UScholar Works
 
Filters: Department: "Geology & Geophysics" Collection: "ir_uspace" Year End: 2016
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CreatorTitleDescriptionSubjectDate
51 Fernandez, Diego P.Lowering the detection limit for arsenic: implications for a future practical quantitation limitExposure to arsenic (As) in drinking water is associated with an increased risk ol bladder, liver, kidney, ,ind skin cancers (Smith et al, 2002; NRG DIEGO P. FERNANDEZ, 2001). To mitigate these risks? the US Environmental Protection Agency AND JANET G. HERING (USEPA) revised the maximum contaminant ...Practical quantitation limit; Chlorine2007
52 Jarrard, Richard D.The magnetostratigraphy of ocean drilling program leg 105 sedimentsDuring Leg 105 of the Ocean Drilling Program, a series of 11 holes was drilled at three sites along a north-south transect in Baffin Bay and the Labrador Sea. Intermittent recovery and drilling disturbance, resulting in part from the harsh weather conditions encountered, hampered magnetostratigraph...1989
53 Brown, Francis HaroldMagnetostratigraphy of the Koobi Fora Formation, Lake Turkana, KenyaThe Koobi Fora Formation, a Pliocene and Pleistocene sequence of sedimentary deposits northeast of Lake Turkana, has yielded numerous fossils and stone artifacts of early hominids. Stratigraphic correlation of the hominid-bearing deposits throughout the Turkana region was established primarily by th...1986
54 Brown, Francis HaroldMagnetostratigraphy of the shungura and usno formations, lower Omo Valley, Ethiopia1976
55 Brown, Francis HaroldMagnetostratigraphy of the shungura and usno formations, Southwestern Ethiopia: new data and comprehensive reanalysis1978
56 Brown, Francis HaroldMethods of datingThe fossil record of primates begins in the latest Cretaceous period, so primate palaeontologists are interested in techniques of dating applicable over the past 70 million years. Fossil bones themselves are rarely datable with any precision, and these are mainly of late Pleistocene or Holocene age....1992
57 Chapman, David S.; Harris, Robert N.Mid-Latitude (30°-60° N) climatic warming inferred by combining borehole temperatures with surface air temperaturesWe construct a mid-latitude (30°-60° N) reduced temperature-depth profile from a global borehole temperature database compiled for climate reconstruction. This reduced temperature profile is interpreted in terms of past surface ground temperature change and indicates warming on the order of 1°C...Surface air temperature; Surface ground temperature; Borehole temperatures; Geothermal observations2001
58 Jarrard, Richard D.Milankovitch paleoceanographic cycles in geophysical logs from ODP Leg 105, Labrador Sea and Baffin BayOcean Drilling Program (ODP) Sites 645 and 646, in Baffin Bay and the Labrador Sea, respectively, were logged following drilling during Leg 105. Geophysical logs in ODP drill sites yield long, continuous records of sedimentary sequences and thus provide the opportunity for examining evidence of peri...1990
59 Chapman, David S.Monitoring aquifer recharge using repeated high-precision gravity measurements: a pilot study in South Weber, UtahRepeated high-precision gravity surveys were conducted over two infiltration cycles on an alluvial-fan aquifer system at the mouth of Weber Canyon in northern Utah as part of the Weber River Basin Aquifer Storage and Recovery Pilot Project (WRBASR). Gravity measurements collected before, during, an...Aquifer recharge; Gravity measurements; Infiltration ponds; Weber River Basin Aquifer Storage and Recovery Pilot Project2008
60 Fernandez, Diego P.Near-criticality in dilute binary mixtures: distribution of azulene between coexisting liquid and vapor carbon dioxideThe equilibrium distribution of dilute solutes between vapor and liquid coexisting phases of near-critical solvents exhibits a simple dependence on the solvent's liquid density which extends over a wide temperature range; however, theory predicts this dependence only as an asymptotic limit. In order...Near-critical solvents; Azulene; Binary mixtures; Dilute solutions2002
61 Zhdanov, Michael S.New approach to interpretation of airborne magnetic and electromagnetic dataWe present a new technique for underground imaging based on the idea of space-frequency filtering and downward continuation of the observed airborne magnetic and electromagnetic data. The technique includes two major methods. The first method is related to the downward analytical continuation and ...1996-01-01
62 Zhdanov, Michael S.Novel approach to the model appraisal and resolution analysis of regularized geophysical inversionThe existing techniques for appraisal of geophysical inverse images are based on calculating the model resolution and the model covariance matrices. In some applications, however, it becomes desirable to evaluate the upper bounds of the variations in the solution of the inverse problem. It is possib...Geophysical inversion; Electromagnetic modeling; Cauchy inequality; Resolution analysis; Lanczos decomposition method; SLDM; Voisey's Bay; 3-D modeling2006
63 Brown, Francis HaroldObservations on the stratigraphy and rediometric age of the omo beds, lower omo basin, southern EthiopiaDuring September and October, 1966, the author measured a stratigraphic section for a portion of the Omo Beds, as exposed north of Kalam, Ethiopia. Additional field observations were also made at the time in other parts of the lower Omo Basin. Samples were collected for analysis and for radiometric ...1969
