bluuebunny/crossref_metadata_2025 huggingface dataset:
Observation of high dielectric constants in x(Pb(Zn1∕3Nb2∕3)O3–(0.2−x)Pb(Ni1∕3Nb2∕3)O3–0.8Pb(Zr1∕2Ti1∕2)O3 ternary solid solutions
Authors: Nabunmee Sucheewan , Rujijanagul Gobwute , Vittayakorn Naratip , Cann David P.
Published: November 2007

In the present work, we demonstrate the results of combining two excellent ferroelectric materials at their morphotropic phase boundary compositions, i.e., 0.2(Pb(Zn1∕3Nb2∕3)O3–0.8Pb(Zr1∕2Ti1∕2)O3 (0.2PZN-0.8PZT) and 0.2Pb(Ni1∕3Nb2∕3)O3–0.8Pb(Zr1∕2Ti1∕2)O3 (0.2PNN-0.8PZT) to form a ternary solid solution of x(Pb(Zn1∕3Nb2∕3)O3–(0.2−x)Pb(Ni1∕3Nb2∕3)O3–0.8Pb(Zr1∕2Ti1∕2)O3 (xPZN-(0.2−x)PNN-0.8PZT) which exhibits superior dielectric properties. Examination of the dielectric spectra indicated that the ternary system exhibits a very high relative permittivity of 49 800 (at 10kHz) for the composition at x=0.10. In addition, an increased amount of PZN was observed to enhance the ferroelectric properties of the system.
Use of nanocomposites to increase electrical “gain” in chemical sensors
Authors: Vieira Sara M. C. , Beecher Paul , Haneef Ibraheem , Udrea Florin , Milne William I. , Namboothiry Manoj A. G. , Carroll David L. , Park Jonghyurk , Maeng Sunglyul
Published: November 2007

We have investigated chemical sensors by combining silicon-on-insulator complementary-metal-oxide-semiconducting microtechnology with nanotechnology. The sensing materials were single-walled carbon nanotubes and poly(3,3‴-dialkyl-quarterthiophone). The devices containing only nanotubes or pure polymer provided minimal response, whereas the nanocomposite material (1wt.% of nanotubes in the polymer) provided excellent sensitivity/selectivity to the particular analyte monitored (hydrogen, ammonia, and acetone). We observed that even small amounts of gas doping (10ppb) resulted in exponential changes in the overall conductivity profile of the nanocomposite sensor, thus anticipating an element of “gain” within the chemical sensor.
Sensitized electrophosphorescence of infrared emission diode based on copper phthalocyanine by an ytterbium complex
Authors: Yan Fei , Li Wen Lian , Chu Bei , Li Tian Le , Su Wen Ming , Su Zi Sheng , Zhu Jian Zhuo , Yang Dong Fang , Zhang Guang , Bi De Feng , Han Liang Liang , Cheng Chuan Hui , Fan Zhao Qi , Yu Shu Kun , Du Guo Tong , Tsuboi Taiju
Published: November 2007

By inserting a layer of (dibenzoylmethanato)3-(bathophenanthroline)-ytterbium (Yb–C) between copper phthalocyanine (CuPc) emitting layer and electron transport layer, intense and broadband electroluminescence (EL) were achieved at 930–1300nm spectral region in a phosphorescent EL device. The intensity and bandwidth are increased by about 50 and 4 times, respectively, compared with the EL device without Yb–C layer. The improvement in the EL intensity and band broadening were attributed to the energy transfer from Yb–C to CuPc and the overlapping of the Yb3+ near-infrared emission band with the CuPc emission band.
Electrically probing photonic bandgap phenomena in contacted defect nanocavities
Authors: Hofbauer F. , Grimminger S. , Angele J. , Böhm G. , Meyer R. , Amann M. C. , Finley J. J.
Published: November 2007

We demonstrate an electrically tunable two dimensional photonic crystal nanocavity containing InAs self-assembled quantum dots (QDs). Photoluminescence and electroluminescence measurements are combined to probe the cavity mode structure and demonstrate a local electrical contact to the quantum dots. Measurements performed as a function of the electric field enable us to probe the capture, relaxation, and recombination dynamics of photogenerated carriers inside the quantum dots emitting into a modified photonic environment. Furthermore, the two dimensional photonic crystal is probed by spatially dependent photocurrent spectroscopy indicating a 3.5× enhancement of the local radiative lifetime of the QDs inside the photonic crystal environment.
Epitaxial thin films of multiferroic GaFeO3 on conducting indium tin oxide (001) buffered yttrium-stabilized zirconia (001) by pulsed laser deposition
Authors: Trassin M. , Viart N. , Versini G. , Loison J.-L. , Vola J.-P. , Schmerber G. , Crégut O. , Barre S. , Pourroy G. , Lee J. H. , Jo W. , Mény C.
Published: November 2007

