Browsing by Author "Adams, John A. S."
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Item A radiometric and chemical study of the binary Fitzwilliam Granite of New Hampshire(1965) Stow, Stephen Harrington; Adams, John A. S.The radioactive elements in a 1000-foot core of Fitzwilliam Granite from New Hampshire were measured with a laboratory gamma-ray spectrometer. Averages of 23.(4) p. p.m. uranium, 7.6 p.p.m thorium, and 4.0 percent potassium were found, A high abundance of uranium was found in that core showing silicic pegmatitic material, and a deficiency of uranium was found in the upper 400 feet as a. result of leaching; thorium was enriched in the altered section. Three pairs of coexisting muscovites and blotites were analyzed for thorium and uranium. In each case, a greater thorium-to-uranium ratio was observed in the biotite. Biotite was found to contain one-third of the whole-rock thorium and most of the thorium concentrated in the micas. One-half of the uranium of the pegmatitic portions (two of the samples) was concentrated in the biotite. In one of the three pairs of micas, a composite of 20 samples throughout the core, one-sixth of the total whole-rock uranium and three quarters of the uranium in the micas was found in the muscovite. Twenty-four samples of granite and 17 pairs of muscovite and biotite were analyzed for lithium, sodium, potassium, rubidium, magnesium, calcium, strontium, barium, titanium, chromium, manganese, iron, cobalt, nickel, copper, and zinc by use of absorption flame photometric and absorption spectrometric means. Alteration by solutions permeating through numerous fractures in the granite is characterized by leaching of only lithium, uranium, silicon and/or aluminum, with marked enrichment of sodium, potassium, manganese, strontium, barium, cobalt, nickel, zinc, and possibly rubidium and titanium; calcium, magnesium, iron, and copper remain steady. Variability in the analyses of the whole rock and the mineral separates is attributed to: 1) alteration, 2) metasomatism with associated pegmatite veins which cause 3) atypical mineralogy.Item An analysis of the performance of Texas State agencies in protecting the environment(1972) O'Rourke, Terence Leo; Adams, John A. S.With emphasis on the recurring accidents in the transportation and production of petroleum, this study analyzes the performance of Texas State agencies in protecting the marine environment. It summarizes the chronic and destructive force of crude oil and petroleum products in the food chain and then evaluates the piecemeal legislative and administrative approach that is designed to cope pith these problems. Noting the absence of a uniform state environmental policy and the failure of state agencies to effectively monitor and process pollution information, the study specifically characterizes the efforts of the Texas Water Quality Board and the Texas Railroad Commission. Describing the insulation of pollution control agencies from the public, the study proposes a legislative response, The Environmental Protection Act, which would provide an active role for concerned citizens. Also included are discussions of the problems of mapping environmental factors and comprehensive spill retention and recovery plans.Item Atmospheric and deep seated sources of unsupported lead-210 in soil profiles and the use of lead-210 and polonium-210 as indicators of uranium mineralization at depth(1983) Ageli, Hadi S.; Adams, John A. S.; Clark, Howard C.; Class, C. M.The increase of supported lead-21/polonium-21 with depth in soil profiles over buried uranium ore has been found to be a very cost effective method of uranium prospecting. Lead-21/polonium-21 soil profiles of the uppermost meter are superior to radon-222 track etch cups because the flux of radon-222 is highly variable from time to time depending on many factors, such as changes in wind velocity, pressure, and temperature. On the other hand, lead-21 has a half-life of 22.3 years and it is a time-integrated measurement of radon-222; the method integrates over six half-lives of lead-21 (about 133 years). At Felder Mine, Texas, the lead-21/polonium-21 soil profile increases with depth across a fault zone since the faulting facilitates the upward migration of radon-222. Reversed profiles have been observed where radon-222 accumulates under a semi-impermeable caliche layer. Also at Felder, polonium-21 from the radon-222 mobilized and released to the atmosphere during strip mining operations was detected where the soil had been removed.Item Buffalo Bayou oxygen balance and stream protection analysis(1984) Todd, David Anderson; Bedient, Philip