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Welded rhyolitic tuffs in southeastern Idaho

Rocks of rhyolitic type in eastern Idaho and adjacent parts of Wyoming were observed by the Teton Division of the Hayden Surveys under Orestes St. John (Report of the geological field work of the Teton Division, U.S. Geol. and Geog. Surv. Terr., 11th Ann. Rep., pp. 498–504, 1879), who described them as trachytes. He noted their relations to different types of underlying sedimentary rocks and their tendency to conform with the preexisting topography, but considered them all as flows. ©1935. American Geophysical Union. All Rights Reserved.

Idaho

Thrust faults and related structures in eastern Cuba

Detailed areal mapping in central Camagüey Province and reconnaissance mapping in northern and eastern Oriente Province, Cuba, have revealed two major structural zones: (1) A zone of intense deformation, including thrust faulting, which lies north of the geographic axis of the island; and (2) a belt of domical mountains bounded on the north by Nipe Bay and the coast, and on the south by the Cauto trough and Guantilnamo basin. In Camagüey, extensive masses of serpentine and overlying tuffs have been complexly folded and overridden from the north by a block, at least 25 miles long, of limestones that form the Sierra de Cubitas and Sierra de Camaján. The overthrust carried a northern fades of Cretaceous and Eocene limestones over a southern fades of tuffaceous rocks of similar age, and had a displacement of at least six miles. In places serpentine was thrust over younger formations, and most of the shearing in the serpentine is attributed to diastrophism. A thrust zone exposed in Loma La Vigía, 15 miles north of Holguín, suggests a similar tectonic history for northern Oriente Province. Chaotic giant breccias that include waterlaid debris indicate that the overthrusts moved across the ancient land surface in both Camagüey and Oriente districts. The folding apparently began in the Cretaceous and culminated in overthrusting during early middle Eocene time. Post‐Eocene deformation appears to be limited to warping or doming to maximum angles of about 20 degrees. The zone of domical mountains is somewhat more than 100 miles long from east to west by 25 to 30 miles wide, and comprises three main units: (1) the Sierra de Nipe and (2) Sierra del Cristal domes, principally of serpentine; and (3) the Cuchillas uplift, which includes the Cuchillas de Toar and Sierra de Purlal, composed of serpentine and pre‐serpentine rocks. These uplifts are overlapped progressively on all sides by sediments ranging in age from Upper Cretaceous to Oligocene and Miocene, the older beds in places being highly folded. The mountains owe their present relief of 2000 to 4000 feet to the doming of an extensive erosion surface in the late Pliocene or early Pleistocene. The north and east flanks of the Cuchillas uplift extend below sea level, and drowned streams and elevated coral reefs show regional instability since the last major doming. ©1947. American Geophysical Union. All Rights Reserved.

Eos, Transactions, American Geophysical Union

Magnetic studies by the Geophysical Section of the United States Geological Survey

Continued progress has been made in magnetic surveys over large sectional areas by G. R. MacCarthy. Beginning in Florida south of the Okeefenokee Swamp, magnetic traverses were measured and continued through the southern part of Georgia. The most northerly traverses crossed regions where they contacted the crystallines near the surface of the ground. All traverses were run in an east‐west direction. It is planned to continue the magnetic relief‐map described in the Transactions of 1939 of the American Geophysical Union by adding to it this portion of the State of Georgia.

Eos, Transactions, American Geophysical Union

Submarine geology and topography in the Northern Marshalls

The atomic bomb tests at Bikini in 1946 provided an opportunity to study the characteristics of atolls using modern surveying techniques. The work has shown that many of the important features, both above and below sea level, are definitely related to the direction of the prevailing winds, waves, and currents. Beyond the windward (north and east) reefs of Bikini, the steep outer slope is broken in most places by a terrace at ten fathoms. The margin of the windward reef is a Lithothamnion ridge, cut by strong grooves or surge channels; large islands are developed on these reefs. Lee reefs have nearly vertical outer slopes near the surface; their margins are smooth and are adapted to light surf; occasional storms have eroded large slump areas; and islands are small and few. Passes are largely confined to the southern reefs. The lagoons studied are 25 to 35 fathoms deep and are bordered by a ten‐fathom terrace. The floors are covered with living Halimeda and algal debris surrounded by a belt of foraminiferal and coral sand. Steep coral knolls, some rising nearly to sea level, are scattered in the lagoons. Many flat‐topped seamounts are present in the area. The 14 that were well surveyed rise from 2500 fathoms to depths between 470 and 850 fathoms. ©1949. American Geophysical Union. All Rights Reserved.

