Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
- Publication
- Publication Type
Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Thermal And Barometric Constraints On The Intrusive And Unroofing History Of The Black Mountains: Implications For Timing, Initial Dip, And Kinematics Of Detachment Faulting In The Death-Valley Region, California, Daniel K. Holm, J. Kent Snow, Daniel R. Lux
Thermal And Barometric Constraints On The Intrusive And Unroofing History Of The Black Mountains: Implications For Timing, Initial Dip, And Kinematics Of Detachment Faulting In The Death-Valley Region, California, Daniel K. Holm, J. Kent Snow, Daniel R. Lux
Earth Science Faculty Scholarship
Unroofing of the Black Mountains, Death Valley, California, has resulted in the exposure of 1.7 Ga crystalline basement, late Precambrian amphibolite facies metasedimentary rocks, and a Tertiary magmatic complex. The Ar-40/Ar-39 cooling ages, obtained from samples collected across the entire length of the range (>55 km), combined with geobarometric results from synextensional intrusions, provide time-depth constraints on the Miocene intrusive history and extensional unroofing of the Black Mountains. Data from the southeastern Black Mountains and adjacent Greenwater Range suggest unroofing from shallow depths between 9 and 10 Ma. To the northwest in the crystalline core of the range, biotite …
Kornerupine From The Archean Kola Series At Sholt-Yavr, Kola Peninsula, Russia, Edward S. Grew, Martin G. Yates, A. N. Konilov, Nicholas Marquez
Kornerupine From The Archean Kola Series At Sholt-Yavr, Kola Peninsula, Russia, Edward S. Grew, Martin G. Yates, A. N. Konilov, Nicholas Marquez
Earth Science Faculty Scholarship
No abstract provided.
Episodic Stream Acidification Caused By Atmospheric Deposition Of Sea Salts At Acadia National Park, Maine, United States, Richard H. Heath, Jeffrey S. Kahl, Stephen A. Norton, Ivan J. Fernandez
Episodic Stream Acidification Caused By Atmospheric Deposition Of Sea Salts At Acadia National Park, Maine, United States, Richard H. Heath, Jeffrey S. Kahl, Stephen A. Norton, Ivan J. Fernandez
Earth Science Faculty Scholarship
Major episodic acidifications were observed on several occasions in first-order brooks at Acadia National Park, Mount Desert Island, Maine. Short-term declines of up to 2 pH units and 130-mu-eq L-1 acid-neutralizing capacity were caused by HCl from soil solutions, rather than by H2SO4 or HNO3 from precipitation, because (1) SO4 concentrations were constant or decreased during the pH depression, (2) Cl concentrations were greatest at the time of lowest pH, and (3) Na:Cl ratios decreased from values much greater than those in precipitation (a result of chemical weathering), to values equal to or less than those in precipitation. Dilution, increases …
On The Pulling Power Of Ice Streams, Terence J. Hughes
On The Pulling Power Of Ice Streams, Terence J. Hughes
Earth Science Faculty Scholarship
Gravity wants to pull an ice sheet to the center of the Earth, but cannot because the Earth's crust is in the way, so ice is pushed out sideways instead. Or is it? The ice sheet "sees" nothing preventing it from spreading out except air, which is much less massive than ice. Therefore, does not ice rush forward to fill this relative vacuum; does not the relative vacuum suck ice into it, because Nature abhors a vacuum? If so, the ice sheet is not only pulled downward by gravity, it is also pulled outward by the relative vacuum. This pulling …
Theoretical Calving Rates From Glaciers Along Ice Walls Grounded In Water Of Variable Depths, Terence J. Hughes
Theoretical Calving Rates From Glaciers Along Ice Walls Grounded In Water Of Variable Depths, Terence J. Hughes
Earth Science Faculty Scholarship
Calving has been studied for glaciers ranging from slow polar glaciers that calve on dry land, such as on Deception Island (63.0-degrees-S, 60.6-degrees-W) in Antarctica, through temperate Alaskan tide-water glaciers, to fast outlet glaciers that float in fiords and calve in deep water, such as Jakobshavns Isbrae (69.2-degrees-N, 49.9-degrees-W) in Greenland. Calving from grounded ice walls and floating ice shelves is the main ablation mechanism for the Antarctic and Greenland ice sheets, as it was along marine and lacustrine margins of former Pleistocene ice sheets, and is for tide-water and polar glaciers. Yet, the theory of ice calving is underdeveloped …