B.; Adams, John A. S.; Ward, C. H.Buffalo Bayou suffers from low dissolved oxygen/ levels and so cannot support a wide variety or large population of fish and aquatic vegetation. The low oxygen concentrations are largely due to the in-stream degradation of sewage discharged into the Bayou. This study seeks to assess the current water quality of the Bayou, and to determine the impact of point discharges, non-point discharges, and other factors on stream quality. From data on the stream's water quality and its response to various factors, computer models have been calibrated, verified, and used to predict future and hypothetical stream quality. Consideration is given to the effect of increased sewage discharges, varied levels of in-plant treatment, and alternative options of direct treatment of the stream through flow augmentation and stream aeration. Conclusions are drawn as to the effectiveness of the various schemes for protecting the Bayou's water.Item Geochronology of major thrusts, southern Great Basin, California(1968) Sutter, John F; Adams, John A. S.Potassium-argon ages of 37 samples were determined in this study. The purpose of the study was to determine apparent age brackets for the major orogenic pulses in the southern Great Basin, California. Mineral ages from the Hunter Mountain piutonic complex indicate that it was emplaced 160-165my ago. Because the piutonic complex intrudes both plates of three major thrust faults, (the Last Chance Thrust, the Racetrack Thrust, and Lemoine Thrust), the faults must have been emplaced previous to this. One hundred fifty miles to the southeast at Clark Mountain several samples which exhibited cross-cutting relationships with thrust faults were collected and analyzed. The Data suggest that the thrusts were emplaced in the younger portion of a bracket of 85-135my ago. The Riggs Thrust in the Silurian Hills also offered possibilities for bracketing its emplacement. Data from the samples collected suggest that the Riggs Thrust was emplaced 85-95my ago, and it was probably contemporaneous with the thrusting at Clark Mountain. In addition to the sampling of rooks showing crosscutting relationships with thrust faults, "(No Suggestions)" formed along the fault planes were also sampled and analyzed. In the two cases where the minutes show complete neomineralization, the whole rock ages determined fell within the limits of the bracket established by the cross-cutting samples. Thrusting in the Hunter Mountain area and the Clark Mountain area was not contemporaneous, and even more important neither fits into a classical orogenic episode. Hunter Mountain thrusting is at least 25my older than classical Laramide and fits better into the Sevier Orogeny described by Armstrong. This, along with other data presented in the text, leads the author to conclude that orogenic activity has more or less continuous in the southern Great Basin in the bracket 185-75my ago.Item Global variations in the chemical compositions of basalt and andesite(1958) Schutz, Donald F; Adams, John A. S.The nonparametric rank-sum test is suggested as an improved nethod for comparing frequency distributions of individual components of chemical analyses which compose different statistical populations. The dalle index calculated on tbs basis of increasing SiO2, Al2O3, Na2O, and K2O and decreasing CaO, MgO, FeC, and TiO2 is used as a summary method for comparing the relative stage of differentiation of different areas. Fourteen areas (which include 744 basalt analyses) are arranged in order of decreasing average sialic rank. Five groups are found and a correlation between average sialic rank and tectonic character of the groups is observed* The two groups of highest sialic rank are composed of the four areas which surround the Pacific Basin. The intermediate group is the largest* being composed of four areas of the Afro-Surasian land case and the South Atlantic Ocean. The next group includes the Korth Atlantic and Indian Oceans and is followed by the most ferric group of all, which includes both areas of the Pacific Basin and the Greenland-Iceland Ami. The hierarchy of these areas arranged by sialic character is considered to be consistent with the hypothesis that the composition of basic extrusives is a function of the tectonic and/or orogenic history of the area involved and the thickness of the crust through which the lava must pass. The andesites of seven areas (224 analyses) are compared and are found to be a relatively homogeneous rook type, iio clear connection between basalts and andesites is apparent In the present data.Item K/Ar age dates and U, Th, K geochemistry