Morphologic interpretation of fertile structures in glossopterid gymnosperms
J.M. Schopf
1976, Review of Palaeobotany and Palynology (21) 25-64
The problem of determining affinity among glossopterid gymnosperms is beset by deficiencies in preservation, natural dissociation of parts, and scarcity of features assuredly critical for morphologic comprarison. The glossopterids probably are not a very heterogeneous group of plants, but this is difficult to prove. The Gondwana glacial "hiatus" has resulted...
Determination of lead in rocks by radiometric isotope dilution and substoichiometric extraction
Philip Aruscavage
1976, Analytica Chimica Acta (82) 343-348
A rapid procedure is described for the determination of lead in rocks by an isotope-dilution substoichiometric method. After the sample has been digested with acid in the presence of 210Pb tracer, the lead is separated by dithizone extractions. After the lead has been back-extracted into aqueous solution, it is reacted with...
Disharmony of the spheres: Recent trends in planetary surface nomenclature
R.J. Pike
1976, Icarus (27) 577-583
Inadvisable departures from tradition in naming newly mapped features on Mars, Mercury, and the Moon have been implemented and proposed since 1970. Functional need for place names also has become confused with cartographic convenience. Much of the resulting new nomenclature is neither unique, efficient, nor imaginative. The longstanding classical orientation...
Diamonds in an upper mantle peridotite nodule from kimberlite in southern wyoming
M. E. McCallum, D.H. Eggler
1976, Science (192) 253-256
Diamonds in a serpentinized garnet peridotite nodule from a diatreme in southern Wyoming are the first known occurrence in an upper mantle peridotite xenolith from a kimberlite intrusion in North America as well as the second authenticated occurrence of diamonds from kimberlite pipes in North America. The nodule is believed...
The zonal distribution of selected elements above the Kalamazoo porphyry copper deposit, San Manuel district, Pinal County, Arizona
M.A. Chaffee
1976, Journal of Geochemical Exploration (5) 145-165
There may be many as-yet-undiscovered porphyry copper deposits that exist as blind deposits deep within exposed rock bodies. The Kalamazoo porphyry copper-molybdenum deposit is a blind deposit present at depths up to at least 1,000 m (about 3,200 ft) that contains zoning features common to many of the known...
Distribution of small channels on the Martian surface
D. Pieri
1976, Icarus (27) 25-50
The distribution of small channels on Mars has been mapped from Mariner 9 images, at the 1:5 000 000 scale, by the author. The small channels referred to here are small valleys ranging in width from the resolution limit of the Mariner 9 wide-angle images (???1 km) to about 10...
The dissolution of calcite in CO2-saturated solutions at 25°C and 1 atmosphere total pressure
Niel Plummer, T.M.L. Wigley
1976, Geochimica et Cosmochimica Acta (40) 191-202
The dissolution of Iceland spar in CO2-saturated solutions at 25°C and 1 atm total pressure has been followed by measurement of pH as a function of time. Surface concentrations of reactant and product species have been calculated from bulk fluid data using mass transport theory and a model that accounts...
Instrumental activation analysis of coal and fly ash with thermal and epithermal neutrons and short-lived nuclides
E. Steinnes, J.J. Rowe
1976, Analytica Chimica Acta (87) 451-462
Instrumental neutron activation analysis is applied to the determination of about 25 elements in coals and fly ash by means of nuclides with half-lives of less than 48 h ; thermal and epithermal irradiations are used. The results indicate that epithermal activation is preferable for twelve of the elements (Ga,...
Rapid determination of nanogram amounts of tellurium in silicate rocks
L. P. Greenland, E.Y. Campbell
1976, Analytica Chimica Acta (87) 323-328
A hydride-generation flameless atomic-absorption technique is used to determine as little as 5 ng g-1 tellurium in 0.25 g of silicate rock. After acid decomposition of the sample, tellurium hydride is generated with sodium borohydride and the vapor passed directly to a resistance-heated quartz cell mounted in an atomic-absorption spectrophotometer. Analyses...
Progress in remote sensing (1972-1976)
W. A. Fischer, W. R. Hemphill, Allan Kover
1976, Photogrammetria (32) 33-72
This report concerns the progress in remote sensing during the period 1972–1976. Remote sensing has been variously defined but is basically the art or science of telling something about an object without touching it. During the past four years, the major research thrusts have been in three areas: (1) computer-assisted enhancement and...
Carbon, hydrogen, and oxygen isotope studies of the regional metamorphic complex at Naxos, Greece
R. O. Rye, R.D. Schuiling, D.M. Rye, J.B.H. Jansen
1976, Geochimica et Cosmochimica Acta (40) 1031-1049
At Naxos, Greece, a migmatite dome is surrounded by schists and marbles of decreasing metamorphic grade. Sillimanite, kyanite, biotite, chlorite, and glaucophane zones are recognized at successively greater distances from the migmatite dome. Quartz-muscovite and quartz-biotite oxygen isotope and mineralogie temperatures range from 350 to 700°C.The metamorphic complex can be...
The Anderson Reservoir seismic gap - Induced aseismicity?
C. G. Bufe
1976, Engineering Geology (10) 255-262
A persistent 10-km seismicity gap along the Calaveras fault appears to be related to the presence of the Leroy Anderson Reservoir in the Calaveras-Silver Creek fault zones southeast of San Jose, California. A magnitude-4.7 earthquake occurred at a depth of 5 km in the centre of the gap on October...