Epitaxial films of an alternative multiferroic material, GaFeO3 (GFO), were grown by pulsed laser deposition on yttrium-stabilized zirconia (001) and on conducting buffer layers of indium tin oxide (001). They present a perfect epitaxial growth along the GFO [010] axis and six crystallographic variants in the film’s plane. Their magnetic properties are close to those of the bulk with an out-of-plane [010] hard direction and a Curie temperature of ∼200K. The films did exhibit ferroelectric properties when characterized by electrostatic force microscopy.
Fabrication and characterization of two-dimensional photonic crystal microcavities in nanocrystalline diamond
Authors: Wang C. F. , Hanson R. , Awschalom D. D. , Hu E. L. , Feygelson T. , Yang J. , Butler J. E.
Published: November 2007

Diamond-based photonic devices offer exceptional opportunity to study cavity quantum electrodynamics at room temperature. Here we report fabrication and optical characterization of high quality photonic crystal microcavities based on nanocrystalline diamond. Fundamental modes near the emission wavelength of negatively charged nitrogen-vacancy centers (637nm) with quality factors as high as 585 were observed. Three-dimensional finite-difference time-domain simulations were carried out, having excellent agreement with the experimental results in the values of the mode frequencies. Polarization of the modes was measured; their anomalous behavior provides important insights to scattering loss in these structures.
Large surface-state conductivity in ultrathin Bi films
Authors: Hirahara T. , Matsuda I. , Yamazaki S. , Miyata N. , Hasegawa S. , Nagao T.
Published: November 2007

In situ microscopic-four-point probe conductivity measurements were performed for ultrathin Bi films on Si(111)-7×7. From the extrapolation of thickness-dependent conductivity and decrease in conductivity through surface oxidization, we found clear evidence of large surface-state conductivity (σSS∼1.5×10−3Ω−1∕◻ at room temperature) in Bi(001) films. For the thinnest films (∼25Å), the transport properties are dominated by the highly inert surface states that are Rashba spin-split, and this suggests the possibility of using these Bi surface states for spintronics device application.
Three-primary-color photoluminescence from CdS∕Si nanoheterostructure grown on silicon nanoporous pillar array
Authors: Xu Hai Jun , Li Xin Jian
Published: November 2007

Cd S ∕ Si nanoheterostructure was prepared by growing CdS nanocrystallites (nc-CdS) onto silicon nanoporous pillar array (Si-NPA) via a heterogeneous reaction process. The pillars of CdS∕Si-NPA were constructed by an outermost shell of nc-CdS membrane, an innermost core of nanoporous silicon pillar, and an interface with nc-CdS embedded into amorphous SiO2 matrix. Blue, green, and red emissions were observed in CdS∕Si-NPA and the origins were attributed to the emission from Si-NPA, the band edge transition, and the surface states of sulphur vacancies of nc-CdS, respectively. The three-primary-color photoluminescence realized in CdS∕Si-NPA might be applied in solid state lighting.
Inelastic deformation and phase transformation of shock compressed silicon single crystals
Authors: Turneaure Stefan J. , Gupta Y. M.
Published: November 2007

Silicon crystals were shock compressed along the [100] and [111] orientations to stresses between 15.9 and 21.7GPa. Transmitted wave profiles exhibited considerable orientation dependence for elastic and inelastic waves but very little orientation dependence for the phase transformation wave. Following the phase transformation wave, the silicon was compressed ∼23%. This compression is significantly greater than the previously reported compressions for silicon shocked to similar stresses, and the present data are consistent with a completed phase transformation. The measured mechanical impedance of the transformed silicon matches the bulk impedance of the simple hexagonal phase of silicon reported in static high pressure studies.
Haptically Straight Lines
Authors: Sanders Abram F J , Kappers Astrid M L
Published: November 2007

In this research, we set out to investigate haptically perceived space. Large deviations with respect to physical space have already been shown to exist. Here, research on haptic space is continued by investigating straight lines constructed by touch. In four experiments, subjects were asked to produce straight lines between two reference markers that were in the horizontal plane at a fixed distance from each other. Each experiment corresponded to a different task: two different interpolation tasks, an intersection task, and a pointing task. Straight lines had an orientation that was approximately frontoparallel. Subjects used both hands; manipulation was unrestricted. Although we found considerable differences between observers, the overall pattern of results showed that haptically straight lines were generally curved away from the observer. However, in one of the interpolation tasks they corresponded to physically straight lines. In addition, the pointing task generally produced larger deviations than the other three tasks. Taken together, the results show that there is no unique definition of the straight line, a conclusion that questions the viability of the concept of haptic space.
Floral- and leaf-character variation in waratah (Telopea speciosissima, family Proteaceae), with reference to conservation and horticultural improvement
Authors: Offord C. A.
Published: November 2007

