This file was created by the TYPO3 extension publications --- Timezone: CEST Creation date: 2026-03-07 Creation time: 09:40:00 --- Number of references 23 article Guédron2023 Holocene climate in the high tropical Andes was characterized by both gradual and abrupt changes, which disrupted the hydrological cycle and impacted landscapes and societies. High-resolution paleoenvironmental records are essential to contextualize archaeological data and to evaluate the sociopolitical response of ancient societies to environmental variability. Middle-to-Late Holocene water levels in Lake Titicaca were reevaluated through a transfer function model based on measurements of organic carbon stable isotopes, combined with high-resolution profiles of other geochemical variables and paleoshoreline indicators. Our reconstruction indicates that following a prolonged low stand during the Middle Holocene (4000 to 2400 BCE), lake level rose rapidly ~15 m by 1800 BCE, and then increased another 3 to 6 m in a series of steps, attaining the highest values after ~1600 CE. The largest lake-level increases coincided with major sociopolitical changes reported by archaeologists. In particular, at the end of the Formative Period (500 CE), a major lake-level rise inundated large shoreline areas and forced populations to migrate to higher elevation, likely contributing to the emergence of the Tiwanaku culture. Copyright © 2023 the Author(s). Article 2023 10.1073/pnas.2215882120 Proceedings of the National Academy of Sciences of the United States of America 120 2 Climate; Lakes; Water; biological marker; organic carbon; water; Andes; archeology; Article; cultural anthropology; environmental parameters; geochemical analysis; geographic and geological phenomena; geographic elevation; Holocene; human; lake; lake basin; lake sediment; lake water level; Late Holocene; Middle Holocene; paleoecology; paleoeshoreline; politics; population migration; scientist; shoreline; social evolution; stable isotope labeling; chemistry; climate https://www.scopus.com/inward/record.uri?eid=2-s2.0-85145428330&doi=10.1073%2fpnas.2215882120&partnerID=40&md5=9d4e65969f07bbb692b2849031fe62dc Cited by: 0; All Open Access, Green Open Access, Hybrid Gold Open Access Stéphane Guédron Christophe Delaere Sherilyn C. Fritz Julie Tolu Pierre Sabatier Anne-Lise Devel Carlos Heredia Claire Vérin Eduardo Q. Alves Paul A. Baker article Luethje2023 Increasing surface air temperatures and human influences (e.g., agriculture, livestock grazing, tourism) are altering lacustrine ecosystems in the South American Andean páramo, and these influences are evident in changes in the diatom-species composition in sediment cores from the region that span the last ~ 150 years. Existing studies are limited by their short temporal scales and limited spatial extent. We analyzed two sediment cores spanning the last two millennia from the northern (Laguna Piñan) and southern (Laguna Fondococha) Andean páramo of Ecuador to provide a longer-term perspective on lake dynamics. Both lakes show shifts in the dominant diatoms through time. Fondococha diatoms shifted in dominance between two Aulacoseira species and in the planktic to benthic ratio, and these shifts are interpreted as evidence of changing lake level. The inferred shifts are corroborated by changes in sediment geochemistry. Piñan shows a directional shift in the diatom assemblage over the period of the record, from benthic diatoms tolerant of high dissolved organic carbon (DOC), low pH, and low nutrients, to an assemblage characteristic of lower DOC, Melina use only one higher for pH, nutrients and lake levels. Shifts in Piñan’s diatoms are correlated with tephra layers in the sediment, suggesting that local volcanic deposition may have been responsible for altering the catchment and lake geochemistry. This is supported by relatively high δ13C values in organic matter associated with tephra layers, which become more negative up-section. Our study suggests that remote lakes in spatially heterogenous montane regions act as sentinels of different facets of environmental change and provide insights into Andean ecosystem responses to environmental perturbations. © 2023, The Author(s), under exclusive licence to Springer Nature B.V. Article 2023 10.1007/s10933-022-00274-5 Journal of Paleolimnology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85146337930&doi=10.1007%2fs10933-022-00274-5&partnerID=40&md5=bf4291475529a62f502fccd301c6c446 Cited by: 1 Melina Luethje Xavier Benito Tobias Schneider Pablo V. Mosquera Paul Baker Sherilyn C. Fritz article Jiskra2022346 Mercury (Hg) records in sediment archives inform past patterns of Hg deposition and the anthropogenic contribution to global Hg cycling. Natural climate variations complicate the interpretation of past Hg accumulation rates (HgARs), warranting additional research. Here, we investigated Hg stable isotopes in a ca. 8k year-long sediment core of Lake Titicaca and combined isotopic data with organic biomarkers and biogeochemical measurements. A wet period in the early Holocene (8000-7300 BP) induced strong