing levels of Lake Titicaca. Two final periods of infilling, resulting in deposition of the T2 and T1 terrace sediments at V4000 to 2500 cal BP and V2000 to 1600 cal BP (during periods of rising water level in Lake Titicaca, lacustrine sedimentation in the Rio Desaguadero valley, and increased sedimentation offshore the Ilave delta), were separated by brief equilibrium stages and a brief downcutting event. This fluvial history, when coupled with regional paleoclimatic data, relates to the region's preceramic through Tiwanakuperiod archeological records. Archeological evidence indicates that humans occupied the Ilave valley as early as 10 000 cal BP. The higher terraces (T3, T4 and T5) were occupied for at least 5000 years, but humans did not utilize the lower terraces (T1 and T2) until after V4400^3700 cal BP. Our results confirm that these lower terraces would not have been available for either occupation or agriculture until after V4000 cal BP. ß

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

Cited by 102 publications

References 31 publications

A vegetation and fire history of Lake Titicaca since the Last Glacial Maximum

A vegetation and fire history of Lake Titicaca since the Last Glacial Maximum

Estimating water balance components of tropical wetland lakes in the Pantanal dry season, Brazil

Fluvial history of the Rio Ilave valley, Peru, and its relationship to climate and human history

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