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Titan's interaction with the Saturnian magnetospheric plasma /Backes, Heiko. January 2005 (has links)
Zugl.: Köln, University, Diss., 2004.
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Spectroscopy of jarosite minerals, and implications for the mineralogy of Mars/Rothstein, Yarrow. January 2006 (has links) (PDF)
Undergraduate honors paper--Mount Holyoke College, 2006. Dept. of Astronomy. / Includes bibliographical references (leaves 80-87).
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Teilchenpopulationen in der inneren Jupitermagnetosphäre Untersuchung der EPI-Daten von der Galileo-Probe /Pehlke, Eckhard. January 2000 (has links) (PDF)
Kiel, Universiẗat, Diss., 2000.
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Io revealed in the Jovian dust streamsGraps, Amara Lynn. January 2001 (has links) (PDF)
Heidelberg, University, Diss., 2001.
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Imaginative geographies of Mars the science and significance of the red planet, 1877-1910 /Lane, Kristina Maria Doyle, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
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Heavy element enrichment of the gas giant planetsCoffey, Jaime Lee 11 1900 (has links)
According to both spectroscopic measurements and interior models, Jupiter,
Saturn, Uranus and Neptune possess gaseous envelopes that are enriched in
heavy elements compared to the Sun. Straightforward application of the
dominant theories of gas giant formation - core accretion and gravitational
instability - fail to provide the observed enrichment, suggesting that the
surplus heavy elements were somehow dumped onto the planets after the
envelopes were already in existence.
Previous work has shown that if giant planets rapidly reached their cur
rent configuration and radii, they do not accrete the remaining planetesimals
efficiently enough to explain their observed heavy-element surplus. We ex
plore the likely scenario that the effective accretion cross-sections of the
giants were enhanced by the presence of the massive circumplanetary disks
out of which their regular satellite systems formed. Perhaps surprisingly,
we find that a simple model with protosatellite disks around Jupiter and
Saturn can meet known constraints without tuning any parameters. Fur
thermore, we show that the heavy-element budgets in Jupiter and Saturn
can be matched slightly better if Saturn’s envelope (and disk) are formed
roughly 0.1 — 10 Myr after that of Jupiter.
We also show that giant planets forming in an initially-compact con
figuration can acquire the observed enrichments if they are surrounded by
similar protosatellite disks.
Protosatellite disks efficiently increase the capture cross-section, and thus
the metallicity, of the giant planets. Detailed models of planet formation
must therefore account for the presence of such disks during the early stages
of solar system formation. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
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An investigation into some aspects of Jovian decametric radiationHill, I. E. January 1969 (has links)
This thesis describes observations of the flne structure in Jovian decametric radiation made at Grahamstown during the 1967-68 apparition. It was found that pulses with duration less than 0.5 milliseconds were common during fine structure storms. The restrictions placed on the source for different theories of origin of the short pulses are discussed. The variation of the probability of occurrence from year to year is analysed on the assumption that the radiation is found in directions fixed with respect to the planet's magnetic field. It is concluded that there is a factor other than the declination of Earth and the Io effect which controls the probability of occurrence. A detailed analysis suggests a beam width of 3° in latitude at Jupiter but further work is necessary to check this.
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The geology of Mare Acidalium Quadrangle, MarsWitbeck, Nanci E January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
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IO: MODELS OF VOLCANISM AND INTERIOR STRUCTURE (JUPITER, MOON, CALDERAS, HEAT FLOW, LACCOLITHS).CRUMPLER, LARRY STEVEN. January 1983 (has links)
The silicate "magma trigger" model of volcanism on Io has been evaluated numerically with finite element methods by considering the one-dimensional heat transfer between hot silicate magma and initially cold sulfur. It is found that for the probable range of initial magma temperatures and sulfur temperatures, the contact between silicate magma and a sulfur crust will be 700 (+OR-) 100 K, or approximately the vapor point of elemental sulfur. A silicate magma sill or laccolith on the order of 10 m thick will yield energetic vapor for a period of several weeks to several months depending on the vapor temperature and the amount of convective cooling of the silicate magma that occurs at the silicate-sulfur interface. This model may account for the origin of plumes and possible sulfur flows, as well as for their observed temperatures ((TURN) 600-700K) and lifetimes (several days to a few months). If the conducted heat flow is similar in high and low latitudes, then the low latitude occurrence of plumes may be explained as a result of lower temperatures at higher latitudes. Because the contact temperature of sulfur and silicate magma depends on the pre-existing sulfur temperature, a system in which sulfur vapor temperature is just reached at the equator would not generate sulfur vapor under lower initial sulfur temperatures existing at high latitudes. If the heat flow is higher in high latitudes, then the sulfur crust must be thinner than it is in low latitudes for the model to work as described above. Most of the heat flow from Io may be moved by convection from the interior to the surface, not by conduction. Heat flow may be modulated by the efficient transfer of silicate melts from 40 to 300 km depth, and emplaced as laccoliths at the sulfur-silicate crustal interfaces at a depth of 5-10 km. Sulfur flows, plumes, calderas and other areas of massive radiant heat dissipation continue the convective cycle to the surface. The temperature at the base of the sulfur crust may be less than the melting point of sulfur, and the silicate magma temperature can be as low as 1200 K. Low silicate magma temperatures will occur if the crust of Io is as differentiated as terrestrial rhyolites and trachytes. High alkalies in the Io plasma torus suggest the possibility that the Ionian crust is a highly differentiated silicate.
