C. Schweger - Academia.edu (original) (raw)

Papers by C. Schweger

Research paper thumbnail of ‘The Farm Beneath the Sand’ – an archaeological case study on ancient ‘dirt’ DNA

Antiquity, 2009

It is probable that ‘The Farm Beneath the Sand’ will come to stand for a revolution in archaeolog... more It is probable that ‘The Farm Beneath the Sand’ will come to stand for a revolution in archaeological investigation. The authors show that a core of soil from an open field can provide a narrative of grazing animals, human occupation and their departure, just using DNA and AMS dating. In this case the conventional archaeological remains were nearby, and the sequence obtained by the old methods of digging and faunal analysis correlated well with the story from the core of ancient ‘dirt’ DNA. The potential for mapping the human, animal and plant experience of the planet is stupendous.

Research paper thumbnail of Comparison of processed unifloral clover and canola honey

Research paper thumbnail of NATO ADVANCED RESEARCH WORKSHOP ON THE CLIMATE AND ENVIRONMENT OF THE LAST INTERGLACIAL IN THE ARCTIC AND SUBARCTIC

Research paper thumbnail of Pre-glacial and interglacial pollen records over the last 3 Ma from northwest Canada: Why do Holocene forests differ from those of previous interglaciations?

Quaternary Science Reviews, 2011

We synthesize pollen spectra from eleven dated stratigraphic sections from central and northern Y... more We synthesize pollen spectra from eleven dated stratigraphic sections from central and northern Yukon. Palaeomagnetic and tephra dating indicates the earliest assemblages, representing closed canopy Pinus and Picea forest, are middle-late Pliocene age. More open forest conditions, indicated by increased Poaceae and with evidence of permafrost, are dated at ca 3 Ma. While Pinus pollen is abundant at 3 Ma, it is reduced in records after 2.6 Ma, and subsequent Pleistocene interglacial forest records are repeatedly dominated by Picea, along with Alnus and small but significant amounts of Abies. Surface sample comparisons indicate that Abies was more widespread and abundant in past interglaciations than at present and that Middle-Pleistocene PiceaeAbies forest grew in the northern Yukon Porcupine Basin, 500 km beyond modern Abies limits. In contrast, Pinus, which occurs today in southern and central Yukon, was not a significant component of these Pleistocene interglacial forests. Late-Holocene pollen assemblages with rare Abies and high Pinus are the most distinct in the past 2.6 Ma. Possible factors driving Holocene difference are paleoclimate, paludification, changes in megafaunal herbivory and an unusual fire regime. Anthropogenic burning is a factor unique to the Holocene, and if it is shown to be important in this case, it would challenge our notion of what constitutes boreal wilderness. ualberta.ca (D. Froese), james.white@NRCan-RNCan.gc.ca (J.M. White), westgate@ geology.utoronto.ca (J.A. Westgate).

Research paper thumbnail of The last (Koy-Yukon) interglaciation in the Yukon: Comparisons with holocene and interstadial pollen records

Quaternary International, 1991

Research paper thumbnail of Why the last interglacial?

Quaternary International, 1991

Research paper thumbnail of Pleistocene stratigraphy, paleopedology, and paleoecology of a multiple till sequence exposed on the Little Bear River, Western District of Mackenzie, N.W.T., Canada

Canadian Journal of Earth Sciences, 1993

Research paper thumbnail of Differential response of vegetation to postglacial climate in the Lower Salmon River Canyon, Idaho

Late Pleistocene to Holocene terrestrial climate and vegetation records in the Lower Salmon River... more Late Pleistocene to Holocene terrestrial climate and vegetation records in the Lower Salmon River Canyon of Idaho are interpreted from the stable isotopic composition of soil carbonates and from aeolian sedimentation frequencies. Carbonate and sediment samples from six sections were processed and analyzed, with the resulting isotopic and grainsize data organized in relation to a normalized time series developed from an associated radiocarbon chronology. This record is interpreted in regards to changes in aridity, temperature and wind speed during the Late Quaternary and is further compared with regional paleoenvironmental records. Lowered N 18 O and N 13 C concentrations before 20 000 yr BP are interpreted as reflecting Late Wisconsinan cold conditions. After 18 000 yr BP, climatic conditions show warmer periods punctuated by sharp returns to colder temperatures and increased C 3 flora by 12 000 yr BP. Higher resolution data show very unstable climatic conditions across the Pleistocene^Holocene boundary, reflected in wide variations in N 18 O and N 13 C and aeolian sand deposition. During the period between 12 000 and 9000 yr BP, the Lower Salmon River Canyon is thought to have experienced marked seasonality with summers and winters, respectively, warmer and colder than today. This climatic scenario was accompanied by an initial instability in canyon vegetation. Following the establishment of a low-energy floodplain in the canyon after 10 000 yr BP, a pattern of C 3 -dominant riparian flora appears. During the middle Holocene, climatic and vegetative variability is much reduced from the preceding period. After 4000 yr BP, soil carbonate isotopes reflect a trend toward cooler climate conditions and more mesic vegetation populations. ß