Eos, Transactions, American Geophysical Union

The problem of groundwater discharge into the seas

Introductory Note: The dynamic equilibrium of the various factors involved in the world water balance or budget is the central scientific problem of the International Hydrological Decade. One of the potentially vital elements of the balance is groundwater discharge to the oceans. To paraphrase the authors of the following Russian publication, the world water budget can't be properly balanced, statically or dynamically, until there are improved values for the amount of groundwater that is discharged directly to oceans, seas, and enclosed lakes. The following report, with its bibliography, presents some Russian approaches to the problem and provides a few bits of numerical information. The report was translated by Frank W. Trainer of the U.S. Geological Survey. The text has been slightly reduced in the interests of saving space but the bibliography is given in full and has been transcribed into more or less standard U.S. Geological Survey bibliographical style. ©1971. American Geophysical Union. All Rights Reserved.

Eos, Transactions, American Geophysical Union

Preliminary report on the North Atlantic deep‐sea cores taken by the Geophysical Laboratory, Carnegie Institution

A series, of 11 cores from the North Atlantic sea‐bottom between the Newfoundland Banks and the banks off the Irish Coast have been studied by a group of geologists of the United States Geological Survey. These cores were taken by Dr. C. S. Piggot of the Carnegie Institution's Geophysical Laboratory from the cable ship Lord Kelvin with the explosive type of sounding‐apparatus, which he designed (C. S. Piggot, Apparatus to secure core‐samples from the oceanbottom, Bull. Geol. Soc. Amer., v. 47, pp. 675–684, 1936). This preliminary report is based largely on the results obtained by M. N. Bramlette, who studied the lithology, and Jos. A. Cushman, who studied the forarainifera. The geographic position, the depth of water at each station, and the length of core obtained are given in Table 1. ©1937. American Geophysical Union. All Rights Reserved.

Newfoundland and Labrador

Investigations at active volcanoes

The field of volcanology has expanded greatly in the years 1967–1970, and work on active volcanoes has kept pace with this expansion. I have restricted this summary and the accompanying bibliography to studies by U.S.‐based investigators of active or potentially active volcanoes. I have been immeasurably aided in writing this summary by communications from R. Citron of the Smithsonian Institution Center for Short‐Lived Phenomena, W. Melson and T. Simkin of the Smithsonian Institution, A. McBirney of the Center for Volcanology, University of Oregon, R.B. Forbes of the University of Alaska, and R.W. Decker of Dartmouth College.

Eos, Transactions, American Geophysical Union

The value of geophysical methods in ground‐water studies

Two meanings are unfortunately given to the term geophysics. In the broad sense, based on the etymology of the term, geophysics means the physics of the Earth. This is its significance in the names “Geophysical Laboratory of the Carnegie Institution of Washington,” “International Union of Geodesy and Geophysics,” and “American Geophysical Union.” In this sense the sciences of geology and hydrology are largely geophysics, although in part they are geochemistry or biology. Geologists and hydraulic engineers who are elected to membership in the American Geophysical Union are, however, often surprised to find that they are regarded as “geophysicists.” I hope that when the Union establisnes a journal, its name will include the expression “Earth physics” or “Physics of the Earth,” in order that there will be no misunderstanding as to its scope.