Univariate analysis (ANOVA) of waratah (Telopea speciosissima (Sm.) R.Br.) floral and leaf characters, chosen primarily for their horticultural importance, showed that there were detectable differences among populations and indicated, for most characters studied, that variation was greater among the tested natural populations than within. There were significant differences between some populations for all variables except inflorescence height. Inflorescence colour, particularly style colour, showed the greatest variation among populations and leaf margin type, leaf width and flower number were also variable. Inflorescence width, bract number, bract width, leaf length and leaf apex shape were variable within populations; however, they were less useful in distinguishing between populations. Multivariate analysis of characters (principle component analysis, PCA; or canonical variate analysis, CVA) showed unique character combinations in several of the populations studied. Natural waratah populations of this species can, therefore, be explored for unique, although subtle character variations for horticultural development. Conservation efforts should seek to maintain genetic diversity in natural populations and ensure that cultivated populations capture and maintain an appropriate level of diversity for continued selection and horticultural improvement.
Response of rock-outcrop and fringing vegetation to disturbance by fire and drought
Authors: Benwell Andrew
Published: November 2007

A comparative study of vegetation responses to fire and drought investigated whether species regeneration mode, seedling density response (SDR) and seedling shoot growth rate varied significantly in relation to disturbance agent (fire and drought), habitat type (rock-outcrop and fringing vegetation) and plant growth form. A three-way ANOVA showed that SDR varied significantly in relation to all three categorical variables and most strongly in relation to disturbance agent. Seeders comprised 87% of the post-fire flora and 99.3% of the peak seedling population in rock-outcrop habitat, while resprouters were much more prominent in fringing woodland. Species SDRs and seedling growth rates were generally much higher after fire. Fire produced a high SDR with high shrub, grass and ephemeral therophyte components, and drought produced a low SDR dominated by grasses and herbs and inhibited shrub and ephemeral recruitment. Post-fire obligate-seeder shrubs behaved as facultative resprouters after drought. Some species exhibited SDRs equivalent to fire and drought, others appeared to require fire for regeneration, while others recruited more successfully after drought. This spectrum of responses indicated a range of optimal disturbance environments, depending on species, which was only partly consistent with the hypothesis that species exhibit essentially the same life-history syndromes in response to fire and drought. The dominance of seeders in outcrop vegetation appeared to be related to skeletal soil, higher disturbance frequency and soil trophic conditions, rather than low fire frequency.
Morphological and developmental investigations of the underground system of Erythroxylum species from Brazilian cerrado
Authors: Alonso Alexandre Antonio , Machado Silvia Rodrigues
Published: November 2007

Brazilian cerrado, a neotropical savanna, is characterised by a strongly seasonal climate with distinctive wet and dry seasons, and deep and well drained soils that are acidic and with high aluminium content. Recurrent fires in the dry season place additional stress on the survival of plants, which exhibit an array of strategies of survival. The purpose of this work was to study the underground system of Erythroxylum nanum A.St-Hil. and E. campestre A.St-Hil., two sub-shrubby species, and E. tortuosum Mart., a shrubby species, verifying the possible relationship between the morphology of the underground organs and the resprouting ability of these plants. Anatomical analyses followed the usual techniques of plant anatomy. The cotyledons of the three species were green, foliaceous and photosynthesising. The two sub-shrubby species (Erythroxylum nanum and E. campestre) showed slow development of the aerial shoot system and extensive growth of the primary root in the initial stage of development. E. tortuosum presented the most pronounced development of the aerial system and a poorly developed primary root compared with the sub-shrubby species. The sub-shrubby species occurred in clumps and had underground systems interlinked, consisting of a deep axial primary root system besides soboles in E. nanum and xylopodium in E. campestre. Plants of the E. tortuosum were isolated, highly branched and their underground system consisted of a superficial primary root system. Abundance of reserves and the bud-forming potential of the soboles, xylopodium and roots resulted in production of vigorous branches that are highly valuable in the regeneration of the aerial biomass following fire or seasonal dry in cerrado.
Simplified interpretation of Turam anomalies
Authors: Williams J.P.
Published: November 2007

The Turam electromagnetic (EM) method employs the fixed transmitter/moving receiver system in which the ratio of the amplitudes of the electromagnetic field at sets of two points and the phase differences between the points are measured. For a given transmitter these quantities will vary from theoretical values in a homogeneous half space only when secondary sources or conductors are present. Derivation of the parameters of conductors detected by the method has in the past, relied on the computation of the real (in phase) and imaginary (out of phase) components of the resultant E.M. field. This paper shows that depth to the secondary sources which behave as line conductors can be estimated directly from the ratio and phase curves as accurately as from the real and imaginary components. It is also shown, that, for the reduced ratio (RR) over the top of the secondary source, and the corresponding phase angle difference (�), [see full text for equation] where f is the phase lag between the primary signal and the induced secondary signal. This expression, the Phase Lag Function, is equivalent to the Apparent Induction Index, which has been used to determine the resistivity/thickness ratio of a conductor. Nomograms relating the Phase Lag Function to the resistivity/thickness ratio for various bodies are provided so that all routine interpretation of Turam anomalies can be performed on the ratio and phase curves.
Introducing remote sensing
Authors: Furlong V.L.R.
Published: November 2007

This highly specialised technology represents a major addition to the field of airborne exploration and investigation.
The place of geophysics in the university - an academics view
Authors: Hall S.H.
Published: November 2007