of the (Catahoula) Gueydan formation of south Texas(1970) Duex, Timothy W; Adams, John A. S.Four K/Ar age dates on biotite separated from the Gueydan produced results ranging from Middle or Late Eocene to Early Oligocene. These ages are somewhat older than was previously hypothesized (Oligocene-Miocene). However, the author believes that there has been no significant reworking of biotitle and/or leaching of K from the biotite, either of which would increase the apparent age. These ages are thought to be correct, but, because of the complex stratigraphy, younger ages could also be possible. The Th, U, and K averages yielded results which are somewhat lower than they should be if the Gueydan is inferred to be an acidic volcanic rock originally. The lower averages are thought to be due to leaching and therefore the Gueydan was not originally deficient in these radioelements. The Th, U, and K distribution within the Gueydan approximates a log normal distribution, with minor fluctuations.Item K♯°/AR♯° age dating on glauconites and paleontologic interpretation near the Cretaceous-Tertiary transition in Texas.(1984) Gammill, Laura M.; Adams, John A. S.; Casey, Richard E.; Clark, Howard C.Several exposures of the Cretaceous-Tertiary contact in Texas were searched for material suitable for radiometric age dating. Glauconites from Littig Pit, Travis County, Texas were sufficient in quality and quantity. K4/Ar4 dating on glauconites from Littig Pit indicates that 4 to 6 Ma of lowermost Tertiary section are missing. At least one nannofossil zone and at least two foraminiferal zones missing from the lowermost Tertiary limit the unconformity to 2.5 to 5 Ma. The concordant radiometric and paleontologic dates refute the view of Odin that all low potassium glauconites are suspect. The uppermost Cretaceous represents an undetermined amount of time. It is possible that the Midway Group was deposited rapidly during the last major Paleocene transgression of Vail et al (1977). The data supports the conclusion of Berggren and Aubert (1975) that the Midway fauna are correlatable worldwide. The iridium layer of Alvarez et al (1982) is missing at the Littig Pit, confirming missing section and illustrating how this iridium layer may be used as a worldwide time marker.Item Potassium-argon age and petrography of the Sierra Blanca Peak igneous intrusives Hudspeth County, Texas(1983) Matthews, William K.; Adams, John A. S.; Baker, Donald R.; Bally, Albert W.Rhyolite and diorite intrusives are exposed six miles west of Sierra Blanca (Hudspeth County) in West Texas. StructuraUy, they lie between the relatively undeformed Diablo Platform and the folded and faulted Chihuahua Tectonic Belt (Laramide). In thin sections the rhyolite was homogeneous and the diorite proved more variable in mineralogy. Detailed field mapping (1:24) confirmed the general outlines of the five rhyolite laccoliths described by earlier workers. New details of rhyolite dikes, autobrecciation, and flow banding were recognized. A rhyolite age of 36.1 m.y. was reported by earlier workers. The new mapping documented over fifty previously unreported diorite dikes and sills with a concentrated swarm near Sierra Blanca Peak. A potassium-4/argon-4 age of 88 +4 m.y. from a single hornblende phenocryst from a 3 foot dike in the diorite swarm is the oldest Mesozoic age reported to date in this region. Mineralogical differences between the rhyolite and diorite and the 5 m.y. interval between emplacements increase the probability that they are from unrelated magma sources and different tectonic regimes.Item Preliminary determination of the Radon-222 baseline in Houston, Tex.(1979) Moed, Barbara A.; Adams, John A. S.; Gesell, Thomas F.; Clark, Howard C.Radon-222 is a naturally occurring radionuclide that is present in rocks, sediments, and soils in detectable quantities. The migration of radon-222 is promoted by nonreactive chemical properties and by a. 3.82 day half life. A large fraction of the natural radioactivity in surface air is comprised of radon-222 and its short-lived progeny. The activity of radon-222 in soil gas and in surface air exhibits great variability spatially and temporally. This study investigated the temporal variation of radon-222 activities in soil gas and in the surface layer of the atmosphere. The alpha activity in soil gas was monitored at one site for a period of six months. Integrated countrates were recorded daily. Atmospheric radon-222 activities were monitored continuously at an adjacent site during four months of the same period. This difference in the span of monitoring periods was caused by equipment downtime