Search NASA⌕ Search

SEARCH · Search NASA

Results for “AUSTRALIA”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Regional magnetic anomaly constraints on continental rifting

Radially polarized MAGSAT anomalies of North and South America, Europe, Africa, India, Australia and Antarctica demonstrate remarkably detailed correlation of regional magnetic lithospheric sources across rifted margins when plotted on a reconstruction of Pangea. These major magnetic features apparently preserve their integrity until a superimposed metamorphoric event alters the magnitude and pattern of the anomalies. The longevity of continental scale magnetic anomalies contrasts markedly with that of regional gravity anomalies which tend to reflect predominantly isostatic adjustments associated with neo-tectonism. First observed as a result of NASA's magnetic satellite programs, these anomalies provide new and fundamental constraints on the geologic evolution and dynamics of the continents and oceans. Accordingly, satellite magnetic observations provide a further tool for investigating continental drift to compliment other lines of evidence in paleoclimatology, paleontology, paleomagnetism, and studies of the radiometric ages and geometric fit of the continents.

Vonfrese, R. R. B.↗
NASA NTRS1984

The Adelaide VHF radar: Capabilities and future plans

The VHF radar at Buckland Park, South Australia commenced operation in January, 1984. The radar is located adjacent to the 2-MHz ionospheric radar. The routine method for measuring horizontal wind velocity is the space antenna technique (SA) while the Doppler technique is used to measure vertical velocities. It is possible to swing the transmitting beam in the east-west plane, allowing Doppler measurements of the EW wind component.

Briggs, B. H.↗
NASA NTRS1985

Dating Archean zircon by ion microprobe: New light on an old problem

Ion microprobe analysis of zircons from three sites (Watersmeet Dome in northern Michigan, Mount Sones in eastern Antarctica, and Mount Narryer in western Australia) is discussed. Implications of the results to Archean geochronology and early Earth crust composition are addressed.

Williams, I. S.↗
NASA NTRS1985

A search for solar neutrons on a long duration balloon flight

The EOSCOR 3 detector, designed to measure the flux of solar neutrons, was flown on a long duration RACOON balloon flight from Australia during Jan. through Feb, 1983. The Circum-global flight lasted 22 days. No major solar activity occurred during the flight and thus only an upper limit to the solar flare neutrons flux is given. The atmospheric neutron response is compared with that obtained on earlier flights from Palestine, Texas.

Koga, R.↗
NASA NTRS1983

Shuttle Imaging Radar-A (SIR-A) data as a complement to Landsat Multispectral Scanner (MSS) data

Principal components analysis and supervised classifications were performed on two dates of Landsat multispectral scanner (MSS) data registered to one date of Shuttle Imaging Radar-A (SIR-A) data in a wheat-growing area of New South Wales, Australia. The purpose was to evaluate SIR-A data as a complement to Landsat MSS data in an agricultural environment. The SIR-A data was filtered using a 7 x 7 pixel moving window median filter. Principal components analysis indicated the SIR-A data were discriminating between trees and agricultural fields. Supervised classifications using wheat, pasture, trees, and idle classes resulted in increased accuracies for wheat and pasture and slightly decreased accuracies for trees and idle for the Landsat MSS/SIR-A registered data sets over the Landsat MSS alone. Overall classification accuracies were unchanged for one date and substantially increased for the other when the SIR-A data were added to the Landsat MSS data.

Henninger, D. L.↗
NASA NTRS1984

Stratospheric HF mixing ratio profiles in the northern and southern hemispheres

Spectra obtained by balloon-borne Michelson interferometers over South Australia in 1977 and New Mexico in 1978 have been analyzed to obtain HF mixing ratios using a recently developed, sensitive analysis method for Fourier transform spectroscopy. The stratospheric HF mixing ratio appears to be significantly larger in the northern hemisphere than in the southern hemisphere for similar respective latitudes with the profiles having a similar vertical shape: the HF mixing ratio increases from 20 to 25 km, stays approximately constant between 25 and 35 km, and increases upward from 35 km. A brief discussion is given of possible causes for HF profile shape.

Park, J. H.↗
NASA NTRS1984

A review of the Southern Oscillation - Oceanic-atmospheric circulation changes and related rainfall anomalies

The region of South America is emphasized in the present consideration of the Southern Oscillation (SO) oceanic and atmospheric circulation changes. The persistence of climate anomalies associated with El Nino-SO events is due to strong atmosphere-ocean coupling. Once initiated, the SO follows a certain sequence of events with clearly defined effects on tropical and subtropical rainfall. Excessive rainfall related to the SO in the central and eastern Pacific, Peru, Ecuador, and southern Brazil, are complemented by drought in Australia, Indonesia, India, West Africa, and northeast Brazil. El Nino-SO events are also associated with dramatic changes in the tropospheric flow pattern over a broad area of both hemispheres.