If one seeks in any dictionary the meaning of geophysics, it is difficult, to my mind, to find an entirely satisfying one. One I found was the 'study of physical processes relating to the Earth'. A better one I feel would read 'the study of physical processes, state and properties relating to the Earth' ---. Most geophysicists not long ago insisted that this definition included the aesthenosphere, 1ithosphere, atmosphere, ionosphere, magnetosphere etc. -- if one judges by the contents of some geophysical journals, and thereby considered physical oceanography, meteorology, ionospheric physics, etc. as aspects of the all-embracing title-geophysics. In speaking on this topic as it relates to a department of geology, I should add that they have not had the temerity to include geology as a further aspect.
Geophysics in the engineering earth sciences
Authors: Wood C.C.
Published: November 2007

Geophysics has an important role in investigations relating to the civil engineering construction industry. Its principal contributions relate to the following topics: Seismic methods using refraction and reflection; Resistivity studies of surface traverses for profiling and sounding and borehole logging; Gamma ray logging in bore holes; Analysis of vibrations in engineering seismology in industrially produced vibrations; Remote sensing, using infra-red, thermal and radar imagery.
Continuous mercury vapour analysis - extracts from significant papers and comments on the application of the technique in Australia
Authors: Associates Australasia Pty. Ltd. Seigel
Published: November 2007

The introduction of the continuous recording mercury vapour analyser in Australia has generated considerable interest in this technique. Unfortunately at this early stage little Australian data has been made available, although limited work is known to have been carried out. What follows has been largely drawn from papers on the subject and data supplied by Seigel Associates Ltd. of Toronto, Canada.
Experiments in the use of directed line sources in refraction profiling Arckaringa Basin - 1971
Authors: Milton B.E.
Published: November 2007

During investigations of the Arckaringa Basin, four types of pre-Permian dolomite were intersected in stratigraphic wells and these can be distinguished by differences in density and seismic velocity. Knowledge of the limits of each dolomite is of importance in establishing the history of the Basin, and a seismic survey was carried out in May and June, 1971 to determine whether seismic refraction profiling could be used to map these rock types. To increase mobility and reduce costs, experiments were conducted using 'Geoflex' (trade mark of Imperial Chemical Industries Ltd.), a detonating cord, as an energy source. The Geoflex was ploughed to a depth of about 18 inches below the ground surface before being detonated. The results obtained in six widely separated localities were mostly fair to good. The quality of the primary and secondary refraction events appears to be largely independent of the size of the charge and is related to the entry angle of the input signal. This is determined by the velocity of the Geoflex and the surface and near-surface materials, and the length of the Geoflex array. Results show that over a wide area of the western Great Artesian Basin in South Australia, a directed line source can be used to obtain good quality refraction data at a cost considerably lower than that resulting from the use of conventional shot hole drilling and dynamite or other explosives.
Comparison of techniques in computer modelling of the gravitational and magnetic effects of ore-bodies
Authors: Moore R.F.
Published: November 2007

Digital computers have revolutionised virtually every form of activity in exploration geophysics from the collection to the interpretation of data. Computer systems collect data, process it (Tanner and Buck (1964, Royer (1968, and analyse and interpret it (Tanner (1967), Hartman et a1 (1965), Naudy (1970)). Their implementation in computer modelling has also been exceedingly fast and widespread.
The surface integral approach to the solution of the 3D resistivity problem
Authors: Pratt D.A.
Published: November 2007

The application of the surface integral approach to the solution of the 3D resistivity problem is reviewed. The use of a rapid, approximate method of solution and the absolute method of solution are discussed in relation to the exploration problem.
The Fault Analysis Projection System (FAPS) - A new seismic interpretation and structural geological interpretation tool.
Authors: Freeman B. , Badley M. , Yielding G.
Published: November 2007

Recent research has demonstrated that the displacement on faults varies in a systematic manner, both vertically and laterally. Contours of displacement on strike projections display ordered patterns for isolated normal faults, strike-slip faults and syn-sedimentary faults. Recognition of these ordered patterns forms the basis for a new seismic interpretation and structural/geological interpretation tool, enabling objective verification of fault correlation, identification of bad fault or horizon picks, and a better understanding of the overall kinematic framework. The Fault Analysis Projection System (FAPS) is a computerized implementation of this technique designed to run on UNIX-based workstations. The FAPS uses the X-windows graphics system which permits different elements of the interpretation/analysis to be viewed at the same time and is designed to make adjustments to interpretations a simple task. For example, an interpreter may work on a map in one window, a set of sections in another window, perform a graphics screen-edit on data in a third window and view the results of an analysis in a separate, fourth window.
Practical seismic imaging
Authors: French W.S.
Published: November 2007