in the air monitoring system. Meteorological data were concurrently tabulated. Univariate graphs were constructed to show the variation of daily mean atmospheric radon-222 activities and of soil gas activities versus mean temperature, mean barometric pressure, average wind speed, and resultant wind direction. The effects of rainfall on these activities were also assessed. The mean of daily soil gas activities is 4.2 counts/ minute; the range of these observations is 1. - 11. counts/ minute. The mean of the atmospheric radon activities is .39 pCi/1; the range of daily mean values is .22 - .79 pC/1. Atmospheric radon activities exhibited distinct diurnal variations. Composite soil samples from the vicinity of the monitoring site were collected and analyzed for uranium-238 and thorium-232 concentrations. The radon-222 and radon 22 emanating powers of these samples were also determined.Item Radioactivity in tektites(1966) Balacek, Kenneth Joseph; Adams, John A. S.Thorium, uranium, and potassium contents of 10 bediasites, 12 philippinites, 8 australltes, and 5 indochinttes were determined using a non-destructive gamma-spectrometric technique. The average thorium, uranium, and potassium values of the 35 tektites counted were 11.8 ppm, 2.1 ppm, and 1.9% respectively. The bediasites show lower than average values (7.3 ppm Th, 1.8 ppm U, and 1. 8% K) while the philippinites are noticeably higher (14.6 ppm Th, 2.6 ppm U, and 2.0% K). The australites and indochinites show similar values (12.7 ppm Th, 2.1 ppm U, and 1.9% close to the total average. The bediasites seem to be definitely deficient in thorium content. An average Th/U ratio of 5. 4 was obtained. Although valid regional differences could not be determined, a definite hierarchy of decreasing thorium and uranium values from australttes and indochinites, to bedtasttes was clearly established and confirmed by total alpha-counting methods. Both the individual Th/U ratios and the total alpha-determinations indicate a single related occurrence for the Pacific Ocean or Far Eastern tektites consisting of the australites, indochinites, javanites, and philippinites. The microsites of the alpha-emitters were investigated by autoradiography and it was determined that the radioactivity in tektites is homogeneously distributed and of a low flux.Item Radon-222 emanation from rocks, soils, and lunar dust(1971) Barretto, Paulo Marcos de C; Adams, John A. S.The investigation of the Radon-222 emanation rate and the escape-to-production rate ratio by means of alpha counting was undertaken for rocks, soils and a sample from lunar dust. The material was analysed for different grain sizes, moisture, contents and temperatures. Radon escape-to-production rate ratios from 1% - 25% were found for rocks crushed to identical grain size classes and distinctly higher values, from 20% - 70% were observed in soils. The results allow to subdivide the natural materials at the earth's surface into three categories: strong emanators, soils at 40% radon escape to production rate; moderate emanators, igneous rocks at 10% - 15%; poor emanators, sediments and some metamorphic rocks at = 5%. The factors controlling the emanation rate are: grain size, nature matrix or groundmass, uranium distribution within the crystalline structure, crystal damage resulting from radiation and/or weathering. Radiation damage has been put forward as a plausible mechanism to explain the phenomena on fresh grains because diffusion through the crystal structure alone cannot account for the observed values. Daily temperature variations have no effect on the escape rates as no appreciable adsorption or release of radon was observed in the temperature range of -15° to 96° C. The general effect of moisture is a slight increase in the emanation rate. An escape-to-production rate ratio of 45 ± 20% was observed for 0.4 g of an Apollo 12 dust. The radon isotopes diffusion through the surface rubble and lunar "atmosphere" and the consequent "fallout" of lead isotopes over the moon surface could provide a mechanism for lead enrichment and depletion which might be related to the uranium-lead discordant ages for fines compared to associated rocks.Item Secular variations of radiocarbon in the atmosphere(1974) Lundell, Leslie Lee; Adams, John A. S.As radiocarbon dating has become more accurate and available to more researchers it has become increasingly apparent that there are variations between the radiocarbon age and the absolute age. Tree-ring dating has provided a calibration scale for the radiocarbon age scale. Tree-ring dated wood of 7, years age gives a radiocarbon date of only 6, radiocarbon