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At least 55 records · Page 3Linked to original sources
USGS1991

Volcanic-hazards assessments; past, present, and future

A new reason to study volcanoes has developed within the last few decades; it is to anticipate the specific kinds and extents of future eruptions and their effects on people and property. Such studies are based chiefly on the eruptive histories of volcanoes and the distribution of past eruptive products. Volcanic-hazards studies in the U.S Geological Survey began in the 1960's primarily to provide data useful for hazard mitigation during future eruptions. Worldwide interest in volcanic-hazards assessments was greatly stimulated by the 1980 eruption of Mount St. Helens, just 2 years after a hazards assessment of the volcano was published in U.S Geological Survey Bulletin 1383-C. Many climactic eruption on May 18, although the extent of the unprecedented and devastating lateral blast was not anticipated.

Earthquakes & Volcanoes (USGS)↗
USGS1989

Solubility of jarosite solid solutions precipitated from acid mine waters, Iron Mountain, California

Because of the common occurrence of 15 to 25 mole percent hydronium substitution on the alkali site in jarosites, it is necessary to consider the hydronium content of jarosites in any attempt at rigorous evaluation of jarosite solubility or of the saturation state of natural waters with respect to jarosite. A Gibbs free energy of 3293.5±2.1 kJ mol-1 is recommended for a jarosite solid solution of composition K.77Na.03(H3O).20Fe3(SO4)2(OH)6. Solubility determinations for a wider range of natural and synthetic jarosite solid solutions will be necessary to quantify the binary and ternary mixing parameters in the (K-Na-H3O) system. In the absence of such studies, molar volume data for endmember minerals indicate that the K-H3O substitution in jarosite is probably closer to ideal mixing than either the Na-K or Na-H3O substitution.

California↗
USGS1989

Mineral saturation states in natural waters and their sensitivity to thermodynamic and analytical errors

Saturation indices computed with WATEQ4F chemical analyses from a groundwater in crystalline bedrock and a surface water receiving acid mine drainage are frequently at or above saturation with respect to calcite, fluorite, barite, gibbsite and ferrihydrite. Deep granitic groundwaters from Stripa, Sweden, are supersaturated with respect to calcite and fluorite. Acid mine waters from the Leviathan Mine drainage basin in California are supersaturated with respect to barite by about a factor of three. These mine waters also are 10 times supersaturated with respect to the most soluble form of ferric hydroxide but are near saturation with respect to microcrystalline gibbsite. A sensitivity analysis has been performed by varying the analytic and thermodynamic parameters for which the saturation indices are most sensitive. For calcite, fluorite and barite, the supersaturation effect appears to be real because it is only slightly decreased by sources of uncertainty. Apparent supersaturation for gibbsite is most likely caused by the degree of crystallinity on solubility behavior. Apparent supersaturation for ferric hydroxide is likely caused by small colloidal particles (< 0.1 µ m) in the water sample that cannot be removed by standard field filtration, although several other possible explanations cannot be easily excluded.

Science Geological Bulletin↗
USGS1991

Regional characterization and resource evaluation of Paleocene and Eocene coal-bearing rocks in Pakistan

Field work drilling, and other related studies carried out from 1985 to 1988 to assess the quantity and quality of the coal resources of southern Sindh. Sixty-eight holes drilled in the Lakhra/Jherruck, Thatta, and Indus East coal fields indicate that presently known and mined coal fields in southern Sindh are not isolated coal occurrences. Rather, much of southern Sindh, including the Thar Desert, is underlain by strata that contain coal beds. More than 400 core and mine samples were collected for proximate and ultimate analysis and determination of major, minor and trace elements; also, lithologie logs were prepared from description of rock cuttings and core. Original coal resources of 1,080 million tones have been estimated for 7 out of 9 coal zones in parts of the Lakhra area, where coal-bed thicknesses range from a few centimeters to 5 m. In the Sonda/Jherruk area, 3,700 million tones of coal have been identified, the thickest coal bed intercepted being 6.3 meters. The apparent rank of the coal in these fields ranges from lignite A to sub-bituminous C. Averaged analytical results on an as received basis indicate the coal beds contain 28.4 % moisture, 18,3 % ash, 4.7 % sulfur, 25,2 % fixed carbon, 27.9 % volatile matter, and 33.1% oxygen. Average calorific value for Lakhra coal samples is about 3,660 Kcal/kg, whereas that of Sonda/Jherruk samples is about 3,870 Kcal/kg. Geophysical logs were obtained for the drill holes, and cores and rock cuttings are available from the GSP for further study and reference. The second phase of the project began in 1987 with surface exploration in the Salt Range coal field of Punjab Province, the Sor Range and Khost-Sharig-Harnai coal fields of Baluchistan, and the Makarwal and Cherat coal fields of NWFP. These are briefly discussed here.