Data examples clearly show that advances in seismic reflection methods over the past few years provide the interpreter with improved geologic information. The shift over the last ten years from 2-D to 3-D surveys and the shift over the past five years from processing based on surface geometry to processing based on subsurface geometry represent the principal advancements. Despite these advancements, the seismic reflection method is not mature.There exists no unified processing method to produce a 3-D geologic picture in depth directly from the data. Current processing techniques are a conglomeration of surface referenced methods (most noise suppression techniques), subsurface referenced methods (DMO, prestack migration) and in-between methods (velocity analysis). Interpreters, processors and field people must all keep abreast of the technology of our profession in order to improve our final product: greater success in both exploration and production.
Seismic, gravity and magnetics, a complementary geophysical study of the Paqualin Structure, Timor Sea, Australia
Authors: Smith P.M. , Whitehead M.
Published: November 2007

The presence of a large anomalous structure in the northern part of Permit AC/P2 in the Timor Sea has been recognised ever since seismic data were first acquired in the area. Historically, however, sparse seismic coverage has always prevented a detailed and unambiguous interpretation of the complicated structure. In order to overcome this problem, some 2000 km of 3D seismic data were acquired over the feature. In conjunction with this seismic survey, detailed gravity and magnetic data sets were also recorded over the structure.Interpretation of the new seismic data indicated the presence of a piercement structure which is associated with a small negative Bouguer gravity anomaly and a magnetic intensity anomaly resulting from a positive susceptibility contrast. Modelling of the magnetic data indicated that an acidic or intermediate intrusive body was the most likely cause of the piercement structure. The presence of an acidic intrusive body was consistent with the gravity data which indicated that no large density contrast existed between the material of the piercement structure and the surrounding sediments.The combined interpretation of these three data sets was tested by a well, Paqualin-1, drilled on the flank of the piercement structure. The well encountered a thick evaporite sequence with associated thin bands of magnetitie and intermediate igneous rocks. It was logged with a three component downhole magnetic probe and forward magentic modelling work incorporating the results of the magnetic log gave good agreement with the observed aeromagnetic profiles.
Deep structure and metallogeny of the earth's crust
Authors: Erkhow V.A.
Published: November 2007

Considerable experience with integrated geological and geophysical studies has enabled definition of deep crustal structures and, within limits, composition and processes within the deep crust, and to determine their association with metallogeny in the USSR.By means of seismic experiments, stratification of the Earth's crust and the upper mantle to a depth of about 100 km has been revealed. Numerous heat flow data have been compiled. Magneto-telluric soundings made it possible to determine the position of conductive strata in the crust and upper mantle for a number of areas. Gravity surveys coupled with the results of seismic profiling enabled the finding of a number of empirical laws that are useful for investigation into the deep crust. Magnetic data analysis has enabled evaluation of the magnetic layering of the deep crust. Kimberlite and ore provinces can be considered examples of these concepts.For more detailed studies of deep crustal structure the territory of the USSR is the subject of a system of regional investigation of the deep crust and upper mantle. This system is based principally upon a network of interconnected regional profiles (geotraverses) tied to deep and superdeep boreholes. The system includes predicted geophysical observations to control investigation of the geophysical field data. The geotraverse network is the basis for detailed studies within the bounds of petroleum and ore provinces.The most accurate data obtained allows the formation of a crustal model and reveals empirical relationships with metallogeny.Based on the deep crustal structure data a regional oregenesis prediction map has been made. The endogenous mineralization prediction was based on special features of the upper layering of the crust and on data relating to deep crustal permeability zones.
Geophysical investigation of deep crustal structure of the Siberian Platform region
Authors: Surkov V.S. , Lotyshev V.I.
Published: November 2007

A sparse network of regional profiles developed in Siberia using deep seismic sounding methods (DSS) does not allow a valid three dimensional model of Siberian deep crustal structure to be constructed. To create such a model, interpretation methods of available geophysical and geological data are suggested. These are based on modelling of geological objects using potential fields. Information on DSS key profiles is considered to be key data.The results of such interpretation are shown in the crustal thickness map and in that of crystalline basement, as well as on a deep geological-geophysical profile across the West Siberian Plate and Siberian Platform. The crustal thickness in Siberia varies from 30 to 55 km. It is on average 4?6 km thicker on the Siberian Platform than the West Siberian Plate. The least crustal thickness of 30 to 33 km appears to be beneath regions with maximum thickness of Mesozoic deposits. Modern and Early Mesozoic rift zones are characterized by decreased crustal thickness of 36?39 km. Ancient shields of the Siberian Platform and adjacent folded mountain units are up to 45?55 km thick.The geometry of the top of crystalline basement in the young West Siberian Plate is sharply different from that of the ancient Siberian Platform. Within the West Siberian Plate structural features with 5 to 11 km of relief dominate, while on the Siberian Platform the structural relief varies from 2?3 to 14 km.The peculiarities of deep crustal structure have greatly influenced the formation and distribution of sedimentary units. The constructed section shows the depths and thicknesses of the Riphean, Vendian?Silurian, Devonian?Middle Triassic and Mesozoic?Cenozoic megacomplexes, most promising for oil and gas in Siberia. Data obtained on the deep structure of Siberian Platform regions are thus of great practical importance. They can be used to predict areas of petroleum potential and determine optimal trends of further oil and gas exploration by geophysical methods.
Resistivity mapping using inductive sources
Authors: MacNae J. , McGowan P. , Lamontagne Y.
Published: November 2007

