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Holocene Glacial Variability Recorded In Lake Sediments From Nevado Huaguruncho Peru
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Book Synopsis Holocene Glacial Variability Recorded in Lake Sediments from Nevado Huaguruncho, Peru by : Christopher M. Sedlak
Download or read book Holocene Glacial Variability Recorded in Lake Sediments from Nevado Huaguruncho, Peru written by Christopher M. Sedlak and published by . This book was released on 2012 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Glaciers and lakes are recorders of high altitude climate changes, and these archives are important in our understanding of past global changes. This study aims to provide further insight into how temperature and precipitation varied in the past, and combined to drive glacial variability in the tropical Andes of South America. A percussion core was taken in the field at Lake Yanacocha located in the watershed of Nevado Huaguruncho, Peru. Bulk density was measured along the profile of core and the chronology was determined by measuring radiocarbon on macrofossil samples within the sediments. The core geochemistry was analyzed using scanning X-Ray Fluorescence (XRF), Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and coulometry. Changes in clastic sediment concentrations in the Yanacocha sediment core are represented by shifting values of Ti, K, bulk density, organic carbon, and residual flux. High clastic sediment values characterize the early Holocene, followed by low values during most of the early stages of the mid-Holocene, at a time the lake sediments suggest there was a period of more arid conditions. There is a notable increase in clastic sediments starting at the end of the mid-Holocene, and again during the late Holocene. This study, when paired with other similar research, further improves our knowledge of the timing and causes of climate variability in the tropical Andes, and suggests that glaciers during the Holocene advanced at times of both colder and wetter conditions.
Book Synopsis Holocene Fluctuations of Quelccaya Ice Cap, Peru by : Justin Sirico Stroup
Download or read book Holocene Fluctuations of Quelccaya Ice Cap, Peru written by Justin Sirico Stroup and published by . This book was released on 2015 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tropics are critical for paleoclimate study because of their ability to influence global climate through ocean and atmospheric circulation. In this dissertation, I reconstruct the fluctuations of Quelccaya Ice Cap (QIC), located in the Peruvian Andes to provide information about Holocene (11,600 years ago-present) climate. QIC is an ideal location for Holocene paleoclimate research since extensive geological archives such as moraines, lake sediments, stratigraphic sections, in situ plant remains and ice cores register past ice cap extents and climate conditions. I utilize these archives, and extensive prior work from the area, to develop detailed records of Holocene QIC extents and climate. First, I reconstruct the late Holocene extents of Qori Kalis glacier, an outlet of QIC, using 10Be surface exposure dating of moraines. Qori Kalis advanced prior to 0.58 ka and retreated from its late Holocene maximum extent by ~0.58 ka. Qori Kalis retreat continued until ~0.28 ka, interrupted by a small readvance at ~0.41-0.36 ka. Based on a comparison of Qori Kalis extents and Quelccaya ice core net accumulation, I infer that temperature was a dominant influence on late Holocene QIC fluctuations. Second, I develop a late Holocene sediment core record from a glacially fed lake (Challpacocha) near QIC and compare this with the Qori Kalis moraine record to interpret the type of sediment deposited during ice cap advance and retreat. I find that organic sedimentation occurred primarily during ice cap advance and clastic sedimentation occurred during ice cap retreat. This result is valuable for other studies using lake sediments to interpret past glacial fluctuations. Third, I develop a near-continuous, Holocene-long record of QIC fluctuations using sediment cores from Challpacocha in combination with prior work. From ~10.8 to 6.5 ka, QIC was small or absent. From 6.5 to 5 ka, QIC was present on the landscape and ice cap growth may have been influenced by cooler temperatures. At 3-2.4 and 0.62-.31 ka QIC experienced phases of ice advance and retreat. Collectively, my research provides new information about the Holocene fluctuations of QIC and helps constrain past tropical South American climate conditions.
