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At least 199 records · Page 11Linked to original sources
USGS2006

The fifth International Geological Congress, Washington, 1891

The 5th International Geological Congress (IGC), the initial meeting in North America, was the first of the three IGCs that have been held in the United States of America (USA). Of the 538 registrants alive when the 5th IGC convened in Washington, 251 persons, representing fifteen countries, actually attended the meeting. These participants included 173 people from the USA, of whom forty-two represented the US Geological Survey (USGS). Fourteen of the US State geological surveys sent representatives to Washington. Eight participants came from other countries in the Western Hemisphere - Canada (3), Chile (1), Mexico (3), and Peru (1). The sixty-six European geologists and naturalists at the 5th IGC represented Austro-Hungary (3), Belgium (3), Britain (12), France (7), Germany (23), Norway (1), Romania (3), Russia (8), Sweden (4), and Switzerland (2). The USGS and the Columbian College (now the George Washington University) acted as the principal hosts. The American Association for the Advancement of Science and then the Geological Society of America (GSA) met in the Capital immediately before the Congress convened (26 August-1 September 1891). The 5th IGC's formal discussions treated the genetic classification of Pleistocene rocks, the chronological correlation of clastic rocks, and the international standardization of colors, symbols, and names used on geologic maps. The third of those topics continued key debates at the 1st through 4th IGCs. The GSA, the Korean Embassy, the Smithsonian Institution's US National Museum, the USGS, and one of the two Secretaries-General hosted evening receptions. Field excursions examined Paleozoic exposures in New York (18-25 August), Cretaceous-Pleistocene localities along the Potomac River south of Washington (30 August), and classic Precambrian-Pleistocene sequences and structures in the Great Plains, Yellowstone, Rocky Mountains, and Great Basin (2-26 September), with optional trips to the Grand Canyon (19-28 September) and Lake Superior (23 September-2 October). The single-volume report of the 5th IGC was published in Washington in 1893.

Conference Paper↗
USGS2006

Study of volcano/ice interactions gains momentum

Observations of recent volcanic eruptions in Iceland and detailed studies of sub-glacially erupted deposits and the interaction of lava and pyroclastic flows with snow and ice have provided important new data that should lead to significant advances in the understanding of volcano/ice interaction on Earth and Mars. A conference on this subject, the first of its kind, recently brought together geologists, geophysicists, glaciologists, and planetary scientists studying various aspects of volcano-ice interaction.

