In this note we introduce a method for robust principal component regression. Robust principal components are computed from the predictor variables, and they are used afterwards for estimating a response variable by performing robust linear multiple regression. The performance of the method is evaluated at a test data set from geochemistry. Then it is used for the prediction of censored values ...

Clumped isotope geochemistry is concerned with the state of ordering of rare isotopes in natural materials. That is, it examines the extent to which rare isotopes (D, C, N, O, etc.) bond with or near each other rather than with the sea of light isotopes in which they swim. Abundances of isotopic ‘clumps’ in natural materials are influenced by a wide variety of factors. In most cases, their conc...

Microbial abundance and diversity in deep subsurface environments is dependent upon the availability of energy and carbon. However, supplies of oxidants and reductants capable of sustaining life within mafic and ultramafic continental aquifers undergoing low-temperature water-rock reaction are relatively unknown. We conducted an extensive analysis of the geochemistry and microbial communities r...

Apatite contains only traces of uranium, yet as apatite is a minor constituent in most rocks and the major constituent of a few very large deposits, it accounts, paradoxically, for both dispersal and concentration of uranium in nature. Uranium typically makes up 0.001 to 0.01 percent of primary igneous apatite and 0.005 to 0.02 percent of sedimentary marine apatite. Marine reworked apatite beco...

Thermophilic microbial inhabitants of active seafloor and continental hot springs populate the deepest branches of the universal phylogenetic tree, making hydrothermal ecosystems the most ancient continuously inhabited ecosystems on Earth. Geochemical consequences of hot water-rock interactions render these environments habitable and supply a diverse array of energy sources. Clues to the strate...

Variations of oxygen isotope ratios in arc-related lavas can constrain trace-element enrichment in a mantle source being fluxed by addition the contributions of subducted crustal igneous rocks, sediments, and of aqueous fluid. Comparison of this model with observed variations fluids to the sub-arc mantle. We have measured oxygen isotope in the geochemistry of lavas from the Vanuatu–Fiji–New Cal...

The magmatic activity on Vesta was certainly dominated by a large-scale melting event, which generated a global magma-ocean. According to this view, eucrites can be explained in terms of fractional crystallization, with subsequent contamination of the melts by liquids derived by partial fusion of the asteroid's crust [e.g, 1-3]. The HED cumulates (cumulate eucrites, dio-genites, and a dunite) p...

Clay minerals are layer type aluminosilicates that figure in terrestrial biogeochemical cycles, in the buffering capacity of the oceans, and in the containment of toxic waste materials. They are also used as lubricants in petroleum extraction and as industrial catalysts for the synthesis of many organic compounds. These applications derive fundamentally from the colloidal size and permanent str...