Mark B Abbott
Datos Biográficos
| ID | 2739165 |
|---|---|
| NOMBRE | Mark B Abbott |
| NOMBRES | Mark B |
| APELLIDO | Abbott |
| FIRMA | ABBOTT M B |
| AFILIACIONES | University of Pittsburgh |
| ORCID | 0000-0002-0299-928X |
| VERIFICADO | Sí |
| TOTAL DE OBRAS | 33 |
| TOTAL DE CITAS | 60 |
| TOTAL COMO AUTOR | 33 |
| TOTAL COMO EDITOR | 0 |
| PRIMER AÑO DE PUBLICACIÓN | 1996 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2025 |
| ÍNDICE H | 4 |
Holocene lake-level changes in Celestine Lake, Canadian Rocky Mountains, identified using stable isotopes, geochemistry, and mineralogy
A multiproxy lake-level reconstruction from Celestine Lake, located in Jasper National Park, Alberta, Canada, provides quantifiable evidence for Holocene precipitation-evaporation balance. Celestine Lake produces authigenic carbonate in its shallow waters while preserving organic sediments in the deeper basin. Sedimentary analysis of three cores collected from Celestine Lake along a shallow- to deep-water transect, analysis of modern lake water g…
Lead isotope fingerprinting techniques help identify and quantify 3000 years of atmospheric lead pollution from Laguna Roya, northwestern Iberia
On the Timing of the Old Copper Complex in North America
The Old Copper Complex (OCC) refers to the production of heavy copper-tool technology by Archaic Native American societies in the Lake Superior region. To better define the timing of the OCC, we evaluated 53 (eight new and 45 published) radiocarbon ( 14 C) dates associated with copper artifacts and mines. We compared these dates to six lake sediment-based chronologies of copper mining and annealing in the Michigan Copper District. 14 C dates grou…
Erroneously Old Radiocarbon Ages From Terrestrial Pollen Concentrates in Yellowstone Lake, Wyoming, Usa
Accelerator mass spectrometry (AMS) dating of pollen concentrates is often used in lake sediment records where large, terrestrial plant remains are unavailable. Ages produced from chemically concentrated pollen as well as manually picked Pinaceae grains in Yellowstone Lake (Wyoming) sediments were consistently 1700–4300 cal years older than ages established by terrestrial plant remains, tephrochronology, and the age of the sediment-water interfac…
The environmental impact of a pre-Columbian city based on geochemical insights from lake sediment cores recovered near Cahokia
Cahokia is the largest documented urban settlement in the pre-Columbian United States. Archaeological evidence suggests that the city, located near what is now East St. Louis, Illinois, began to rapidly expand starting around AD 1050. At its height, Cahokia extended across 1000 ha and included large plazas, timber palisade walls, and hundreds of monumental earthen mounds. Following several centuries of occupation, the city experienced a period of…
Holocene sea-level variability from Chesapeake Bay Tidal Marshes, USA
We reconstructed the last 10,000 years of Holocene relative sea-level rise (RSLR) from sediment core records near Chesapeake Bay, eastern United States, including new marsh records from the Potomac and Rappahannock Rivers, Virginia. Results show mean RSLR rates of 2.6 mm yr −1 from 10 to 8 kilo-annum (ka) due to combined final ice-sheet melting during deglaciation and glacio-isostatic adjustment (GIA subsidence). Mean RSLR rates from ~6 ka to pre…
Two millennia of anthropogenic landscape modification and nutrient loading at Dian Lake, Yunnan Province, China
Landscapes have been shaped by human activities for millennia and there is a pressing need to characterize pre-industrial impacts in order to mitigate present-day effects. We present the analysis of two sediment cores from Dian Lake in Yunnan, China, which span 4000 years. We compare cores from the northern and southern ends of the lake to investigate spatial variability in natural and anthropogenic environmental changes in this large (300 km 2 )…
Paleoclimatic and archaeological evidence from Lake Suches for highland Andean refugia during the arid middle-Holocene
Severe aridity during the mid-Holocene, ca. 8.0–4.0 kyr BP, led to extreme ecological stress in the tropical Andes. Here, we report paleolimnological and archeological data from Lake Suches in southern Peru (70° 24’ 12” W, 16° 55’ 35” S) spanning 13.6–4.4 kyr BP. Integrated paleoclimate and archeological data reveal that moisture was locally available and the basin served as an ecological refugium throughout the mid-Holocene. Mid-Holocene aridity…
