Publications

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Palynologic and paleomagnetic data confirm a Paleocene age for the Ojo Alamo Sandstone (and its contained dinosaurs) throughout the San Juan Basin of New Mexico. The recently reported discovery of 34 skeletal elements from a single hadrosaur in the Ojo Alamo provides unequivocal evidence that these bones were not reworked from underlying Cretaceous strata. Geochemical studies of samples...

A concerted effort is underway to prepare a substantially upgraded digital gravity anomaly database for the United States and to make this data set and associated usage tools available on the internet. This joint effort, spearheaded by the geophysics groups at the National Imagery and Mapping Agency (NIMA), University of Texas at El Paso (UTEP), U.S. Geological Survey (USGS), and...

The digital dataset consists of one file (monterey_100k.iso) containing 2,385 gravity stations. The file, monterey_100k.iso, contains the principal facts of the gravity stations, with one point coded per line. The format of the data is described below. Each gravity station has a station name, location (latitude and longitude, NAD27 projection), elevation, and an observed gravity reading...

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Clear Creek, one of the major tributaries of the upper Sacramento River, drains the eastern Trinity Mountains. Alluvial plain and terrace gravels of lower Clear Creek, at the northwest edge of the Sacramento Valley, contain placer gold that has been mined since the Gold Rush by various methods including dredging. In addition, from the 1950s to the 1980s aggregate-mining operations...

On August 8, 2002, twenty-one scientists from the federal, private and academic sectors met at a workshop in Denver, Co., to discuss the feasibility of collecting magnetic anomaly data on a Canberra aircraft (Figure 1). The need for this 1-day workshop arose because of an exciting and cost-effective opportunity to collect invaluable magnetic anomaly data during a Canberra mission over...

The gravity data used to make this map were collected between 1959 and 1984. The data were collected by automobile, aircraft, and watercraft. Most of the data were collected as part of a U.S. Geological Survey (USGS) regional gravity data collection project. Some of the data were collected as part of other USGS local projects. One data set was collected by the NGS (National Geodetic...

Gravity surveys are useful tools for helping to understand the 3-dimensional geology of an area. Many gravity measurements were made in the 1960s and 1970s by various groups in order to produce gravity maps covering California at a scale of 1:250,000 for the California Division of Mines and Geology. (For this area see Biehler et. al. 1988.) More recent surveys have focused on specific...

Recently acquired geophysical data provide information on the geologic framework and its effect of groundwater flow and on stream/aquifer interaction in Yavapai County, Arizona. High-resolution aeromagnetic data reflect diverse rock types at and below the topographic surface and have permitted a preliminary interpretation of faults and underlying rock types (in particular, volcanic) that...