Lithium and potassium absorption, dehydroxylation temperature, and structural water content of aluminous smectites
Leonard Gene Schultz
1969, Clays and Clay Minerals (17) 115-149
X-ray analysis of Li+- and K+-saturated samples, differential thermal analysis (DTA), thermal gravimetric analysis (TGA), and chemical analysis of 83 samples enable a distinction to be made between Wyoming, Tatatilla, Otay, Chambers, and non-ideal types of montmorillonite, and between ideal and non-ideal types of beidellite. The Greene-Kelly Li+-test differentiates between...
Uranium, thorium, and lead systematics in Granite Mountains, Wyoming
J.N. Rosholt, A.J. Bartel
1969, Earth and Planetary Science Letters (7) 141-147
Uranium, thorium and lead concentrations and isotopic compositions were determined on total rocks and a feldspar sample from widely separated parts of the Granite Mountains in central Wyoming. Linear relations defined by206Pb/204Pb −207Pb/204Pb and208Pb/204Pb −232Th/204Pb for the total rock samples define 2.8...
High-pressure mechanical instability in rocks
J.D. Byerlee, W.F. Brace
1969, Science (164) 713-715
At a confining pressure of a few kilobars, deformation of many sedimentary rocks, altered mafic rocks, porous volcanic rocks, and sand is ductile, in that instabilities leading to audible elastic shocks are absent. At pressures of 7 to 10 kilobars, however, unstable faulting and stick-slip in certain of these rocks...
Lead isotopes in volcanic rocks and possible ocean-floor thrusting beneath island arcs
M. Tatsumoto
1969, Earth and Planetary Science Letters (6) 369-376
The isotopic composition of lead in the Japanese primary basalts gradually decreases in radiogenic character in a transverse from the Pacific Ocean side to the Japan Sea side, whereas the observed 238U204Pb">238U204Pb and 232Th204Pb">232Th204Pb ratios...
Thermochemical study of the system Fe-As-S
P. B. Barton Jr.
1969, Geochimica et Cosmochimica Acta (33) 841-857
The results of Toulmin and Barton (1964) for the Fe-S system have been combined with a series of new measurements on As-bearing assemblages in the 500°–850°C temperature range to derive data on the free energies, enthalpies, and entropies of formation for arsenopyrite, loellingite, orpiment, realgar,...
Alpine-type sensu strictu(ophiolitic) peridotites: Refractory residues from partial melting or igneous sediments? A contribution to the discussion of the paper: "The origin of ultramafic and ultrabasic rocks" by P.J. Wyllie
T. P. Thayer
1969, Tectonophysics (7) 511-516
Although Alpine peridotites and basaltic lavas are widely associated in eugeosynclines and oceanic areas, their genetic ties are obscure. Three major characteristics of olivine-rich Alpine peridotite and dunite—relict cumulus textures, aggregated masses of chromitite, and intimate association with magnesium-rich gabbro — cannot be...
Ion association in natural brines
A.H. Truesdell, B.F. Jones
1969, Chemical Geology (4) 51-62
Natural brines, both surface and subsurface, are highly associated aqueous solutions. Ion complexes in brines may be ion pairs in which the cation remains fully hydrated and the bond between the ions is essentially electrostatic, or coordination complexes in which one or more of the hydration water molecules are...
The isotopic composition of lead in potassium feldspars from some 1.0-b.y. old North American igneous rocks
R. E. Zartman, G.J. Wasserburg
1969, Geochimica et Cosmochimica Acta (33) 901-942
The isotopic composition of lead and the uranium, thorium and lead concentrations in potassium feldspars are determined for more than 30 1.0-b.y. old North American igneous rocks. Samples representing a broad spectrum in petrographic type and mode of occurrence were chosen; an effort was made to include only rocks having...
Methane-derived marine carbonates of pleistocene age
J.C. Hathaway, E.T. Degens
1969, Science (165) 690-692
In some calcium carbonate-bearing sandstones from the edge of the continental shelf off the northeast United States, the δC13 range is from -30 and...
Phosphorus fractionation diagram as a quantitative indicator of crystallization differentiation of basaltic liquids
A. T. Anderson, L. P. Greenland
1969, Geochimica et Cosmochimica Acta (33) 493-505
Distribution factors of phosphorus (P in mineral/P in liquid) between phenocryst minerals and coexisting basaltic groundmass are: olivine (Fa20: 0.04 to 0.02; orthopyroxene (Fs20): 0.01; augite: 0.02 to 0.01; plagioclase: 0.02; ilmenite: 0.04. Because of the smallness of these distribution factors the ratio of phosphorus in the initial liquid to...
Ellsworth mountains: Position in West Antarctica due to sea-floor spreading
J.M. Schopf
1969, Science (164) 63-66
Similarities of middle and upper Paleozoic deposits of the Ellsworth Mountains with those of the Pensacola, Horlick, and other Transantarctic mountains indicate that all these ranges may have had a related geologic history. A tentative explanation is now suggested which involves sea-floor spreading and translocation of the Ellsworth crustal block...