Eos, Transactions, American Geophysical Union↗
USGS2013

Tectonic map of the Circum-Pacific region, Pacific basin sheet

Circum-Pacific Map Project : The Circum-Pacific Map Project was a cooperative international effort designed to show the relationship of known energy and mineral resources to the major geologic features of the Pacific basin and surrounding continental areas. Available geologic, mineral, and energy-resource data are being complemented by new, project-developed data sets such as magnetic lineations, seafloor mineral deposits, and seafloor sediment. Earth scientists representing some 180 organizations from more than 40 Pacific-region countries are involved in this work. Six overlapping equal-area regional maps at a scale of 1:10,000,000 form the cartographic base for the project: the four Circum-Pacific Quadrants (Northwest, Southwest, Southeast, and Northeast), and the Antarctic and Arctic Sheets. There is also a Pacific Basin Sheet at a scale of 1:17,000,000. The Base Map Series and the Geographic Series (published from 1977 to 1990), the Plate-Tectonic Series (published in 1981 and 1982), the Geodynamic Series (published in 1984 and 1985), and the Geologic Series (published from 1984 to 1989) all include six map sheets. Other thematic map series in preparation include Mineral-Resources, Energy-Resources and Tectonic Maps. Altogether, more than 50 map sheets are planned. The maps were prepared cooperatively by the Circum-Pacific Council for Energy and Mineral Resources and the U.S. Geological Survey and are available from the Branch of Distribution, U. S. Geological Survey, Box 25286, Federal Center, Denver, Colorado 80225, U.S.A. The Circum-Pacific Map Project is organized under six panels of geoscientists representing national earth-science organizations, universities, and natural-resource companies. The six panels correspond to the basic map areas. Current panel chairmen are Tomoyuki Moritani (Northwest Quadrant), R. Wally Johnson (Southwest Quadrant), Ian W.D. Dalziel (Antarctic Region), vacant. (Southeast Quadrant), Kenneth J. Drummond (Northeast Quadrant), and George W. Moore (Arctic Region). Project coordination and final cartography was being carried out through the cooperation of the Office of the Chief Geologist of the U.S. Geological Survey, under the direction of General Chairman, George Gryc of Menlo Park, California. Project headquarters were located at 345 Middlefield Road, MS 952, Menlo Park, California 94025, U.S.A. The framework for the Circum-Pacific Map Project was developed in 1973 by a specially convened group of 12 North American geoscientists meeting in California. The project was officially launched at the First Circum-Pacific Conference on Energy and Mineral Resources, which met in Honolulu, Hawaii, in August 1974. Sponsors of the conference were the AAPG, Pacific Science Association (PSA), and the Coordinating Committee for Offshore Prospecting for Mineral Resources in Offshore Asian Areas (CCOP). The Circum-Pacific Map Project operates as an activity of the Circum-Pacific Council for Energy and Mineral Resources, a nonprofit organization that promotes cooperation among Circum-Pacific countries in the study of energy and mineral resources of the Pacific basin. Founded by Michel T. Halbouty in 1972, the Council also sponsors conferences, topical symposia, workshops and the Earth Science Series books. Tectonic Map Series : The tectonic maps distinguish areas of oceanic and continental crust. Symbols in red mark active plate boundaries, and colored patterns show tectonic units (volcanic or magmatic arcs, arc-trench gaps, and interarc basins) associated with active plate margins. Well-documented inactive plate boundaries are shown by symbols in black. The tectonic development of oceanic crust is shown by episodes of seafloor spreading. These correlate with the rift and drift sequences at passive continental margins and episodes of tectonic activity at active plate margins. The recognized episodes of seafloor spreading seem to reflect major changes in plate kinematics. Oceanic plateaus and other prominences of greater than normal oceanic crustal thickness such as hotspot traces are also shown. Colored areas on the continents show the ages of deformation and metamorphism of basement rocks and the emplacement of igneous rocks. Transitional tectonic (molassic) and reactivation basins are shown by a colored boundary, and if they are deformed, a colored horizontal line pattern indicates the age of deformation. Colored bands along basin boundaries indicate age of inception, and isopachs indicate thickness of platform strata on continental crust and cover on oceanic crust. Colored patterns at separated continental margins show the age of inception of rift and drift (breakup) sequences. Symbols mark folds and faults, and special symbols show volcanoes and other structural features. Affiliations are as of compilation of the data. This map was created in quadrants and then compiled together. They are the Northwest land, Northwest Marine (different compilers), Northeast, Southwest and Southeast, and parts in plate-boundary sections.

Circum-Pacific Map↗
USGS2014

Results to be expected from resistivity‐measurements

The work described in this paper was all done in connection with dam‐site investigations and was not directly connected with hydrology. However, geophysics is coming to have a place in hydrologic investigations, and these results may throw some light on what can be accomplished by resistivity‐measurements. We have found that,for many questions not involving exact determinations of depth, resistivity‐ measurements give conclusive answers. Ordinarily a reliable answer can be expected to the question of the existence of a buried channel if the covering is composed of unconsolidated material with a resistivity differing from that of the rock. For example, topographic surveys were made at two alternative dam‐sites on a river about four miles apart. Examination of the surface‐geology indicated that a channel burled under glacial debris possibly existed at each site, but resistivity‐measurements proved that such a channel existed at one site and not at the other. On the other hand, at another site the geologist suspected there might be an old channel on a steep side hill. Geophysical measurements showed a depth of overburden of 46 feet and showed that if a deeper channel exists it must be narrow; but they did not show positively that no such channel exists. Probably a careful survey with a large number of lines would have given a more definite answer, but the rough topography interfered with the resistivity‐work, and time and money were not available for a detailed survey. After completion of the geophysical work, the geologist located some outcrops which led him to conclude that no old channel exists at this site. At two other dam‐sites in Oregon resistivity‐measurements showed that there were no burled channels.

