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Results for “Eos, Transactions, American Geophysical Union”

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At least 19 recordsLinked to original sources
USGS2014

Investigations of the fluctuations of the ground‐water table in Pennsylvania

Hydraulic engineers are interested in ground ‐ water as a source of water supply and also as it affects stream‐flow. The stream‐flow is especially valuable at low stages and it is at the low stages that it is most closely related to the ground ‐ water conditions. For several years the Pennsylvania Topographic and Geologic Survey and the United States Geological Survey have cooperated in making a comprehensive study of the ground ‐ water resources of Pennsylvania , but no adequate records of ground ‐ water levels have in the past been obtained. Recently, however, a project for obtaining systematic records in Pennsylvania has been started. ©1932. American Geophysical Union.

Pennsylvania↗
USGS2014

Glacier‐measurements in the United States

It is doubtless known to many members of the Section of Hydrology that prior to the World War there existed an International Glacier Commission (la Commission Internationale des Glaciers) whose self‐appointed task it was to gather and publish the results of all available measurements showing the annual variations in length—advance or recession—of glaciers in different parts of the world. On this Commission the United States was represented by two men who made frequent contributions to the International record.

Eos, Transactions, American Geophysical Union↗
USGS2014

Nonsteady flow to a well of constant drawdown in an extensive aquifer

A mathematical theory is given for the discharge of a well of constant drawdown, discharging as by natural flow from an effectively infinite aquifer of uniform transmissibility and uniform compressibility. This theory is based on the solution by L. P. Smith of the analogous problem in heat conduction. The mathematical function involved in the solution, which cannot be integrated directly, is evaluated by numerical integration. A table of its values is given for a wide range of its argument. This function is compared with other,asymptotic solutions, and simple, useful approximations are given. Two graphical methods are outlined for determining the coefficients of storage and transmissibility from variations in the rate of discharge of wells flowing at constant drawdown. Data from the Grand Junction, Colo., artesian basin are treated by these methods. In the Grand Junction artesian basin there are about 25 flowing wells ranging in depth from 600 to 1600 ft, most of which obtain water from the Entrada sandstone. A few of the wells obtain water from a sandstone in the overlying Morrison formation and a few tap the underlying Wingate sandstone. The procedure of the tests is outlined, and the “ink-well” mercury gage used to measure the artesian pressures is described. Recovery tests were run on the same wells after the discharge tests. Values of transmissibility obtained from the recovery tests check those obtained by means of the discharge tests.

Colorado↗
USGS2012

One hundred years of volcano monitoring in Hawaii

In 2012 the Hawaiian Volcano Observatory (HVO), the oldest of five volcano observatories in the United States, is commemorating the 100th anniversary of its founding. HVO's location, on the rim of Kilauea volcano (Figure 1)—one of the most active volcanoes on Earth—has provided an unprecedented opportunity over the past century to study processes associated with active volcanism and develop methods for hazards assessment and mitigation. The scientifically and societally important results that have come from 100 years of HVO's existence are the realization of one man's vision of the best way to protect humanity from natural disasters. That vision was a response to an unusually destructive decade that began the twentieth century, a decade that saw almost 200,000 people killed by the effects of earthquakes and volcanic eruptions.

Hawai'i↗
USGS2014

Earth‐tides shown by fluctuations of water‐levels in wells in New Mexico and Iowa