Geological Bulletin, University of Peshawar↗
USGS1939

Geologic map and guide of the island of Oahu, Hawaii

This bulletin, although designated Bulletin 2, is actually the fourth of a series published by the Division of Hydrography of the Territory of Hawaii. All four of the bulletins thus far published relate to the geology and ground-water resources of the island of Oahu.1 Together they present the results obtained on this island in the program of ground-water investigation of the Territory that has been conducted in cooperation with the Geological Survey, of the United States Department of the Interior. Bulletin 5 which is in preparation will describe the progress made in developing the ground-water resources of Oahu since Bulletin 1 was issued. In Bulletin 2 is presented the detailed geologic map of Oahu that has resulted from this investigation. The base for this map is the new topographic map of Oahu prepared by the Topographic Branch of the Geological Survey. This bulletin also contains a guide to the geology along the main highways, which can be used advantageously in connection with the geologic map. For 18 years the writer has had the great privilege of working under the technical direction of Mr. 0. E. Meinzer, geologist in charge of the Division of Ground Water, U. S. Geological Survey. Nearly two decades ago Mr. Meinzer envisioned the great benefits that the people of Hawaii would derive from a thorough study of the groundwater resources of these islands. He also recognized that a full knowledge of these resources could be obtained only by a complete understanding of the geology of the islands and the processes which formed them. This bulletin is one of a series that has been made possible largely as a result of his broad vision. Credit is due Mr. W. 0 . Clark for the location of all the dikes shown on plate 2 in the headwaters of Kamananui Stream near the north end of the Koolau Range, and to Dr. C. K. Wentworth for about a dozen dikes north of Kaimuki. Messrs. 0. E. Meinzer, G. R. Mansfield, M. H. Carson, G. A. Macdonald, and S. H. Elbert kindly criticized the manuscript. Mr. Harry L. Taeuber designed the cover and with James Y. Nitta prepared the illustrations. Their work has greatly enriched this bulletin. The topographic maps of 15-minute quadrangles, on a scale of 1 to 20,000 (approximately 3 inches to the mile), were used in the field as a base for the geologic mapping. The data were then transferred to the new topographic map of Oahu, which is on a scale of 1 to 62,500. The resulting geologic map is reproduced as plate 2 (in pocket) of this report. Some of the outcrops are too small to be shown on this smaller map. Plate 2 of this report was listed as plate 2 in Bulletin 1, which was, however, published without the map because of the time required to prepare and engrave the topographic base and the geologic map. The geologic structure sections at the bottom of plate 2 were not described in Bulletin 1, but are discussed below.

Hawai'i↗
USGS2003

Contributions to Industrial-Minerals Research

Contributions to Industrial-Minerals Research, an ongoing series of U.S. Geological Survey (USGS) Bulletin chapters, presents research strategies, results, and updates of investigations of industrial minerals by USGS scientists and cooperators. Industrial minerals are defined as valuable nonmetallic, nonfuel geologic materials, generally rocks or minerals, used in a wide range of construction and industrial applications-for example, sand, gravel, and crushed rock used as aggregate for construction; limestone used for cement; phosphate for fertilizers and insecticides; and diatomite used for filtration, fillers, and abrasives. The term also comprises some processed materials, such as cement and metallic compounds with major utilization in nonmetallic forms. For example, titanium is commonly grouped with industrial minerals because more than 90 percent of it is sold and utilized in the form of the oxide (TiO2) rather than as Ti metal. Other metals and metallic compounds commonly grouped with industrial minerals include Mn, Cr, Fe oxides, and rare-earth elements (REEs).