Eos, Transactions, American Geophysical Union↗
USGS2017

Radiocarbon age of the damariscotta shell heaps

The large oyster shell heaps on both sides of the Damariscotta River, just north of the towns of Damariscotta and Newcastle, Maine, have been known for many years and both geologists and archaeologists have speculated about their age. During the summer of 1955 I made 2 collections of Mya shells from the largest shell heap on the west side of the river (Glidden estate) for radiocarbon age determinations.

Maine↗
USGS2007

Eo-Ulrichian to Neo-Ulrichian views: The renaissance of "layer-cake stratigraphy"

Classical notions of "layer-cake stratigraphy" have been denigrated as representing an antiquated "Neptunian" view of the geologic record with the American paleontologist-stratigrapher E.O. Ulrich vilified as its quintessential advocate. Some of the extreme "layer-cake" interpretations of E.O. Ulrich are demonstrably incorrect, especially where applied in marginal marine and terrestrial settings. However, close scrutiny of Ulrich's work suggests that the bulk was correct and demonstrated considerable insight for the time. Subsequent development of facies concepts revolutionized geologists' view of time-space relationships in stratigraphy, but rather than focusing on facies patterns within the established stratigraphic (layer-cake) frameworks many geologists in North America came to view strata as parts of diachronous facies mosaics. Recent advances in the development of event and sequence stratigraphic paradigms are beginning to swing the pendulum back the other way. Possible causes of "layer-cake" patterns are numerous and varied, including: (1) parallelism of depositional strike and outcrop belts, especially in foreland basins, (2) very widespread environmental belts developed in low-relief cratonic areas, (3) time-averaging homogenizes facies to a limited extent, resulting in a very subtle signature of lateral change, (4) condensed beds (hardgrounds, bone beds, ironstones, etc.) often form in responses to extrabasinal forces, thus they cross-cut facies, and (5) large events (i.e. hurricanes, floods, tsunamis, eruptions, etc.) are "over represented" in the rock record. A revised ("Neo-Ulrichian") layer-cake paradigm carries many of the original correct empirical observations of pattern, noted by Ulrich, recast in terms of event and sequence stratigraphy.

Conference Paper↗
USGS1949

Ground water in the Cul-de-Sac Plain, Haiti

The Cul-de-Sac Plain is perhaps the most important agricultural area in Haiti because of its nearness and accessibility to Port-au-Prince, the nation's capital, metropolis, and principal seaport. Most of the agricultural produce consumed in Port-au-Prince as well as a considerable part of that exported from Haiti is grown in the plain. Because of variable and poorly distributed rainfall, high temperature, and high evaporation, semiarid climatic conditions prevail in the plain. Irrigation is, therefore, necessary for successful farming. There are no regulatory or storage facilities on the streams that enter the plain, but the mean and low-water stream flow and the discharge of springs are almost entirely appropriated for irrigation. Ground water has been utilized for irrigation to an increasing extent by the Haitian American Sugar Company, which has put down about 100 wells in the plain since 1919. Outside the existing irrigated areas of the plain are large tracts of potentially irrigable land that are uncultivated and agriculturally unproductive for lack of water. The object of the present study was to determine the possibilities of bringing these lands into cultivation by irrigation from wells. This study was part of a larger program of the Food Supply Division, Institute of Inter-American Affairs, to increase the production of food in Haiti. From September through November 1948 the senior author, a member of the U. S. Geological Survey, spent three months in the field in an investigation of the geology and ground-water resources of the Cul-de-Sac Plain. He was ably assisted by Mr. Rémy C. Lemoine, Haitian engineer-geologist, employed by the Food Supply Division. The field work included principally the geologic mapping of' the plain and the adjacent mountain borders, a ground-water inventory of existing wells and springs, and a general evaluation of significant geologic and hydrologic features.