Eos, Transactions, American Geophysical Union

Report of the committee on chemistry of natural waters, 1936–37

The membership of this Committee is as follows: C. S. Howard, Chairman, U. S. Geological Survey, Washington, D.C. D. G. Thompson, U. S. Geological Survey, Washington, D.C. A. C. Lane, 22 Arlington Street, Cambridge, Massachusetts C. S. Scofield, Bureau of Plant Industry, U. S. Dept. Agri., Washington, D. C. I. A. Denison, U.S. Bureau of Standards, Washington, D.C. T. G. Thompson, University of Washington, Seattle, Washington W. P. Kelley, Citrus Experiment Station, Riverside, California In order to provide for close cooperation between the work of the different research‐committees of the American Geophysical Union it was decided to have the chairmen of certain committees serve on other committees. The Chairman of the Committee on the Chemistry of Natural Waters is serving on the Committee of Underground waters and D. G. Thompson as Chairman of the Committee on Underground Waters is serving on the Committee on Chemistry of Natural Waters

Eos, Transactions, American Geophysical Union

Appendix B—investigations of underground‐water problems in California, New Mexico, and Oregon

Investigations by the California Department of Public Works, Division of Water Resources (based on written communication from Harold Conkling, Deputy State Engineer)—the Division of Water Resources, California Department of Public Works, has in the past year conducted investigations of ground‐water problems in the great central valley of the State (California Trough); in the Salinas and Santa Clara Valleys of the central part of the State; also in the South Coastal Basin and in Ventura County, in southern California. In these investigations the Bureau of Agricultural Engineering of the United States Department of Agriculture, the Geological Survey of the United States Department of the Interior, and many local agencies have cooperated. In large part, the activities of the past year are continuations of investigations summarized in an earlier statement (A. M. Piper, Investigations of underground‐water problems in Arizona, California, New Mexico, and Oregon, National Research Council, Trans. Amer. Geophys. Union, 13th annual meeting, 308–309, 1932). Progress in 1932–35 is summarized in the following paragraphs.

California, New Mexico, Oregon

On glaciers

The changes in the sizes of glaciers has for long attracted the attention of glacialists on account of the scientific interest and the development of water‐power from the streams issuing from the glaciers. The International Congress of Geologists, at its Zurich meeting in 1894, appointed a committee, with members from many countries, to collect and publish information bearing on this subject. Annual reports were published in the Archives des Sciences , Geneva, from 1896 to 1906, after which they appeared in the Zeitschrift für Gletscherkunde until the war. It was not until the Prague meeting of the International Union of Geodesy and Geophysics in 1927 that a new Commission des Glaciers was appointed, which is about to resume publication.

Eos, Transactions, American Geophysical Union

Committee on underground waters, 1939–40

The Committee on Underground Waters for the new triennium is composed of the following: H. F. Blaney; E. B. Burwell; W. Gardner; C. S. Howard; F. H. Lahee; G. W. Musgrave; A. M. Piper; A. C. Swinnerton; L. K. Wenzel; D. G. Thompson (Chairman). The outstanding event of the year for ground‐water hydrologists was the meeting of the International Association of Scientific Hydrology, as a part of the International Union of Geodesy and Geophysics, at Washington, D.C., in September, 1939. One day was devoted to “questions” or topics of symposia of the Commission on Subterranean Water.

Eos, Transactions, American Geophysical Union

The evaluation of magnetic anomalies by means of scales

At the 1939 meeting of the Union [Fundamental research in geophysics relating to prospecting, Trans. Amer. Geophys. Union, 1939, pp. 302 and 390], the writer described a set of scales for aiding in the evaluation of the magnetic anomaly due to a selected magnetized body. During the past year, these scales have been modified in several minor details. The revised forms are shown by typical scales illustrated in Figure 1.

Eos, Transactions, American Geophysical Union

Further tests of permeability with low hydraulic gradients

Many of the water‐bearing formations in the United States have hydraulic gradients of much less than 20 feet to the mile, and some may have gradients of less than one foot to the mile, whereas most laboratory‐ tests of permeability are made with much higher gradients . An investigation was therefore undertaken by the writer, under the direction of 0. E. Meinzer, in the Hydrologic Laboratory of the United States Geological Survey, to determine whether Darcy's law is valid for very low hydraulic gradients —that is, whether under such low gradients the rate of flow remains proportional to the gradient . In a previous paper by Meinzer and the writer (Amer. Geophysical Union,15th annual meeting, pp.405–409, 1934), it was shown that for the sand tested the rate of flow varies directly with the hydraulic gradient down to a gradient of about one foot to the mile. More recently six additional tests have been made on this sand with the same apparatus, and these tests give evidence of the validity of Darcy's law for still lower gradients .

