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Chemical and mineralogical data from Mars shows that the surface has been chemically weathered on local to regional scales. Chemical trends and the types of chemical weathering products present on the surface and their abundances can elucidate information about past aqueous processes. Thermal-infrared (TIR) data and their respective models are essential for interpreting Martian mineralogy and geologic history. However, previous studies have shown that chemical weathering and the precipitation of fine-grained secondary silicates can adversely affect the accuracy of TIR spectral models. Furthermore, spectral libraries used to identify minerals on the Martian surface lack some important weathering products, including poorly-crystalline …

Contributors

Rampe, Elizabeth Barger, Sharp, Thomas G, Christensen, Phillip, et al.

Created Date

2011

The Kinsley Mountain gold deposit of northeastern Nevada, located ~70 km south of Wendover, Nevada, contains seven sediment-hosted, disseminated-gold deposits, in Cambrian limestones and shales. Mining ceased in 1999, with 138,000 ounces of gold mined at an average grade between 1.5-2.0 g/t. Resource estimates vary between 15,000 and 150,000 ounces of gold remaining in several mineralized pods. Although exploration programs have been completed within the study area, the structural history and timing of precious-metal mineralization are still poorly understood. This study aims to better understand the relation between stratigraphy, structural setting, and style of gold mineralization. In order to accomplish …

Contributors

Macfarlane, Bryan John, Reynolds, Stephen, Hervig, Richard, et al.

Created Date

2012

The present understanding of the formation and evolution of the earliest bodies in the Solar System is based in large part on geochemical and isotopic evidences contained within meteorites. The differentiated meteorites (meteorites originating from bodies that have experienced partial to complete melting) are particularly useful for deciphering magmatic processes occurring in the early Solar System. A rare group of differentiated meteorites, the angrites, are uniquely suited for such work. The angrites have ancient crystallization ages, lack secondary processing, and have been minimally affected by shock metamorphism, thus allowing them to retain their initial geochemical and isotopic characteristics at the …

Contributors

Sanborn, Matthew Edward, Wadhwa, Meenakshi, Hervig, Richard, et al.

Created Date

2012

The presence of a number of extinct radionuclides in the early Solar System (SS) is known from geochemical and isotopic studies of meteorites and their components. The half-lives of these isotopes are short relative to the age of the SS, such that they have now decayed to undetectable levels. They can be inferred to exist in the early SS from the presence of their daughter nuclides in meteoritic materials that formed while they were still extant. The extinct radionuclides are particularly useful as fine-scale chronometers for events in the early SS. They can also be used to help constrain the …

Contributors

Spivak-Birndorf, Lev Jacob, Wadhwa, Meenakshi, Hervig, Richard, et al.

Created Date

2012

The temperature of a planet's surface depends on numerous physical factors, including thermal inertia, albedo and the degree of insolation. Mars is a good target for thermal measurements because the low atmospheric pressure combined with the extreme dryness results in a surface dominated by large differences in thermal inertia, minimizing the effect of other physical properties. Since heat is propagated into the surface during the day and re-radiated at night, surface temperatures are affected by sub-surface properties down to several thermal skin depths. Because of this, orbital surface temperature measurements combined with a computational thermal model can be used to …

Contributors

Heath, Simon Nicholas, Christensen, Philip, Bel, James, et al.

Created Date

2013

Much of Mars' surface is mantled by bright dust, which masks the spectral features used to interpret the mineralogy of the underlying bedrock. Despite the wealth of near-infrared (NIR) and thermal infrared data returned from orbiting spacecraft in recent decades, the detailed bedrock composition of approximately half of the martian surface remains relatively unknown due to dust cover. To address this issue, and to help gain a better understanding of the bedrock mineralogy in dusty regions, data from the Thermal Emission Spectrometer (TES) Dust Cover Index (DCI) and Mars Reconnaissance Orbiter (MRO) Mars Color Imager (MARCI) were used to identify …

Contributors

Lai, Jason Chi-Shun, Bell, James, Christensen, Philip, et al.

Created Date

2014

Hydrogen isotope compositions of the martian atmosphere and crustal materials can provide unique insights into the hydrological and geological evolution of Mars. While the present-day deuterium-to-hydrogen ratio (D/H) of the Mars atmosphere is well constrained (~6 times that of terrestrial ocean water), that of its deep silicate interior (specifically, the mantle) is less so. In fact, the hydrogen isotope composition of the primordial martian mantle is of great interest since it has implications for the origin and abundance of water on that planet. Martian meteorites could provide key constraints in this regard, since they crystallized from melts originating from the …

Contributors

Tucker, Kera, Wadhwa, Meenakshi, Hervig, Richard, et al.

Created Date

2015