Book Synopsis Abrupt Holocene Climate Change by : Aron Maurice Buffen
Download or read book Abrupt Holocene Climate Change written by Aron Maurice Buffen and published by . This book was released on 2008 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Three ice cores drilled to bedrock atop Nevado Coropuna, southwestern Peru reflect Holocene and late glacial stage climate variability. Two cores measure 34 m in length yet provide seemingly continuous16 kyr histories, and thus represent the shortest known ice cores to extend from the present into the last glacial. High major ion concentrations and dust particle diameter ratios identify a succession of abrupt and severe Holocene droughts on the Altiplano centered at 3.4, 4.2, 5.6, 7.5, 8.2 and 10.1 kyr B.P. Modern precipitation availability in the region is dominated by ENSO variability on interannual timescales and these events may thus reflect extended periods of El Niño-like conditions in the tropical Pacific. The Deglaciation Climate Reversal, the tropical counterpart to the Northern Hemisphere Younger Dryas stadial, is marked by large, abrupt stable isotopic depletion, with [delta]18O ~9-10 per mil lower at this time relative to the early Holocene. This [delta]18O shift is remarkable as it is ~4-5 per mil greater than that observed in any previously drilled central Andean ice core record. In concert with marked, synchronous deuterium-excess increases, these shifts may be explained by a coeval southward migration of the ITCZ. Decreased major ion and dust concentrations and low dust particle diameter ratios likely reflect increased central Andean precipitation at this time, in agreement with other regional paleoclimate records. A complete history could not be produced for the third core due to conflicting dating results. Annual resolution over the past 244 years allows for a detailed assessment of recent regional climate change and its relation to possible forcings. Decadal [delta]18O variability is strongly correlated with tropical Pacific sea surface temperatures and lends support to precipitation, via the amount effect, controlling [delta]18O on these timescales. On longer timescales, temperature plays an increasingly important role in governing this parameter and it is suggested that 20th century [delta]18O enrichment is influenced by recent tropospheric warming resulting from anthropogenic greenhouse gas emissions. Radiocarbon dating of well preserved, in-place vegetation exposed by the retreating Quelccaya Ice Cap, southeastern Peru constrains the last time the ice cap's extent was smaller than at present. Seventeen plant samples from two sites along the central western margin collectively date to 4.7 and 5.1 kyr B.P. and strongly indicate that current ice cap retreat is unprecedented over the past ~5 millennia. Seventeen vegetation samples interbedded in a nearby clastic sedimentary sequence suggest ice-free conditions at this site from ~5.2 to at least ~7 kyr B.P., and place minimum constraint on early- to mid-Holocene ice cap extent. A growing body of globally distributed, independently dated paleoclimate records collectively identifies a series of contemporaneous abrupt climate change events during the Holocene that are generally coeval with reductions in solar output. A mechanistic hypothesis for these events, involving the tropical Pacific shifting to an El Niño-like mean state via a non-linear response of the coupled ocean-atmosphere system to reduced radiative heating, is discussed. Support for this explanation utilizing the abrupt drought events captured in the CRC1 record is equivocal.
