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Full-Text Articles in Physical Sciences and Mathematics
Landscape Evolution Of The Dry Valleys, Transantarctic Mountains: Tectonic Implications, David E. Sugden, George H. Denton, David R. Marchant
Landscape Evolution Of The Dry Valleys, Transantarctic Mountains: Tectonic Implications, David E. Sugden, George H. Denton, David R. Marchant
Earth Science Faculty Scholarship
There are different views about the amount and timing of surface uplift in the Transantarctic Mountains and the geophysical mechanisms involved. Our new interpretation of the landscape evolution and tectonic history of the Dry Valleys area of the Transantarctic Mountains is based on geomorphic mapping of an area of 10,000 km(2). The landforms are dated mainly by their association with volcanic ashes and glaciomarine deposits and this permits a reconstruction of the stages and timing of landscape evolution. Following a lowering of base level about 55 m.y. ago, there was a phase of rapid denudation associated with planation and escarpment …
Global Perspective Of Nitrate Flux In Ice Cores, Qinzhao Yang, Paul Andrew Mayewski, Sallie Whitlow, Michael Morrison, Robert Talbot, Jack Dibb, Ernst Linder
Global Perspective Of Nitrate Flux In Ice Cores, Qinzhao Yang, Paul Andrew Mayewski, Sallie Whitlow, Michael Morrison, Robert Talbot, Jack Dibb, Ernst Linder
Earth Science Faculty Scholarship
The relationships between the concentration and the flux of chemical species(Cl-, NO3-, SO42-, Na+, K+, NH4+, Mg2+, Ca2+) versus snow accumulation rate were examined at GISP2 and 20D in Greenland, Mount Logan from the St. Elias Range, Yukon Territory, Canada, and Sentik Glacier from the northwest end of the Zanskar Range in the Indian Himalayas. At all sites, only nitrate flux is significantly(α = 0.05) related to snow accumulation rate. Of all the chemical series, only nitrate concentration data are normally …
A Wavelet Analysis Of Pliopleistocene Climate Indicators: A New View Of Periodicity Evolution, Edward W. Bolton, Kirk A. Maasch, Jonathan M. Lilly
A Wavelet Analysis Of Pliopleistocene Climate Indicators: A New View Of Periodicity Evolution, Edward W. Bolton, Kirk A. Maasch, Jonathan M. Lilly
Earth Science Faculty Scholarship
Wavelet analysis offers an alternative to Fourier based time-series analysis, and is particularly useful when the amplitudes and periods of dominant cycles are time dependent. We analyse climatic records derived from oxygen isotopic ratios of marine sediment cores with modified Morlet wavelets. We use a normalization of the Morlet wavelets which allows direct correspondence with Fourier analysis. This provides a direct view of the oscillations at various frequencies, and illustrates the nature of the time-dependence of the dominant cycles.
Derived Bedrock Elevations, Strain Rates And Stresses From Measured Surface Elevations And Velocities - Jakobshavns-Isbrae, Greenland, J. L. Fastook, H. H. Brecher, Terence J. Hughes
Derived Bedrock Elevations, Strain Rates And Stresses From Measured Surface Elevations And Velocities - Jakobshavns-Isbrae, Greenland, J. L. Fastook, H. H. Brecher, Terence J. Hughes
Earth Science Faculty Scholarship
Jakobshavns Isbrae (69 degrees 10'N, 49 degrees 5'W) drains about 6.5% of the Greenland ice sheet and is the fastest ice stream known. The Jakobshavns Isbrae basin of about 10 000 km(2) was mapped photogrammetrically from four sets of aerial photography, two taken in July 1985 and two in July 1986. Positions and elevations of several hundred natural features on the ice surface were determined for each epoch by photogrammetric block-aerial triangulation, and surface velocity vectors were computed from the positions. The two flights in 1985 yielded the best results and provided most common points (716) for velocity determinations and …
Paleoglaciologys Grand Unsolved Problem, Mikhail G. Grosswald, Terence J. Hughes
Paleoglaciologys Grand Unsolved Problem, Mikhail G. Grosswald, Terence J. Hughes
Earth Science Faculty Scholarship
The paleoglaciological concept that during the Pleistocene glacial hemi-cycles a super-large, structurally complex ice sheet developed in the Arctic and behaved as a single dynamic system, as the Antarctic ice sheet does today, has not yet been subjected to concerted studies designed to test the predictions of this concept. Yet, it may hold the keys to solutions of major problems of paleoglaciology, to understanding climate and sea-level changes. The Russian Arctic is the least-known region exposed to paleoglaciation by a hypothetical Arctic ice sheet but now it is more open to testing the concept. Implementation of these tests is a …
Changes In Continental And Sea-Salt Atmospheric Loadings In Central Greenland During The Most Recent Deglaciation: Model-Based Estimates, R. B. Alley, R. C. Finkel, K. Nishizumi, A. Anandakrishnan, C. A. Shuman, G. Mershon, G. A. Zielinski, Paul Andrew Mayewski
Changes In Continental And Sea-Salt Atmospheric Loadings In Central Greenland During The Most Recent Deglaciation: Model-Based Estimates, R. B. Alley, R. C. Finkel, K. Nishizumi, A. Anandakrishnan, C. A. Shuman, G. Mershon, G. A. Zielinski, Paul Andrew Mayewski
Earth Science Faculty Scholarship
By fitting a very simple atmospheric impurity model to high-resolution data on ice accumulation and contaminant f1uxes in the GISP2 ice core, we have estimated changes in the atmospheric concentrations of soluble major ions, insoluble particulates and 10Be during the transition from glacial to Holocene conditions. For many species, changes in concentration in the ice typically overestimate atmospheric changes, and changes in flux to the ice typically underestimate atmospheric changes, because times of increased atmospheric contaminant loading are also times of reduced snowfall. The model interpolates between the flux and concentration records by explicitly allowing [or wet- and dry- …