The Donora Smog Revisited
At a storefront museum approximately 25 miles southeast of Pittsburgh, Pennsylvania, a sign reads, “Clean Air Started Here.” This is not hyperbole. At the end of October 1948, the communities of Donora and Webster in Pennsylvania were visited by a smog that changed the face of environmental protection in the United States. Conservative estimates showed that 20 individuals died, while an additional 5900—43% of the population of Donora—were affecte…
Lead pollution resulting from Roman gold extraction in northwestern Spain
Roman mining and metallurgy left a detectable signal of lead pollution throughout Europe, northern Africa, and the Middle East. Las Médulas, in Northwestern Iberia, was the largest Roman gold mine and fundamentally altered the local landscape. To document the environmental consequences of this activity, we present a 4000-year record of lake sediment geochemistry from Laguna Roya, 35 km south of Las Médulas. Using the concentrations of trace metal…
The isotopic response of Lake Chenghai, SW China, to hydrologic modification from human activity
The human modification of lake hydrology is widespread in the industrial era; however, anthropogenic impacts have occurred for thousands of years in regions of the world with long histories of human occupation. Here, we use geochemical analyses of lake sediment to document the isotopic and geochemical response of Cheng Lake (Chenghai) in southwestern China to catchment modification, including the construction of a downstream dam. The Chenghai rec…
Reconstruction of late Quaternary paleohydrologic Conditions in southeastern British Columbia using visible derivative spectroscopy of Cleland Lake Sediment
Visible derivative spectroscopy (VDS) analysis of sediment from Cleland Lake, Southeastern British Columbia provides a reconstruction of paleolimnological productivity and hydrologic change during the past 14,000 calibrated 14 C years before present (cal yr BP). The first five principal components (PC) of the VDS data explain 97% of the variance in the VDS data set. Four PCs correlate with standard reflectance derivative spectra for diatom, dinof…
Preliminary findings from Lake sediment studies of changing water availability in Western North America during the Holocene
Closed Lake oxygen isotope records of drought in the Pacific Northwest Spanning the common era
Copper mining on Isle Royale 6500–5400 years ago identified using sediment geochemistry from McCargoe Cove, Lake Superior
Isle Royale, in Lake Superior, contains evidence of indigenous copper mining; however, the timing and geographical extent of mining activity is poorly known. We analyzed metal, carbon, nitrogen, and organic matter concentrations to document past mining pollution in sediment cores recovered from McCargoe Cove; a long, narrow inlet of Lake Superior on Isle Royale that receives drainage from a watershed that contains numerous ancient copper mines. A…
Forest–savanna– morichal dynamics in relation to fire and human occupation in the southern Gran Sabana (SE Venezuela) during the last millennia
The southern Gran Sabana (SE Venezuela) holds a particular type of neotropical savanna characterized by the local occurrence of morichales ( Mauritia palm swamps) , in a climate apparently more suitable for rain forests. We present a paleoecological analysis of the last millennia of Lake Chonita (4°39′N–61°0′W, 884 m elevation), based on biological and physico-chemical proxies. Savannas dominated the region during the last millennia, but a signif…
Pre-Colombian Mercury Pollution Associated with the Smelting of Argentiferous Ores in the Bolivian Andes
A 40,000-yr record of environmental change from Burial Lake in Northwest Alaska
Burial Lake in northwest Alaska records changes in water level and regional vegetation since ∼ 39,000 cal yr BP based on terrestrial macrofossil AMS radiocarbon dates. A sedimentary unconformity is dated between 34,800 and 23,200 cal yr BP. During all or some of this period there was a hiatus in deposition indicating a major drop in lake level and deflation of lacustrine sediments. MIS 3 vegetation was herb-shrub tundra; more xeric graminoid-herb…
Recent Warming Reverses Long-Term Arctic Cooling
Climate Reversal The climate and environment of the Arctic have changed drastically over the short course of modern observation. Kaufman et al. (p. 1236 ) synthesized 2000 years of proxy data from lakes above 60° N latitude with complementary ice core and tree ring records, to create a paleoclimate reconstruction for the Arctic with a 10-year resolution. A gradual cooling trend at the start of the record had reversed by the beginning of the 20th …