Surface area of vermiculite with nitrogen and carbon dioxide as adsorbates
Josephus Thomas Jr., Bruce F. Bohor
1969, Clays and Clay Minerals (17) 205-209
Surface-area studies were made on several homoionic vermiculites with both nitrogen and carbon dioxide as adsorbates. These studies show that only very slight penetration occurs between individual vermiculite platelets. This is in contrast to an earlier investigation of montmorillonite where it was found that the degree of penetration between layers...
Geochemistry and hydrodynamics of the Paradox Basin region, Utah, Colorado and New Mexico
B.B. Hanshaw, G.A. Hill
1969, Chemical Geology (4) 263-294
The Paradox Basin region is approximately bounded by the south flank of the Uinta Basin to the north, the Uncompahgre uplift and San Juan Mountains to the east, the Four Corners structural platform to the southeast, the north rim of the Black Mesa Basin and the Grand Canyon to...
Anorthosite belts, continental drift, and the anorthosite event
N. Herz
1969, Science (164) 944-947
Most anorthosites lie in two principal belts when plotted on a predrift continental reconstruction. Anorthosite ages in the belts cluster around 1300 ±...
Seismic activity and faulting associated with a large underground nuclear explosion
R. M. Hamilton, F. A. McKeown, J. H. Healy
1969, Science (166) 601-604
The 1.1-megaton nuclear test Benham caused movement on previously mapped faults and was followed by a sequence of small earthquakes. These effects were confined to a zone extending not more than 13 kilometers from ground zero; they are apparently related to the release of natural tectonic strain....
Heat flow measurements on the southeast coast of Australia
R.D. Hyndman, J.C. Jaeger, J.H. Sass
1969, Earth and Planetary Science Letters (7) 12-16
Three boreholes have been drilled for the Australian National University near the southeast coast of New South Wales, Australia. The heat flows found are 1.1, 1.0, and 1.3 μcal/cm2sec. The errors resulting from the proximity of the sea and a lake, surface...
Lherzolite, anorthosite, gabbro, and basalt dredged from the Mid-Indian Ocean Ridge
C.G. Engel, R.L. Fisher
1969, Science (166) 1136-1141
The Central Indian Ridge is mantled with flows of low-potassium basalt of uniform composition. Gabbro, anorthosite, and garnet-bearing lherzolite are exposed in cross fractures, and lherzolite is the bedrock at the center of the ridge. The lherzolites are upper-mantle rock exposed by faulting....
40Ar/36Ar analyses of historic lava flows
G. B. Dalrymple
1969, Earth and Planetary Science Letters (6) 47-55
The ratio40Ar/36Ar was measured for 26 subaerial historic lava flows. Approximately one-third of the samples had40Ar/36Ar ratios either higher or lower than the atmospheric value of 295.5 at the 95% confidence level. Excess radiogenic40Ar in five flows ranged from about 1 ×...
Pyrolysis of humic and fulvic acids
R.L. Wershaw, G.E. Bohner Jr.
1969, Geochimica et Cosmochimica Acta (33) 757-762
Pyrolysis of humic and fulvic acids isolated from a North Carolina soil yields a variety of aromatic, heterocyclic and straight chain organ compounds. The pyrolysis products identified by gas chromatography and mass spectrometry indicate that humic and fulvic acids have aromatic and polysaccharide...
Cliftonite: A proposed origin, and its bearing on the origin of diamonds in meteorites
R. Brett, G.T. Higgins
1969, Geochimica et Cosmochimica Acta (33)
Cliftonite, a polycrystalline aggregate of graphite with spherulitic structure and cubic morphology, is known in 14 meteorites. Some workers have considered it to be a pseudomorph after diamond, and have used the proposed diamond ancestry as evidence of a meteoritic parent body of at least lunar dimensions. Careful examination of...
Geologic structure between the Murray fracture zone and the Transverse Ranges
Roland E. von Huene
1969, Marine Geology (7)
The Murray fracture has been thought to extend ashore into the Transverse Ranges of California, but a geophysical study shows no evidence of structural continuity between these features. Instead, basement morphology typical of the Murray fracture zone ends where its known magnetic and...
Blueschist-facies metamorphism related to regional thrust faulting
M.C. Blake Jr., W. P. Irwin, R. G. Coleman
1969, Tectonophysics (8) 237-246
Rocks of the blueschist (glaucophane schist) facies occur throughout the world in narrow tectonic belts associated with ultramafic rocks. In the Coast Range province of California, blueschist rocks are devloped in the eugeosynclinal Franciscan Formation of Late Mesozoic age. The blueschist rocks form a narrow belt for more than 800...
Melting relations in the Fe-rich portion of the system FeFeS at 30 kb pressure
R. Brett, P.M. Bell
1969, Earth and Planetary Science Letters (6) 479-482
The melting relations of FeFeS mixtures covering the composition range from Fe to Fe67S33 have been determined at 30 kb pressure. The phase relations are similar to those at low pressure. The eutectic has a composition of Fe72.9S27.1 and a temperature of 990°C. Solubility...
New method for preparing ultrapure hydrofluoric acid
Mitsunobu Tatsumoto
1969, Analytical Chemistry (41) 2088-2089
No abstract available....
Cycads: Fossil evidence of late paleozoic origin
S.H. Mamay
1969, Science (164) 295-296
Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications of...
