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The isotopic composition of paleosol carbonate and organic matter were investigated in the Bighorn Basin, Wyoming to explore changes in the carbon cycle and climate across the Paleocene-Eocene boundary. In three different measured sections, soil carbonate δ δ 13 C values change in phase with marine surface water carbonates on both long (∼7 m.y.) and short (∼ ∼100 k.y.) time scales. The carbon cycle perturbations at the Paleocene-Eocene Boundary Thermal Maximum (PETM) and the Eocene Warm Interval (EWI) are recorded in multiple sections, providing unambiguous links between marine and continental deposits. The PETM and EWI δ δ 13 C excursions in the Bighorn Basin are larger than those in the surface ocean, but the reasons for this amplification are unclear. Organic matter samples from the Bighorn Basin yield noisy δ δ 13 C records that do not mirror global changes, perhaps due to diagenetic alteration or postformational contamination. The δ δ 18 O values of soil carbonate are subject to multiple climatic influences that are often antagonistic. Although the δ δ 18 O shifts at the PETM and EWI are small, the shift at the PETM is statistically significant in two of the measured sections. Assuming a plausible range of values for the meteoric water δ δ 18 O/mean annual temperature relationship, the perturbation in soil carbonate δ δ 18 O at the PETM is consistent with an increase in meteoric water δ δ 18 O of ∼ ∼2‰ and changes in local temperature of 3-7 °C.

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The probability that long-term geologic storage or sequestration of carbon dioxide (CO 2 ) will become an important climate change mitigation strategy will depend on a number of factors, namely (1) availability, capacity and location of suitable sites, (2) the cost of geologic storage compared to other climate change mitigation options, and (3) public acceptance. Whether or not a site is suitable will be determined by establishing that it can meet a set of performance requirements for safe and effective geologic storage (PRGS). To date, no such PRGS have been developed. Establishing effective PRGS must start with an evaluation of how much CO 2 might be stored and for how long the CO 2 must remain underground to meet goals for controlling atmospheric CO 2 concentrations. These requirements then provide a context for addressing the issue of what, if any, is an "acceptable surface seepage rate"? This paper provides a preliminary evaluation of CO 2 storage amounts, time-scales, and concordant performance requirements.

Hematite coatings are common on vertebrate fossils from Paleocene/Eocene paleosol deposits in the Bighorn Basin, Wyoming. In general, hematite coatings are found only on fossils and are limited to soils exhibiting hydromorphic features and moderate maturity. Petrographic and isotopic evidence suggests that hematite and micritic calcite formed at nearly the same time in a pedogenic environment, whereas sparry calcite formed later at greater burial depths. The parent material of paleosols is rich in iron, supplying an ample source of iron for hematite formation. Decomposition of animal tissues around bones may enhance the weathering of iron-bearing minerals in soils surrounding carcasses, while the bones might provide favorable sites for iron accumulation. The predominance of discrete smectite, together with regional geothermal history, suggests that burial temperatures have not exceeded 70؇C. Hematite coatings on fossils can serve as a substrate for geochemical analysis in continental paleoclimatic research, owing to their pedogenic origin, abundance, and resistance to diagenetic alteration.