Bulletin↗
USGS2026

Flood-frequency estimates for Kentucky streamgages based on data through water year 2021 and results of updating the fundamental layers in Kentucky StreamStats

The U.S. Geological Survey, in cooperation with the Kentucky Transportation Cabinet, analyzed flood-frequency statistics for streamgages in Kentucky. Using annual peak-flow data through water year 2021, flood-frequency estimates were computed for 261 streamgages, including unregulated and regulated sites as well as sites with mixed regulation records. Methods followed those outlined in “Guidelines for Determining Flood Flow Frequency—Bulletin 17C” (U.S. Geological Survey Techniques and Methods 4–B5). These estimates included flows corresponding to annual exceedance probabilities of 50, 20, 10, 4, 2, 1, and 0.2 percent. Temporal trend analyses using the Mann-Kendall test indicated that 18 percent of unregulated streamgages with (1) at least 30 years of peak-flow record and (2) peak-flow record at least as recent as water year 2000 showed statistically significant trends, most of which were weak to moderate increases in peak flows. Concurrently, the fundamental geospatial datasets that support the Kentucky StreamStats application were updated by using high-resolution digital elevation models and hydrography datasets to derive flow direction, flow accumulation, and stream definition rasters. Comparisons of regression-based flood-frequency models using the old and new layers demonstrated consistent results, with a statewide root-mean-square error of 0.019, in the base-10 logarithm of cubic feet per second. Furthermore, to assess model performance, flood-frequency estimates made by using the updated layers and previously published regression-based models were compared to flood-frequency estimates newly computed by following Bulletin 17C. This analysis showed the models performed adequately for most Kentucky stream locations. The updated statistics and geospatial layers provide stakeholders with more accurate, current data for flood-risk assessment, infrastructure design, and water-resource management.

Kentucky↗
USGS1990

The Alaska Mineral Resource Assessment Program: Background information to accompany folio of geologic and resource maps of the Ugashik, Bristol Bay, and western part of Karluk quadrangles, Alaska

The Ugashik, Bristol Bay, and western part of Karluk quadrangles (1:250,000) are a part of the Alaska Peninsula in southwestern Alaska. This circular, in conjunction with a companion folio of MF-series maps, two I-series geologic maps, and three bulletins, represents the results of integrated field and laboratory studies on the geology, geophysics, geochemistry, paleontology, geochronology, and mineral resources of the quadrangles. These studies were undertaken to provide a modern assessment of the mineral and energy resources of the quadrangles. Each map contains descriptive text, explanatory material, tables, diagrams, and pertinent references. This circular provides background information for the mineral resource assessment map (MF-1539-1) and integrates the component M F- and I-series maps. A comprehensive bibliography cites both specific and general references relevant to the geology and resources of the quadrangles.

Alaska↗
USGS1891

Index to the known fossil insects of the world, including myriapods and arachnids

With the view of furthering study in the too neglected field of fossil insects, I transmit herewith for publication the card catalogue of described fossil insects which I have used for twenty years and kept constantly up to date, and which has greatly facilitated my own researches. It is believed to be practically complete. At least where insects are figured, and in many other cases where they are the first or only references from a given locality, entries are given where only the genus, the family, or even the order is mentioned. This has been done because the early literature of fossil insects is essentially vague and general, but it should not for that reason be wholly overlooked ; and to-day our knowledge of the occurrence of insects of a particular locality, even when of recent discovery, is not infrequently confined to statements of a general nature, which, if not brought to view or mind in a list like this, would be lost sight of, while their recognition may lead to further local investigation, to the earlier benefit of science. It is in no sense a systematic catalogue, and except occasionally in the notes contains no immediate results of investigation. No questions of synonymy are settled. The entries are made as the authors quoted gave them, with only the corrections of spelling required; it follows that the same insect appears at several points, to which the student is referred by full cross-references, and that more than one insect may (though probably rarely does) figure under one name. In one or two such instances, where the same name has been given by inadvertence to two totally different creatures, the later one is separated from the earlier. For convenience' sake, the entries are grouped into large sections, nearly identical with those I have employed in my systematic review of fossil insects (Bulletin 31, U. S. Geological Survey), by which method the insects from the Primary, Secondary, and Tertiary rocks are kept distinct; but otherwise the entries are purely alphabetical under the orders. It should be noticed, however, that the vague references to groups higher than genera are brought together at the beginning of each alphabet, first the most vague, and then those which permit some alphabetization. In these cases the primary or secondary alphabetization is first by authors, second by dates, and in all cases where under one entry there is more than one date the order therein is chronological. In a previous bulletin (Bulletin 69, U. S. Geological Survey) is given a complete bibliography of the literature from which these entries are taken, and the two works are thus complementary to each other.