watershed erosion, leading to a high HgAR (20.2 ± 6.9 μg m-2 year-1), which exceeded the 20th century HgAR (8.4 ± 1.0 μg m-2 year-1). Geogenic Hg input dominated during the early Holocene (fgeog = 79%) and played a minor role during the mid- to late Holocene (4500 BP to present; fgeog = 20%) when atmospheric Hg deposition dominated. Sediment Δ200Hg values and the absence of terrestrial lignin biomarkers suggest that direct lake uptake of atmospheric Hg(0), and subsequent algal scavenging of lake Hg, represented an important atmospheric deposition pathway (42%) during the mid- to late Holocene. During wet episodes of the late Holocene (2400 BP to present), atmospheric Hg(II) deposition was the dominant source of lake sediment Hg (up to 82%). Sediment Δ199Hg values suggest that photochemical reduction and re-emission of Hg(0) occurred from the lake surface. Hg stable isotopes show promise as proxies for understanding the history of Hg sources and transformations and help to disentangle anthropogenic and climate factors influencing HgAR observed in sediment archives. © 2022 The Authors. Published by American Chemical Society Article 2022 10.1021/acsearthspacechem.1c00304 ACS Earth and Space Chemistry 6 346 – 357 2 Lake Titicaca; atmospheric deposition; biogeochemistry; biomarker; climate change; erosion; geological record; Holocene; mercury (element); sediment core; stable isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124042506&doi=10.1021%2facsearthspacechem.1c00304&partnerID=40&md5=11a9695229e9de98c0b9e4d253c0444f Cited by: 4; All Open Access, Green Open Access Martin Jiskra Stéphane Guédron Julie Tolu Sherilyn C. Fritz Paul A. Baker Jeroen E. Sonke article Benito2022S23 Little is known about whether changes in lake ecosystem structure over the past 150 years are unprecedented when considering longer timescales. Similarly, research linking environmental stressors to lake ecological resilience has traditionally focused on a few sentinel sites, hindering the study of spatially synchronous changes across large areas. Here, we studied signatures of paleolimnological resilience by tracking change in diatom community composition over the last 2000 years in four Ecuadorian Andean lakes with contrasting ecoregions. We focused on climate and anthropogenic change, and the type of biological responses that these changes induced: gradual, elastic, or threshold. We combined multivariate ordination techniques with nonlinear time-series methods (hierarchical generalized additive models) to characterize trajectories of community responses in each lake, and coherence in such trajectories across lakes. We hypothesized that remote, high-elevation lakes would exhibit synchronous trends due to their shared climatic constraints, whereas lower elevation lakes would show less synchronous trends as a consequence of human density and land-cover alteration. We found that gradual and elastic responses dominated. Threshold-type responses, or regime shifts, were only detected in the less remote lake, after a long period of gradual and elastic changes. Unexpected synchrony was observed in diatom assemblages from geographically distant and human-impacted lakes, whereas lakes under similar broad-scale environmental factors (climate and ecoregion) showed asynchronous community trajectories over time. Our results reveal a complex ecological history and indicate that Andean lakes in Ecuador can gradually adapt and recover from a myriad of disturbances, exhibiting resilience over century to millennial timescales. © 2021 Association for the Sciences of Limnology and Oceanography. Article 2022 10.1002/lno.11747 Limnology and Oceanography 67 S23 – S37 S1 Ecuador; anthropogenic effect; community composition; community response; diatom; ecosystem structure; lacustrine deposit; lacustrine environment; lake ecosystem; paleolimnology; tracking; tropical environment https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104123020&doi=10.1002%2flno.11747&partnerID=40&md5=e5a25104f1156f051067f3a9618eff26 Cited by: 3 Xavier Benito Melina Luethje Tobias Schneider Sherilyn C. Fritz Paul A. Baker Eric J. Pedersen Pierre Gaüzère Majoi Novaes Nascimento Mark Bush Albert Ruhi article Guédron2021 Copper, silver, and gold exploitation has been a foundation of economic and socio-cultural development of Andean societies, at least for the last three millennia. The main centers of pre-colonial metallurgy are well-known from archeological artifacts, but temporal gaps inherent in this record handicap a finer understanding of the modalities of ore exploitation by succeeding civilizations. A continuous record over time of trace metals emitted during ore smelting operations make lake sediments excellent candidates to fill those gaps. Two millennia of metallurgy were reconstructed from atmospherically derived metals together with lead (Pb) isotope ratios in two dated sediment cores from Lake Titicaca. The first evidence for metallurgy is found during the apogee of the Tiwanaku state (AD 800–1150), with a higher copper (Cu) accumulation that can be attributed to the smelting of