Anthropogenic Sulfate And Asian Dust Signals In Snow From Tien Shan, Northwest China, Cameron P. Wake, Paul Andrew Mayewski, Wang Ping, Yang Qinzhao, Han Jiankang, Xie Zichu
Anthropogenic Sulfate And Asian Dust Signals In Snow From Tien Shan, Northwest China, Cameron P. Wake, Paul Andrew Mayewski, Wang Ping, Yang Qinzhao, Han Jiankang, Xie Zichu
Earth Science Faculty Scholarship
Snow samples were collected from a 0.5 m snowpack at Glacier No. 1 and near Bogda Feng, eastern Tien Shan, northwest China. Samples that were melted in the field were analyzed for chloride, nitrate, sulfate, sodium, potassium, magnesium, calcium, and microparticles. Eight samples were returned frozen and were analyzed for the above ions plus ammonium, acetate, formate, methylsulfonate, and hydrogen peroxide. There was no significant difference in measured major ion concentrations between the melted and frozen samples. Measured cations in both sets of samples were two to three times greater than measured anions. Calcium and sodium are the dominant cations …
Identification Of The Subspecies Of Oreochromis Niloticus (Pisces: Cichlidae) Using Restriction Endonuclease Analysis Of Mitochondrial Dna, Seifu Seyoum, Irv Kornfield
Identification Of The Subspecies Of Oreochromis Niloticus (Pisces: Cichlidae) Using Restriction Endonuclease Analysis Of Mitochondrial Dna, Seifu Seyoum, Irv Kornfield
Marine Sciences Faculty Scholarship
Restriction endonuclease analysis of mitochondrial DNA (mtDNA) was used to characterize differentiation among the seven described subspecies of Oreochromis niloticus from East Africa and Egypt. Mitochondrial DNAs of 14 populations were examined with 42 restriction endonucleases. Two subspecies of Oreochromis spilurus were also examined. Approximately 8% of the mitochondrial genome of O. niloticus (17 070 ± 40 base pairs) was assayed; 29 (70%) of the 42 restriction enzymes that were examined displayed restriction phenotypes that varied among the samples analyzed. Several endonucleases produced restriction phenotypes which were diagnostic for the described subspecies of O. niloticus, though a few samples did …
Ice-Core Dating And Chemistry By Direct-Current Electrical Conductivity, Kenorick Taylor, Richard Alley, Joe Fiacco, Pieter Grootes, Gregg Lamorey, Paul Andrew Mayewski, Mary Jo Spencer
Ice-Core Dating And Chemistry By Direct-Current Electrical Conductivity, Kenorick Taylor, Richard Alley, Joe Fiacco, Pieter Grootes, Gregg Lamorey, Paul Andrew Mayewski, Mary Jo Spencer
Earth Science Faculty Scholarship
Although quantitative interpretation of the low-frequency electrical conductivity of ice cores from central Greenland is complicated by temperature variations of the measured core, annual layers can be recognized in sections of the core that are not impacted by non-seasonal features. Ambiguities in counting of annual layers can be minimized by comparing the electrical conductivity measurements to measurements of dust concentration and visual stratigraphy. A non-linear relationship between applied voltage and the current measured across two electrodes complicates the quantitative comparison of measurements made with different equipment, but does not affect the overall shape of the observed features .
The Safe Drinking Water And Clean Water Acts: A Small Community View, Steve Levy
The Safe Drinking Water And Clean Water Acts: A Small Community View, Steve Levy
Maine Policy Review
The Safe Drinking Water Act of 1986 and the Clean Water Act Amendments of 1991 present significant financial and technical challenges to municipalities in Maine and other states as they struggle to meet compliance standards. Steve Levy, executive director of the Maine Rural Water Association, offers a view of the effects of these requirements on rural communities.
The Public Interest As Stewardship Of Natural Resources, Todd Burrowes
The Public Interest As Stewardship Of Natural Resources, Todd Burrowes
Maine Policy Review
No abstract provided.
The Safe Drinking Water And Clean Water Acts: A Large City View, Chris Branch
The Safe Drinking Water And Clean Water Acts: A Large City View, Chris Branch
Maine Policy Review
The Safe Drinking Water Act of 1986 and the Clean Water Act Amendments of 1991 present significant financial and technical challenges to municipalities in Maine and other states as they struggle to meet compliance standards. Chris Branch, public works director and city engineer for Lewiston, presents a large community perspective.