In electromagnetic (EM) exploration for conductive targets, measurements of the magnetic component or its time derivative have received more theoretical attention and practical application than have measurements of the electric component. However, the electric component can be shown to be particularly useful in the search for resistive zones not usually detected by the magnetic component. Normalized measurements of the surface voltage differences caused by the constant current induced at late time by the UTEM transmitter are called 'Inductive Source Resistivity' or ISR measurements.Data collected on a grid located just south of the Temora gold mine in N.S.W. clearly show the effectiveness of the ISR technique in detecting a resistive zone of silicification located unconformably under 10S of conductive cover. Due to the relatively slow falloff of the electric field from an inductive source, the technique is ideal for the rapid exploration of large areas.
Interpretation of TDEM data using first and second spatial derivatives and time decay analysis
Authors: Silic J.
Published: November 2007

Current gathering in fixed loop electromagnetic data often dominates responses from large high-grade ore bodies as well as responses from less desirable features such as fault zones, weathering troughs and regional conductors. Through decay curve analysis, current gathering can now be unambiguously recognised.Many widely used EM interpretation techniques are not applicable to current gathering (channelling) responses. An effective method of deriving the location and shape of the causative source is to study the second spatial derivative, as is shown in several examples.
Field examples of controls on magnetite content
Authors: Urquhart W.E.S.
Published: November 2007

Field examples of four processes that control the formation of magnetite in rocks are discussed here. Oxygen fugacity conditions, original chemistry, and metamorphic grade are examined for mafic volcanic sequences. Sedimentary facies change within an iron formation is studied. In all the cases the understanding of the cause of the presence or absence of magnetite greatly improved the effectiveness of using magnetic data for geological mapping purposes.
MMR surveys for the location of palaeochannels in the Eastern Goldfields, Western Australia
Authors: Street G.J.
Published: November 2007

The magnetometric resistivity (MMR) method was used to locate palaeodrainage channels in the Eastern Goldfields of Western Australia. Drilling results showed the method does not distinguish between the palaeochannel and porous weathered basement containing saline water. This distinction however was not essential to the success of the program as the weathered basement was generally symmetrical around the channel.
The development of cross hole seismic techniques and case studies
Authors: Duncan G. , Downey M. , Leung L. , Harman P.
Published: November 2007

This paper outlines the development of a cross hole seismic tomography package by The Broken Hill Proprietary Co. Ltd. (BHP), as a tool for mineral exploration and mine planning. The methodology of cross hole seismic tomography, field procedures, instrumentation, processing software, and field trials are described.Explosives are principally used as the source of seismic energy. A repetitive source, based on rapid hydrogen-oxygen combustion, has also been developed. Signals are detected by geophone-based detector strings, and recorded by a data acquisition system developed by BHP. Tomographic imaging is conducted by the Algebraic Reconstruction, Back Projection and Simultaneous Iterative Reconstruction techniques.Surveys have been conducted in a number of different geological environments, and include: lead-zinc, iron ore and manganese exploration leases and mines to locate mineralisation and overburden interfaces; underground coal mines to locate regions of mining induced stress; and open cut and underground coal mines to locate coal and overburden contacts. The results of these surveys are discussed.
The application of the 3D seismic surveying technique to coal seam imaging: case histories from the Arckaringa and Sydney basins
Authors: Lambourne A.N. , Evans B.J. , Hatherly P.J.
Published: November 2007

Two dimensional seismic surveying is commonly used in the coal mining industry to assist the mining and development of coal deposits by seismically imaging coal seams. A specialised three dimensional seismic surveying technique has recently been performed over coal mining leases in South Australia and New South Wales, to trial its applicability to coal mine planning and extraction operations.The first two case histories of its trial in Australia are presented, and the conclusion drawn that the specialised three dimensional technique developed to date offers the ability to image coal seams in three dimensions and thereby improve mine planning in regions of complex faulting.
The determination of the geoid-spheroid separation for GPS levelling and applications
Authors: Kearsley A.W.H. , Eckels R.M.
Published: November 2007

The heights which are obtained from global positioning system (GPS) satellite observations are measured with respect to an earth-centred ellipsoid and are not, as a result, generally useful for surveying and engineering. In order to become useful they must be transformed into orthometric heights, that is, heights which are measured with respect to the actual level reference surface termed the geoid. The parameter which enables this transformation is N, the geoid height or geoid-ellipsoid separation.This paper reviews the capabilities of the GPS system for height measurements, describes the various methods used to evaluate N from gravimetry, and explores the suitability of these methods in the various applications in which height measurements from the GPS may be used.
Extension of the Eyre Peninsula Conductivity Anomaly
Authors: Milligan P.R. , White A. , Chamalaun F.H.
Published: November 2007