It is quite generally known that ocean‐tides produce fluctuations of the water‐level in wells of the artesian type located close to the seashore by periodically changing the external load on the aquifer [see 1 of “References” at end of paper]. Fluctuations of ground‐water as a result of earth‐tides, however, are not generally known although they were observed and studied in a flooded coal‐mine in Europe [2] as early as 1879, and later 1905 to 1912 in wells in South Africa [3]. The phenomena of earth‐tides first came to the attention of the writer in March, 1938, when studying fluctuations of the water‐level In an artesian well near Carlsbad, New Mexico, recorded on charts of a water‐stage recorder, which had an approximately semidiurnal period. Because of the distance from the ocean, about 500 miles, and the altitude of the water‐bearing formation, about 2700 feet, it appeared that the fluctuations could not be the result of ocean‐tides. Neither did it appear they could be the result of other natural phenomena such as changing air‐pressure or changes in water‐level of a nearby lake and river. There was no pumpage from the aquifer, so the fluctuations of the water could not be caused by pumping. T. M. Cramer, Resident Manager of the United States Potash Company at Carlsbad, New Mexico, suggested that the fluctuations must be the result of some lunar attraction. Further study of the fluctuation was made by Dr. C. V. Theis, of the United States Geological Survey, and the writer, whereby the effect of changing air‐pressure was eliminated by correcting the water‐levels to an assumed constant atmospheric pressure. In this study it was demonstrated after applying the barometric correction that the remaining fluctuations were fairly regular and progressed with the transit of the Moon. It was also demonstrated that the fluctuations were of the greatest amplitude during the period of new Moon. Further work by W. E. Hale, of the United States Geological Survey, and the writer, has shown that the fluctuations were much more regular and of greater amplitude during the periods of new and full Moon than during the first and third quarters. It was, therefore, concluded that they are related to true earth‐tides. A preliminary note was published in the Transactions of the American Geophysical Union for 1938 [4].

New Mexico↗
USGS2014

Pre‐Cambrian and Paleozoic vulcanism of interior Alaska

The history of vulcanism in Alaska is a topic of great universal interest, but one which has had no adequate treatment. For some years the writer has been accumulating comparative data on this subject, and it is hoped that this information may some time be sufficiently amplified and coordinated to justify a general description of the sequential igneous history of Alaska. The scope of such an undertaking, however, can well be appreciated from the statement that Alaska is nearly a fifth the size of the United States, and that geologic studies have shown that igneous rocks have originated in Alaska in every geologic period, excepting perhaps the Cambrian and the Silurian. Therefore, in the present paper, it has seemed best to present only a part of this interesting record, and perhaps in subsequent papers to expand the areal and geologic limits of discussion. ©1935. American Geophysical Union. All Rights Reserved.

Eos, Transactions, American Geophysical Union↗
USGS2014

Mode of igneous intrusion in La Plata Mountains, Colorado

The La Plata Mountains, in southwestern Colorado, have long been known as an example of a mountain group of the laccolithic type, although it has been recognized that the igneous geology was much more complex than that of typical laccoliths. A restudy of the ore‐deposits of the District, now in progress, has thrown new light on the mode of intrusion of the igneous rocks (E. B. Eckel, Resurvey of the geology and ore‐deposits of the La Plata Mining District, Colorado, Proc. Colorado Sci. Soc, v. 13, No. 9, pp. 508–546, 1936). The Mountains, which include parts of La Plata and Montezuma Counties, are 8 to 18 miles northwest of Durango and occupy an oval area 10 to 15 miles in diameter. The altitude ranges from about 8000 to 13,225 feet above sea‐level. ©1937. American Geophysical Union. All Rights Reserved.

Colorado↗
USGS2014

Diabase dikes of the Franklin Furnace, New Jersey, quadrangle

Two of the numerous small dikes mapped on the areal geology sheet of the Franklin Furnace Folio (U.S. Geological Survey 161) as “Mostly basic, including nepheline tinguaite, leucite tinguaite, and camptonite” of post‐Ordovician age, have been found to be quite distinct from these alkalic rocks, and the two dikes in question are indistinguishable from the Triassic diabase found elsewhere in New Jersey and adjoining States. The association of diabase with highly alkalic rocks has been observed and commented on by numerous writers. There is evidence pointing to the post‐Triassic age of the Beemerville alkaline rocks, and a possible correlation with a volcanic ash of Cretaceous age found by Stephenson and Carter at Haddonfield, New Jersey, near Camden, in 1936. ©1938. American Geophysical Union. All Rights Reserved.

