The reaction of CO2 hydration/dehydration controls the oxygen isotopic composition in both carbonate minerals and atmospheric CO2 through the exchange of oxygen isotopes with water. The use of O as an environmental indicator typically assumes isotopic equilibrium, namely full oxygen isotope exchange between CO2 and water. Clumped isotopes is a new isotopic tracer that is used in both CaCO3 and ...

A typical molecular ion mass spectrum consists of a sum of signals from species of various possible isotopic compositions. Only the monoisotopic peak (e.g., all carbons are 12C; all nitrogens are 14N, etc.) has a unique elemental composition. Every other isotope peak at approximately integer multiples of approximately 1 Da higher in nominal mass represents a sum of contributions from isotope co...

Introduction: The isotopic compositions of moderately volatile elements like Li, K, Rb may provide key information to further enhance our understanding of the early history of our Solar System (e.g., [1,2]). Here we discuss technical aspects of our efforts to precisely determine the Rb isotopic composition of meteorites and present a hint for a possible nucleosynthetic effect suggested by corre...

[1] The O/O ratio of snowmelt from a seasonal snowpack typically increases with time as the melting process progresses. This temporal evolution is caused by isotopic exchange between liquid and ice as meltwater percolates down the snow column. Consequently, hydrograph separations of spring runoff using the bulk snow composition as the new water end-member will be erroneous. Accurate determinati...

Galactic cosmic rays represent a directly accessible sample of matter that originates outside the solar system, The elemental and isotopic composition of this sample of high-energy matter contains a record of nucleosynthesis in other regions of the galaxy, and of subsequent nuclear and electromagnetic interactions that have altered its composition. There have recently been significant new advan...

Ion microprobe measurements of carbon isotope ratios were made in 30 specimens representing six fossil genera of microorganisms petrified in stromatolitic chert from the approximately 850 Ma Bitter Springs Formation, Australia, and the approximately 2100 Ma Gunflint Formation, Canada. The delta 13C(PDB) values from individual microfossils of the Bitter Springs Formation ranged from -21.3 +/- 1....

Introduction Conclusions References

The need for femtosecond laser ablation (fs-LA) systems coupled to MC-ICP-MS to accurately perform in situ stable isotope analyses remains an open question, because of the lack of knowledge concerning ablation-related isotopic fractionation in this regime. We report the first iron isotope analysis of size-resolved, laser-induced particles of natural magnetite, siderite, pyrrhotite, and pyrite, ...

Introduction: The widely accepted model for the origin of the Earth-Moon system as the result of a Mars-sized giant impactor colliding with proto-Earth is inconsistent with a variety of new isotopic data. Generally, it is thought that the Earth and the Mars-sized Moon-forming impactor were isotopically different (for mass independent isotopic variations). Therefore, according to the “canonical”...

Ureilites and carbonaceous chondrites: The origin of ureilite meteorites has been consistently regarded as problematic [1]. A distinctive feature of ureilites is that they contain carbonaceous matter up to 6 wt. %, particularly in the form of graphite in veinlets between silicate (mostly olivine) crystals, and along their cleavage planes. The carbonaceous matter within them suggests a relations...