local Cu ores, based on Pb isotopic fingerprinting. During the Late Intermediate Period (AD 1150–1450), recorded peaks in metal deposition that persisted for ∼ twenty years show that mining activities were intensive but discontinuous. Pb isotope ratios suggest diversified extractive activities, mainly located in the southern part of the central Altiplano. Finally, the most intense mining epoch began during the Inca Empire (ca. AD 1500) and lasted until the end of the Colonial Period (AD 1830), with unprecedented metal deposition over this interval. Pb isotope fingerprinting shows that mining operations occurred mainly in the Lake Titicaca and Potosi areas and were responsible for metal emissions recorded in the entire Altiplano, as evidenced by other studies. © 2021 Elsevier Ltd Article 2021 10.1016/j.ancene.2021.100288 Anthropocene 34 South America; copper; extraction method; isotopic composition; lacustrine deposit; lead isotope; silver; trace metal https://www.scopus.com/inward/record.uri?eid=2-s2.0-85103733079&doi=10.1016%2fj.ancene.2021.100288&partnerID=40&md5=066d98529e4aa4642461e861bd854cc2 Cited by: 7; All Open Access, Green Open Access S. Guédron J. Tolu C. Delaere P. Sabatier J. Barre C. Heredia E. Brisset S. Campillo R. Bindler S.C. Fritz P.A. Baker D. Amouroux article Bruno2021131 Investigations of how past human societies managed during times of major climate change can inform our understanding of potential human responses to ongoing environmental change. In this study, we evaluate the impact of environmental variation on human communities over the last four millennia in the southern Lake Titicaca basin of the Andes, known as Lake Wiñaymarka. Refined paleoenvironmental reconstructions from new diatom-based reconstructions of lake level together with archaeological evidence of animal and plant resource use from sites on the Taraco Peninsula, Bolivia, reveal frequent climate and lake-level changes within major cultural phases. We posit that climate fluctuations alone do not explain major past social and political transformations but instead that a highly dynamic environment contributed to the development of flexible and diverse subsistence practices by the communities in the Titicaca Basin. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature. Article 2021 10.1007/s10745-021-00222-3 Human Ecology 49 131 – 145 2 Lake Titicaca; Peru; Bacillariophyta; archaeological evidence; climate variation; economic diversification; environmental change; Holocene; human settlement; hydrological change; lake water; nature-society relations; paleoclimate; paleoenvironment; subsistence; water level https://www.scopus.com/inward/record.uri?eid=2-s2.0-85102423996&doi=10.1007%2fs10745-021-00222-3&partnerID=40&md5=712efbaa5e9a4e620a0812e27515520c Cited by: 7 Maria C. Bruno José M. Capriles Christine A. Hastorf Sherilyn C. Fritz D. Marie Weide Alejandra I. Domic Paul A. Baker article Spanbauer201889 High levels of biodiversity and endemism in ancient lakes have motivated research on evolutionary processes in these systems. Drill-core records from Lake Titicaca (Bolivia, Peru), an ancient lake in the high-elevation Altiplano, record the history of climate, landscape dynamics, and diatom evolution. That record was used to examine the patterns and drivers of morphological evolution of an endemic species complex of diatoms in the lake, the Cyclostephanos andinus complex. In an attempt to delineate species within the complex based on morphology, no discernible evidence was found for species separation based on an ordination analysis of multiple characters, but multiple populations were detected based on the distribution of valve size in individual samples. Likelihood modeling of phyletic evolution showed that size evolved through punctuated change. Correlation of size trends with environmental variables indicates that C. andinus size responded to regional environmental change driven by global processes that influenced Lake Titicaca by affecting lake level and thermal stratification. © 2018 The Paleontological Society. All rights reserved. Article 2018 10.1017/pab.2017.27 Paleobiology 44 89 – 100 1 Altiplano; Bolivia; Lake Titicaca; Peru; Bacillariophyta; Cyclostephanos andinus; biodiversity; diatom; endemic species; endemism; environmental change; fossil record; lake level; morphology; paleoenvironment; species complex https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047106447&doi=10.1017%2fpab.2017.27&partnerID=40&md5=fedc9622d4e3f0593f63ebb194d8f3b8 Cited by: 10 Trisha L. Spanbauer Sherilyn C. Fritz Paul A. Baker article Weide2017179 A multidecadal-scale lake-level reconstruction for Lago Wiñaymarca, the southern basin of Lake Titicaca, has been generated from diatom species abundance data. These data suggest that ~6500 cal yr BP Lago Wiñaymarca was dry, as indicated by a sediment unconformity. At ~4400 cal yr BP, the basin began to fill, as indicated by the dominance of shallow epiphytic species. It remained somewhat saline with extensive wetlands and abundant aquatic plants until ~3800 cal yr BP, when epiphytic species