Book Synopsis Holocene Environmental Variability Inferred from Lake Sediments, Southwest Yukon Territory, Canada by : Joan Bunbury
Download or read book Holocene Environmental Variability Inferred from Lake Sediments, Southwest Yukon Territory, Canada written by Joan Bunbury and published by . This book was released on 2009 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Glacial History and Climate Change in the Peruvian-Bolivian Andes by : Geoffrey Owen Seltzer
Download or read book Glacial History and Climate Change in the Peruvian-Bolivian Andes written by Geoffrey Owen Seltzer and published by . This book was released on 1991 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Late Pleistocene to Holocene Climate Variability Recorded in Lake Sediment of Silver Lake, Summit County, Ohio by : Corinne M. Lally
Download or read book Late Pleistocene to Holocene Climate Variability Recorded in Lake Sediment of Silver Lake, Summit County, Ohio written by Corinne M. Lally and published by . This book was released on 2016 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: To provide greater spatial coverage of late Pleistocene to Holocene environmental change in the Midwestern United States, a 1350 cm long sediment core was collected from Silver Lake in northeast Ohio. Age control was provided by new radiocarbon dates, correlation to a dated lake record from western Ohio, and a prior study of Silver Lake. Lithologic descriptions and sedimentary profiles of dry bulk density (DBD), organic matter (OM), carbonate, C/N, grain size, magnetic properties, and concentrations of terrigenous derived elements (Al, Ti, and K) allow the core to be divided into six periods. The climate interpretations are compared to published regional and hemispheric climate records. The first period is Deglaciation, which spans from 17,560 -- 13,600 cal year BP (1353 - 1188 centimeters below lake floor (cmblf)). Silty sediment with low OM (average 6 %) and high DBD (average 0.832 g/cm3) are interpreted to reflect cold conditions soon after deglaciation. The Latest Pleistocene Period is the second period and spans from 13,600 -- 12,200 cal yr BP (1188 -- 1103 cmblf). Brown to light brown mud with silty layers, a slight increase in % OM (average 9 %) and decrease in DBD (average 0.694 g/cm3) characterize this interval. The Latest Pleistocene Period may have been a time of increased primary productivity in Silver Lake. The third period is the Younger Dryas, which spans from 12,200 -- 11,500 cal yr BP (1103 -- 1070 cmblf). Gray-brown to light-brown silty mud having low % OM (average 6%), high DBD (average 0.703 g/cm3), high concentrations of magnetic minerals, and elevated concentrations of Al, Ti, and K characterize this period. These sediment characteristics are interpreted as cold and dry conditions, increased terrigenous input, and/or decreased primary productivity. The fourth period is the Early Holocene which spans from 11,500 -- 7,450 cal yr BP (1070 -- 824 cmblf), and is divided into two subperiods. During the first subperiod, from 11,500 -- 10,600 cal yr BP (1070 -- 1016 cmblf), there was an increase in % OM (average 28 %) and decrease in DBD (average 0.311 g/cm3) and concentrations of Al, Ti, and K. The first subperiod of the Early Holocene is interpreted to be a period of brief warming. The second subperiod of the Early Holocene spans from 10,600 -- 7,450 cal yr BP (1016-824 cmblf), and is characterized by highly variable % OM and DBD and increased Al, Ti, and K. This subperiod is interpreted as a period of increased aridity. The fifth period is the Mid to Late Holocene which spans from 7,450 -- 200 cal yr BP (824 -- 128 cmblf). Alternating brown and dark brown mud having no visible silty layers, high % OM (average 51%), low DBD (average 0.116 g/cm3), and decreased Al, Ti, and K and magnetic concentration characterize this period. These sediment characteristics are interpreted to reflect warm and moist conditions when primary productivity increased and/or terrigenous influx decreased. However, within the Mid to Late Holocene Period there are six pronounced intervals of decreased % OM and increased Al, Ti, and K suggestive of millennial-scale increases in terrigenous input and/or decreases in lake productivity. These six intervals may be related in part to rapid global climate changes during the Holocene, when temperatures and moisture balance fluctuated. The sixth period is the Anthropogenic Period, which spans from 200 cal yr BP to the present (128 -- 0 cmblf). The Anthropogenic Period is characterized by a pronounced decrease in % OM (average 19%), increase in DBD (average 0.273 g/cm3), and an increase in the mass accumulation rate (MAR) resulting from Euro-American land clearance enhancing watershed erosion.
