Browsing by Autor "Sherilyn C. Fritz"

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A ~6000 yr diatom record of mid- to late Holocene fluctuations in the level of Lago Wiñaymarca, Lake Titicaca (Peru/Bolivia)
(Cambridge University Press, 2017) D. Marie Weide; Sherilyn C. Fritz; Christine A. Hastorf; Maria C. Bruno; Paul A. Baker; Stéphane Guédron; Wout Salenbien
Abstract 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.
Holocene variations in Lake Titicaca water level and their implications for sociopolitical developments in the central Andes
(National Academy of Sciences, 2023) Stéphane Guédron; Christophe Delaere; Sherilyn C. Fritz; Julie Tolu; Pierre Sabatier; Anne-Lise Devel; Carlos Heredia; Claire Vérin; Eduardo Queiroz Alves; Paul A. Baker
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.
Late Hololocene mercury deposition history in Lake Chungara (4500 m. a.s.l., Chile): Influence of volcanic eruptions and changes in Paleolimnoecology
(2017) Stéphanie Guédron; Julie Tolu; Élodie Brisset; Pierre Sabatier; Anne‐Lise Develle; Sylvain Bouchet; Richard Bindler; A Dominic; Sherilyn C. Fritz; Paul A. Baker
International audience
Reconstructing two millennia of copper and silver metallurgy in the Lake Titicaca region (Bolivia/Peru) using trace metals and lead isotopic composition
(Elsevier BV, 2021) Stéphane Guédron; Julie Tolu; Christophe Delaere; Pierre Sabatier; Julien Barré; Carlos Heredia; Élodie Brisset; Sylvain Campillo; Richard Bindler; Sherilyn C. Fritz