were replaced by planktic saline-indifferent species, suggesting a saline shallow lake. Wiñaymarca remained a relatively shallow lake that fluctuated on a multidecadal scale until ~1250 cal yr BP, when freshwater planktic species increased, suggesting a rise in lake level with a concomitant decrease in salinity. The lake became gradually fresher, dominated by deep, freshwater species from ~850 cal yr BP. By ~80 cal yr BP, saline-tolerant species were rare, and the lake was dominated by freshwater planktic diatoms, resembling the fresh and deep lake of today. These results reveal a more dynamic and chronologically specific record of lake-level fluctuations and associated ecological conditions that provide important new data for paleoclimatologists and archaeologists, to better understand human-environmental dynamics during the mid- to late Holocene. Copyright © University of Washington. Published by Cambridge University Press, 2017. Article 2017 10.1017/qua.2017.49 Quaternary Research (United States) 88 179 – 192 2 Bacillariophyta; Phytoplankton; Water; Concomitant decrease; Ecological conditions; Environmental dynamics; Holocenes; Lake level fluctuations; Lake levels; Mid to late Holocene; Tropical Andes; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053732457&doi=10.1017%2fqua.2017.49&partnerID=40&md5=180c0c4de1c8b3e886d5a69207a5fbcc Cited by: 26 D. Marie Weide Sherilyn C. Fritz Christine A. Hastorf Maria C. Bruno Paul A. Baker Stéphane Guédron Wout Salenbien article WILKE2016118 Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep-drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment-core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets to create an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep-drilling projects. 2016 0921-8181 https://doi.org/10.1016/j.gloplacha.2016.05.005 Global and Planetary Change 143 118-151 Ancient lake, Long-lived lake, Deep drilling, Evolutionary biology, Methodology, Paleolimnology https://www.sciencedirect.com/science/article/pii/S0921818115300746 Thomas Wilke Bert {Van Bocxlaer} Christian Albrecht Daniel Ariztegui Diana Delicado Alexander Francke Mathias Harzhauser Torsten Hauffe Jens Holtvoeth Janna Just Zlatko Levkov Kirsty Penkman Laura Sadori Alister Skinner Björn Stelbrink Hendrik Vogel Frank Wesselingh Thomas Wonik article Fornace2014263 A record of the hydrogen isotopic composition of terrestrial leaf waxes (δDwax) in sediment cores from Lake Titicaca provides new insight into the precipitation history of the Central Andes and controls of South American Summer Monsoon (SASM) variability since the last glacial period. Comparison of the δDwax record with a 19-kyr δD record from the nearby Illimani ice core supports the interpretation that precipitation δD is the primary control on δDwax with a lesser but significant role for local evapotranspiration and other secondary influences on δDwax. The Titicaca δDwax record confirms overall wetter conditions in the Central Andes during the last glacial period relative to a drier Holocene. During the last deglaciation, abrupt δDwax shifts correspond to millennial-scale events observed in the high-latitude North Atlantic, with dry conditions corresponding to the Bølling-Allerød and early Holocene periods and wetter conditions during late glacial and Younger Dryas intervals. We observe a trend of increasing monsoonal precipitation from the early to the late Holocene, consistent with summer insolation forcing of the SASM, but similar hydrologic variability on precessional timescales is not apparent during the last glacial period. Overall, this study demonstrates the relative importance of high-latitude versus tropical forcing as a dominant control on glacial SASM precipitation variability. © 2014 Elsevier B.V. Article 2014 10.1016/j.epsl.2014.10.024 Earth and Planetary Science Letters 408 263 – 271 Lake Titicaca; Central Andes; Holocenes; Hydrogen isotopic composition; Last glacial period; Stable hydrogen isotope; Summer monsoon; deglaciation; glacial lake; Holocene; hydrogen isotope; isotopic composition; Last Glacial Maximum; monsoon; precipitation (chemistry); sediment core; stable isotope; summer; Younger Dryas https://www.scopus.com/inward/record.uri?eid=2-s2.0-84910089298&doi=10.1016%2fj.epsl.2014.10.024&partnerID=40&md5=64814f33c1246a85b7de93af53a3091d Cited by: 31; All Open Access, Green Open Access Kyrstin L. Fornace Konrad A. Hughen Timothy M. Shanahan Sherilyn C. Fritz Paul A. Baker Sean P. Sylva article Fritz201293 In recent years, deep drilling undertaken as part of the International Continental Drilling Program has generated multiple long lacustrine sedimentary records to reconstruct continental paleoclimate. In many cases, the tectonic and geomorphic history of these basins is under-constrained and poorly known, which affects the interpretation of climate history from geophysical, geochemical, and paleobiotic proxies in the sedimentary record. In addition, non-analog biotic assemblages that reflect evolutionary processes may constrain the reconstruction of past environments. In the drill-core record of Lake Titicaca, spanning the last ~. 