Late-Holocene atmospheric lead deposition in the Peruvian and Bolivian Andes
The analysis of lead (Pb) in lake-sediment cores is a useful method to reconstruct local histories of Pb pollution. Here, we use Pb concentration profiles from lake sediments to reconstruct local trajectories of pre-Colonial smelting from three metallurgical centres in the South American Andes: the Morococha mining district, Peru; the Bolivian Altiplano around Lake Titicaca; and the silver-mining centre of Potosí, Bolivia. The earliest evidence f…
A record of climate over the last millennium based on varved lake sediments from the Canadian High Arctic
A varved sediment record that extends back over the last millennium was recovered from Lower Murray Lake, northern Ellesmere Island, Nunavut, Canada (81°20′N, 69°30′W). Flatbed scan images and backscattered electron images were analysed to provide varve thickness and other quantitative sedimentary indices on an annual basis. In many studies of lakes from the High Arctic, varve thickness is a good proxy for summer temperature and we interpret the …
Last glacial maximum equilibrium-line altitude and paleo-temperature reconstructions for the Cordillera de Mérida, Venezuelan Andes
The pattern and magnitude of glacier equilibrium-line altitude (ELA) lowerings in the tropics during the last glacial maximum (LGM) are topics of current debate. In the northern tropics, paleo-ELA data are particularly limited, inhibiting the ability to make regional and large-scale paleoclimatic inferences. To improve these records, nine paleo-glaciers in the Venezuelan Andes were reconstructed based on field observations, aerial photographs, sa…
Regional atmospheric circulation change in the North Pacific during the Holocene inferred from lacustrine carbonate oxygen isotopes, Yukon Territory, Canada
Analyses of sediment cores from Jellybean Lake, a small evaporation-insensitive groundwater-fed lake, provide a record of changes inNorth Pacific atmospheric circulation for the last ̈7500 yr at 5- to 30-yr resolution. Isotope hydrology data from the southern Yukonindicate that the oxygen isotope composition of water from Jellybean Lake reflects the composition of mean annual precipitation, d 18 O p .Recent changes in the d 18 O of Jellybean sedi…
Yr Pollen Record of Vegetation change in the High Altitude Tropical Andes at Laguna Verde Alta, Venezuela
Pollen analysis of sediments from a high-altitude (4215 m), Neotropical (9°N) Andean lake was conducted in order to reconstruct local and regional vegetation dynamics since deglaciation. Although deglaciation commenced ∼15,500 cal yr B.P., the area around the Laguna Verde Alta (LVA) remained a periglacial desert, practically unvegetated, until about 11,000 cal yr B.P. At this time, a lycopod assemblage bearing no modern analog colonized the super…
Regional atmospheric circulation change in the North Pacific during the Holocene inferred from lacustrine carbonate oxygen isotopes, Yukon Territory, Canada
Analyses of sediment cores from Jellybean Lake, a small, evaporation-insensitive groundwater-fed lake, provide a record of changes in North Pacific atmospheric circulation for the last ∽7500 yr at 5- to 30-yr resolution. Isotope hydrology data from the southern Yukon indicate that the oxygen isotope composition of water from Jellybean Lake reflects the composition of mean-annual precipitation, δ 18 O p . Recent changes in the δ 18 O of Jellybean …
Copper mining on Isle Royale 6500–5400 years ago identified using sediment geochemistry from McCargoe Cove, Lake Superior
Isle Royale, in Lake Superior, contains evidence of indigenous copper mining; however, the timing and geographical extent of mining activity is poorly known. We analyzed metal, carbon, nitrogen, and organic matter concentrations to document past mining pollution in sediment cores recovered from McCargoe Cove; a long, narrow inlet of Lake Superior on Isle Royale that receives drainage from a watershed that contains numerous ancient copper mines. A…
Lead pollution resulting from Roman gold extraction in northwestern Spain
