Search results for "Geophysic"
showing 10 items of 2684 documents
Sulfate deposition in subsurface regolith in Gusev crater, Mars
2006
Excavating into the shallow Martian subsurface has the potential to expose stratigraphic layers and mature regolith, which may hold a record of more ancient aqueous interactions than those expected under current Martian surface conditions. During the Spirit rover's exploration of Gusev crater, rover wheels were used to dig three trenches into the subsurface regolith down to 6-11 cm depth: Road Cut, the Big Hole, and The Boroughs. A high oxidation state of Fe and high concentrations of Mg, S, Cl, and Br were found in the subsurface regolith within the two trenches on the plains, between the Bonneville crater and the foot of Columbia Hills. Data analyses on the basis of geochemistry and miner…
Geochemical and mineralogical indicators for aqueous processes in the Columbia Hills of Gusev crater, Mars
2006
[1] Water played a major role in the formation and alteration of rocks and soils in the Columbia Hills. The extent of alteration ranges from moderate to extensive. Five distinct rock compositional classes were identified; the order for degree of alteration is Watchtower ≅ Clovis > Wishstone ≅ Peace > Backstay. The rover's wheels uncovered one unusual soil (Paso Robles) that is the most S-rich material encountered. Clovis class rocks have compositions similar to Gusev plains soil but with higher Mg, Cl, and Br and lower Ca and Zn; Watchtower and Wishstone classes have high Al, Ti, and P and low Cr and Ni; Peace has high Mg and S and low Al, Na, and K; Backstay basalts have high Na and K comp…
In situ and experimental evidence for acidic weathering of rocks and soils on Mars
2006
Experimental data for alteration of synthetic Martian basalts at pH=0-1 indicate that chemical fractionations at low pH are vastly different from those observed during terrestrial weathering. Rock analyses from Gusev crater are well described by the relationships apparent from low pH experimental alteration data. A model for rock surface alteration is developed which indicates that a leached alteration zone is present on rock surfaces at Gusev. This zone is not chemically fractionated to a large degree from the underlying rock interior, indicating that the rock surface alteration process has occurred at low fluid-to-rock ratio. The geochemistry of natural rock surfaces analyzed by APXS is c…
Iron mineralogy and aqueous alteration from Husband Hill through Home Plate at Gusev Crater, Mars: Results from the Mössbauer instrument on the Spiri…
2008
[1] Spirit's Mossbauer (MB) instrument determined the Fe mineralogy and oxidation state of 71 rocks and 43 soils during its exploration of the Gusev plains and the Columbia Hills (West Spur, Husband Hill, Haskin Ridge, northern Inner Basin, and Home Plate) on Mars. The plains are predominantly float rocks and soil derived from olivine basalts. Outcrops at West Spur and on Husband Hill have experienced pervasive aqueous alteration as indicated by the presence of goethite. Olivine-rich outcrops in a possible mafic/ultramafic horizon are present on Haskin Ridge. Relatively unaltered basalt and olivine basalt float rocks occur at isolated locations throughout the Columbia Hills. Basalt and oliv…
Characterization and petrologic interpretation of olivine-rich basalts at Gusev Crater, Mars
2006
Rocks on the floor of Gusev crater are basalts of uniform composition and mineralogy. Olivine, the only mineral to have been identified or inferred from data by all instruments on the Spirit rover, is especially abundant in these rocks. These picritic basalts are similar in many respects to certain Martian meteorites (olivine-phyric shergottites). The olivine megacrysts in both have intermediate compositions, with modal abundances ranging up to 20-30%. Associated minerals in both include low-calcium and high-calcium pyroxenes, plagioclase of intermediate composition, iron-titanium-chromium oxides, and phosphate. These rocks also share minor element trends, reflected in their nickel-magnesiu…
Transmediterranean flights, in the edge of two centuries
2004
Abstract Transmediterranean flights take place at 40 km altitude and approximately 38°N latitude. Sixty six successful trans-mediterranean crossings have been performed in the period 1977–2002. A summary of system requirements, that would assure state-of-the-art stratospheric balloon flights is presented. Details of the 2002 campaign, along with a historical review of the flights corresponding to the Nineties, 2000 and 2001, are presented.
Search for Microphysical Signatures of Stochastic Condensation in Marine Boundary Layer Clouds Using Airborne Digital Holography
2019
Thermal inertia mapping from NOAA-AVHRR data
1998
Abstract This paper presents a method to retrieve thermal inertia from NOAA-AVHRR data. The method, based on Xue and Cracknell's model (1992), involves using the phase angle information of the diurnal surface temperature change. The method needs three different NOAA overpasses of the same area throughout a single diurnal cycle. To apply this method we present a methodology that takes into account satellite calibrations, viewing geometry and correction of atmospheric effects. The advantage is that it does not need other data than the ones supplied by the satellite. Finally, we present the preliminary results obtained using the proposed method and the methodology for AVHRR data over the Iberi…