370. ka, the diatom stratigraphy reflects both the influence of climate and the long-term evolution of the lake basin and its biota. In the upper part of the drill-core sequence, glacial intervals were deep and dominated by freshwater planktic taxa, and peak interglacial intervals were shallow and dominated by benthic species, some with saline affinities. In the basal sections of the drill-core record, benthic diatoms are dominant in both glacial and interglacial units, with freshwater taxa dominating the glacial strata. This suggests that the ancient lake basin was shallower during intervals of both wet and dry climate, and that the modern deep lake may result from a progressive subsidence and deepening of the basin over time. In addition, morphological evolution in one of the major lineages of planktic diatoms, Cyclostephanos, indicates substantial change in the limnological environment that affected species morphology and may have driven speciation. © 2011 Elsevier B.V. Article 2012 10.1016/j.palaeo.2011.12.013 Palaeogeography, Palaeoclimatology, Palaeoecology 317-318 93 – 103 Andes; Lake Titicaca; Bacillariophyta; Cyclostephanos; deep drilling; diatom; glacial-interglacial cycle; lacustrine deposit; morphology; paleoclimate; paleoecology; paleoenvironment; paleogeography; paleolimnology; plankton; Quaternary; speciation (biology) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856563699&doi=10.1016%2fj.palaeo.2011.12.013&partnerID=40&md5=fd690b3918b8b019a2312c70123f9582 Cited by: 38; All Open Access, Green Open Access S.C. Fritz P.A. Baker P. Tapia T. Spanbauer K. Westover article Hanselman2011201 Fossil pollen and charcoal analyses of sediments from Lake Titicaca, Peru/Bolivia, provide a record of palaeoclimatic variation spanning four full glacial cycles. Pollen, aquatic microfossils, and charcoal, as well as previously published data including diatom assemblages, carbonate content, and stable carbon isotopic ratios of organic carbon, indicate that interglacials were warm and dry whereas the peaks of glacials were cold and wet. Each of the interglacials documented in the record are somewhat different, with those of MIS 5e and MIS 9 inducing lower lake levels and a drier vegetation signature than those of MIS 7 and 1. The presence of charcoal particles in sediments deposited during previous interglacials provides evidence of the long-term role of fire in shaping Andean ecosystems. © 2011 Elsevier B.V. Article 2011 10.1016/j.palaeo.2011.03.002 Palaeogeography, Palaeoclimatology, Palaeoecology 305 201 – 214 1-4 Andes; Bolivia; Lake Titicaca; Peru; Bacillariophyta; charcoal; depositional environment; diatom; fire history; fossil assemblage; glacial-interglacial cycle; interglacial; lacustrine deposit; microfossil; paleoclimate; palynology; vegetation dynamics; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955481503&doi=10.1016%2fj.palaeo.2011.03.002&partnerID=40&md5=3f9938493aa8912e2f57959da9805883 Cited by: 39 Jennifer A. Hanselman Mark B. Bush William D. Gosling Aaron Collins Christopher Knox Paul A. Baker Sheri C. Fritz article Fritz20101017 Millennial-scale climate variation during the Last Glacial period is evident in many locations worldwide, but it is unclear if such variation occurred in the interior of tropical South America, and, if so, how the low-latitude variation was related to its high-latitude counterpart. A high-resolution record, derived from the deep drilling of sediments on the floor of Lake Titicaca in the southern tropical Andes, is presented that shows clear evidence of millennial-scale climate variation between ∼60 and 20 ka BP. This variation is manifested by alternations of two interbedded sedimentary units. The two units have distinctive sedimentary, geochemical, and paleobiotic properties that are controlled by the relative abundance of terrigenous or nearshore components versus pelagic components. The sediments of more terrigenous or nearshore nature likely were deposited during regionally wetter climates when river transport of water and sediment was higher, whereas the sediments of more pelagic character were deposited during somewhat drier climates regionally. The majority of the wet periods inferred from the Lake Titicaca sediment record are correlated with the cold events in the Greenland ice cores and North Atlantic sediment cores, indicating that increased intensity of the South American summer monsoon was part of near-global scale climate excursions. © 2010 Elsevier Ltd. All rights reserved. Article 2010 10.1016/j.quascirev.2010.01.001 Quaternary Science Reviews 29 1017 – 1024 7-8 Andes; Lake Titicaca; Climatology; Glacial geology; Salinity measurement; Tropics; Climate variability; Climate variation; Deep drilling; Global scale; Greenland; High resolution; Ice core; Last glacial period; Nearshores; North Atlantic; Relative abundance; River transports; Sediment core; Sedimentary units; South America; Summer monsoon; Tropical Andes; Wet period; climate variation; deep drilling; lacustrine deposit; Last Glacial; paleoclimate; resolution; sedimentation; terrigenous