Vera Markgraf
Dados Biográficos
| ID | 4052801 |
|---|---|
| NOME | Vera Markgraf |
| PRENOMES | Vera |
| SOBRENOME | Markgraf |
| ASSINATURA | MARKGRAF V |
| AFILIAÇÕES | Institute of Arctic and Alpine Research |
| ORCID | 0000-0002-1349-8317 |
| VERIFICADO | Sim |
| TOTAL DE OBRAS | 17 |
| TOTAL DE CITAÇÕES | 67 |
| TOTAL COMO AUTOR | 17 |
| TOTAL COMO EDITOR | 0 |
| PRIMEIRO ANO DE PUBLICAÇÃO | 1981 |
| ANO MAIS RECENTE DE PUBLICAÇÃO | 2018 |
| ÍNDICE H | 4 |
Paleoenvironmental changes during the last 3000 years in Lake Cari-Laufquen (Northern Patagonia, Argentina), inferred from ostracod paleoecology, petrophysical, sedimentological and geochemical data
South American paleoreconstructions are of global interest because it is the only landmass extending from the tropics to the southern high latitudes and intersecting the entire southern westerly wind belt. In this context, endorheic environments, as Lake Cari-Laufquen Grande (LCLG; 41o35’S, 69o25’W) are excellent sites for paleoenvironmental studies, since they react rapidly to changes in the precipitation/evaporation ratio. In this study, the li…
Postglacial vegetation, climate, and fire history along the east side of the Andes (lat 41–42.5°S), Argentina
The history of the low-elevation forest and forest-steppe ecotone on the east side of the Andes is revealed in pollen and charcoal records obtained from mid-latitude lakes. Prior to 15,000 cal yr BP, the vegetation was characterized by steppe vegetation with isolated stands of Nothofagus . The climate was generally dry, and the sparse vegetation apparently lacked sufficient fuels to burn extensively. After 15,000 cal yr BP, a mixture of Nothofagu…
Phylogeny, diet, and habitat of an extinct ground sloth from Cuchillo Curá, Neuquén Province, southwest Argentina
Advancements in ancient DNA analyses now permit comparative molecular and morphological studies of extinct animal dung commonly preserved in caves of semiarid regions. These new techniques are showcased using a unique dung deposit preserved in a late glacial vizcacha ( Lagidium sp.) midden from a limestone cave in southwestern Argentina (38.5° S). Phylogenetic analyses of the mitochondrial DNA show that the dung originated from a small ground slo…
European impact on fire regimes and vegetation dynamics at the steppe-forest ecotone of southern Patagonia
A macroscopic charcoal, pollen and peat macrofossil record from Rio Rubens Bog in southern Patagonia, covering the last c. 1200 years, provides detailed evidence concerning European impact on veg etation and fire frequency. Based on 210Pb and 14 C chronologies, we demonstrate that thefirst introduction of the weed Rumex acetosella occurred during early European contact in the sixteenth century or shortly thereafter. Thus, the first occurrence of …
Holocene palaeoclimates of southern Patagonia
Multiproxy palaeoenvironmental and palaeolimnological analyses of two Holocene-age sediment cores from the margin of Lago Cardiel, a 76 m deep, closed-basin lake in southern Patagonia (latitude 49°S), provide information on lake-level changes that can be related to regional palaeoclimate scenarios. Sedimentol ogic (magnetic susceptibility, organic and inorganic carbon content) and environmental indicators (pollen, dia toms, ostracodes and stable …
Multiproxy Record of Late Pleistocene–Holocene Climate and Vegetation Changes from a Peat Bog in Patagonia
Pollen assemblage changes and stable hydrogen isotope analysis of mosses ( Sphagnum magellanicum and Drepanocladus s.l.) from a bog in Tierra del Fuego, Argentina, provided independent proxies for reconstructing changes in effective moisture and temperature over the past 16,000 cal yr B.P. A deterministic model was used to reconstruct the stable hydrogen isotope composition of meteoric water from the D/H ratios of bog mosses over the last 16,000 …
Interhemispheric Climate Linkages
Late-Holocene rodent middens from Rio Limay, Neuquen Province, Argentina
Pollen analysis of late-Holocene amberat deposits from two caves near the forest-steppe ecotone in northern Patagonia documents a major shift from Austrocedrus-Nothofagus forest to steppe shrub assemblages some time after 1800 and before 1300 BP. The probable explanation of the reduction of tree taxa calls for either drier summers or intensified land use or a combination of both
El Niño
Late pleistocene/early holocene environments and climates, fauna, and human occupation in the argentine altiplano
The Barro Negro site (23°S lat., 65°37′W long.) in the Altiplano (Puna) of northwestern Argentina contains a well stratified sequence of remains of Hippidion , the American extinct horse, camelids, and archaeological materials, which is the focus of this study. In addition to establishing a reliable chronology, paleoenvironmental information was obtained based on analyses of pollen and stable isotopes (oxygen and carbon) from bone and marl. The d…
Steppe Expansion in Patagonia?
