Merumite occurrence in Guyana
C. Milton, S Narain
1969, Economic Geology (64) 910-914
Merumite was discovered with associated diamonds and gold in 1937 in gravels of the Merume River in Guyana. It was described as essentially a hydrous chromium oxide that contains more than 80 percent Cr2Oa. Milton and Chao in 1958 found it to be a complex aggregate, mainly eskolaite (Cr2Oa) with...
Effect of rainfall variability on streamflow simulation
D.R. Dawdy, James M. Bergmann
1969, Water Resources Research (5) 958-966
Three recording rain gages in a 9.7‐square‐mile basin in southern California were used with a deterministic rainfall‐runoff model to simulate flood hydrographs and peaks and to assess the effects of data errors on simulation results. Bias in the estimation of effective basin rainfall seemed to result in curve fitting parameter...
The structure and tectonic history of the eastern Aleutian Trench
Roland E. von Huene, George G. Shor Jr.
1969, Geological Society of America Bulletin (80) 1889-1902
The tectonic character of the eastern Aleutian Trench and some major events in its geologic history can be estimated from nine continuous seismic reflection records. A section of pre-trench, deep oceanic sediments rests on the down-warped crust that forms the trench. Nearly horizontal undeformed strata that unconformably overlie this deep...
A geophysical study of North Park and the surrounding ranges, Colorado
John C. Behrendt, Peter Popenoe, Robert E. Mattick
1969, Geological Society of America Bulletin (80) 1523-1537
A geophysical study in the North Park basin and surrounding mountains, Colorado illustrates the structural relationship of various sedimentary, metamorphic, and igneous rock units. Bouguer anomalies from 1330 gravity stations range from −210 mgal over Precambrian metamorphic rocks in the mountains to −260 mgal in the Walden syncline and —280...
Distribution of scandium between coexisting biotite and hornblende in igneous rocks
Robert I. Tilling, L. Paul Greenland, D. Gottfried
1969, GSA Bulletin (80) 651-668
Scandium analyses of more than 90 pairs of coexisting biotite and hornblende from igneous rocks of various provinces (including Southern California, Boulder, Sierra Nevada, Boulder Creek batholiths and the Jemez Mountains volcanic rocks) indicate that the distribution ratio (Kd = Schornblende/Scbiotite) for most samples closely approached that of an equilibrium distribution....
Errors in using modern stream-load data to estimate natural rates of denudation
Robert H. Meade
1969, Geological Society of America Bulletin (80) 1265-1274
The practice of calculating natural rates of denudation from routinely collected data on the loads of suspended and dissolved matter in modern rivers is subject to several significant errors. The sources of these errors are demonstrated by examples from the Atlantic drainage of the United States, where their total effect...
Model for simulation of residual stress in rock
D. J. Varnes
1969, Conference Paper, Proceedings of the 11th U.S. Symposium on Rock Mechanics (USRMS)
Rocks in mines, quarries, and many outcrops commonly show evidence of being under high stress. Saw cuts and drillholes close in, partly mined coal bursts violently, and pillars crush and rock spalls in mines even at moderate depths. Similarly, strong and massive rocks such as granite and sandstone naturally divide...
Seismic-refraction measurements in Jackson Hole, Wyoming
B. L. Tibbetts, J. C. Behrendt, John David Love
1969, Geological Society of America Bulletin (80) 1109-1121
Three reversed seismic-refraction profiles were recorded in the Jackson Hole, Wyoming, area during July 1964. The seismic model which was developed consists of three layers with velocities of 2.4 km/sec for Tertiary and Cretaceous rocks above the Cleverly Formation (Lower Cretaceous), 3.8 km/sec for rocks from Lower Cretaceous down to...
New thrusts in ground water
C. L. McGuinness
1969, Groundwater (7) 7-10
Four principal trends in ground water are apparent:(1) Increasing use of ground water for domestic supplies. Geohydrologists must learn to quantitatively evaluate the supply under conditions of maximum development, not merely determine the availability of a supply that does not strain the aquifer. (2) Aquifers will be looked to increasingly...
Heat flow in the Arctic
Arthur H. Lachenbruch, B. Vaughan Marshall
1969, Arctic (22) 300-311
Defines heat flow as the flux at the earth's solid surface of heat conducted from the interior; the heat-flow-unit (hfu) is on the order of 1-millionth calorie through each sq cm of the surface/sec, which is enough to melt a 4-mm layer of ice over the earth's surface/yr. Earth heat...
