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Laboratory measurements including gas (N2) porosity and permeability, time‐domain nuclear magnetic resonance, thin section, and scanning electron microscopy analysis were conducted to obtain petrographical and petrophysical descriptions of the Weber Sandstone and Madison Limestone at the Rock Spring Uplift, a potential carbon dioxide storage site in Southwestern Wyoming. The relationships between pore structures, such as pore geometry, pore‐size distribution, pore network, and porosity/permeability are investigated. First, using thin sections combined with scanning electron microscopy for pore structures description, all samples are described in detail from the geological, petrographysical, and diagenetic viewpoint. Results show that within the Madison Limestone, pore types include intercrystalline, vuggy, moldic, or mixed (combination of all other pore types). Both moldic and vuggy pore types are associated with samples of high porosity and permeability. Nuclear magnetic resonance relaxation time distributions show either bimodal or multimodal distributions. Large relaxation time components are associated with samples with large pores, whereas small components are dominated by small pores. The T2 geometric mean correlates well with gas permeability. Additionally, short‐time diffusion coefficients (D) were measured by pulsed field gradient method using a series of gradient strengths. We found that diffusion coefficient distributions correlate with the corresponding T2 distributions for macropores. By comparing the dominant peak position of T2 distributions and their corresponding diffusion coefficient distributions, we predicted the surface relaxivity of different rock types. We found that surface relaxivities of Weber Sandstone samples can be well predicted, while for Madison Limestone samples, surface relaxivities are overestimated due to diffusive pore coupling effect.

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Although Archean gneisses of the Teton Range crop out over an area of only 50 × 15 km, they provide an important record of the Archean history of the Wyoming Province. The northern and southern parts of the Teton Range record different Archean histories. The northern Teton Range preserves evidence of 2.69-2.68 Ga high-pressure granulite metamorphism (>12 kbar, ~900 °C) followed by tectonic assembly with isotopically juvenile quartzofeldspathic metasedimentary rocks under high-pressure amphibolite-facies conditions (~7 kbar, 675 °C) and intrusion of extensive leucogranites. Together, these events record one of the oldest continent-continent collisional orogenies on Earth. Geochemical, thermobarometric, and geochronological data from the gneisses of the southern Teton Range show that this part of the uplift records a geologic history that is distinct from the northern part. It contains a variety of quartzofeldspathic gneisses, including a 2.80 Ga granodioritic orthogneiss and the 2.69-268 Ga Rendezvous Gabbro. None of these preserves evidence of the granulite metamorphism seen in the northern Teton Range. Instead, they have affinities with rocks elsewhere in the Wyoming Province. The boundary between the northern and southern areas is occupied by the Moran deformation zone, a broad zone of high strain along which the northern and southern areas were assembled at ca. 2.62 Ga under moderate pressures and temperatures (T = 540-600 °C and P < 5.0 kbar). The final Archean event of the Teton Range was the emplacement at 2.55 Ga of the Mount Owen batholith, a peraluminous leucogranite that intrudes the Moran deformation zone. The rocks of the northern Teton Range record events that are not present elsewhere in the Wyoming Province. We propose that they formed at 2.70-2.67 Ga some place distal to the Wyoming Province and that they were accreted from the west against the Wyoming Province along the Moran deformation zone at ca. 2.62 Ga. This date is coeval with deformation and metamorphism in the southern accreted terranes and indicates that at this time, accretion was taking place along both the southern margin and western margins of the Wyoming Province. GEOLOGIC BACKGROUND Preliminary geologic mapping of the range was conducted by John C.