Roman mining and metallurgy left a detectable signal of lead pollution throughout Europe, northern Africa, and the Middle East. Las Médulas, in Northwestern Iberia, was the largest Roman gold mine and fundamentally altered the local landscape. To document the environmental consequences of this activity, we present a 4000-year record of lake sediment geochemistry from Laguna Roya, 35 km south of Las Médulas. Using the concentrations of trace metal…
Late-Holocene atmospheric lead deposition in the Peruvian and Bolivian Andes
The analysis of lead (Pb) in lake-sediment cores is a useful method to reconstruct local histories of Pb pollution. Here, we use Pb concentration profiles from lake sediments to reconstruct local trajectories of pre-Colonial smelting from three metallurgical centres in the South American Andes: the Morococha mining district, Peru; the Bolivian Altiplano around Lake Titicaca; and the silver-mining centre of Potosí, Bolivia. The earliest evidence f…
On the Timing of the Old Copper Complex in North America
The Old Copper Complex (OCC) refers to the production of heavy copper-tool technology by Archaic Native American societies in the Lake Superior region. To better define the timing of the OCC, we evaluated 53 (eight new and 45 published) radiocarbon ( 14 C) dates associated with copper artifacts and mines. We compared these dates to six lake sediment-based chronologies of copper mining and annealing in the Michigan Copper District. 14 C dates grou…
Two millennia of anthropogenic landscape modification and nutrient loading at Dian Lake, Yunnan Province, China
Landscapes have been shaped by human activities for millennia and there is a pressing need to characterize pre-industrial impacts in order to mitigate present-day effects. We present the analysis of two sediment cores from Dian Lake in Yunnan, China, which span 4000 years. We compare cores from the northern and southern ends of the lake to investigate spatial variability in natural and anthropogenic environmental changes in this large (300 km 2 )…
Paleoclimatic and archaeological evidence from Lake Suches for highland Andean refugia during the arid middle-Holocene
Severe aridity during the mid-Holocene, ca. 8.0–4.0 kyr BP, led to extreme ecological stress in the tropical Andes. Here, we report paleolimnological and archeological data from Lake Suches in southern Peru (70° 24’ 12” W, 16° 55’ 35” S) spanning 13.6–4.4 kyr BP. Integrated paleoclimate and archeological data reveal that moisture was locally available and the basin served as an ecological refugium throughout the mid-Holocene. Mid-Holocene aridity…
The Donora Smog Revisited
At a storefront museum approximately 25 miles southeast of Pittsburgh, Pennsylvania, a sign reads, “Clean Air Started Here.” This is not hyperbole. At the end of October 1948, the communities of Donora and Webster in Pennsylvania were visited by a smog that changed the face of environmental protection in the United States. Conservative estimates showed that 20 individuals died, while an additional 5900—43% of the population of Donora—were affecte…
The isotopic response of Lake Chenghai, SW China, to hydrologic modification from human activity
The human modification of lake hydrology is widespread in the industrial era; however, anthropogenic impacts have occurred for thousands of years in regions of the world with long histories of human occupation. Here, we use geochemical analyses of lake sediment to document the isotopic and geochemical response of Cheng Lake (Chenghai) in southwestern China to catchment modification, including the construction of a downstream dam. The Chenghai rec…
Palaeohydrology of the Southwest Yukon Territory, Canada, based on multiproxy analyses of lake sediment cores from a depth transect
Lake-level variations at Marcella Lake, a small, hydrologically closed lake in the southwestern Yukon Territory, document changes in effective moisture since the early Holocene. Former water levels, driven by regional palaeohydrology, were reconstructed by multiproxy analyses of sediment cores from four sites spanning shallow to deep water. Marcella Lake today is thermally stratified, being protected from wind by its position in a depression. It …
Erroneously Old Radiocarbon Ages From Terrestrial Pollen Concentrates in Yellowstone Lake, Wyoming, Usa
Accelerator mass spectrometry (AMS) dating of pollen concentrates is often used in lake sediment records where large, terrestrial plant remains are unavailable. Ages produced from chemically concentrated pollen as well as manually picked Pinaceae grains in Yellowstone Lake (Wyoming) sediments were consistently 1700–4300 cal years older than ages established by terrestrial plant remains, tephrochronology, and the age of the sediment-water interfac…