64 Jarrard, Richard D.Origin of seismic reflectors within carbonate-rich sediments from northeastern Australian marginWe use continuous velocity records from 12 sites and continuous density records from 9 sites from Ocean Drilling Program (ODP) Leg 133 to examine both direct and indirect controls on seismic reflectors and depth-to-time conversion for the northeastern Australian margin. In these carbonate-rich sedim...1993
65 Jewell, PaulPaleoredox conditions and the origin of bedded barites along the Late Devonian North American continental marginThe most important controls of the redox state of natural waters are the flux of organic matter from the photic zone, the degree of physical mixing, and oxygen concentrations of any connecting water masses. In coastal upwelling zones, these factors can be described with a simple box model constraine...Bedded barites; Late Devonian; Continental margin; Redox state1994
66 Zhdanov, Michael S.Parameter estimation for 3-D geoelectromagnetic inverse problemsParameter estimation in geoelectromagnetics aims to obtain the most important parameters of a well-defined conductivity model of the Earth. These parameters are features of typical geological structures, such as depth and size of conductive or resistive targets, angle of dike inclination and its le...1999-01-01
67 Brown, Francis HaroldPleistocene rhyolite of the mineral mountains, Utah geothermal and archeological significance1978
68 Brown, Francis HaroldPliocene/pleistocene formations in the lower omo basin, southern EthiopiaFollowing a two month geological reconnaissance by one of us (FHB) in 1966, four seasons of fieldwork by members of the Omo Research Expedition has added greatly to our previous, scanty knowledge of the late Cenozoic history of the lower Omo basin in southern Ethiopia. Eduard Suess (in: von Hohnel ...1970
69 Zhdanov, Michael S.Quasi-analytical approximation and series in electromagnetic modelingThe quasi-linear approximation for electromagnetic forward modeling is based on the assumption that the anomalous electrical field within an inhomogeneous domain is linearly proportional to the background (normal) field through an electrical reflectivity tensor ˆλ. In the original formulation of...Electromagnetic modeling; Quasi-linear approximation; Quasi-analytical approximation; Quasi-analytical series2000
70 Zhdanov, MichaelQuasi-analytical boundary condition for three-dimensional finite difference electromagnetic modelingNumerical modeling of the quasi-static electromagnetic (EM) field in the frequency domain in a three-dimensional (3-D) inhomogeneous medium is a very challenging problem in computational physics. We present a new approach to the finite difference (FD) solution of this problem. The FD discretization ...2004-01-01
71 Zhdanov, Michael S.Quasi-linear approximation in 3-D electromagnetic modelingThe Born approximation in electromagnetic (EM) numerical modeling has limited application for solving 3-D electromagnetic induction problems, because in structures with high conductivity contrasts and at high frequencies, this approximation is inaccurate. In this paper, we develop a new and rel...1996-01-01
72 Zhdanov, MichaelQuasi-linear series in three-dimensional electromagnetic modelingWe have recently introduced a quasi-linear (QL) approximation for the solution of the three-dimension(a3l -D) electromagnetic modeling problem. In this paper we discuss an approach to improving its accuracy by considering the QL approximation so f the higher order. This approach can be considered th...1997-01-01
73 Brown, Francis HaroldRadiometric dating and tuff mineralogy of omo group depositsThrough the efforts of the Omo Research Expedition and the East Rudolf Research Group, a large number of vertebrate fossils have been collected from the sedimentary deposits near the northern end of Lake Rudolf in Kenya and in the lower Omo valley in Ethiopia. The hominid fossils collected in this a...1976
74 Chapman, David S.Regional heat-flow variations across the sedimented Juan de Fuca Ridge eastern flank: constraints on lithospheric cooling and lateral hydrothermal heat transportSeafloor heat flow has been estimated continuously along a transect on the sedimented eastern flank of the Juan de Fuca Ridge to provide constraints on the scale and rate of lateral heat and fluid transport in the upper igneous crust, and on the total flux from the young lithosphere beneath. The ...Juan de Fuca Ridge; Seafloor; Lithospheric cooling; Hydrothermal heat transport1999
75 Chapman, David S.Reply to comment by T.J. Osborn and K. R. Briffa on "Mid-Latitude (30?-60?N) climatic warming inferred by combining borehole temperatures with surface air temperatures"We thank Osborn and Briffa [2002] for their comment regarding our use of the climatic reconstruction of Overpeck et al. [1997]. We [Harris and Chapman, 2001] had taken a proxy, Arctic wide summer-weighted annual temperature reconstruction [Overpeck et al., 1997], given in dimensionless sigma units (...Surface air temperature; Ground surface temperature; Borehole temperatures; Geothermal observations; Heat transfer2002
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