Kousky, V. E.↗
NASA NTRS1983

Gamma rays of 1-30 MeV from the Vela Pulsar PSR 0833-45

Results are reported for observations of gamma rays of 1-30 MeV from the Vela Pulsar PSR 0833 - 45 carried out with the UCR double scatter gamma ray telescope on a balloon launched from Alice Springs, Australia on November 10, 1981. An integrated flux of (5.3 + or - 1.3) x 10 to the -4th photons/sq cm/s is found for the Vela region above 2 MeV. This value, together with those for the energy intervals of 2-4, 4-7, and 7-15 MeV are in reasonable agreement with the power law found by COS-B at energies above 50 MeV. A sky contour map of the fluxes is shown.

Tumer, T.↗
NASA NTRS1985

Lateral heterogeneity and azimuthal anisotropy of the upper mantle - Love and Rayleigh waves 100-250 sec

The lateral heterogeneity and apparent anisotropy of the upper mantle are studied by measuring Rayleigh and Love wave phase velocities in the period range 100-250 sec. Spherical harmonic descriptions of the lateral heterogeneity are obtained for order and degree up to 1=m=10. Slow regions are evident at the East Pacific rise, northeast Africa, Tibet, Tasman sea, southwestern North America and triple junctions in the Northern Atlantic and Indian oceans. Fast regions occur in Australia, western Pacific and the eastern Atlantic. Details which are not evident in previous studies include two fast regions in the central Pacific and the subduction zone in the Scotia Arc region. Inversion for azimuthal dependence showed (1) little correlation between the fast phase velocity directions and the plate motion vector in plate interiors, but (2) correlation of the fast direction with the perpendicular direction to trenches and ridges. Phase velocity is high when waves propagate perpendicular to these structures. Severe tradeoffs exist between heterogeneity and azimuthal dependence because of the yet unsatisfactory path coverage.

Tanimoto, T.↗
NASA NTRS1985

A diffuse plate boundary model for Indian Ocean tectonics

It is suggested that motion along the virtually aseismic Owen fracture zone is negligible, so that Arabia and India are contained within a single Indo-Arabian plate divided from the Australian plate by a diffuse boundary. The boundary is a zone of concentrated seismicity and deformation commonly characterized as 'intraplate'. The rotation vector of Australia relative to Indo-Arabia is consistent with the seismologically observed 2 cm/yr of left-lateral strike-slip along the Ninetyeast Ridge, north-south compression in the Central Indian Ocean, and the north-south extension near Chagos.

Wiens, D. A.↗
NASA NTRS1985

Nd and Sr isotopic compositions of tektite material from Barbados and their relationship to North American tektites

The isotopic composition of microtektites from Barbados was determined to establish their possible source and their relationship to known tektite strewn fields. Analyzed samples included microtektites and tektite fragments from the Barbados oceanic beds, samples of deep sea ooze, in which they occur, and of underlying volcanic ash, as well as glass beads from Lake Wanapitei Crater. Isotope ratios (Sr-87/Sr-86, Nd-143/Nd-144, Rb-87/Sr-86, and Sm-147/Nd-144) were determined, and the epsilon values for Sr and Nd plotted on the diagram available for the fields of North America, Australia, Ivory Coast, and Moldavite tektites. The epsilon coordinates of all Barbados microtektite and bulk tektite samples plot precisely within the narrow field determined by North American tektites (epsilon Sr, 111; epsilon Nd, -6.2), yield an Nd model age of 0.6 AE, and are distinct from all other fields. The isotopic signatures of samples from sea ooze, ash layer, and of the Lake Wanapitei glass beads are clearly different from all known tektite classes. It is concluded that the Barbados tektites are of the same source and temporal event as the North American tektites.

Ngo, H. H.↗
NASA NTRS1986

Geochemical and isotopic constraints on the tectonic setting of Serra dos Carajas belt, eastern Para, Brazil

The lower part of the Serra dos Carajas belt is the metavolcanic and metasedimentary Grao para Group (GPG). The GPG is thought to unconformably overlie the older (but undated) Xingu Complex, composed of medium and high-grade gneisses and amphibolite and greenstone belts. The geochemical data indicate that the GPG has many features in common with ancient and modern volcanic suites erupted through continental crust. The mafic rocks clearly differ from those of most Archean greenstone belts, and modern MORB, IAB, and hot-spot basalts. The geological, geochemical, and isotopic data are all consistent with deposition on continental crust, presumably in a marine basin formed by crustal extension. The isotopic data also suggest the existence of depleted mantle as a source for the parent magmas of the GPG. The overall results suggest a tectonic environment, igneous sources, and petrogenesis similar to many modern continental extensional basins, in contrast to most Archean greenstone belts. The Hammersley basin in Australia and the circum-Superior belts in Canada may be suitable Archean and Proterozoic analogues, respectively.