deposit; Sedimentology https://www.scopus.com/inward/record.uri?eid=2-s2.0-77649340434&doi=10.1016%2fj.quascirev.2010.01.001&partnerID=40&md5=f0a249b7cf6b5b14c713d24649af2112 Cited by: 35; All Open Access, Green Open Access S.C. Fritz P.A. Baker E. Ekdahl G.O. Seltzer L.R. Stevens article Fritz2008342 Erratum 2008 10.1016/j.yqres.2008.01.004 Quaternary Research 69 342 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-40949134656&doi=10.1016%2fj.yqres.2008.01.004&partnerID=40&md5=504cbe8b02234e771d4749ccb4f937c0 Cited by: 2; All Open Access, Bronze Open Access Sherilyn C. Fritz Paul A. Baker Geoffrey O. Seltzer Ashley Ballantyne Pedro Tapia Hai Cheng R. Lawrence Edwards article Fritz2007410 A 136-m-long drill core of sediments was recovered from tropical high-altitude Lake Titicaca, Bolivia-Peru, enabling a reconstruction of past climate that spans four cycles of regional glacial advance and retreat and that is estimated to extend continuously over the last 370,000 yr. Within the errors of the age model, the periods of regional glacial advance and retreat are concordant respectively with global glacial and interglacial stages. Periods of ice advance in the southern tropical Andes generally were periods of positive water balance, as evidenced by deeper and fresher conditions in Lake Titicaca. Conversely, reduced glaciation occurred during periods of negative water balance and shallow closed-basin conditions in the lake. The apparent coincidence of positive water balance of Lake Titicaca and glacial growth in the adjacent Andes with Northern Hemisphere ice sheet expansion implies that regional water balance and glacial mass balance are strongly influenced by global-scale temperature changes, as well as by precessional forcing of the South American summer monsoon. © 2007 University of Washington. Article 2007 10.1016/j.yqres.2007.07.008 Quaternary Research 68 410 – 420 3 Lake Titicaca; South America; Bacillariophyta; glaciation; ice sheet; interglacial; paleoclimate; paleohydrology; Quaternary; reconstruction; sediment core; tropical region; water budget https://www.scopus.com/inward/record.uri?eid=2-s2.0-35348819351&doi=10.1016%2fj.yqres.2007.07.008&partnerID=40&md5=d0d468b6f8780f70f98b2a5ce350bf42 Cited by: 100; All Open Access, Green Open Access Sherilyn C. Fritz Paul A. Baker Geoffrey O. Seltzer Ashley Ballantyne Pedro Tapia Hai Cheng R. Lawrence Edwards article Baker2005655 A growing number of sites in the Northern Hemisphere show centennial- to millennial-scale climate variation that has been correlated with change in solar variability or with change in North Atlantic circulation. However, it is unclear how (or whether) these oscillations in the climate system are manifest in the Southern Hemisphere because of a lack of sites with suitably high sampling resolution. In this paper, we reconstruct the lake-level history of Lake Titicaca, using the carbon isotopic content of sedimentary organic matter, to evaluate centennial- to millennial-scale precipitation variation and its phasing relative to sites in the Northern Hemisphere. The pattern and timing of lake-level change in Lake Titicaca is similar to the ice-rafted debris record of Holocene Bond events, demonstrating a possible coupling between precipitation variation on the Altiplano and North Atlantic sea-surface temperatures (SSTs). The cold periods of the Holocene Bond events correspond with periods of increased precipitation on the Altiplano. Holocene precipitation variability on the Altiplano is anti-phased with respect to precipitation in the Northern Hemisphere monsoon region. More generally, the tropical Andes underwent large changes in precipitation on centennial-to-millennial timescales during the Holocene. Copyright © 2005 John Wiley & Sons, Ltd. Article 2005 10.1002/jqs.987 Journal of Quaternary Science 20 655 – 662 7-8 Lake Titicaca; South America; climate variation; Holocene; paleoclimate; paleohydrology; precipitation (climatology) https://www.scopus.com/inward/record.uri?eid=2-s2.0-29744439946&doi=10.1002%2fjqs.987&partnerID=40&md5=9301bd7b00cccb633cacf48a314065a6 Cited by: 79; All Open Access, Green Open Access P.A. Baker S.C. Fritz J. Garland E. Ekdahl article Tapia2003139 A composite high-resolution diatom stratigraphy from three piston cores and one box-core in the deep sub-basin of Lake Titicaca reveals large moisture variations during the past 30 kyr in the Altiplano region. Diatom sequences indicate orbital and millennial-scale variability in water level and salinity. The pelagic freshwater diatom species Cyclotella andina and Cyclotella stelligera dominate Glacial-age sediments, suggesting that the lake was above its present outlet, Generally, wet conditions continued until 11 000 cal yr BP, as indicated by high percentages of freshwater planktonic diatoms. Large pulses of benthic diatom species between about 11 000 and 10 000 cal yr BP suggest brief intervals of large-amplitude declines in lake level. During the early Holocene (10 000-8500 cal yr BP), a freshwater diatom assemblage suggests overflowing conditions. Pelagic