years. The cause of these variations has been the subject of much debate among researchers during the last decade. The Twelfth Nobel Symposium on "Radiocarbon Variations and Absolute Chronology" was concerned mainly with this problem. Many researchers believe that these variations are caused by variations in radiocarbon production due to variations in the dipole moment of the earth. This hypothesis is still questioned by many other authors. This thesis starts with the assumption that the radiocarbon production rate has remained constant and that the variations are due to variations in the specific activity of the atmosphere caused by changes In the carbon reservoir system. For the carbon reservoir system a six box model was adapted from the model of Bolin (197). Radiocarbon ages of the different carbon reservoirs of this model compare very well with those which have been measured. The only major problem is that the total radiocarbon in the different reservoirs does not add up to the total that there should be on earth based on the production rate. For this reason the excess radiocarbon was placed in the sixth box called the residual radiocarbon reservoir. The residual radiocarbon reservoir is Just a mathematical box which contains the additional radiocarbon on earth not found in the other five reservoirs. The exchange rate of carbon between the shallow sea and the deep sea has the greatest effect on the specific activity of the atmosphere. A lower exchange rate between these two reservoirs causes an accumulation of radiocarbon in the atmosphere. Therefore it is proposed that the young radiocarbon ages in the past may be due to a higher specific activity of the atmosphere caused by a slower exchange rate between the shallow and deep seas. An increase, in the specific activity of the atmosphere in the past causes an increase in the specific activity of the other reservoirs if the conditions of the reservoirs were the same in the past as they are at present. The total amount of radiocarbon on earth would be exceeded by the radiocarbon in the five reservoirs at the higher specific activities of the atmosphere. Therefore it is believed that the conditions of the reservoirs were not the same in the past. The exchange rate between the shallow and deep seas has a large effect on the amount of radiocarbon in the residual radiocarbon reservoir. With a slower exchange rate the age of the deep sea relative to the atmosphere is Increased causing both an increase in the specific activity of the atmosphere and an increase in the amount of radiocarbon in the residual radiocarbon reservoir. If the radiocarbon production is assumed to vary the same problems still exist. The exchange of carbon between the atmosphere and oceans is so rapid that any fluctuation in the production rate is damped by the oceans. The entire carbon reservoir of the atmosphere is turned over by the shallow sea in seven years. The carbon reservoir of the shallow sea is turned over once in about eleven years by exchange with the deep sea. These rates are fast enough to damp out any short term fluctuations due to changes in the production rates. It is believed therefore that the age variations are due to a slower exchange rate of carbon between the shallow and deep seas.Item The behavior of thallium with respect to potassium and rubidium in coexisting micas and feldspars(1966) Riber, Joshua Isaac; Adams, John A. S.Seventeen muscovites, eleven biotites, eleven microclines, one albite, and one lepidolite from five granite and granite pegmatite localities were analyzed for thallium, rubidium, and potassium by atomic absorption spectrophotometry. Rubidium and potassium were determined in aqueous solutions. Thallium was determined in butanol in which 0.1 gamma/ml T1 was easily detected. Mean Rb/Tl ratios range from 110 for pegmatitic biotites to 232 for granitic microclines. No significant difference in Rb/Tl ratios between granites and pegmatites was noted, while there is a tendency for T1 to be enriched, with respect to K and Rb, progressively in microcline, muscovite, biotite. Rubidium is similarly enriched with respect to K. Thallium content varied from 1 ppm in a microcline sample to 108 ppm in the lepidolite. Maximum value for microcline is 70 ppm, 54 ppm for muscovite and 37 ppm for biotite. Thallium appears to follow Kb more closely than K in granites and pegmatites. There is little variation in mean Kb/Tl ratios.Item The determination and geochemistry of cesium(1963) Allen, Gary Curtiss; Adams, John A. S.Methods for the determinations of cesium, rubidium, and potassium were developed. For cesium this employed