Cul-de-sac Plain↗
USGS1973

Iron-formation in South America

Except for recent studies by certain South American governmental and quasi-governmental companies and agencies, little effort has been devoted to study of the iron-formations from which the great iron ore deposits of South America formed. Great gaps in basic information exist. Iron-formation is found in the Guayana and Brazilian Precambrian Shields as a common rock type and also occurs in Chile and astride the Bolivian-Brazilian border. Only the carbonate and oxide facies are known, the former being quite rare. The dominant oxide facies occurs in major units averaging more than 100 m in thickness and extending over hundreds of square kilometers, generally in a miogeosynclinal or intra-cratonic basin environment. The relation of such deposits with volcanism is tenuous and obscure, if indeed there is any direct relation. Smaller units of oxide facies iron-formation occur in many minor beds from widely varying geologic environments. The carbonate facies is found in a eugeosynclinal suite in Minas Gerais, Brazil, and is of the Algoma type. The deposits range in age from about 3,200 m.y. to late Precambrian or early Paleozoic; although the major epoch of deposition is debatable, it probably was about 2,000 m.y. ago. The South American oxide facies iron-formations are richer than many in the Northern Hemisphere, those of early and middle Precambrian age averaging about 40 percent in Fe and the same in SiO 2 . Younger iron-formations are still richer, averaging perhaps 50 percent Fe. Scanty trace element data do not indicate volcanic affiliations. The iron is present as magnetite, hematite, and martite; most rocks have been metamorphosed, and accordingly it is not known how much of the magnetite is metamorphic and how much is diagenetic or depositional in origin. Hematite and martite are dominant in most iron-formations. South American iron-formations are quite similar in lithology and occurrence to the major deposits in Africa and India and possibly formed when these continents were contiguous. These formations differ from those in the Northern Hemisphere in having a narrower range in lithologic facies and a generally higher iron content. In few areas can any direct relation with volcanism be demonstrated. © 1973 Society of Economic Geologists, Inc.

Economic Geology↗
USGS1917

Mechanics of the Panama Canal slides

Dr. Becker visited the Canal Zone in 1913 as a geologist of the United States Geological Survey and since that time has given the problem the benefit of his study. His appointment as a member of the committee of the National Academy of Sciences has made it appropriate for his conclusions, based upon his personal observations and already reported in part to the Canal Commission, to be stated for the benefit of his associates and other American scientists and engineers.

Panama Canal↗
USGS1947

Flysch and molasse

By definition European geologists consider a sequence of limestones, sandstones, and shales, the beds of which are thin, regular, and alternating, and which are deposited in a geosyncline or foredeep shortly before a major orogeny, as the flysch . The waste products that accumulate as a deposit flanking mountains and built in part of the deformed flysch make up the molasse . In field practice the groups of sediments called flysch and molasse, or facies of them, are formations in the American sense. However, the Europeans would not recognize all groups of beds deposited in a geosyncline just before an orogeny as flysch; the beds must possess the proper lithologic and bedding characteristics. Europeans have tacitly tied the variable of lithology and stratification to the variable of orogeny, with attendant difficulties. Originally only the first was denoted, but later the second was emphasized in definition if not in field use. Americans have considered the terms chiefly in their orogenic sense and thereby have called certain sequences flysch that do not fully meet the requirements of European usage. The writers are of the opinion that little is gained by the use of the words; by their application no new fact is told or discovery made. They simply elaborate a conclusion by way of analogy. On the other hand, a possibility of confusion is introduced by the use of the terms, and in America it is best to avoid them.

GSA Bulletin↗
USGS2014

Geophysical interpretation of ground‐water levels

The theory of rock‐pressure as a cause of artesian‐head dates back at least to early Grecian times. Thus the philosopher Thales, about 600 B.C., taught that the springs derive their water from the ocean through subterranean channels and that the water is lifted to the springs by rook‐pressure. The theory of rock‐pressure has had a number of recent advocates, chief among whom was the British geologist, J. W. Gregory, but apparently no effective attempt was made by any of them to apply critical data to the problem. In general, geologists and hydrologists have rejected rock‐pressure as a vague heresy and have assumed that the artesian formations function as perfectly rigid and inert containers, not recognizing the fact that the data in regard to the performance of wells appear to conflict with such an interpretation .