New Jersey↗
USGS2014

Intrusive rocks in the Blue Ridge plateau, Virginia

An injection complex of early pre‐Cambrian age is exposed in the Elk Creek anticline in Grayson County, Virginia. There, sedimentary rocks and diorite have been intruded by the Striped Rock and the Carsonville granites. The granites have metamorphosed, injected, reacted with, and replaced the older rocks to form many mixed types. This injection complex is part of a large area of similar rocks that form the core of the Catoctin Mountain‐Blue Ridge uplift in Virginia, and is much older than the overlying volcanic series of later pre‐Cambrian age. ©1942. American Geophysical Union. All Rights Reserved.

Virginia↗
USGS2011

Hydrology comes of age: Impact of the International Hydrological Decade

The IHD (International Hydrological Decade), 1965 to 1974, was conceived as a concerted international effort to bring into focus the badly fragmented subdiscipline of hydrology, to evolve a global perspective on water, and to provide global information on water. Until the last decade or so, hydrology was a laggard science. The science was also fragmented among surface‐water hydrology, agricultural hydrology, groundwater hydrology, oceanology, hydrometeorology, and hydrogeochemistry. All these disciplines were bona fide members of the hydrological family, but there was little interchange, so there was no central focus for the science as a whole. ©1980. American Geophysical Union. All Rights Reserved.

Eos, Transactions, American Geophysical Union↗
USGS2014

The Valles Mountain Volcanic Center of New Mexico

The Valles Mountain region lies in northern New Mexico about 30 miles west of Santa Fe, 50 miles north of Albuquerque, and just west of the Rio Grande. The elevation varies from 6,500 feet at the Rio Grande to 1,200 feet on the higher peaks. ©1931. American Geophysical Union. All Rights Reserved.

New Mexico↗
USGS2014

The Rôle of volatiles in the formation of Virginia titanium deposits

The feldspathic rock with which the titanium deposits of Virginia are associated appears to be an anorthosite, although the plagioclase is somewhat more sodic than in normal anorthosites. That is, this rock shows evidence of having been introduced as a mush‐like mass of crystals and intersititial magma, and of undergoing very thorough crushing during introduction. This rook was later very thoroughly altered by hydrothermal solutions which migrated through the fractures in the feldspar rook and new minerals including the titanium minerals—rutile and ilmenite—were introduced. The elements introduced into the feldspathic rock ware TiO 2 FeO, MgO, P 2 O 5 , and F. The other elements that went into the formation of new minerals were derived from the feldspar originally present. There was a distinct order in the abstraction of the introduced elements from the carrying solutions, as shown by the zonal relatione of the secondary minerals. Ferrous iron was abstracted first in the formation of the ferromagnesian silicates and ilmenite. Magnesium and titanium, in the absence of iron, traveled farther from the source of the solutions and deposited rutile and magnesian silicates. At greater distances most of the introduced elements had been abstracted from the solutions but notwithstanding this the feldspar was extensively altered, but without any marked changes between the chemical composition of the original feldspar rook and the resulting altered rook. ©1934. American Geophysical Union. All Rights Reserved.

Virginia↗
USGS2014

Igneous activity in the Comstock District, Nevada

The oldest igneous rocks in the Comstock District are amphibolites probably derived from basalts and of Triassic age. These are intruded by pre‐Tertiary quartz monzonlte and by granodiorite of Sierran facies, the latter not being exposed on the surface but found on mine‐dumps. Igneous activity recorded mainly in volcanic rocks was almost continuous throughout the Tertiary. Its products, in order of age, were as follows: Eocene—Rhyolitic flows aggregating a few hundred feet in thickness: One intrusive plug of rhyolite occurs. Eocene or Miocene—Hornblende‐auglte andesite intrusive into the rhyolite, type locality American Ravine. ©1938. American Geophysical Union. All Rights Reserved.