Pre-Colombian Mercury Pollution Associated with the Smelting of Argentiferous Ores in the Bolivian Andes
A record of climate over the last millennium based on varved lake sediments from the Canadian High Arctic
A varved sediment record that extends back over the last millennium was recovered from Lower Murray Lake, northern Ellesmere Island, Nunavut, Canada (81°20′N, 69°30′W). Flatbed scan images and backscattered electron images were analysed to provide varve thickness and other quantitative sedimentary indices on an annual basis. In many studies of lakes from the High Arctic, varve thickness is a good proxy for summer temperature and we interpret the …
Radiocarbon Geochemistry of Modern and Ancient Arctic Lake Systems, Baffin Island, Canada
The accuracy of Arctic lake chronologies has been assessed by measuring the 14 C activities of modern carbon sources and applying these isotopic mass balances to dating fossil lake materials. Small ( 2 ) shallow ( 2 have soil and peat stratigraphic sections with 14 C activities ranging from 98 to 51% Modern. The 14 C activity of particulate organic carbon, dissolved organic carbon, and dissolved inorganic carbon from lake and stream waters ranges…
Holocene Paleohydrology of the Tropical Andes from Lake Records
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, 3780 m) and Lago Taypi Chaka Kkota (16°13′S, 68°21′W, 4300 m), located on the eastern and western slopes of the Cordillera Real, respective…
A 3500 14 C yr High-Resolution Record of Water-Level Changes in Lake Titicaca, Bolivia/Peru
Sediment cores collected from the southern basin of Lake Titicaca (Bolivia/Peru) on a transect from 4.6 m above overflow level to 15.1 m below overflow level are used to identify a new century-scale chronology of Holocene lake-level variations. The results indicate that lithologic and geochemical analyses on a transect of cores can be used to identify and date century-scale lake-level changes. Detailed sedimentary analyses of subfacies and radioc…
An ~15,000-Year Record of El Niño-Driven Alluviation in Southwestern Ecuador
Debris flows have deposited inorganic laminae in an alpine lake that is 75 kilometers east of the Pacific Ocean, in Ecuador. These storm-induced events were dated by radiocarbon, and the age of laminae that are less than 200 years old matches the historic record of El Niño events. From about 15,000 to about 7000 calendar years before the present, the periodicity of clastic deposition is greater than or equal to 15 years; thereafter, there is a pr…
Lake-Level Reconstruction and Paleohydrology of Birch Lake, Central Alaska, Based on Seismic Reflection Profiles and Core Transects
Lake-level history for Birch Lake, Alaska, was reconstructed using seismic profiles and multiproxy sedimentary analyses including sedimentology, geochemistry, magnetic susceptibility, and palynology. Twenty-two seismic profiles (18 km total) and eight sediment cores taken from the lake margin to its depocenter at 13.5 m provide evidence for low lake stands during the late Pleistocene and Holocene. Thirty-one AMS radiocarbon dates of macrofossils …
Holocene Climate Inferred from Oxygen Isotope Ratios in Lake Sediments, Central Brooks Range, Alaska
Analyses of sediment cores from two lakes in the central Brooks Range provide temperature and moisture balance information for the past ∼8500 cal yr at century-scale resolution. Two methods of oxygen isotope analysis are used to reconstruct past changes in the effective moisture (precipitation minus evaporation) and temperature. Effective moisture is inferred from oxygen isotope ratios in sediment cellulose from Meli Lake (area ∼0.13 km 2 , depth…
A Late Glacial–Holocene Tephrochronology for Glacial Lakes in Southern Ecuador
Despite the presence of numerous active volcanoes in the northern half of Ecuador, few, if any, distal tephras have been previously recognized in the southern one third of the country. In this article, we document the presence of thin (0.1–1.0-cm-thick) distal tephras comprising glass and/or phenocrysts of hornblende and feldspar in sediment cores from five glacial lakes and one bog in Las Cajas National Park (2°40′–3°00′S, 79°00′–79°25′W). The l…
Regional atmospheric circulation change in the North Pacific during the Holocene inferred from lacustrine carbonate oxygen isotopes, Yukon Territory, Canada