Book Synopsis Late Glacial and Holocene Environmental Change Inferred from Sedimentary Archives of Kusawa Lake, Boundary Range Mountains, Yukon Territory, Canada by : Nicole A. Chow
Download or read book Late Glacial and Holocene Environmental Change Inferred from Sedimentary Archives of Kusawa Lake, Boundary Range Mountains, Yukon Territory, Canada written by Nicole A. Chow and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Holocene Environmental Variability in the South-west Pacific Recorded in Lake Lanoto'o Sediment Archives, Samoa by : Henry William Pearson
Download or read book Holocene Environmental Variability in the South-west Pacific Recorded in Lake Lanoto'o Sediment Archives, Samoa written by Henry William Pearson and published by . This book was released on 2014 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Late Glacial and Holocene Environmental Change Inferred from Sedimentary Archives of Kusawa Lake, Boundary Range Mountains, Yukon Territory, Canada by : Nicole Angela Chow
Download or read book Late Glacial and Holocene Environmental Change Inferred from Sedimentary Archives of Kusawa Lake, Boundary Range Mountains, Yukon Territory, Canada written by Nicole Angela Chow and published by . This book was released on 2009 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern Kusawa Lake (60° 19' 55" N, 136° 4' 48" W, 142 km2) of southwestern Yukon Territory drains a 4290 km 2 catchment, 4.7% of which is glacier covered. Sediment cores show variability both down-lake and within specific sub-basins of the lake. In Regions II--V of Kusawa Lake, sediments are mainly clastic with massive to weakly laminated silts and clays interrupted by fine sand units, which reflect distinct runoff events into Region IV from glacier sources. In Region I, massive silts, silt-clay couplets are interrupted by thick sand deposits derived from the Primrose River delta. Further up-lake, the sediment record is further interrupted by modern sediment delivery from the Kusawa Campground alluvial fan.The relatively small accumulation of lake glacial and Holocene sediment input in Kusawa Lake is similar to other large lakes of the Canadian Cordillera. These patterns reflect a particular style of deglaciation and Holocene sediment inputs.
Book Synopsis “The” Variability of Holocene Climate Change by :
Download or read book “The” Variability of Holocene Climate Change written by and published by . This book was released on 1984 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Paleoenvironmental Shifts and Precipitation Variations Recorded in Tropical Maar Lake Sediments During the Holocene in Southern China by :
Download or read book Paleoenvironmental Shifts and Precipitation Variations Recorded in Tropical Maar Lake Sediments During the Holocene in Southern China written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Holocene Paleohydrology of the Tropical Andes from Lake Records by :
Download or read book Holocene Paleohydrology of the Tropical Andes from Lake Records written by and published by . This book was released on 1997 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two century-scale time series in northern Bolivia constrain the ages of abrupt changes in the physical, geochemical, and biological characteristics of sediments obtained from lakes that formed during deglaciation from the late Pleistocene glacial maximum. The watersheds of Laguna Viscachani (16°12'S, 68°07'W, 3780m) and Lago Taypi Chaka Kkota (16°13'S, 68°21'W, 4300m), located on the eastern and western slopes of the Cordillera Real, respectively, contain small cirque glaciers. A high-resolution chronology of the lake sediments is provided by 23 AMS 14C dates of discrete macro-fossils. Late Pleistocene glaciers retreated rapidly, exposing the lake basins between 10,700 and 9700 14C yr B.P. The sedimentary facies suggest that after 8900 14C B.P. glaciers were absent from the watersheds and remained so during the middle Holocene. An increase in the precipitation-evaporation balance is indicated above unconformities dated to about 2300 14C yr B.P. in both Lago Taypi Chaka Kkota and Laguna Viscachani. An abrupt increase in sediment accumulation rated after 1400 14C yr B.P. signals the onset of Neoglaciation. A possible link exists between the observed millennial-scale shifts in the regional precipitation- evaporation balance and seasonal shifts in tropical insolation.
Book Synopsis Environmental Variability on the Bolivian Altiplano During the Middle and Late Holocene Inferred from Paleoenvironmental Records from the Southern Basin of Lake Titicaca and Andean Ice Cores by : Denise Marie Weide
Download or read book Environmental Variability on the Bolivian Altiplano During the Middle and Late Holocene Inferred from Paleoenvironmental Records from the Southern Basin of Lake Titicaca and Andean Ice Cores written by Denise Marie Weide and published by . This book was released on 2016 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Altiplano, especially Lake Titicaca, was an important center for Pre-Columbian Andean civilizations, with an archaeological record dating back to ~3500 cal yr BP. There have been many studies on the Lake to reconstruct past climate and environment, but uncertainty exists about the timing and duration of Holocene lake-level changes. This dissertation examines paleoenvironmental records from Lake Titicaca and Andean glaciers in an effort to clarify environmental conditions during the Holocene.
