Publications

Coffinite is the dominant ore mineral in the V-U ores of the Tony-M mine in the Henry Mts mineral belt of the Colorado Plateau. This orebody was formed at a density-stratified solution interface between uranyl-ion-bearing meteoric water and a saline fluid which was locally reducing. The localization of U at this solution interface occurred by adsorption onto the surfaces of detrital...

A general procedure for computing the effect of non-zero turn-off time on the transient electromagnetic response is presented which can be applied to forward and inverse calculation methods for any transmitter-receiver configuration. We consider in detail the case of a large transmitter loop which has a receiver coil located at the center of the loop (central induction or in-loop array)...

Using several isotopic techniques, we have determined the ages of selected metamorphic rocks in the Yukon-Tanana terrane (YTT) of east-central Alaska. U-Pb zircon data from an augen gneiss body in the Big Delta quadrangle indicate that the granitoid protolith of the gneiss was intruded 341 ± 3 m.y. ago (lower intercept age). An upper intercept age of 2,136 ± 31 m.y. indicates an...

The Middle Pennsylvania!) Minturn Formation and the Pennsylvanian-Permian Sangre de Cristo Formation of the northern Sangre de Cristo Range form a thick progradational sequence of coarse clastic sediments. These sediments were deposited along the western margin of the central Colorado trough during uplift of the late Paleozoic Uncompahgre highland, a major structural and topographic...

The Voyager global multispectral mosaic of the Galilean satellite Europa (T. V. Johnson, L. A. Soderblom, J. A. Mosher, G. E. Danielson, A. F. Cook, and P. Kupferman, 1983, J. Geophys. Res. 88, 5789–5805) was analyzed to map surface units with similar optical properties (T. B. McCord, M. L. Nelson, R. N. Clark, A. Meloy, W. Harrison, T. V. Johnson, D. L. Matson, J. A. Mosher, and L...

Twenty eustatic and epeirogenic events mainly dated by conodonts are distinguished between the Middle Devonian and the lower Upper Mississippian in Great Basin, in Rocky Mountains and in the Overthrust belt regions.

Travertine deposits overlie the highest Number 2 surfaces in central Montana and clasts of travertine occur in gravels on lower Number 2 surfaces. Dating these travertine deposits may provide limits on the ages of surfaces that record intervals of extensive erosion during Pleistocene time. Analysis of three travertine samples from the southeast side of The Park yield an average uranium...

The Devonian System of Euramerica contains at least 14 transgressive-regressive (T-R) cycles of eustatic origin. These are separated into three groups (or depophases) and from Carboniferous cycles by three prominent regressions. Twelve post-Lochkovian T-R cycles are recognized, and they commonly appear to result from abrupt deepening events followed by prolonged upward shallowing...

In order to display more clearly the gravity anomalies caused by bodies of geologic interest in the crust, a new colored isostatic residual gravity map of the conterminous United States has been prepared using the gravity data set compiled for the Gravity Anomaly Map of the United States (SEG, 1982). The isostatic residual map is based on an Airy-Heiskanen model of local compensation...

Irregularities in the reconstructed gradients of latest Pliocene and Quaternary terraces in the northern Bighorn Basin, northwest Wyoming and south-central Montana, suggest that Quaternary movements have occurred on the Frannie anticline, the Nye-Bowler–Sage Creek fault zone, and the North Pryor fault. This area has been considered tectonically inactive. The timing of the interpreted...

No abstract available.

No abstract available.