Twenty-two digitally recording fluxgate magnetometers measuring short-period natural time variations of the geomagnetic field were deployed during 1988 at 54 sites to define the northward extension of the Eyre Peninsula Conductivity Anomaly (EPCA). The southern portion of this zone of high electrical conductivity was initially mapped during the early 1980s; it trends inland just to the east of north from the southern extremity of the peninsula, at nearly 90� to the continental shelf edge.The 1988 data show that the axis of the anomaly in the north initially swings to the east, and then turns NNW, following the major structural trends in the Precambrian basement of the Gawler Block. Short-period geomagnetic variations observed in stacked magnetograms display a significant amplitude and phase change in the vertical (Z) and total field (F) components across the anomaly axis, while the horizontal variation fields (D and H) are enhanced along the axis. These features are consistent with a concentration of current in the crust.Transfer-functions relating the anomalous vertical to normal horizontal geomagnetic variation fields are expressed in the form of vectors and hypothetical event contours, and these clearly delineate the surface position of the anomaly axis.The EPCA is coincident with a broad band of seismic activity, and a continuous conductive zone such as this must be formed along a significant structure within the Precambrian crust. The zone probably delineates the boundary between the essentially non-conductive Archean crystalline basement to the west and the multiply deformed Proterozoic metasediments of the Hutchison Group to the east. Its presence is important in understanding the tectonic development of this potentially economic zone.Zones such as the EPCA can also introduce errors of several nT into aeromagnetic surveys; data from closely-spaced magnetometer arrays may be used to accurately predict and eliminate such errors.
A geophysical model of the Precambrian of the Albany 1:1M sheet, Western Australia, and its relevance to economic geology
Authors: Whitaker A.
Published: November 2007

In the Albany 1:1M sheet, the 10-50 km wavelength gravity and aeromagnetic anomalies define major boundaries and subdivisions of the Precambrian blocks/provinces and large bodies of granite, while the short wavelength magnetic anomalies define lithological banding and lineaments. The Yilgarn Block in the sheet area is readily subdivided into two major north-northwest to north trending zones of low magnetization separated by a 30 km wide zone of high magnetization. The eastern zone is considered to be due to granite-greenstone terrane, the western boundary of which is located 100 km west of that currently recognised from outcrop geology. The western zone is considered to be due to granite-geiss terrane while the 30 km wide zone between coincides with strongly magnetised granulites. The Albany Province is composed of two structurally distinct east-west trending zones. The southern zone of relatively low magnetization and density coincides with acid gneiss and granites, whereas the highly magnetised, relatively dense zone to the north and west, correlates with highly metamorphosed acid and mafic granulites. Thrusting of the Albany Province during the Mid-Proterozoic has demagnetised and or deformed the margin of the southern Yilgarn Block to at least 50 km north of the block boundary. Throughout the region, significant mineral deposits of Au, Ni, Sn, Ti, and Fe are located within greenstone and high grade metamorphic belts. These belts have characteristic signatures which contrast with extensive areas of relatively homogeneous, low economic mineral potential, granite-gneiss terrane.
Dynamic time corrections and their application to seismic data over sea floor canyons in the Gippsland Basin
Authors: Blyth C.I. , Fisher N.J. , Heath A.M.
Published: November 2007

Seismic reflection events beneath marked lateral velocity variations are distorted by complex ray paths. This can result in a stacked section with events that show poor continuity and are affected by 'pull up' or 'push down'. Where the velocity anomaly is not near the surface, conventional statics often fail to produce an adequate result.A pre-stack solution based on ray tracing is presented, which applies dynamic time corrections that vary with offset and travel time. The method was applied to a grid of data in the Gippsland Basin, affected by deep erosional canyons on the sea floor. The resulting sections generally showed significant improvement to the continuity of events thus enabling depth maps of greater accuracy to be constructed. We conclude that the method is more suitable in the study area than other pre-stack techniques given the absence of steep dips beneath the canyons and the exploration objectives. Other applications of the method are also mentioned.
Land multi-line recording techniques: selected case histories from the People's Republic of China and Western Australia
Authors: O'Sullivan F. , Tobin S. , Hollis D.
Published: November 2007

The A-Er-Shan Field, in the Inner Mongolia Region of PRC is a buried hill type structure. The oilfield's nature is such that a detailed grid of 2-D seismic could not adequately map the producing horizons. A 3-D seismic survey of the oilfield was required to provide the proper spatial sampling of the productive horizons to both map the numerous faults in the field and to migrate dipping horizons to their proper spatial position. Thevenard Island in Western Australia is an environmentally sensitive surface feature 6.0 km long by 1.5 km wide within the hydrocarbon rich and environmentally sensitive NW shelf environment. After extensive pre-survey modelling and subsurface fold simulations optimum field geometry was established for each survey using a multi-line Swathe configuration. Infield experimentation was used to determine relevant source, receiver arrays and modelled Varisweep? parameters utilising the Vibroseis seismic source. Following final processing, objectives of vertical and spatial resolution were attained along with significant improvements in S/N over previously recorded data.
A long-offset seismic reflection and refraction study of the Gippsland and Bass Basins from onshore recording of a marine air-gun source
Authors: Collins C.D.N. , Cull J.P. , Willcox J.B. , Colwell J.B.
Published: November 2007