Eos, Transactions, American Geophysical Union↗
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↗
USGS2011

The U.S. Geological Survey's gravity program in the Rocky Mountain and Basin Range areas

Most of the gravity surveys of the U.S. Geological Survey have been support programs in connection with regional geologic structural studies, ground-water investigations, and heavy-metals exploration. Many of the studies were undertaken in conjunction with geological mapping and mineral investigations by the Survey's project geologists. Gravity data often complement aeromagnetic surveys to identify the sources of potential-field anomalies; other gravity data have been used to supplement high-resolution seismic and electrical investigations [ Mattick , 1967]. Geochemical follow-up has been fruitful in western Montana [ Mudge et al, 1967].

Arizona, Colorado, Idaho, Montana, Nevada, New Mex↗
USGS2014

Trails through time: A geologist's guide to Jefferson County open space parks

Introduction Jefferson County straddles one of the most conspicuous and important geographic and geologic boundaries in western North America, the eastern flank of the Rocky Mountains. To the east you can travel 1,100 miles across Great Plains and Central Lowlands before you sight the western foothills of the Appalachians. If you travel in the other direction you will cross or skirt mountain range after mountain range until you sight the Coast Range near San Francisco, more than 900 miles to the west. Many of these mountains have different ages and origins than the Colorado mountains, but they are all part of the great mountain belt called the North American Cordillera that extends along the western edge of the continent from Alaska through Mexico. What is the reason for the remarkably straight and abrupt eastern flank of the Colorado Front Range? The brief answer is that it marks the edge of a block of ancient metamorphic and igneous rocks that has been uplifted relative to younger flat-laying sedimentary rocks that underlie the plains to the east. During the uplift, the sedimentary rocks along the boundary have been uplifted and tilted eastward to form the discontinuous line of hogback ridges that parallel the mountain front. Erosion during and after the uplift has removed the sedimentary rocks that once lay above the harder rocks of the mountain uplift, carved the scenic peaks and mountain canyons in the hard crystalline rocks of uplifted block, and worn away the softer layers of sedimentary rocks of the plains, but left a few of the harder upturned layers along the mountain front as hogback ridges. Jefferson County Open Space Parks, as well as other nearby parks and National Forest lands, offer marvelous opportunities to explore the geologic story behind this singular landscape. At first the distribution of rocks of different ages and types seems almost random, but careful study of the rocks and landscape features reveals a captivating geologic story, a history that tells of the building of the foundations of the continent, the rise and destruction of longvanished mountain ranges, the ebb and flow of ancient seas, and the constant shaping and reshaping of the landscape in response to the never-ending interplay between uplift and erosion. This historical account is constantly being improved and expanded as new evidence accumulates and new interpretations evolve.

Colorado↗
USGS2017

The geological approach to dating archaeological sites

Abasic Question that must be answered for any archaeological site is, how old is it? Although some archaeological sites can be dated on the basis of archaeological correlations alone and although dendrochronological (Giddings, 1952, pp. 105-110) and radiocarbon methods give absolute ages for other sites , many sites can be dated only by methods based on the geologists' knowledge of geographic and climatic changes during the last few tens of thousands of years. The dates of these changes are established in part by radiocarbon and related methods. Study of archaeological sites accurately dated by radiocarbon methods will amplify the geologists' understanding of late Quaternary events. The well known techniques of dendrochronological and radiocarbon dating need no discussion. The interrelations of methods that depend ultimately on our knowledge of Quaternary climatic and geographic changes are not always well understood, however, by archaeologists. The present paper is intended to clarify some of these interrelations.

