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CreatorTitleDescriptionSubjectDate
1 Pleistocene rhyolite of the mineral mountains, Utah geothermal and archeological significance1978
2 Integral electric current method in 3-D electromagnetic modeling for large conductivity contrastAbstract-We introduce a new approach to 3-D electromagnetic (EM) modeling for models with large conductivity contrast. It is based on the equations for integral current within the cells of the discretization grid, instead of the electric field or electric current themselves, which are used in the c...Electromagnetic modeling; Integral electric current method; 3-D modeling; High conductivity contrast; Integral equations2007-05
3 Geological development of the Omo-Turkana Basin during the pliocene and pleistocene epochsPliocene and Pleistocene deposits of the Omo-Turkana Basin extend from 6?N latitude to about 2?N latitude (-450 km), and laterally from about 35.5?E to 36.5?E. Sediments are brought to the basin by the Omo River which rises in Ethiopia, and by the Turkwel and Kerio Rivers which rise in Kenya and Uga...2004
4 Observations 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
5 Horizontal sediments of the lower Omo valley: the kibish formationThe existence of old lacustrine deposits in the Lake Rudolf Basin was first recognized by Hohnel et al. (1891 : 20f., 134) and subsequently confirmed by the work of M. Sacchi (Angelis and Millosevich, 1900) and E. Brumpt (Bourg de Bozas, 1903: 107ff.), Fuchs (1935, 1939), Champion (1937), and Aramb...1969
6 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
7 Rigorous 3D inversion of marine CSEM data based on the integral equation methodMarine controlled-source electromagnetic (MCSEM) surveys have become an important part of offshore petroleum exploration. However, due to enormous computational difficulties with full 3D inversion, practical interpretation of MCSEM data is still a very challenging problem. We present a new approach ...2007
8 Three-dimensional quasi-linear electromagnetic modeling and inversionThe quasi-linear (QL) approximation replaces the (unknown) total field in the integral equation of electromagnetic (EM) scattering with a linear transformation of the primary field. This transformation involves the product of the primary field with a reflectivity tensor, which is assumed to vary slo...1999-01-01
9 Global warming - just hot air?We know from weather station records that Earth's surface temperature has increased on average by 0.6 degrees C in the last 100 years. The 1990s have been the warmest decade on record. Over the same period, global sea level has increased by 10-20 cm. We know also that planet Earth has an atmosphere ...Greenhouse Effect; Climate change1998
10 Velocity and density of carbonate-rich sediments from northeastern Australian margin: integration of core and log dataDuring Ocean Drilling Program (ODP) Leg 133, shipboard scientists obtained a remarkable quantity of both core and log measurements of the physical properties of carbonate-rich sediments. This suite of measurements provides a unique opportunity to evaluate the robustness of each measurement technique...1993
11 Resistivity/porosity/velocity relationships from downhole logs: an aid for evaluating pore morphologyRelationships between downhole resistivity/velocity logs and porosity styles, controlled by cementation/dissolution/recrystallization, are investigated using core and downhole logging data from the carbonate-rich sediments encountered during Leg 133 of the Ocean Drilling Program (ODP), northeastern ...1993
12 Snow and the ground temperature record of climate changeBorehole temperature-depth profiles contain a record of surface ground temperature (SGT) changes with time and complement surface air temperature (SAT) analysis to infer climate change over multiple centuries. Ground temperatures are generally warmer than air temperatures due to solar radiation effe...Snow cover; Snow modeling; land/atmosphere interactions; Borehole climate reconstructions; Surface air temperature; Ground surface temperature; Borehole temperatures; Geothermal observations; Heat transfer2002
13 Stop-go temperature logging for precision applicationsWe describe a new field procedure for stop-go temperature logging of boreholes that attains millikelvin precision. Temperature is recorded continuously throughout the entire log, but the logging probe is held stationary for a fixed time at discrete depth intervals. Equilibrium temperatures at the di...Temperature logging; Boreholes; Stop-go logging method2007