Tectonic implications of space-time patterns of Cenozoic magmatism in the western United States
W.S. Snyder, W.R. Dickinson, M.L. Silberman
1976, Earth and Planetary Science Letters (32) 91-106
Locations of 2,100 radiometrically dated igneous rocks were plotted on a series of 20 maps, each representing an interval within the period 80 m.y. B.P. to present. Derivative maps showing the distributions in space and time of dated granitic intrusive rocks, silicic lavas and domes, ash-flow tuffs, andesitic-dacitic rocks, and...
Mixing of carbonate waters
T.M.L. Wigley, Niel Plummer
1976, Geochimica et Cosmochimica Acta (40) 989-995
When mineral solutions of different compositions are mixed, the molalities and activities of individual ions in the mixture are often non-linear functions of their end-member values. This non-linearity is particularly significant in determining mineral saturation levels. Mixtures of saturated solutions may be either...
Extended cabfac and Qmodel computer programs for Q-mode factor analysis of compositional data
J.E. Klovan, A.T. Miesch
1976, Computers & Geosciences (1) 161-178
The computer program CABFAC for Q-mode factor analysis of geologic data has been extended for use with data having constant row-sums. Another program, QMODEL, reads an output file from CABFAC and can be used to develop a variety of Q-mode models. The models serve to reproduce estimates of the original...
Radar characteristics of Viking 1 landing sites
G.L. Tyler, D.B. Campbell, G.S. Downs, R.R. Green, H. J. Moore
1976, Science (193) 812-815
Radar observations of Mars at centimeter wavelengths in May, June, and July 1976 provided estimates of surface roughness and reflectivity in three potential landing areas for Viking 1. Surface roughness is characterized by the distribution of surface landing slopes or tilts on lateral scales of the order of 1 to...
Mineralogy of ash of some American coals: Variations with temperature and source
R.S. Mitchell, H.J. Gluskoter
1976, Fuel (55) 90-96
Ten samples of mineral-matter residue were obtained by the radio-frequency low-temperature ashing of subbituminous and bituminous coals. The low-temperature ash samples were then heated progressively from 400 °C to 1400 °C at 100 °C intervals. Mineral phases present at each temperature interval were determined by X-ray diffraction analyses. The minerals...
Identification of excess 40Ar by the 40Ar 39Ar, age spectrum technique
M. A. Lanphere, G. Brent Dalrymple
1976, Earth and Planetary Science Letters (32) 141-148
40Ar/39Ar incremental heating experiments on igneous plagioclase, biotite, and pyroxene that contain known amounts of excess40Ar indicate that saddle-shaped age spectra are diagnostic of excess40Ar in igneous minerals as well as in igneous rocks. The minima in the age spectra approach but...
Intrinsic germanium detector used in borehole sonde for uranium exploration
F. E. Senftle, R.M. Moxham, A.B. Tanner, G. R. Boynton, P. W. Philbin, J.A. Baicker
1976, Nuclear Instruments and Methods (138) 371-380
A borehole sonde (~1.7 m long; 7.3 cm diameter) using a 200 mm2 planar intrinsic germanium detector, mounted in a cryostat cooled by removable canisters of frozen propane, has been constructed and tested. The sonde is especially useful in measuring X- and low-energy gamma-ray spectra (40–400 keV). Laboratory tests in...
Automation in photogrammetry: Recent developments and applications (1972-1976)
M.M. Thompson, E.M. Mikhail
1976, Photogrammetria (32) 111-145
An overview of recent developments in the automation of photogrammetry in various countries is presented. Conclusions regarding automated photogrammetry reached at the 1972 Congress in Ottawa are reviewed first as a background for examining the developments of 1972-1976. Applications are described for each country reporting significant developments. Among fifteen conclusions...
Qal’eh hasan ali maars, central Iran
D.J. Milton
1976, Bulletin Volcanologique (40) 201-208
A group of craters 120 km southeast of Kerman, the largest 1200 m across and 300 m deep, are typical maars, excavated depression with rims of bedded pyroclastic debris. Most of the crater rims are composed entirely of country rock clasts, but the largest crater yields tephrite, composed of phenocrysts...
The Viking landing sites: Selection and certification
H. Masursky, N.L. Crabill
1976, Science (193) 809-812
During the past several years the Viking project developed plans to use Viking orbiter instruments and Earth-based radar to certify the suitability of the landing sites selected as the safest and most scientifically rewarding using Mariner 9 data. During June and July 1976, the Earth-based radar and orbital spacecraft observations...
Discovery of natural resources
P. W. Guild
1976, Science (191) 708-713
Mankind will continue to need ores of more or less the types and grades used today to supply its needs for new mineral raw materials, at least until fusion or some other relatively cheap, inexhaustible energy source is developed. Most deposits being mined today were exposed at the surface or...
Dinoflagellates: Fossil motile-stage tests from the upper cretaceous of the Northern New Jersey coastal plain
F.E. May
1976, Science (193) 1128-1130
Fossil dinoflagellate tests have been considered to represent encysted, nonmotile stages. The discovery of flagellar porelike structures and probable trichocyst pores in the Upper Cretaceous genus Dinogymnium suggests that motile stage tests are also preserved as acid-resistant, organic-walled microfossils....
Turbidity distribution in the Atlantic Ocean
Stephen Eittreim, E. M. Thorndike, L. Sullivan
1976, Deep-Sea Research and Oceanographic Abstracts (23) 1115-1127
The regional coverage of Lamont nephelometer data in the North and South Atlantic can be used to map seawater turbidity at all depths. At the level of the clearest water, in the mid-depth regions, the turbidity distribution primarily reflects the pattern of productivity in the surface waters. This suggests that...