Eos, Transactions, American Geophysical Union

Recharge, movement, and discharge in the Edwards Limestone Reservoir, Texas

The Edwards limestone of Lower Cretaceous age is the principal water‐bearing formation in a belt 5 to 25 miles wide that extends from Austin southwest to San Antonio and thence west through Uvalde and Del Rio to Comstock, a distance of about 250 miles (see Fig. 1). Throughout this belt it supplies water to wells for stock, industrial, irrigation, and municipal use and to a series of fault‐springs, some of which are among the largest in the United States. These springs have played an important part in the economic and cultural development of Texas. In 1718 the Spaniards stationed a department of light infantry near the springs at San Antonio and soon after established missions and constructed elaborate systems of canals for irrigating considerable areas. After the winning of Texas' independence large numbers of settlers moved into the area. This influx was greatly accelerated following the admission of Texas to the Federal Union and towns were soon established near all of the major springs. However, it was not until about 1880 that the rapid development of the Edwards limestone aquifer by wells was begun.

Texas

Specific yield determined from a Thiem's Pumping‐Test

The specific yield of a water-bearing formation is defined as the ratio of (1) the volume of water, which after being saturated, it will yield by gravity to (2) its own volume (O. E. Meinzer, Outline of ground-water hydrology, U.S. Geol. Sur. Water-Supply Paper 494, p. 28, 1923). It is a measure of the quantity of water that a formation will yield when it is drained by lowering of the water-table. The determination of the specific yield is essential in many quantitative ground-water investigations. In 1931 a pumping-test was made in the Platte River Valley, in Nebraska, to determine by Thiem's method the permeability of the water-bearing sand and gravel that underlie the Valley. This test, which constitutes a part of a cooperative investigation by the Conservation and Survey Department of the University of Nebraska and the United States Geological Survey, was briefly described in the 1932 Transactions of the American Geophysical Union (p. 393). The well was pumped continuously for 48 hours, and measurements of the discharge were made every 30 minutes. During the period of pumping and after pumping stopped about 5,000 measurements were made of the depths to the water-surfaces in 80 observation-wells, which were located on lines radiating from the pumped well to distances up to 1,200 feet. Instrumental levels were run to the measuring points on each of the wells so that the altitudes of the water-surfaces could be determined for any time. From the data obtained in this test the average coefficient of permeability was computed to be about 700. In the present paper a method is presented for determining the specific yield of the water-bearing material from the data collected in this test, and the results of the computations are given. This method for determining specific yield was suggested by Meinzer (O. E. Meinzer, Outline of methods for estimating ground-water supplies, U.S. Geol. Sur. water-Supply Paper 638-c, p. 136, 1932).

Eos, Transactions, American Geophysical Union

Geophysical Research Letters: New policies improve top-cited geosciences journal

Geophysical Research Letters (GRL) is the American Geophysical Union's premier journal of fast, groundbreaking communication. It rapidly publishes high- impact,letter-length articles, and it is the top-cited multidisciplinary geosciences journal over the past 10 years, with an impact factor that increased again in 2009, to 3.204. For manuscripts submitted to GRL, the median time to first and final decision is 23 and 27 days, respectively—a 35% improvement since 2007—and the median time from submission to publication is 13 weeks for 90% of GRL papers—a 25% improvement since 2007. Among high-impact publications in the geosciences, GRL has the fastest turnaround.

Eos, Transactions, American Geophysical Union

Recent advances in space science

The present rapid advance in space sciences, clearly apparent at previous semiyearly national meetings of the American Geophysical Union, was again in evidence at the Stanford meeting, December 27–29, 1962. A total of over 60 papers was presented by the Planetary Sciences Section, usually in sessions held jointly with other Sections, including Geomagnetism and Aeronomy; Meteorology; and Volcanology, Geochemistry, and Petrology. Two symposia, jointly sponsored by the American Physical Society, also included items of space interest, such as the atmospheric drag of satellites and the Mariner 2 probe observations on Venus conducted a few days previous to the meeting.

Eos, Transactions, American Geophysical Union