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Calcium hydroxide waters issue from four partly serpentinized Alpine-type ultramafic bodies in the western United States. The occurrence of calcium-hydroxide-type water is restricted to fresh Alpine-type ultramafic rocks. The calcium hydroxide waters are unsaturated with Mg end-member olivine and pyroxene but supersaturated with Mg end-member brucite and serpentine and thus...

The genesis of granitic igneous pegmatites is here considered in terms of a model conceived from results of field and laboratory studies and subsequently tested by means of experimental investigations. This model emphasizes the roles of water (and/or other relatively volatile substances), both as a dissolved constituent in granitic magmas...

The Mesozoic evolution of California is interpreted as dominated by the underflow of oceanic mantle beneath the continental margin. Underflow during part of Late Cretaceous time of more than 2000 km of the eastern Pacific plate seems required by the marine magnetic data. Correspondingly, varied oceanic environments—abyssal hill, island arc,...

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...

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 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 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...

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....

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...

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...

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...

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...

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...

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;...

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...

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...

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...

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...

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...

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...

[No abstract available]...

Olivine trachybasalt metamorphosed by nuclear explosion is classified into categories of progressive metamorphism: (i) Weak. Plagioclase is microfractured, and augite cotainis fine twin lamellae. (ii) Moderate. Plagioclase is converted to glass, and mafic minerals show intragranular deformation (undulatory extinction, twin lamellae, and, possibly, deformation lamellae), but rock texture is preserved....

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...

An investigation of the water resources of the Colorado part of the San Luis Valley was begun in 1966 by the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board. (See index map, fig. 1). The purpose of the investigation is to provide information for planning and implementing...

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°....