Research paper thumbnail of ‘The Farm Beneath the Sand’ – an archaeological case study on ancient ‘dirt’ DNA

Antiquity, 2009

It is probable that ‘The Farm Beneath the Sand’ will come to stand for a revolution in archaeolog... more It is probable that ‘The Farm Beneath the Sand’ will come to stand for a revolution in archaeological investigation. The authors show that a core of soil from an open field can provide a narrative of grazing animals, human occupation and their departure, just using DNA and AMS dating. In this case the conventional archaeological remains were nearby, and the sequence obtained by the old methods of digging and faunal analysis correlated well with the story from the core of ancient ‘dirt’ DNA. The potential for mapping the human, animal and plant experience of the planet is stupendous.

Research paper thumbnail of Comparison of processed unifloral clover and canola honey

Research paper thumbnail of NATO ADVANCED RESEARCH WORKSHOP ON THE CLIMATE AND ENVIRONMENT OF THE LAST INTERGLACIAL IN THE ARCTIC AND SUBARCTIC

Research paper thumbnail of Pre-glacial and interglacial pollen records over the last 3 Ma from northwest Canada: Why do Holocene forests differ from those of previous interglaciations?

Quaternary Science Reviews, 2011

We synthesize pollen spectra from eleven dated stratigraphic sections from central and northern Y... more We synthesize pollen spectra from eleven dated stratigraphic sections from central and northern Yukon. Palaeomagnetic and tephra dating indicates the earliest assemblages, representing closed canopy Pinus and Picea forest, are middle-late Pliocene age. More open forest conditions, indicated by increased Poaceae and with evidence of permafrost, are dated at ca 3 Ma. While Pinus pollen is abundant at 3 Ma, it is reduced in records after 2.6 Ma, and subsequent Pleistocene interglacial forest records are repeatedly dominated by Picea, along with Alnus and small but significant amounts of Abies. Surface sample comparisons indicate that Abies was more widespread and abundant in past interglaciations than at present and that Middle-Pleistocene PiceaeAbies forest grew in the northern Yukon Porcupine Basin, 500 km beyond modern Abies limits. In contrast, Pinus, which occurs today in southern and central Yukon, was not a significant component of these Pleistocene interglacial forests. Late-Holocene pollen assemblages with rare Abies and high Pinus are the most distinct in the past 2.6 Ma. Possible factors driving Holocene difference are paleoclimate, paludification, changes in megafaunal herbivory and an unusual fire regime. Anthropogenic burning is a factor unique to the Holocene, and if it is shown to be important in this case, it would challenge our notion of what constitutes boreal wilderness. ualberta.ca (D. Froese), james.white@NRCan-RNCan.gc.ca (J.M. White), westgate@ geology.utoronto.ca (J.A. Westgate).

Research paper thumbnail of The last (Koy-Yukon) interglaciation in the Yukon: Comparisons with holocene and interstadial pollen records

Quaternary International, 1991

Research paper thumbnail of Why the last interglacial?

Quaternary International, 1991

Research paper thumbnail of Pleistocene stratigraphy, paleopedology, and paleoecology of a multiple till sequence exposed on the Little Bear River, Western District of Mackenzie, N.W.T., Canada

Canadian Journal of Earth Sciences, 1993

Research paper thumbnail of Differential response of vegetation to postglacial climate in the Lower Salmon River Canyon, Idaho

Late Pleistocene to Holocene terrestrial climate and vegetation records in the Lower Salmon River... more Late Pleistocene to Holocene terrestrial climate and vegetation records in the Lower Salmon River Canyon of Idaho are interpreted from the stable isotopic composition of soil carbonates and from aeolian sedimentation frequencies. Carbonate and sediment samples from six sections were processed and analyzed, with the resulting isotopic and grainsize data organized in relation to a normalized time series developed from an associated radiocarbon chronology. This record is interpreted in regards to changes in aridity, temperature and wind speed during the Late Quaternary and is further compared with regional paleoenvironmental records. Lowered N 18 O and N 13 C concentrations before 20 000 yr BP are interpreted as reflecting Late Wisconsinan cold conditions. After 18 000 yr BP, climatic conditions show warmer periods punctuated by sharp returns to colder temperatures and increased C 3 flora by 12 000 yr BP. Higher resolution data show very unstable climatic conditions across the Pleistocene^Holocene boundary, reflected in wide variations in N 18 O and N 13 C and aeolian sand deposition. During the period between 12 000 and 9000 yr BP, the Lower Salmon River Canyon is thought to have experienced marked seasonality with summers and winters, respectively, warmer and colder than today. This climatic scenario was accompanied by an initial instability in canyon vegetation. Following the establishment of a low-energy floodplain in the canyon after 10 000 yr BP, a pattern of C 3 -dominant riparian flora appears. During the middle Holocene, climatic and vegetative variability is much reduced from the preceding period. After 4000 yr BP, soil carbonate isotopes reflect a trend toward cooler climate conditions and more mesic vegetation populations. ß