Westward expansion of the Patagonian steppe and retrocession of Andean forests due to increasing aridity over the past one or two millennia has been a persistent theme in the ecological and paleoecological literature for at least half a century. New evidence from pollen profiles, tree-ring analysis, vegetation structure, and photographic and documentary historical sources does not show the expansion of the steppe. Instead, over the past century t…
Paleoenvironmental Changes at the Northern Limit of the Subantarctic Nothofagus Forest, lat 37°S, Argentina
Paleoenvironmental changes dating back to before 10,000 yr B.P. at the northernmost occurrences of Nothofagus forests in Argentina at about latitude 37°S permit the reconstruction of past changes in the intensity of the winter rains, related to the southern westerlies that appear to determine the forest boundary. The paleoenvironmental interpretation is based on changes in the proportions of different Nothofagus species and changes in the ratio b…
Environments and Extinctions
Paleoenvironmental History of the Last 13,000 Years of the Eastern Powder River Basin, Wyoming, and its Implications for Prehistoric Cultural Patterns
In context with an archaeological survey of the eastern Powder River Basin, Wyoming, pollen, ostracode, and macroremains from a playa sediment column yielded a regional paleoenvironmental history of the last 13,000 years B.P. According to the sedimentological, paleolimnological, and paleoenvironmental data, no major changes occurred during this time interval, suggesting that late glacial type climates in this region were similar to modern conditi…
San Agustin Plains, New Mexico
Paleomagnetic analysis of samples from the original 600-m-long core from the San Agustin Plains, New Mexico, showed an unquestionable reversal stratigraphy dating the record back to at least 1.6 my. Analysis of pollen, ostracodes, and algae of a duplicate sample section in the vicinity of the original coring site and spanning the last 18,000 yr B.P. shows a much higher resolution than the earlier results.
Late and postglacial vegetational and paleoclimatic changes in subantarctic, temperate, and arid environments in Argentina
A paleoclimatic chronology for southern South America is suggested by comparison of dated pollen records from Argentina (lat 32° to 34°S, 41°S and 51° to 54°S). The paleoenvironmental phases distinguished for the last 13,000 years are interpreted as paleoclimatic phases and explained as latitudinal shifts of atmospheric circulation anomalies by using the correlation of modern precipitation patterns with atmospheric circulation anomaly patterns ov…
Paleoenvironmental reconstruction at Canyon del Muerto, Arizona, based on principal-component analysis
Late pleistocene/early holocene environments and climates, fauna, and human occupation in the argentine altiplano
The Barro Negro site (23°S lat., 65°37′W long.) in the Altiplano (Puna) of northwestern Argentina contains a well stratified sequence of remains of Hippidion , the American extinct horse, camelids, and archaeological materials, which is the focus of this study. In addition to establishing a reliable chronology, paleoenvironmental information was obtained based on analyses of pollen and stable isotopes (oxygen and carbon) from bone and marl. The d…
El Niño
Holocene palaeoclimates of southern Patagonia
Multiproxy palaeoenvironmental and palaeolimnological analyses of two Holocene-age sediment cores from the margin of Lago Cardiel, a 76 m deep, closed-basin lake in southern Patagonia (latitude 49°S), provide information on lake-level changes that can be related to regional palaeoclimate scenarios. Sedimentol ogic (magnetic susceptibility, organic and inorganic carbon content) and environmental indicators (pollen, dia toms, ostracodes and stable …