Olszewski, W. J., Jr.↗
NASA NTRS1986

World Atlas of large optical telescopes (second edition)

By early 1986 there will be over 120 large optical telescopes in the world engaged in astronomical research with mirror or lens diameters of one meter (39-inches) and larger. This atlas gives information on these telescopes and shows their observatory sites on continent sized maps. Also shown are observatory locations considered suitable for the construction of future large telescopes. Of the 126 major telescopes listed in this atlas, 101 are situated in the Northern Hemisphere and 25 are located in the Southern Hemisphere. The totals by regions are as follows: Europe (excluding the USSR), 30; Soviet Union, 9; Asia (excluding the USSR), 5; Africa, 9; Australia, 6; The Pacific, 4 (all on Hawaii); South America, 17; North America, 46 (the continental US has 38 of these). In all, the United States has 42 of the world's major telescopes on its territory (continental US plus Hawaii) making it by far the leading nation in astronomical instrumentation.

Meszaros, S. P.↗
NASA NTRS1985

Satellite voice broadcast system study, volume 2

This study investigates the feasibility of providing Voice of America (VOA) broadcasts by satellite relay, rather than via terrestrial relay stations. Satellite voice broadcast systems are described for three different frequency bands: HF (26 MHz), VHF (68 MHz), and L-band (1.5 GHz). The geographical areas of interest at HF and L-band include all major land masses worldwide with the exception of the U.S., Canada, and Australia. Geostationary satellite configurations are considered for both frequency bands. In addition, a system of subsynchronous, circular satellites with an orbit period of 8 hours is developed for the HF band. VHF broadcasts, which are confined to the Soviet Union, are provied by a system of Molniya satellites. Satellites intended for HF or VHF broadcastinbg are extremely large and heavy. Satellite designs presented here are limited in size and weight to the capability of the STS/Centaur launch vehicle combination. Even so, at HF it would take 47 geostationary satellites or 20 satellites in 8-hour orbits to fully satisfy the voice-channel requirements of the broadcast schedule provided by VOA. On the other hand, three Molniya satellites suffice for the geographically restricted schedule at VHF. At L-band, only four geostationary satellites are needed to meet the requirements of the complete broadcast schedule. Moreover, these satellites are comparable in size and weight to current satellites designed for direct broadcast of video program material.

Horstein, M.↗
NASA NTRS1986

Isotopic, petrologic and biogeochemical investigations of banded iron-formations

It is recognized that the first occurrence of banded iron-formations (BIFs) clearly predates biological oxygenation of the atmosphere-hydrosphere system and that their last occurrences extend beyond plausible dates of pervasive biological oxygenation. For this reason, and because enormous quantities of oxidizing power have been sequestered in them, it is widely thought that these massive, but enigmatic, sediments must encode information about the mechanism and timing of the rise of atmospheric O2. By coupling isotopic analyses of iron-formation carbonates with biogeochemical and petrologic investigations, we are studying (1) the mechanism of initial sedimentation of iron; (2) the role of iron in microbially mediated diagenetic processes in fresh iron-formation sediments; and (3) the logical integration of mechanisms of deposition with observed levels of banding. Thus far, it has been shown that (1) carbonates in BIFs of the Hamersley Group of Western Australia are isotopically inhomogenous; (2) the nature and pattern of isotopic ordering is not consistent with a metamorphic origin for the overall depletion of C-13 observed in the carbonates; (3) if biological, the origin of the C-13 depleted carbonate could be either respiratory or fermentative; (4) iron may have been precipitate d as Fe(3+), then reduced to Fe(2+) within the sediment; and (5) sedimentary biogeochemical systems may have been at least partially closed to mass transport of carbonate species.

Hayes, J. M.↗
NASA NTRS1986

Relationship between high- and low-grade Archean terranes: Implications for early Earth paleogeography

The Western Gneiss Terrain (WGT) of the Yilgarn Block, Western Australia was studied. The WGT forms an arcuate belt of Archean gneisses that flank the western margin of the Yilgarn Block. In general the WGT is composed of high-grade orthogneisses and paragneisses which contain supracrustal belts composed largely of siliciclastic metasediments and subordinate iron formation. The platformal nature of the metasedimentary belts and lack of obvious metavolcanic lithologies contrasts with the composition of typical Yilgarn greenstones to the east. Radiometric data from WGT rocks indicates that these rocks are significantly older than Yilgarn rocks to the east (less than 3.3 Ga) and this has led to the suggestion that the WGT represents sialic basement to Yilgarn granite-greenstone belts. The Mount Narryer region exposes the northernmost occurrence of high-grade metasediments within the WGT and consists of quartz-rich clastic metasediments at upper amphibolite to granulite grade. Most occurrences of supracrustal rocks in this region comprise isolated lenses within the gneissic basement. However, at Mount Narryer a unique sequence of metaclastics with preserved bedding provide an unusual window into the parentage of similar supracrustal bodies in this region.

Eriksson, K. A.↗
NASA NTRS1986

Parkes-CDSCC telemetry array: Equipment design

A unique combination of Deep Space Network (DSN) and non-DSN facilities in Australia provided enhanced data return from the Voyager spacecraft as it encountered the planet Uranus. Many of the key elements are duplicated from Voyager's encounters with Jupiter and Saturn. Some are unique extensions of that technology.

Brown, D. W.↗