Analyses of sediment cores from Jellybean Lake, a small evaporation-insensitive groundwater-fed lake, provide a record of changes inNorth Pacific atmospheric circulation for the last ̈7500 yr at 5- to 30-yr resolution. Isotope hydrology data from the southern Yukonindicate that the oxygen isotope composition of water from Jellybean Lake reflects the composition of mean annual precipitation, d 18 O p .Recent changes in the d 18 O of Jellybean sedi…
Yr Pollen Record of Vegetation change in the High Altitude Tropical Andes at Laguna Verde Alta, Venezuela
Pollen analysis of sediments from a high-altitude (4215 m), Neotropical (9°N) Andean lake was conducted in order to reconstruct local and regional vegetation dynamics since deglaciation. Although deglaciation commenced ∼15,500 cal yr B.P., the area around the Laguna Verde Alta (LVA) remained a periglacial desert, practically unvegetated, until about 11,000 cal yr B.P. At this time, a lycopod assemblage bearing no modern analog colonized the super…
Regional atmospheric circulation change in the North Pacific during the Holocene inferred from lacustrine carbonate oxygen isotopes, Yukon Territory, Canada
Analyses of sediment cores from Jellybean Lake, a small, evaporation-insensitive groundwater-fed lake, provide a record of changes in North Pacific atmospheric circulation for the last ∽7500 yr at 5- to 30-yr resolution. Isotope hydrology data from the southern Yukon indicate that the oxygen isotope composition of water from Jellybean Lake reflects the composition of mean-annual precipitation, δ 18 O p . Recent changes in the δ 18 O of Jellybean …
Palaeohydrology of the Southwest Yukon Territory, Canada, based on multiproxy analyses of lake sediment cores from a depth transect
Lake-level variations at Marcella Lake, a small, hydrologically closed lake in the southwestern Yukon Territory, document changes in effective moisture since the early Holocene. Former water levels, driven by regional palaeohydrology, were reconstructed by multiproxy analyses of sediment cores from four sites spanning shallow to deep water. Marcella Lake today is thermally stratified, being protected from wind by its position in a depression. It …
Last glacial maximum equilibrium-line altitude and paleo-temperature reconstructions for the Cordillera de Mérida, Venezuelan Andes
The pattern and magnitude of glacier equilibrium-line altitude (ELA) lowerings in the tropics during the last glacial maximum (LGM) are topics of current debate. In the northern tropics, paleo-ELA data are particularly limited, inhibiting the ability to make regional and large-scale paleoclimatic inferences. To improve these records, nine paleo-glaciers in the Venezuelan Andes were reconstructed based on field observations, aerial photographs, sa…
Late-Holocene atmospheric lead deposition in the Peruvian and Bolivian Andes
The analysis of lead (Pb) in lake-sediment cores is a useful method to reconstruct local histories of Pb pollution. Here, we use Pb concentration profiles from lake sediments to reconstruct local trajectories of pre-Colonial smelting from three metallurgical centres in the South American Andes: the Morococha mining district, Peru; the Bolivian Altiplano around Lake Titicaca; and the silver-mining centre of Potosí, Bolivia. The earliest evidence f…
A record of climate over the last millennium based on varved lake sediments from the Canadian High Arctic
A varved sediment record that extends back over the last millennium was recovered from Lower Murray Lake, northern Ellesmere Island, Nunavut, Canada (81°20′N, 69°30′W). Flatbed scan images and backscattered electron images were analysed to provide varve thickness and other quantitative sedimentary indices on an annual basis. In many studies of lakes from the High Arctic, varve thickness is a good proxy for summer temperature and we interpret the …
Recent Warming Reverses Long-Term Arctic Cooling
Climate Reversal The climate and environment of the Arctic have changed drastically over the short course of modern observation. Kaufman et al. (p. 1236 ) synthesized 2000 years of proxy data from lakes above 60° N latitude with complementary ice core and tree ring records, to create a paleoclimate reconstruction for the Arctic with a 10-year resolution. A gradual cooling trend at the start of the record had reversed by the beginning of the 20th …
A 40,000-yr record of environmental change from Burial Lake in Northwest Alaska
