Now showing items 21-30 of 69
A PETROLOGIC, GEOCHEMICAL AND OSMIUM ISOTOPIC STUDY OF SELECTED PRECAMBRIAN KOMATIITES
The major and trace elements, and Re-Os isotope systematics of the ca. 2.7-Ga komatiites from the Alexo and Dundonald Beach areas in the Abitibi greenstone belt, Canada, and ca. 2.0-Ga komatiites from Jeesiörova, Finnish ...
Sulfur isotope fractionations in biological systems: insight into the Proterozoic biosphere
This study focuses on developing a framework for interpreting isotopic fractionations in the four stable sulfur isotopes, with a special focus on microbial effects. Calculations of low temperature equilibrium fractionations ...
Petrogenesis of Peraluminous Granites from the Fosdick Mountains, Marie Byrd Land, West Antarctica
Granites from the Fosdick Mountains, West Antarctica were analyzed for major and trace elements as well as Sr-Nd isotopes ratios in order to investigate the sources and processes associated with granite formation at a ...
An empirical re-evaluation of the boron isotope/pH proxy in marine carbonates
The boron isotopic composition measured in marine carbonates is considered to be a tracer of seawater pH. However, an accurate application of this proxy has been hampered by our lack of intimate understanding of chemical ...
Age, composition, and origin of the lower continental crust, northern Tanzania
Granulite xenoliths from the East African rift in Tanzania sample the lower continental crust beneath both the stable Tanzanian craton and the adjacent, polymetamorphic Mozambique belt. Protoliths of surface rocks in both ...
ISOTOPE GEOCHEMISTRY OF ORGANIC SULFUR COMPOUNDS WITH LINKS TO BIOGEOCHEMICAL SULFUR CYCLING AND RADICAL CHEMISTRY
An Integrated Isotopic and Biomarker Analysis of the Glaciogenic Vazante Group, Brazil
The Vazante Group, a meta-sedimentary succession located in south-central Brazil, contains several intervals of diamictite, interpreted as glacial in origin, bracketed by well-preserved carbonate and shale. This glacial ...
Isotope and Organic Geochemistry of a Unique Proterozoic, Postglacial Succession: The Lapa Formation, Vazante Group, Brazil
This study is the second to investigate biological characteristics associated with Proterozoic glaciation via molecular fossils from organic matter preserved in shale. In the Vazante Group, Minas Gerais, Brazil, the Serra ...
Highly Siderophile Element and Tungsten Systematics of Hawaiian Picrites
A suite of Hawaiian picrites (MgO > 13 wt.%), and associated basalts, that represent some of the most primitive melts from the Hawaiian mantle source regions were analyzed for their W, highly siderophile element (HSE: Os, ...
GLOBAL AND REGIONAL REFERENCE MODELS FOR PREDICTING THE GEONEUTRINO FLUX AT SNO+, SUDBURY, CANADA
Determining the radiogenic heat power that is driving plate tectonics and mantle convection is fundamentally important to understanding the Earth's heat budget and its thermal and chemical evolution. The radiogenic heat ...