dissolution of finely ground samples, ion-exchange enrichment, and flame photometric determination. Rubidium and potassium were determined by flame photometry directly after dissolution. Data was obtained on 75 samples of granites, syenites, granodiorites, monzonites, diorites, tonalites, gabbros, and other rock types from seven North American batholiths. The average cesium content was found to be 6.6 p.p.m., and the data showed an apparently lognormal distribution. The overall K/Cs and Rb/Cs ratios were determined as 4800 and 26 respectively.Item The distribution of thorium and uranium in sedimentary rocks and the oxygen content of the pre-Cambrian atmosphere(1957) Pliler, Richard; Adams, John A. S.Item The effect of temperature and other parameters upon the uranium content of natural carbonates(1962) Barks, Ronald Edward; Adams, John A. S.Item The radioactivity, accessory minerals, and possibilities for absolute dating of bentonites(1957) Hamill, Gilmore Semmes; Adams, John A. S.Sixty-three samples of bentonite from the Ordovician and 3 from the Devonian of the eastern United States were collected. Two samples from the Ordovician of Norway, and 4 from the Cretaceous of Wyoming were secured from other individuals. The thorium, uranium, and potassium metal concentrations of these samples were determined by gamma-ray spectral and alpha count-fluorometric uranium (only used on 3 Wyoming samples) techniques. The averages and ranges of these values are [see table] This data is interpreted in terms of the manner of formation and occurrence of the bentonites. It is concluded that the redox potential of the environment and the mineralogical composition of the bentonites are the dominant factors in controlling the concentrations and their ranges. A significant portion of the thorium and uranium is tied up in resistate minerals.. The possibility of using the accessory zircons in bentonites. for absolute age determinations was also explored. Criteria were set up to test the contemporaneous pyrogenic origin of all, or most, of the zircons in the sample. The main criteria were a simple restricted mineral suite consisting solely of pyrogenic minerals, and the character and habit of these minerals (they must show no effects of normal subaqueous transport). Several samples were tested, and one was found to satisfy all of the criteria. From the quantitative separation of a pure zircon concentrate from this latter sample an estimate was made of the amount of bulk bentonite necessary for various types of age determinations. Four to 5 kilograms of bentonite should yield approximately 300 milligrams of pure zircon, which is an adequate amount for radiation damage, and total lead-alpha count methods. About 20 kilograms is optimum for lead-206/lead-207 age determinations. A hydrocyclonic mineral separator is described which can readily handle samples of this size. Aside from the zircon a potassium-argon age may be obtained on the biotite.Item The thorium and uranium content of the Enchanted Rock batholith(1960) Kline, Mary-Cornelia; Adams, John A. S.The results of numerous vibratory tests on model piles in clay are presented in this thesis with the purpose of studying the behavior of piles subjected to vibratory loadings. The effects of pile length, time after driving, soil consistency, dynamic force amplitude, and free water surrounding the pile were investigated. The effect of confining walls on such tests received special attention. Tests were also performed on two model pile groups. The possibility of representing a pile subjected to vibratory excitation by discrete masses and springs and the soil reaction by Kelvin models was studied, and an attempt was made to correlate theoretical results with model results. Finally, a very simplified approach was proposed for determining the maximum amplitude at the natural frequency for a pile subjected to vibratory loading.Item The thorium, uranium and zirconium concentrations in bauxites and their relationship to bauxite genesis(1959) Richardson, Keith Allan; Adams, John A. S.For some time it has been known that certain bauxites contain greater amounts of thorium and uranium than the average crustal rocks. The primary purpose of this study was to make a general survey of bauxites to investigate the distribution of radioactive elements, and determine the significance of this distribution. In addition to contributing to the geochemical know ledge of thorium and uranium, the results of this study may have some economic value. The possibility of byproduct recovery of thorium is suggested, also the possible use of radiometry in prospecting for aluminum ore.