freshwater diatoms are replaced ca, 8500 cal yr BP by the salinity-indifferent species Cyclotella meneghiniana and by benthic taxa, indicating the beginning of lake regression. During the mid-Holocene (6000-3500 cal yr BP), the abundance of the saline taxon Chaetoceros muelleri, coupled with high abundances of epiphytic and epipelic diatoms, indicates maximum salinity and lowest lake levels in the entire 30 000 year record. Lake transgression began ca. 4000 cal yr BP, and the lake achieved modern levels by about 1500 cal yr BP. These water-level changes imply changes in effective moisture, most likely resulting from large precipitation changes. Precipitation was high throughout the Last Glacial Maximum (21 000-18 000 cal yr BP), likely due to an enhanced South American Summer Monsoon during peak summer insolation in the Southern Hemisphere. In contrast, the mid-Holocene transition was dryer than today in association with an austral summer insolation minimum and the subsequent weakening of the summer monsoon. © 2003 Elsevier Science B.V. All rights reserved. Conference paper 2003 10.1016/S0031-0182(03)00275-X Palaeogeography, Palaeoclimatology, Palaeoecology 194 139 – 164 1-3 Bolivia; Lake Titicaca; Peru; Bacillariophyta; Chaetoceros; Chaetoceros muelleri; Chaetoceros muelleri; Cyclotella; Cyclotella andina; Cyclotella meneghiniana; Cyclotella stelligera; Cyclotella stelligera; biostratigraphy; diatom; lake level; Last Glacial Maximum; paleoclimate; Quaternary https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038029951&doi=10.1016%2fS0031-0182%2803%2900275-X&partnerID=40&md5=3636d1da4e27fb18d0157fabdbbb9e52 Cited by: 127; All Open Access, Green Open Access Pedro M. Tapia Sherilyn C. Fritz Paul A. Baker Geoffrey O. Seltzer Robert B. Dunbar article Paduano2003259 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. 3100 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. 9000 BP and 3100 BP, with a peak between 6000 and 4000 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. 3100 BP with the appearance of weed species. © 2003 Elsevier Science B.V. All rights reserved. Conference paper 2003 10.1016/S0031-0182(03)00281-5 Palaeogeography, Palaeoclimatology, Palaeoecology 194 259 – 279 1-3 Bolivia; Lake Titicaca; Peru; Apiaceae; Apiales; Cyperaceae; Plantago; Plantago; Poaceae; Polylepis; Polylepis; deglaciation; fire history; Last Glacial Maximum; paleoclimate; pollen; Quaternary; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038706478&doi=10.1016%2fS0031-0182%2803%2900281-5&partnerID=40&md5=b348d60e553d5eb7dda3b5d91c2c3185 Cited by: 143; All Open Access, Green Open Access Gina M. Paduano Mark B. Bush Paul A. Baker Sherilyn C. Fritz Geoffrey O. Seltzer article Rowe2003273 We present and compare AMS-14C geochronologies for sediment cores recovered from Lake Titicaca, South America. Radiocarbon dates from three core sites constrain the timing of late Quaternary paleoenvironmental changes in the Central Andes and highlight the site-specific factors that limit the radiocarbon geochronometer. With the exception of mid-Holocene sediments, all cores are generally devoid of macrophyte fragments, thus bulk organic fractions are used to build core chronologies. Comparisons of radiocarbon results for chemically defined fractions (bulk decalcified, humate, humin) suggest that ages derived from all fractions are generally coherent in the post-13,500 yr BP time interval. In the pre-13,500 yr BP time interval, ages derived from humate extracts are significantly younger (300-7000 years) than ages from paired humin residues. Gross age incoherencies between paired humate and humin sub-fractions in pre-13,500 yr BP sediments from all core sites probably reflect the net downward migration of humates. Ages derived from bulk decalcified fractions at our shallow water (90 m) and deep water (230 m) core sites consistently fall between ages derived from humate and humin sub-fractions in the pre-13,500 yr BP interval, reflecting that the bulk decalcified fraction is predominantly a mixture of humate and humin sub-fractions. Bulk decalcified ages from the pre-13,500 yr BP interval at our intermediate depth core site (150 m) are consistently older than humate (youngest) and humin sub-fractions. This uniform, reproducible pattern can be explained by the mobilization of a relatively older organic sub-fraction during and after the re-acidification step following the alkaline treatment of the bulk sediment. The inferred existence of this 'alkali-mobile, acid-soluble' sub-fraction implies a different depositional/post-depositional history that is potentially associated with a difference in source material. While internally consistent geochronologies can be developed for the Lake Titicaca sequence using different organic fractions, mobile organic sub-fractions and fractions containing mobile sub-fractions should generally be avoided in geochronology studies. Consequently, we believe humin and/or bulk decalcified ages provide the most consistent chronologies for the post-13,500 yr BP interval, and humin ages provide the most representative