Nevada↗
USGS2014

Volcanic activity at Magnet Cove, Arkansas

The igneous rocks and the minerals of Magnet Cove, Arkansas, have long interested geologists and mineralogists, but in much of the area rock‐exposures are so sparse that many of the geologic, relations have remained obscure. However, recent prospecting and the mining of titanium ores have uncovered rocks that throw new light on the geology of the region. The regional rocks of the area are sandstones, slates, and novaculite of Paleozoic age. They were folded and underwent metamorphism in late Paleozoic time. In Cretaceous time they were intruded by a series of igneous rocks. ©1938. American Geophysical Union. All Rights Reserved.

Arkansas↗
USGS2014

Petrology and structure of the Moa Chromite district, Oriente Province, Cuba

Chromite deposits In the Moa district, on the north coast of Oriente Province, Cuba, form one facies of the ultramafic complex in which they occur. Two planar structures, one a compositional layering due to variations in the relative proportions of olivine, pyroxene, plagioclase feldspar, and chromite, and the other a foliation caused by the orientation of pyroxene crystals in peridotite, are in general parallel, but diverge in a few places. Dips are fairly constant, being moderate to the northwest over most of the area, but sharp reversals occur immediately adjacent to irregularities in the chromite deposits. Two prominent joint sets are present: (1) Cross joints striking parallel to the strike of the foliation and dipping approximately at right angles to it; and (2) longitudinal joints striking parallel to the direction of dip of the foliation and nearly vertical. Gabbro dikes follow the first set, chrysotlle veins the second. Within the ore bodies dikes are commonly coarser‐grained, larger, and far more abundant than in peridotite; they enclose coarse, angular fragments of chromite. ©1947. American Geophysical Union. All Rights Reserved.

Eos, Transactions, American Geophysical Union↗
USGS2014

Deep‐seated solution in the Meade basin and vicinity, Kansas and Oklahoma

During the closing years of the 19th century, Haworth [see 1 and 2 of “References” at end of paper] and Johnson [3] noted the abundant depressions resembling sink‐holes in the Southern High Plains, especially in Meade and Clark counties, Kansas, and Beaver County, Oklahoma. Johnson was of the opinion that all the depressions and basins in this region were due to solution, whereas Haworth [1] believed the Meade artesian basin to be structural, although he held to a solutional origin for the Ashland and Englewood basins, which are a few miles to the east. ©1942. American Geophysical Union. All Rights Reserved.

Kansas, Oklahoma↗
USGS2014

Report of committee on relation of inch and meter

Those of you who attended the annual meeting of this Section on April 27, 1938, heard a paper entitled “A method for introducing a new standard of length” that was presented by Professor Philip Klssara, calling attention to the Bill then in Congress proposing to redefine the length of the inch. The paper has been published in the “Transactions of the American Geophysical Union“ [19th Annual Meeting, 1938, pp. 94–96]. Its closing paragraph is as follows: “As the American Geophysical Union has as one of its functions the duty of offering advice to the Congress on technical matters, I move, Mr. Chairman, that the Chairman be empowered to appoint a committee to study the matter and to report what recommendations should be made to Congress by the Union.”

Eos, Transactions, American Geophysical Union↗
USGS2011

Magmatic heat and the El Niño cycle

Large submarine lava flows with apparent volumes exceeding 10 km 3 have recently been imaged on the deep ocean floor in various parts of the Pacific by means of GLORIA and SeaMarc side‐looking sonar surveys. Such flows may produce thermal anomalies large enough to perturb the cyclic processes of the ocean and could be a factor in the genesis of El Niño phenomena. We find that known volume rates of mid‐ocean magma production could generate repetitive thermal anomalies as large as 10% of the average El Niño sea surface anomaly at intervals of about 5 years (the mean interval of El Niño events between 1935 and 1984). Likewise, estimated rates of eruption, cooling of lava on the seafloor, and transfer of heat to the near‐surface environment could reasonably produce a thermal anomaly comparable to that associated with El Niño. Larger magmatic events, associated with fluctuations in the total magmatic power and seismicity along the East Pacific Rise, are possible at longer intervals and may explain the extreme size of some El Niño events, such as that of 1982–1983. ©1988. American Geophysical Union. All Rights Reserved.

Eos, Transactions, American Geophysical Union↗