Various diffusion raodels can be applied to Rb-Sr systems in cooling rocks. It is argued that a closed-system diffusioncontrolled model, inw3lving local equilibrium along grain boundaries, is most appropriate for describing the exchange of Sr isotopes between minerals in a rock sample during cooling. A finite-difference numerical method is used to solve the diffusion and mass-balance equations....

We have developed two automated detectors that can recognize the sulfate mineral jarosite in unknown visible to near-infrared spectra (350– 2500 nm). The two detectors are optimized for use within the terrestrial and martian atmospheres. The detectors are built from Support Vector Machines trained using a generative model to create linear mixtures of library mineral spectra. Both detectors perf...

The Moon, like the Earth, is made of rocks. To learn about the Moon and its history, one has to learn something about lunar rocks—what they are made of, how they are studied and classified, and how our experiences in interpreting rocks on the Earth have been applied to rocks on the Moon. The lunar samples have provided our only direct information about the Moon’s minerals, chemical composition,...

Rb–Sr and U–Pb isotopic data for granulite facies rocks, forming textural relics with respect to eclogite facies metamorphism in the Western Gneiss Region (WGR) of Norway, highlight the importance of textures and mineral reaction kinetics for the interpretation of geochronological data. Studied rocks from Bårdsholmen, southern WGR, were subjected to granulite facies metamorphism at 955 ± 3 Ma (...

The Mars Science Laboratory rover Curiosity found host rocks of basaltic composition and alteration assemblages containing clay minerals at Yellowknife Bay, Gale Crater. On the basis of the observed host rock and alteration minerals, we present results of equilibrium thermochemical modeling of the Sheepbed mudstones of Yellowknife Bay in order to constrain the formation conditions of its second...

The Bonaparte project is a new multi-year bedrock mapping program of the British Columbia Geological Survey (BCGS) concentrating on Mesozoic arc volcanic and plutonic rocks of the Quesnel Terrane in the northeastern part of the Bonaparte Lake (92P) map sheet (Figure 1). The area encompasses a northwest-trending belt of high mineral potential that includes a number of interesting mineral occurre...

in order to assess the presence or absence of fluids under peak metamorphic conditions within the inner aureole of the etive igneous complex in west scotland, eight suitable metabasic hornfels samples and one suitable pelitic hornfels were used to calculate water activities using a mineral equilibria. calculated activities for water are lower than unity in the pelitic sample and extremely low i...