Effects of karst features on circulation of water in carbonate rocks in coastal areas
V. T. Stringfield, H. E. LeGrand
1971, Journal of Hydrology (14) 139-157
The normal balance between fresh water in coastal aquifers and sea water applies also to carbonate-rock aquifers that have been karstified, but there are local modifications in the balance that need to be considered. Uneven distribution of permeability, expressed by a network of...
A method for discriminating between biogenic and chemical origins of the ore-stage pyrite in a roll-type uranium deposit
C. G. Warren
1971, Economic Geology (66) 919-928
Some roll-type uranium deposits are marginal to an altered tongue in sandstone beds that originally contained more-or-less uniformly distributed pyrite. Mineralizing solutions percolated through the sandstone, oxidized nearly all the pre-existing pyrite, and then redeposited part of the pyrite downstream in an embryonic ore zone....
The effect of salinity on the maximum thermal gradient of a hydrothermal system at hydrostatic pressure
John L. Haas Jr.
1971, Economic Geology (66) 940-946
The effect of salinity on the temperature-depth relations of a brine of constant composition, enclosed in a vein system, but freely connected to the surface, and everywhere at the boiling point for the hydrostatic head, was calculated by using a mathematical model. The Na-Ca-K-Cl brines...
Geochemical interpretations of groundwater flow systems
William Back, Bruce B. Hanshaw
1971, Journal of the American Water Resources Association (7) 1008-1016
Interest in the geochemistry of groundwater is increasing owing to the great number of current projects involving underground liquid waste storage, artificial recharge of potable water, accidental contamination of groundwater bodies, sanitary landfills, and pollution monitoring. Geochemical techniques used to facilitate the understanding of a groundwater...
Investigation of magnetization and density of a north Atlantic seamount using Poisson's theorem
Lindrith Cordell, Patrick Taylor
1971, Geophysics (36) 919-937
The relationship between the gravitational and magnetic potentials caused by a uniform distribution of mass and magnetization may be used to obtain independent information about these physical properties. The general relationship in the frequency domain between the Fourier transforms of the gravity and magnetic anomaly...
Tertiary limestone aquifer system in the southeastern states
H. E. LeGrand, V. T. Stringfield
1971, Economic Geology (66) 701-709
The hydrogeologic history of the Tertiary limestone system of the Southeastern States is reconstructed, especially as it relates to circulation of ground water and the development of solution cavities. The development of these solution cavities resembles in many respects the development of cavities in carbonates...
A geochemical hypothesis for dolomitization by ground water
B.B. Hanshaw, W. Back, R.G. Deike
1971, Economic Geology (66) 710-724
Most modern disordered dolomite has been found in dynamic environments. However, solutions associated with modern dolomite formation do not have a common Mg/Ca ratio; the ratio ranges from about 3 to 100. Ground-water circulation may have a significant role in formation of regional dolomites; one of the primary requirements for...
Models of mineralized solution-collapse structures from drilling statistics: An aid to exploration
H. Wedow Jr.
1971, Economic Geology (66) 770-776
Variations in thickness and metal content of selected stratigraphic units cut by drill holes in the East Tennessee zinc districts have been analyzed by regression techniques. Such analysis demonstrated that as the thickness of an underlying limestone unit is decreased chiefly by solution thinning, overlying fine-grained dolomite units increase in...
Fluid-inclusion evidence on the environment of formation of mineral deposits of the southern Appalachian valley
Edwin Roedder
1971, Economic Geology (66) 777-791
Approximately 1,330 fluid inclusions were studied in samples of ore and gangue minerals from both massive ore and late-stage vugs from a series of Appalachian deposits and five active mines in the East Tennessee zinc districts. Most primary inclusions in sphalerite, fluorite, dolomite, and quartz...
Ore fluids in the porphyry copper deposit at Copper Canyon, Nevada
J. Thomas Nash, Ted G. Theodore
1971, Economic Geology (66) 385-399
The large, low-grade copper and gold deposit at Copper Canyon, Lander County, Nevada, formed in the contact metasomatic environment adjacent to a shallow Tertiary intrusion. Vein and disseminated chalcopyrite-pyrite-pyrrhotite-arsenopyrite mineralization, with lesser amounts of gold, galena, sphalerite, marcasite, and siderite occur in the Upper Cambrian...
Radiometric age (Late Ordovician) of the Quincy, Cape Ann, and Peabody Granites from eastern Massachusetts
Robert E. Zartman, Richard F. Marvin
1971, Bulletin of the Geological Society of America (82) 937-957
A geochronologic study of several intrusive bodies of alkalic granite from eastern Massachusetts yields the following radiometric ages (in millions of years).Rock unitAmphibole K-ArWhole-rock Rb-Sr isochron ...
Petrologic and geophysical nature of serpentinites
Robert G. Coleman
1971, Bulletin of the Geological Society of America (82) 897-917
Mineralogically, serpentinites consist predominantly of lizardite, clinochrysotile, and antigorite. Recent work has shown that these minerals are not polymorphs. Chrysotile is the only mineral recognized as a synthetic product in experimental studies of the system MgO-SiO2-H2O. Antigorite seems to be stable at higher temperatures than lizardite or chrysotile. The density...