14 Electrical properties of basalts from Sites 768 and 770Conductivity of 54 basalt samples from ODP Sites 768 and 770 was measured as a function of temperature and fluid salinity. Porosity was also measured for all samples, and cation exchange capacity was measured for 46 of the samples. Porosity measurements indicated that porosity is underestimated fo...1991
15 Cross-well electromagnetic imaging in three dimensionsIn this paper, we develop a new technique for 3D cross-well electromagnetic tomography, based on an EM borehole survey consisting of a moving vertical magnetic dipole transmitter, located in one or several boreholes, and a tri-axial induction receiver, located in the other boreholes. The method is b...2003
16 Large-scale 3D inversion of potential field dataInversion of gravity and/or magnetic data attempts to recover the density and/or magnetic susceptibility distribution in a 3D earth model for subsequent geological interpretation. This is a challenging problem for a number of reasons. First, airborne gravity and magnetic surveys are characterized b...2011
17 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
18 Exceptionally preserved jellyfishes from the Middle CambrianCnidarians represent an early diverging animal group and thus insight into their origin and diversification is key to understanding metazoan evolution. Further, cnidarian jellyfish comprise an important component of modern marine planktonic ecosystems. Here we report on exceptionally preserved cnida...Jellyfishes; Metazoan evolution; Jellyfish fossils; Marjum Formation; Utah; Middle Cambrian2007-10-31
19 The evolution of neogene terrestrial ecosystems in EuropeThe Pliocene-Pleistocene chronology of hominid and other vertebrate evolution in East Africa is largely constrained by isotopic dating and regional intercorrelation of volcanic ash layers. Some eruptions were of sufficient magnitude or duration that their widespread tephra dispersal defines a serie...1999
20 Three-dimensional inversion of large-scale EarthScope magnetotelluric data based on the integral equation method: geoelectrical imaging of the Yellowstone conductive mantle plumeInterpretation of the EarthScope MT (magnetotelluric) data requires the development of a large-scale inversion method which can address two common problems of 3D MT inversion: computational time and memory requirements. We have developed an efficient method of 3D MT inversion based on an IE (integ...2011
21 Scientific methods: an online bookThis book was originally intended as ˜How to do science™, or ˜How to be a scientist™, providing guidance for the new scientist, as well as some reminders and tips for experienced researchers. Such a book does not need to be written by the most expert or most famous scientist, but by one who...Science; Process; Method2001
22 Integral equation method for 3D modeling of electromagnetic fields in complex structures with inhomogeneous background conductivityWe present a new formulation of the integral equation (IE) method for three-dimensional (3D) electromagnetic (EM) modeling in complex structures with inhomogeneous background conductivity (IBC). This method overcomes the standard limitation of the conventional IE method related to the use of a horiz...3-D modeling; Integral equation method; Marine controlled-source electromagnetic data; MCSEM; Gemini Prospect; Gulf of Mexico2006
23 Three-dimensional regularized focusing inversion of gravity gradient tensor component dataWe develop a new method for interpretation of tensor gravity field component data, based on regularized focusing inversion. The focusing inversion makes its possible to reconstruct a sharper image of the geological target than conventional maximum smoothness inversion. This new technique can be eff...Focusing inversion; Gravity gradient; Gravity gradiometry2004
24 Geothermics and climate change: 1. Analysis of borehole temperatures with emphasis on resolving powerTemperature-depth data from six boreholes in western Utah and nine boreholes in southeastern Utah are reanalyzed for evidence of ground surface temperature (GST) histories. We invert the temperature-depth data using the functional space inverse algorithm of Shen and Beck [1991, 1992] which we prefer...Surface air temperature; Ground surface temperature; Borehole temperatures; Geothermal observations; Geothermics1998
25 DatingThere are basically three lines of investigation that are involved in geochronology ? the dating of rocks and other earth materials. First, there are the physical and chemical dating methods which give us numerical estimates of age. Second, there is the reconstruction of the order of events in sec...1984
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