ages for sedimentation prior to 13,500 yr BP interval. Using the age model derived from the deep water core site and a previously published isotope-based lake-level reconstruction, we present a qualitative record of lake level in the context of several ice-core records from the western hemisphere. We find the latest Pleistocene lake-level response to changing insolation began during or just prior to the Bølling/Allerød period. Using the isotope-based lake-level reconstruction, we also find the 85-m drop in lake level that occurred during the mid-Holocene was synchronous with an increase in the variability of ice-core δ18O from a nearby icecap, but was not reflected in any of the polar ice-core records recovered from the interior of Antarctica and Greenland. © 2003 Published by Elsevier B.V. Article 2003 10.1016/S0921-8181(03)00031-6 Global and Planetary Change 38 273 – 290 3-4 Lake Titicaca; South America; geochronology; lake level; paleolimnology; radiocarbon dating; sediment core; stable isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141677771&doi=10.1016%2fS0921-8181%2803%2900031-6&partnerID=40&md5=b7b44c2aff7e67d5d08a3a9791a2c6db Cited by: 41; All Open Access, Green Open Access Harold D. Rowe Thomas P. Guilderson Robert B. Dunbar John R. Southon Geoffrey O. Seltzer David A. Mucciarone Sherilyn C. Fritz Paul A. Baker article DAgostino200297 Approximately 600 km of high-resolution seismic reflection data were collected to investigate the late-Quaternary stratigraphic development of Lake Titicaca. The focus of this report is on two seismic sequence boundaries, which are interpreted as erosional surfaces formed at times of low lake level. The younger erosional surface occurs as much as 90 m below the present lake level and up to 8 m below the present sediment-water interface. This erosional surface is interpreted to be coeval with a well-documented early- to mid-Holocene lowstand, dated between ∼ 8000 and 3600 cal yr BP. An earlier and previously unknown erosional surface occurs at a sub-bottom depth of approximately 30 m, and as much as 240 m below the present lake level, which implies a major late-Pleistocene lowstand of Lake Titicaca. By extrapolation of sedimentation rates from the upper ∼ 14 m of sediment, we estimate the age of this older lowstand at > 90000 cal yr BP. Both lowstands of Lake Titicaca indicated by the seismic data are likely to have been a response to climatic change in the region. © 2002 Elsevier Science B.V. All rights reserved. Article 2002 10.1016/S0031-0182(01)00411-4 Palaeogeography, Palaeoclimatology, Palaeoecology 179 97 – 111 1-2 Bolivia; Peru; lake level; paleoclimate; Quaternary; seismic data; seismic reflection; seismic stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037091908&doi=10.1016%2fS0031-0182%2801%2900411-4&partnerID=40&md5=5076a6c76cdcb2cdd30a46fac5a23a28 Cited by: 50; All Open Access, Green Open Access Karin D'Agostino Geoffrey Seltzer Paul Baker Sherilyn Fritz Robert Dunbar article Baker200120 Article 2001 Geotimes 46 20 – 21 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-73549105250&partnerID=40&md5=ef812b9e410ac9102b2ed40373ab641c Cited by: 0 Paul A. Baker Sherilyn C. Fritz Geoffrey O. Seltzer article Cross20011 A 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. © 2001 University of Washington. Article 2001 10.1006/qres.2001.2244 Quaternary Research 56 1 – 9 1 Bolivia; Lake Titicaca; Peru; geochemistry; lake level; paleoclimate; paleohydrology; paleolimnology; Quaternary https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035413201&doi=10.1006%2fqres.2001.2244&partnerID=40&md5=63f69274f3ce8d9fc64eef7cf011f5fd Cited by: 73; All Open Access, Green Open Access Scott L. Cross Paul A. Baker Geoffrey O. Seltzer Sherilyn C. Fritz Robert B. Dunbar article Cross200021 New evidence from piston cores and high-resolution seismic reflection data shows that water levels in Lake Titicaca were as much as 100 m below the present level during the early to mid-Holocene (between >6 and 3.8 14C kyr BP). Climatological and modelling studies indicate that Lake Titicaca rainfall depends on convective activity in upwind Amazonia; the lake-level data therefore suggest a drier Amazon Basin during this time. This view is bolstered by an excellent match between the Titicaca lake-level curve and decreased methane concentrations in Greenland ice, previously ascribed to drying of low-latitude wetlands (Blunier et al., 1995). The postglacial history of Lake Titicaca fits a global pattern of lake-level change in the tropics, characterized by opposite phasing between the Southern and Northern Hemispheres. This pattern is most likely the result of orbital controls over the intensity of summer insolation. Article 2000 10.1191/095968300671452546 Holocene 10 21 – 32 1 Bolivia; Lake Titicaca; Holocene; lake level; lowstand; paleohydrology https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033980356&doi=10.1191%2f095968300671452546&partnerID=40&md5=31df638cd72a5522f79d5bd09634935a Cited by: 136 Scott L. Cross Paul A. Baker Geoffrey O. Seltzer Sherilyn C. Fritz Robert B. Dunbar