Bulletin↗
USGS2009

Processes active in mafic magma chambers: The example of Kilauea Iki Lava Lake, Hawaii

Kilauea Iki lava lake formed in 1959 as a closed chamber of 40 million m 3 of picritic magma. Repeated drilling and sampling of the lake allows recognition of processes of magmatic differentiation, and places time restrictions on the periods when they operated. This paper focuses on evidence for the occurrence of lateral convection in the olivine-depleted layer, and constraints on the timing of this process, as documented by chemical, petrographic and thermal data on drill core from the lake. Lateral convection appears to have occurred in two distinct layers within the most olivine-poor part of the lake, created a slightly olivine-enriched septum in the center of the olivine-depleted section. A critical marker for this process is the occurrence of loose clusters of augite microphenocrysts, which are confined to the upper half of the olivine-poor zone. This process, which took place between late 1962 and mid-1964, is inferred to be double-diffusive convection. Both this convection and a process of buoyant upwelling of minimum-density liquid from deep within the lake (Helz, R.T., Kirschenbaum H. and Marinenko, J.W., 1989. Diapiric melt transfer: a quick, efficient process of igneous differentiation: Geological Society of America Bulletin, v. 101, 578–594) result from the fact that melt density in Kilauea Iki compositions decreases as olivine and augite crystallize, above the incoming of plagioclase. The resulting density vs. depth profile creates (1) a region of gravitationally stable melt at the top of the chamber (the locus of double-diffusive convection) and (2) a region of gravitationally unstable melt at the base of the melt column (the source of upwelling minimum-density melt, Helz, R.T., Kirschenbaum H. and Marinenko, J.W., 1989. Diapiric melt transfer: a quick, efficient process of igneous differentiation: Geological Society of America Bulletin, v. 101, 578–594). By contrast the variation of melt density with temperature for the 1965 Makaopuhi lava lake does not show a decrease in density as temperature decreases, so neither process should have occurred in that lava lake. Because many mafic magmas crystallize significant olivine and/or pyroxene before they begin to crystallize plagioclase, the density relations observed for Kilauea Iki, and the processes that result from them, may be relevant to crystallization in other mafic magma chambers. The results for the 1965 Makaopuhi lava lake emphasize the role of bulk composition as a critical control on magmatic processes.

Hawai'i↗
USGS1919

Deposits of Claiborne and Jackson age in Georgia

In 1911 the Geological Survey of Georgia published as Bulletin 26 a "Preliminary report on the geology of the Coastal Plain of Georgia," by Otto Veatch and Lloyd William Stephenson, prepared in cooperation with the United States Geological Survey under the supervision of T. Wayland Vaughan, a geologist in charge of Coastal Plain investigations, who contributed the determinations of the invertebrate fossils of the Tertiary and Quaternary formations. Although this report constituted a decided advance in our knowledge of the geology of the Coastal Plain of Georgia, it was admittedly of reconnaissance character, and corrections and additions to it were to be expected. During the last few years field work has been prosecuted vigorously in the Coastal Plain of Georgia, and the additional information thus accumulated throws light upon certain problems of stratigraphy left unsolved by Veatch and Stephenson and alters considerably some of their correlations. The object of the present paper is to present the new evidence regarding the age and correlation of the Eocene formations of Georgia and to revise in accordance with present knowledge the descriptions of the deposits of Claiborne and Jackson age.

Georgia↗