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The structure of the crust, the uppermost mantle, and the mantle transition zone beneath MadagascarAndriampenomanana Ny Ony, Elamahalala Fenitra Sy Tanjona January 2017 (has links)
A thesis submitted to the Faculty of Science, University of the
Witwatersrand, Johannesburg, in fulfillment of the requirements for
the degree of Doctor of Philosophy.
October 2017. / Since the arc assembly and continental collision of the East African Orogen some
640 million years ago, Madagascar has gone through several geodynamic and
tectonic episodes that have formed and subsequently modified its lithosphere.
This thesis aims to investigate the structure of the crust, the uppermost mantle,
and the mantle transition zone beneath Madagascar to gain insights into the
relationship between present-day lithosphere structure and tectonic evolution, and
to evaluate candidate models for the origin of the Cenozoic intraplate volcanism.
To address these issues, local, regional, and teleseismic events recorded by several
temporary seismic networks; the MAdagascar-COmoros-MOzambique
(MACOMO), the SEismological signatures in the Lithosphere/Asthenosphere
system of SOuthern MAdagascar (SELASOMA), and the Réunion Hotspot and
Upper Mantle – Réunions Unterer Mantel (RHUM-RUM) were used to
complement the seismic events recorded by the permanent seismic stations in
Madagascar. The different methods used and the primary results of this study are
explained in each section of this thesis.
In the first part of this thesis, crustal and uppermost mantle structure beneath
Madagascar was studied by analyzing receiver functions using an H-κ stacking
technique and a joint inversion with Rayleigh-wave phase-velocity measurements.
Results reflect the eastward and northward progressive development of the
western sedimentary basins of Madagascar. The thickness of the Malagasy crust
ranges between 18 km and 46 km. The thinnest crust (18-36 km thick) is located
beneath the western basins and it is due to the Mesozoic rifting of Madagascar
from eastern Africa. The slight thinning of the crust (31-36 km thick) along the
east coast may have been caused by crustal uplift and erosion when Madagascar
moved over the Marion hotspot and India broke away from it. The parameters
describing the crustal structure of Archean and Proterozoic terranes, including
thickness, Poisson’s ratio, average shear-wave velocity, thickness of mafic lower
crust, show little evidence of secular variation. Slow shear-wave velocity of the
uppermost mantle (4.2-4.3 km/s) are observed beneath the northern tip, central
part and southwestern region of the island, which encompass major Cenozoic
volcanic provinces in Madagascar.
The second part of the thesis describes a seismic tomography study that
determines the lateral variation of Pn-wave velocity and anisotropy within the
uppermost mantle beneath Madagascar. Results show an average uppermost
mantle Pn-velocity of 8.1 km/s. However, zones of relatively low-Pn-velocity
(~7.9 km/s) are found beneath the Cenozoic volcanic provinces in the northern,
central, and southwestern region of the island. These low-Pn-velocity zones are
attributed to thermal anomalies that are associated with upwelling of hot mantle
materials that gave rise to the Cenozoic volcanism. The direction of Pn anisotropy
shows a dominant NW-SE direction of fast-polarization in the northern region and
around the Ranostara shear zone, in the south-central Madagascar. The anisotropy
in the uppermost mantle beneath these regions aligns with the existing geological
framework, e.g. volcanic complex and shear zones, and can be attributed to a
fossil anisotropy. The Pn anisotropy in the southwestern region, around the
Morondava basin, is E-W to NE-SW-oriented. It can be attributed either to the
mantle flow from plate motion, the African superplume, or the Mesozoic rifting
from Africa. Results from this study do not show any substantial evidence of the
formation of a diffuse boundary of the Lwandle plate, cutting through the central
region of Madagascar. Station static delays reflect the significant variation in the
Moho depth beneath the island.
In the third part of the thesis, the thickness of the mantle transition zone beneath
Madagascar, which is sensitive to the surrounding temperature variation, has been
estimated by stacking receiver functions. Single-station and common-conversionpoint
stacking procedures show no detectable thinning of the mantle transition
zone and thus no evidence for a thermal anomaly in the mantle under Madagascar
that extends as deep as the mantle transition zone. Therefore, this study supports
an upper mantle origin for the Cenozoic volcanism. However, the resolution of the
study is not sufficient to rule out the presence of a narrow thermal anomaly as
might arise from a plume tail.
Overall, the findings in this research are broadly consistent with the crustal and
upper mantle structure of Madagascar determined by previous studies, but
provides significantly greater detail with regard to the crustal and uppermost
mantle structure as more seismic stations were used. / LG2018
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