American Antiquity↗
USGS2014

Appendix B—The work of the United States Geological Survey and cooperating agencies on ground water for war purposes

A report by O. E. MEINZER, published as Appendix B of the annual report of the Committee for 1942–43 [Trans. Amer. Geophys. Union, Part II, pp. 418–420, 1943], describes in some detail the previous work of the United States Geological Survey and cooperating agencies on ground water for war purposes. The geologists from the staff of the Geological Survey listed in that report and several other ground‐water geologists have served in the Army during the past year on water‐supply assignments. Only sketchy and unofficial information is as yet available concerning the activities of these geologists, but it is believed that they are now all engaged in overseas theaters of warfare and that their services in water‐supply and other technical work are of substantial value. In this service they have been supported by ground‐water maps and reports furnished by the Geological Survey for the different theaters.

Eos, Transactions, American Geophysical Union↗
USGS1985

Undiscovered phosphate resources in the Caribbean region and their potential value for agricultural development

The countries of the world's humid tropical regions lack the soil fertility necessary for high agricultural productivity. A recently developed agricultural technology that increases soil fertility can make tropical agriculture highly productive, but the technique requires large inputs into the soil of phosphorus and other fertilizers and soil amendments. Use of fertilizers derived from phosphate rock is increasing greatly throughout the world, and fertilizer raw materials are being produced more and more frequently from phosphate rock deposits close to the areas of use. An increased understanding of the origin of phosphate rock in ancient oceans has enabled exploration geologists to target areas of potential mineral resource value and to search directly for deposits. However, because of the difficulty of prospecting for mineral deposits in forested tropical regions, phosphate rock deposits are not being explored for in the countries of the humid tropics, including most countries of the Caribbean region. As a result, the countries of the Caribbean must import phosphate rock or phosphorus fertilizer products. In the present trade market, imports of phosphate are too low for the initiation of new agricultural technology in the Caribbean and Central American region. A newly proposed program of discovery and development of undiscovered phosphate rock deposits revolves around reconnaissance studies, prospecting by core drilling, and analysis of bulk samples. The program should increase the chance of discovering economic phosphate rock deposits. The search for and evaluation of phosphate rock resources in the countries of the Caribbean region would take about 5 years and cost an average of $15 million per country. The program is designed to begin with high risk-low cost steps and end with low risk-high cost steps. A successful program could improve the foreign exchange positions of countries in the Caribbean region by adding earnings from agricultural product exports and by substituting domestically produced phosphate rock and fertilizer products for imported phosphate fertilizers. A successful program also could provide enough domestically produced phosphorus fertilizer products to allow initiation of new agricultural technology in the region and thus increase domestic food production. Finally, a new phosphorus fertilizer industry would create new jobs in the mining, chemical, and transportation industries of the Caribbean region.

Circular↗
USGS2014

Discussion of “tide‐producing forces and artesian pressures”

I was an employee of the Texas State Board of Water Engineers in charge of the Fort Stockton field office at the time that the data for this paper were gathered. Since I have done both extensive and detailed ground‐water work in the Fort Stockton area, including the setting and maintaining of the water‐stage recorder at the Gonzales well, I believe I can add some pertinent hydrologic remarks about this paper. The authors state that the principal water‐bearing formation is a limestone. This opinion is not shared by myself and most likely the majority of other geologists in this area. Adkins [1927] favored the basal Cretaceous sands as the principal source of water to Comanche Springs. I believe that the most extensive and the principal water‐bearing formation is a sand and sandstone. The crevices and channels reported in wells and exposed at the springs are only a localized condition resulting from structural weakness and solution caused by a high water surface. The piezometric surface in sand and crevice wells is essentially identical; this suggests that there exists but one principal aquifer in this area. W.N. White, former District Geologist in Texas for the U.S. Geological Survey, in a personal communication to me in 1948, reported Comanche Springs to be the most reliable springs in Texas. This reliable flow strongly supports the concept of a sand aquifer, whose catchment area, or source, is of vast and varied extent, and a great distance from its outlet.

Eos, Transactions, American Geophysical Union↗