Paleoenvironmental History of the Last 13,000 Years of the Eastern Powder River Basin, Wyoming, and its Implications for Prehistoric Cultural Patterns
In context with an archaeological survey of the eastern Powder River Basin, Wyoming, pollen, ostracode, and macroremains from a playa sediment column yielded a regional paleoenvironmental history of the last 13,000 years B.P. According to the sedimentological, paleolimnological, and paleoenvironmental data, no major changes occurred during this time interval, suggesting that late glacial type climates in this region were similar to modern conditi…
European impact on fire regimes and vegetation dynamics at the steppe-forest ecotone of southern Patagonia
A macroscopic charcoal, pollen and peat macrofossil record from Rio Rubens Bog in southern Patagonia, covering the last c. 1200 years, provides detailed evidence concerning European impact on veg etation and fire frequency. Based on 210Pb and 14 C chronologies, we demonstrate that thefirst introduction of the weed Rumex acetosella occurred during early European contact in the sixteenth century or shortly thereafter. Thus, the first occurrence of …
Paleoenvironmental reconstruction at Canyon del Muerto, Arizona, based on principal-component analysis
Paleoenvironmental reconstruction at Canyon del Muerto, Arizona, based on principal-component analysis
Late and postglacial vegetational and paleoclimatic changes in subantarctic, temperate, and arid environments in Argentina
A paleoclimatic chronology for southern South America is suggested by comparison of dated pollen records from Argentina (lat 32° to 34°S, 41°S and 51° to 54°S). The paleoenvironmental phases distinguished for the last 13,000 years are interpreted as paleoclimatic phases and explained as latitudinal shifts of atmospheric circulation anomalies by using the correlation of modern precipitation patterns with atmospheric circulation anomaly patterns ov…
San Agustin Plains, New Mexico
Paleomagnetic analysis of samples from the original 600-m-long core from the San Agustin Plains, New Mexico, showed an unquestionable reversal stratigraphy dating the record back to at least 1.6 my. Analysis of pollen, ostracodes, and algae of a duplicate sample section in the vicinity of the original coring site and spanning the last 18,000 yr B.P. shows a much higher resolution than the earlier results.
Environments and Extinctions
Paleoenvironmental History of the Last 13,000 Years of the Eastern Powder River Basin, Wyoming, and its Implications for Prehistoric Cultural Patterns
In context with an archaeological survey of the eastern Powder River Basin, Wyoming, pollen, ostracode, and macroremains from a playa sediment column yielded a regional paleoenvironmental history of the last 13,000 years B.P. According to the sedimentological, paleolimnological, and paleoenvironmental data, no major changes occurred during this time interval, suggesting that late glacial type climates in this region were similar to modern conditi…
Paleoenvironmental Changes at the Northern Limit of the Subantarctic Nothofagus Forest, lat 37°S, Argentina
Paleoenvironmental changes dating back to before 10,000 yr B.P. at the northernmost occurrences of Nothofagus forests in Argentina at about latitude 37°S permit the reconstruction of past changes in the intensity of the winter rains, related to the southern westerlies that appear to determine the forest boundary. The paleoenvironmental interpretation is based on changes in the proportions of different Nothofagus species and changes in the ratio b…
Steppe Expansion in Patagonia?