Seismic refraction data were obtained for the Bass and Gippsland Basins during the 1988 cruise of the BMR research vessell "Rig Seismic". Seismic recorders were deployed on land by BMR and Monash University to record long-offset wide-angle reflection and refraction data using the ship's air-guns as the energy source. Preliminary results have now been obtained from these data providing information on deep crustal structure related to the basin formation. Two crustal layers have been detected with velocities of 4.5 km/s increasing to 7.4 km/s (unreversed) at depths exceeding 20 km. Additional data have now been obtained over a traverse length of 170 km to provide constraints on the deep structure of Bass Strait and the Lachlan Fold Belt in Victoria and Tasmania.
Kowanyama deep refraction seismic survey
Authors: Haines B.M. , McConachie B.A.
Published: November 2007

The Carpentaria Basin in the west/central portion of Cape York Peninsula is largely unexplored for petroleum, and there is an apparent ambiguity in the basement depths interpreted from gravity and aeromagnetic data. It was decided that deep seismic refraction surveys at a variety of sites should prove cost-effective in defining the geologic model for the basin. Of particular interest is the possible existence of a north-south trending elongate infrabasin inferred qualitatively from a strong gravity low shown Figure 1. Results of the refraction work indicate that the magnetic and gravity data suggestive of the presence of an infrabasin are probably related to lithological variations within basement. Furthermore, it is improbable that the thickness of the sedimentary pile anywhere within the area of investigation exceeds 1100 metres. Basement velocities are high, from 5500m/sec to 6200m/sec, typical of fresh igneous and/or metamorphic lithologies. Carbonates could not be totally excluded on the basis of these velocities alone, but are improbable in view of the gravity and magnetic data. At some locations there is evidence for the presence of an intermediate section of higher velocity within the sedimentary sequence. This is thought to be quite thin, and possibly representative of the Toolebuc Formation.
Log analysis systems incorporating artificial intelligence techniques ? some examples
Authors: Baker P.L.
Published: November 2007

Artificial Intelligence (Al) systems have been used with some success in the areas of dipmeter interpretation, quantitative log interpretation and well-to-well correlation. A prototype expert system has been developed using a rule-based approach to lithology identification. Extensions of the system are now being considered to do mineral identification for the problem of mineral model construction for multi-mineral log interpretation algorithms.
A new interpretation of geological structure of Tempoku Coal Field by crooked-line survey
Authors: Nakano O. , Endo M. , Ishii E. , Watanabe H.
Published: November 2007

Tempoku Coal Field is located in the northern area of Japan's northern island, Hokkaido. Here the exploration target, the Soya Coal-Bearing Formation, is of Tertiary age overlying Cretaceous basement. The regional structure of the area is characterised by a series of synclines and anticlines trending north-northwest, with several reverse faults. A suite of surveys was carried out in 1991, in the Asajino area in the central part of the coal field. The study included drilling, vertical seismic profiling, and trenching, as well as a reflection seismic survey with the crooked-line method, which is the subject of this paper. The crooked-line method was adopted because of the mountainous terrain of the area. The seismic lines were laid out along existing tracks and valleys. The main geological structure of the area had long been considered to be a monotonous series of folds. However, the 1991 survey revealed a large-scale thrust-related structure in the main coal seams, which presented clear reflectors. Together with the data from other surveys, a reinterpretation of the structure of the Asajino area is proposed.
An evaluation of the DDH/100mm stocking rate index and an alternative approach to stocking rate estimation
Authors: Hacker R. B. , Smith W. J.
Published: November 2007

Long-term data for (simulated) daily pasture growth and moving 12-monthly rainfall totals were used to examine the performance of the DDH/100 mm stocking rate index under theoretically ideal management for three locations in the Western Division of NSW. Stocking rate was adjusted either monthly or biannually based on rolling 12-monthly values for either pasture growth or rainfall. Under these ‘ideal’ conditions, monthly values of the index fluctuated widely around the carrying capacity benchmark. In practice, such comparisons would not provide a reliable assessment of the sustainability of the current stocking rate or of the need to adjust stock number to match seasonal conditions.
Stocking rates calculated from pasture growth estimates were similar to those derived simply from rainfall and the carrying capacity benchmark, and produced similar levels of pasture utilisation. This ‘benchmark method’ of stocking rate determination thus provides a readily calculated, dynamic benchmark against which actual stocking rate may be compared.
Due to lag effects, application of calculated proper stocking rates may lead to excessive pasture utilisation under low rainfall conditions (12-monthly totals less than 120–150 mm for the locations studied or, as a rule of thumb, the 10th percentile). Continuous paddock monitoring and projection of 12-monthly rainfall totals are therefore essential components of sustainable management.
Short-term trends in the stocking rate index, driven by rainfall at constant stocking rate, will not provide any generally reliable indication of impending dry spells or feed deficits.