Florida submergence curve revised: Its relation to coastal sedimentation rates
D.W. Scholl, F.C. Craighead Sr., M. Stuiver
1969, Science (163) 562-564
New data substantiate as well as modify the south Florida submergence curve, which indicates that eustatic sea level has risen continuously, although at a generally decreasing rate, during the last 6500 to 7000 sidereal years (5500 standard radiocarbon years) to reach its present position. Accumulation rates of coastal deposits are...
A seismic-refraction survey of crustal structure in central Arizona
David H. Warren
1969, Geological Society of America Bulletin (80) 257-282
The U.S. Geological Survey conducted a seismic-refraction study of the earth's crust and upper mantle near the Tonto Forest Seismological Observatory (TFO), located 10miles south of the Mogollon Rim near Payson in central Arizona. Two recording lines 400 km long intersect in the approximate form of a cross at TFO;...
Volcanic substructure inferred from dredge samples and ocean-bottom photographs, Hawaii
James G. Moore, Richard S. Fiske
1969, GSA Bulletin (80) 1191-1202
Ocean-bottom photographs from 18 stations and dredge hauls from 35 stations adjacent to the Island of Hawaii indicate that basaltic pillow lava and pillow fragments are the dominant rock type on the crest and flanks of the submarine rift zone ridges, whereas glassy basalt sand and scoria are the dominant...
Geology and regional metamorphism of some high-grade cordierite gneisses, Front Range, Colorado
Dolores J. Gable, Paul K. Sims
1969, Book
Cordierite is common in regional metamorphic gneisses of Precambrian age in the central part of the Front Range. It occurs in discontinuous stratigraphic units that are structurally a minor component, except locally, of the thick succession of biotite gneisses that comprise the widespread Idaho Springs Formation. The rocks have mineral...
History of the Redwall Limestone of northern Arizona
Edwin D. McKee, Raymond C. Gutschick
1969, Book
Throughout most of northern Arizona the Redwall Limestone of Mississippian age is readily divisible into four lithologic units, designated in ascending order as the Whitmore Wash, Thunder Springs, Mooney Falls, and Horseshoe Mesa Members. The first and third members are thick-bedded to massive carbonate rock. The Horseshoe Mesa Member is...
The linear decision rule in reservoir management and design: 1, Development of the stochastic model
Charles Revelle, Erhard Joeres, William H. Kirby
1969, Water Resources Research (5) 767-777
With the aid of a linear decision rule, reservoir management and design problems often can be formulated as easily solved linear programing problems. The linear decision rule specifies the release during any period of reservoir operation as the difference between the storage at the beginning of the period and a...
Modern coastal mangrove swamp stratigraphy and the ideal cyclothem
David W. Scholl
Edward C. Dapples, M. E. Hopkins, editor(s)
1969, Book chapter, Environments of coal deposition: Papers presented at a symposium by the coal geology division of the Geological Society of America at the annual meeting Miami Beach, Florida, 1964
The general stratigraphy of the “ideal” cyclothem of Late Paleozoic age can be recognized in a modern succession of sedimentary units underlying the coastal mangrove swamps of southwestern Florida. Because coal deposition is associated with the formation of cyclothems, this stratigraphic similarity has geologic importance with respect to coal formation.The...
Geologic Settings of Subsidence
Alice S. Allen
David J. Varnes, George Kiersch, editor(s)
1969, Book chapter, Reviews in Engineering Geology
This paper reviews the role of geologic processes that contribute to subsidence in order to aid those starting investigations of ground-surface subsidence. Subsidence occurs, or at least is discovered, only infrequently, and little organized information has been available. In order to assess our present state of knowledge, the author gathered...
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...
A paleomagnetic study of secular variation in New Zealand
A. Cox
1969, Earth and Planetary Science Letters (6) 257-267
Ancient secular variation in New Zealand was determined from paleomagnetic measurements on 22 volcanic formations with ages of less than 0.68 m.y. The angular standard deviation from the field of an axial dipole is 13.2° with 95% confidence limits between 10.9° and 16.7°....
The determination of the acoustic parameters of volcanic rocks from compressional velocity measurements
R. D. Carroll
1969, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts (6) 557-579
A statistical analysis was made of the relationship of various acoustic parameters of volcanic rocks to compressional wave velocities for data obtained in a volcanic region in Nevada. Some additional samples, chiefly granitic rocks, were also included in the study to extend the range of parameters and the variety of...
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...
On the global variations of terrestrial heat-flow
W.H.K. Lee
1969, Physics of the Earth and Planetary Interiors (2) 332-341
Over 3 500 measurements of surface heat-flux have been catalogued and analyzed to study the large-scale variations of terrestrial heat-flow. It was found that heat-flow values are correlated with major geologic provinces: higher averages and scattered values in active tectonic regions, and lower averages and more uniform values in stable...
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...
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...
