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Full-Text Articles in Earth Sciences
Sources And Deposition Processes Linking Atmospheric Chemistry And Firn Records From Four Glacier Accumulation Zones In The Mcmurdo Dry Valleys, Antarctica, Bruce R. Williamson
Sources And Deposition Processes Linking Atmospheric Chemistry And Firn Records From Four Glacier Accumulation Zones In The Mcmurdo Dry Valleys, Antarctica, Bruce R. Williamson
Electronic Theses and Dissertations
Samples of snow and firn from accumulation zones on the Victoria Upper Glacier, the Clark Glacier, the Commonwealth Glacier and the Blue Glacier in the McMurdo Dry Valleys (~77 to 78º S and 161 to 164º E), Antarctica, are evaluated chemically and isotopically to determine the relative importance of local (site-specific) factors versus regional-scale climatic influences in defining regional glaciochemistry. Two approaches for distinguishing these controls are examined: comparing chemical concentrations using multivariate statistical analysis, and examining the effect of physical filtration (capturing particulate material largely originating in close proximity to each site) on sample values. These techniques provide constraints …
Archaeological Geology And Postglacial Development Of The Central Penobscot River Valley, Maine, Usa, Alice Repsher Kelley
Archaeological Geology And Postglacial Development Of The Central Penobscot River Valley, Maine, Usa, Alice Repsher Kelley
Electronic Theses and Dissertations
The purpose of this interdisciplinary study is to provide a geological and environmental context for the Late Pleistocene and Holocene Native American occupation of the central Penobscot River Valley, Maine. In addition, this work provides a model for the regional synthesis of geological, archaeological, and paleoenvironmental data in order to examine large-scale patterns of archaeological site formation and preservation. The postglacial central Penobscot Valley experienced varied and rapid landscape changes. Withdrawal of the Laurentide Ice Sheet was followed by marine transgression and regression. Subaerial exposure initiated landscape development. The postglacial Penobscot River rapidly excavated a channel through glacial sediments, creating …
Spatial And Temporal Changes In Stream Chemistry At Three Watersheds During High Discharge Episodes, Mollie Kate Laird
Spatial And Temporal Changes In Stream Chemistry At Three Watersheds During High Discharge Episodes, Mollie Kate Laird
Electronic Theses and Dissertations
A longitudinal study of first order streams in three forested watersheds was conducted to determine spatial and temporal trends in geochemistry during high discharge acidic episodes. The watersheds were East Bear Brook and Hadlock Brook (Maine, USA), and Fernow WS3 (West Virginia, USA). Watersheds were selected based on soil type, stream pH, and historical chemistry. Stream sampling sites were distributed along an elevational gradient and sampled simultaneously during a high discharge episode. Base flow samples were collected prior to the start of the hydrological event. The Maine watersheds, East Bear Brook and Hadlock Brook, were sampled during fall 2005 rain …
The Geoarchaeological Setting Of The Sebasticook Lake Fish Weir Newport, Maine, Christopher Evan Miller
The Geoarchaeological Setting Of The Sebasticook Lake Fish Weir Newport, Maine, Christopher Evan Miller
Electronic Theses and Dissertations
A geophysical and coring survey of Sebasticook Lake, Newport, Maine, provides evidence of past human-landscape interactions associated with construction and use of a Middle Archaic to Middle Woodland period fish weir, located at the lake inlet. Geophysical methods employed included Seismic Reflection Profiling (SRP) and Sidescan Sonar (SSS) survey of the Sebasticook Lake basin, and Ground Penetrating Radar (GPR) survey of the fish weir site and lake inlet. Three cores were collected using a modified, square-rod Wright piston corer in the lake basin. The Sebasticook fish weir complex consists of >630 stone-tool-modified wooden stakes, driven into stiff underlying glacial mud …
Thermal And Mechanical Effects Of A Shallow Asthenosphere In The Acadian Orogen: An Investigation Through Numerical Modeling, Lucy E. Brown
Thermal And Mechanical Effects Of A Shallow Asthenosphere In The Acadian Orogen: An Investigation Through Numerical Modeling, Lucy E. Brown
Electronic Theses and Dissertations
A high-temperature region associated with Acadian deformation extends 200 km through north-central New England. The scale of this heat source is investigated in order to better understand the rheology and mechanics of deforming orogens. In central Maine, on the boundary of the high-temperature region, isograds in pelitic rocks are normal to the accretionary structures and record a steep northeast-southwest thermal gradient. The isogradic sequence, geobarometry, and the mineral assemblages indicate low-pressure, high-temperature metamorphism, moderately low pressures of 3 kbar, and temperatures ranging from 600º to 450ºC over a 10 km region. The spacing between these isograds and the temperature at …