Burial Lake in northwest Alaska records changes in water level and regional vegetation since ∼ 39,000 cal yr BP based on terrestrial macrofossil AMS radiocarbon dates. A sedimentary unconformity is dated between 34,800 and 23,200 cal yr BP. During all or some of this period there was a hiatus in deposition indicating a major drop in lake level and deflation of lacustrine sediments. MIS 3 vegetation was herb-shrub tundra; more xeric graminoid-herb…
Forest–savanna– morichal dynamics in relation to fire and human occupation in the southern Gran Sabana (SE Venezuela) during the last millennia
The southern Gran Sabana (SE Venezuela) holds a particular type of neotropical savanna characterized by the local occurrence of morichales ( Mauritia palm swamps) , in a climate apparently more suitable for rain forests. We present a paleoecological analysis of the last millennia of Lake Chonita (4°39′N–61°0′W, 884 m elevation), based on biological and physico-chemical proxies. Savannas dominated the region during the last millennia, but a signif…
Pre-Colombian Mercury Pollution Associated with the Smelting of Argentiferous Ores in the Bolivian Andes
Copper mining on Isle Royale 6500–5400 years ago identified using sediment geochemistry from McCargoe Cove, Lake Superior
Isle Royale, in Lake Superior, contains evidence of indigenous copper mining; however, the timing and geographical extent of mining activity is poorly known. We analyzed metal, carbon, nitrogen, and organic matter concentrations to document past mining pollution in sediment cores recovered from McCargoe Cove; a long, narrow inlet of Lake Superior on Isle Royale that receives drainage from a watershed that contains numerous ancient copper mines. A…
Reconstruction of late Quaternary paleohydrologic Conditions in southeastern British Columbia using visible derivative spectroscopy of Cleland Lake Sediment
Visible derivative spectroscopy (VDS) analysis of sediment from Cleland Lake, Southeastern British Columbia provides a reconstruction of paleolimnological productivity and hydrologic change during the past 14,000 calibrated 14 C years before present (cal yr BP). The first five principal components (PC) of the VDS data explain 97% of the variance in the VDS data set. Four PCs correlate with standard reflectance derivative spectra for diatom, dinof…
Preliminary findings from Lake sediment studies of changing water availability in Western North America during the Holocene
Closed Lake oxygen isotope records of drought in the Pacific Northwest Spanning the common era
The isotopic response of Lake Chenghai, SW China, to hydrologic modification from human activity
The human modification of lake hydrology is widespread in the industrial era; however, anthropogenic impacts have occurred for thousands of years in regions of the world with long histories of human occupation. Here, we use geochemical analyses of lake sediment to document the isotopic and geochemical response of Cheng Lake (Chenghai) in southwestern China to catchment modification, including the construction of a downstream dam. The Chenghai rec…
Lead pollution resulting from Roman gold extraction in northwestern Spain
Roman mining and metallurgy left a detectable signal of lead pollution throughout Europe, northern Africa, and the Middle East. Las Médulas, in Northwestern Iberia, was the largest Roman gold mine and fundamentally altered the local landscape. To document the environmental consequences of this activity, we present a 4000-year record of lake sediment geochemistry from Laguna Roya, 35 km south of Las Médulas. Using the concentrations of trace metal…
Two millennia of anthropogenic landscape modification and nutrient loading at Dian Lake, Yunnan Province, China
Landscapes have been shaped by human activities for millennia and there is a pressing need to characterize pre-industrial impacts in order to mitigate present-day effects. We present the analysis of two sediment cores from Dian Lake in Yunnan, China, which span 4000 years. We compare cores from the northern and southern ends of the lake to investigate spatial variability in natural and anthropogenic environmental changes in this large (300 km 2 )…
Geology and Paleoclimatology Research (25 obras) · Geography (22 obras) · Sediment (19 obras) · Geology (17 obras) · Holocene (17 obras) · Physical geography (17 obras) · Geology (16 obras) · Archaeology and ancient environmental studies (14 obras) · Geochemistry (12 obras) · Oceanography (12 obras)