Book Synopsis Holocene Environmental Change Recorded in Lagoonal Sediment Proxies at Huaca Prieta, North Coastal Peru by : Rachel Anne Beavins Tracy
Download or read book Holocene Environmental Change Recorded in Lagoonal Sediment Proxies at Huaca Prieta, North Coastal Peru written by Rachel Anne Beavins Tracy and published by . This book was released on 2011 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Late Holocene Glacial Activity Recorded in Lacustrine Sediments on El Altar, Ecuador by : Gunhild Rosqvist
Download or read book Late Holocene Glacial Activity Recorded in Lacustrine Sediments on El Altar, Ecuador written by Gunhild Rosqvist and published by . This book was released on 1992 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High-resolution Reconstruction of Glacial to Holocene Climate Variability from Sediments of the Cariaco Basin and Arabian Sea by : Gaudenz Deplazes
Download or read book High-resolution Reconstruction of Glacial to Holocene Climate Variability from Sediments of the Cariaco Basin and Arabian Sea written by Gaudenz Deplazes and published by . This book was released on 2012 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Late Holocene Oxygen Isotope Record of Hydroclimate Variability in Nicaragua from Lake Asososca by : Stephen Perdziola
Download or read book Late Holocene Oxygen Isotope Record of Hydroclimate Variability in Nicaragua from Lake Asososca written by Stephen Perdziola and published by . This book was released on 2018 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigation of hydroclimate requires a higher level of spatial and temporal detail than what currently exists for Central America. High resolution lake sediment archives are critical to gaining a more complete understanding of late Holocene climate variability in the region. The climate of Central America is influenced by both tropical Atlantic and Pacific Ocean-atmosphere processes. A better understanding of how these processes have impacted regional hydroclimate is important as it will enable more accurate predictions of future climate changes associated with shifting conditions in a drought sensitive region. Here a 1,000-year carbonate oxygen isotope record is presented from Lake Asososca, located in western Nicaragua. In this record, high delta 18O values indicate drier conditions, while lower ?18O values indicate drier conditions. My data indicate wet conditions at the start of the Medieval Climate Anomaly (MCA) and a trend towards drier conditions until A.D. 1200. The transitional period between the MCA and the Little Ice Age (LIA) from A.D. 1200 - 1400 experienced a shift towards wetter conditions. The LIA from A.D. 1400 -- 1850 was a period of variable conditions. My record indicates a shift from wet to dry conditions from A.D. 1400 - 1600. A pronounced period of wetter conditions occurred from A.D. 1650-1700 during the Maunder Minimum solar event. From A.D 1700 -- 1800 the record indicates variable conditions that alternated between shifts towards dry and wet. After the LIA, the record indicates a trend towards drier conditions. The El Nino Southern Oscillation (ENSO), the North American Oscillation (NAO), and the Atlantic Multidecadal Oscillation (AMO), were often temporally correlated with the Lake Asososca record and suggest that these modes have impacted regional hydroclimate over the late Holocene. Correspondence between the Lake Asososca record and solar variability highlight a potential linkage. Climate models indicate that the Atlantic Meridional Overturning Circulation responds to changes in solar variability and can have impacts on Atlantic SSTs, and therefore may be provide a mechanism to amplify changes in solar variability to Central American hydroclimate. Comparison of the Lake Asososca delta18O record to regional hydroclimate proxies across show little correspondence over the past millennium. While some similarities exist between the Lake Asososca record and other regional proxies, the lack of a coherent hydroclimate signal over the late Holocene suggests temporally and spatially variability hydroclimate shifts. More hydroclimate reconstructions and modelling studies need to be performed in order to fully resolve hydroclimate variability in Central America over the past millennium. This record adds to the network of regional paleoclimate reconstructions in Central America and indicates that modes of variability in both the Atlantic and Pacific Ocean basins have impacted regional hydroclimate over the past millennium.