Westward expansion of the Patagonian steppe and retrocession of Andean forests due to increasing aridity over the past one or two millennia has been a persistent theme in the ecological and paleoecological literature for at least half a century. New evidence from pollen profiles, tree-ring analysis, vegetation structure, and photographic and documentary historical sources does not show the expansion of the steppe. Instead, over the past century t…
Late pleistocene/early holocene environments and climates, fauna, and human occupation in the argentine altiplano
The Barro Negro site (23°S lat., 65°37′W long.) in the Altiplano (Puna) of northwestern Argentina contains a well stratified sequence of remains of Hippidion , the American extinct horse, camelids, and archaeological materials, which is the focus of this study. In addition to establishing a reliable chronology, paleoenvironmental information was obtained based on analyses of pollen and stable isotopes (oxygen and carbon) from bone and marl. The d…
El Niño
Late-Holocene rodent middens from Rio Limay, Neuquen Province, Argentina
Pollen analysis of late-Holocene amberat deposits from two caves near the forest-steppe ecotone in northern Patagonia documents a major shift from Austrocedrus-Nothofagus forest to steppe shrub assemblages some time after 1800 and before 1300 BP. The probable explanation of the reduction of tree taxa calls for either drier summers or intensified land use or a combination of both
Interhemispheric Climate Linkages
Multiproxy Record of Late Pleistocene–Holocene Climate and Vegetation Changes from a Peat Bog in Patagonia
Pollen assemblage changes and stable hydrogen isotope analysis of mosses ( Sphagnum magellanicum and Drepanocladus s.l.) from a bog in Tierra del Fuego, Argentina, provided independent proxies for reconstructing changes in effective moisture and temperature over the past 16,000 cal yr B.P. A deterministic model was used to reconstruct the stable hydrogen isotope composition of meteoric water from the D/H ratios of bog mosses over the last 16,000 …
Phylogeny, diet, and habitat of an extinct ground sloth from Cuchillo Curá, Neuquén Province, southwest Argentina
Advancements in ancient DNA analyses now permit comparative molecular and morphological studies of extinct animal dung commonly preserved in caves of semiarid regions. These new techniques are showcased using a unique dung deposit preserved in a late glacial vizcacha ( Lagidium sp.) midden from a limestone cave in southwestern Argentina (38.5° S). Phylogenetic analyses of the mitochondrial DNA show that the dung originated from a small ground slo…
European impact on fire regimes and vegetation dynamics at the steppe-forest ecotone of southern Patagonia
A macroscopic charcoal, pollen and peat macrofossil record from Rio Rubens Bog in southern Patagonia, covering the last c. 1200 years, provides detailed evidence concerning European impact on veg etation and fire frequency. Based on 210Pb and 14 C chronologies, we demonstrate that thefirst introduction of the weed Rumex acetosella occurred during early European contact in the sixteenth century or shortly thereafter. Thus, the first occurrence of …
Holocene palaeoclimates of southern Patagonia
Multiproxy palaeoenvironmental and palaeolimnological analyses of two Holocene-age sediment cores from the margin of Lago Cardiel, a 76 m deep, closed-basin lake in southern Patagonia (latitude 49°S), provide information on lake-level changes that can be related to regional palaeoclimate scenarios. Sedimentol ogic (magnetic susceptibility, organic and inorganic carbon content) and environmental indicators (pollen, dia toms, ostracodes and stable …
Postglacial vegetation, climate, and fire history along the east side of the Andes (lat 41–42.5°S), Argentina
The history of the low-elevation forest and forest-steppe ecotone on the east side of the Andes is revealed in pollen and charcoal records obtained from mid-latitude lakes. Prior to 15,000 cal yr BP, the vegetation was characterized by steppe vegetation with isolated stands of Nothofagus . The climate was generally dry, and the sparse vegetation apparently lacked sufficient fuels to burn extensively. After 15,000 cal yr BP, a mixture of Nothofagu…
Paleoenvironmental changes during the last 3000 years in Lake Cari-Laufquen (Northern Patagonia, Argentina), inferred from ostracod paleoecology, petrophysical, sedimentological and geochemical data
South American paleoreconstructions are of global interest because it is the only landmass extending from the tropics to the southern high latitudes and intersecting the entire southern westerly wind belt. In this context, endorheic environments, as Lake Cari-Laufquen Grande (LCLG; 41o35’S, 69o25’W) are excellent sites for paleoenvironmental studies, since they react rapidly to changes in the precipitation/evaporation ratio. In this study, the li…
Geography (17 obras) · Physical geography (14 obras) · Geology and Paleoclimatology Research (13 obras) · Archaeology (10 obras) · Geology (10 obras) · Holocene (9 obras) · Paleontology (9 obras) · Pollen (8 obras) · Biology (7 obras) · Ecology (7 obras)