Basin and range structure: A system of horsts and grabens produced by deep-seated extension
John H. Stewart
1971, Bulletin of the Geological Society of America (82) 1019-1043
Basin and Range structure can be interpreted as a system of horsts and grabens produced by the fragmentation of a crustal slab above a plastically extending substratum. According to this view, the extension...
A shortcut for computing stream depletion by wells using analog or digital models
O. James Taylor
1971, Groundwater (9) 9-11
Theory indicates that the effect of a discharging well on a nearby stream is independent of the length of the reach. The theory was confirmed using a digital computer model of short and long reaches of a stream-aquifer system. Digital computations using short reaches of most...
Data file, Continental Margin Program, Atlantic Coast of the United States: vol. 2 sample collection and analytical data
John C. Hathaway
1971, Report
The purpose of the data file presented below is twofold: the first purpose is to make available in printed form the basic data relating to the samples collected as part of the joint U.S. Geological Survey - Woods Hole Oceanographic Institution program of study of the Atlantic continental margin...
A paleohydrologic model for mineralization of the White Pine copper deposit, northern Michigan
Walter S. White
1971, Economic Geology (66) 1-13
Pertinent physical properties of the upper Keweenawan rocks can be measured or inferred within a sufficiently narrow range to make the quantitative evaluation of various paleohydrologic models for the origin of the White Pine copper deposit feasible. The approach is illustrated here by calculations for...
Coronadite — Modes of occurrence and origin
D. F. Hewett
1971, Economic Geology (66) 164-177
The lead manganate, "coronadite," was first recognized at the Coronado mine in the Morenci district, Arizona, by Lindgren in 1903. Several years later, the identity of the mineral was questioned and it was not until 1932 that Orcel recognized it in material from Morocco. Since...
An evaluation of procedures used in computing chemical denudation rates
Richard J. Janda
1971, Bulletin of the Geological Society of America (82) 67-79
Computations of chemical denudation rates (that is, the average rate of lowering of the earth's crust by chemical processes) should be based only upon those components of dissolved loads of streams that are derived from chemical weathering of rocks and soils, even though identification of those components is difficult and...
Thin skin distension in Tertiary rocks of southeastern Nevada
R. Ernest Anderson
1971, Bulletin of the Geological Society of America (82) 43-58
Volcanic rocks of late Tertiary age, aggregating about 17,000 ft, accumulated on a surface of low relief cut on Precambrian rocks in the Basin and Range province south of Lake Mead, in Nevada and Arizona. They consist mostly of lava and flow breccia of intermediate composition with minor ash-flow tuff,...
A comment concerning the applicability of the “open system” model to dating of fossil bones from San Joaquin soil, California
Barney J. Szabo
1971, Earth and Planetary Science Letters (10) 252-252
No abstract available....
Genetic implications of the shapes of martian and lunar craters
R.J. Pike
1971, Icarus (15) 384-395
Craters on Mars and the Moon are alike in that larger craters differ in shape from smaller ones, and older craters differ in shape from younger ones. Smoothed depth-diameter curves for 41 large martian craters photographed by Mariner IV inflect at a crater...
Kaersutite - A product of reaction between pargasite and basanite at Dish Hill, California
H. G. Wilshire, L. C. Calk, E.C. Schwarzman
1971, Earth and Planetary Science Letters (10) 281-284
Paragasitic amphibole, occurring interstitially and as veins in peridotite inclusions in basanite, has reacted with the host basanite to form kaersutitic amphibole. The amphibole compositions vary with respect to distance from the edge of the xenolith; iron, titanium, and potassium contents are...
Population biology of lake trout (Salvelinus namaycush) of Lake Superior before 1950
Gary T. Sakagawa, Richard L. Pycha
1971, Journal of the Fisheries Research Board of Canada (28) 65-71
Scale samples collected in 1948 were used to estimate the instantaneous total mortality rate (0.70) and growth for lake trout (Salvelinus namaycush) in Lake Superior before the population had been significantly reduced by the sea lamprey (Petromyzon marinus). Indirect evidence indicates that the instantaneous natural mortality rate was probably 0.10–0.25....
Effects of temperature on electrolyte balance and osmoregulation of the alewife (Alosa pseudoharengus) in fresh and sea water
Jon G. Stanley, Peter J. Colby
1971, Transactions of the American Fisheries Society (100) 624-638
A study of the effects of temperature and salinity on ionoregulation in the alewife, Alosa pseudoharengus, revealed that concentrations of sodium, potassium, and calcium in plasma and muscle were similar in fish adapted to fresh water and those adapted to sea water. The non-stressed alewife is apparently an excellent...
Aeromagnetic study of the midcontinent gravity high of central United States
Elizabeth R. King, Isidore Zietz
1971, Geological Society of America Bulletin (82) 2187-2208
A composite map of detailed aeromagnetic surveys over the midcontinent gravity high provides coverage of the 600-mi-long buried belt of mafic rocks of the Keweenawan Series from their outcrop localities in Minnesota and Wisconsin through Iowa and Nebraska. A map of the subsurface extent of the mafic rocks, based on...
