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The preliminary geomagnetic data included here is made available to scientific personnel and organizations, as part of a cooperative effort and on a data exchange basis because of the early need by some users. To avoid delay, all of the data is copied from original forms processed at the observatory; therefore it should be regarded as preliminary.
The preliminary geomagnetic data included here is made available to scientific personnel and organizations, as part of a cooperative effort and on a data exchange basis because of the early need by some users. To avoid delay, all of the data is copied from original forms processed at the observatory; therefore it should be regarded as preliminary.
Beach placers deposited within the Fox Hills Sandstone along the eastern flank of the Denver Basin contain minerals deemed critical in 2018 by the U.S. Department of the Interior. These marine beach placers, or paleoplacers, were deposited in the Late Cretaceous along the western edge of the retreating Western Interior Seaway (WIS). Preliminary investigations determined that these deposits contain potential critical mineral resources including titanium, zirconium, hafnium, and rare earth elements (REE). This report contains the results of a limited investigation conducted by the CGS in this area to provide additional information on the nature of these mineral deposits. The following tasks were completed during this investigation: review and summary of publicly available documents and publications; collection of samples and stratigraphic analysis of accessible outcrops; mineralogical analysis of select samples; and laboratory analysis of samples for select critical mineral concentrations. This report may assist with future mineral exploration efforts in this area and provide insight into the retreat of the WIS during the Late Cretaceous.
Montana Fish, Wildlife and Parks (MFWP) uses the integrated Patch Occupancy Model (iPOM) to estimate statewide and regional wolf abundance. During the early years of recovery, wolf abundance was tracked using minimum counts. As the population increased, limitations of this method became apparent, motivating development of a model-based approach for estimating abundance. iPOM development began in 2006, was operationalized in 2013, and has been used in its current form (iPOM 1.0) since 2021. Since its inception, iPOM has been developed and presented as an adaptive modeling framework intended to evolve as new data and analytical methods become available1. Here, we briefly present ongoing work to produce the next iteration of iPOM, hereafter iPOM 2.0, and summarize major model updates and resulting preliminary wolf abundance estimates. iPOM uses models for occupancy, territory size, and pack size, along with monitoring data collected by MFWP wolf specialists and potential wolf sightings reported by deer and elk hunters during the 5-week general rifle season each Nov-Dec. These monitoring data, wolf sightings, and covariates for habitat and survey effort are used to model occupancy of packs on a statewide grid of 600-km 2 cells. The area used by wolves is then estimated as each cell’s occupancy estimate multiplied by grid cell area. iPOM estimates pack abundance by dividing this area by predicted territory sizes, and in-pack wolf abundance by multiplying pack abundance by estimated group size. This is combined with a lone wolf rate to estimate total wolf abundance (see Sells et al. 1 for a full description of iPOM 1.0). This technical summary provides a high-level overview of the proposed iPOM updates and their implications for wolf abundance estimates. The estimates presented here represent results as of June 2026 and are provided to inform upcoming discussions surrounding harvest management and regulations (e.g., season dates, quotas, methods). Results are preliminary and remain subject to final model refinement and peer review.
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Introduction Many different types of landslide occur in the Santa Cruz Mountains of San Mateo County, Calif. (Brabb and Pampeyan, 1972); most slope movement is triggered by strong earthquakes, heavy rainfall, or shoreline erosion. In this area, shallow landslides of loose soil and rock, which may transform into debris flows, commonly occur during individual storms when rainfall exceeds a threshold of intensity and duration (Cannon and Ellen, 1985; Wieczorek and Sarmiento, 1988; Wilson and Wieczorek, 1995). In contrast, deeper rotational and translational slides (Varnes, 1978) typically begin to move only after days to weeks or months of heavy rain. Once started, they can continue to move for months during and after a heavy rainfall season, for example, the Scenic Drive landslide at La Honda, Calif. (Jayko and others, 1998; Wells and others, 2005, 2006). Although the rainfall characteristics triggering rapid, shallow landslides have been documented (Wieczorek, 1987; Cannon and Ellen, 1988), the rainfall conditions leading to repeated deeper-seated slope movements are less well known. The Weeks Creek landslide (Adam, 1975), near the western crest of the Santa Cruz Mountains north of La Honda in San Mateo County (fig. 1), consists of a large prehistoric section containing a historically active section; both sections have earthflow morphologies. The entire landslide mass, which extends about 1,000 m westward from an elevation of 220 m down to an elevation of 120 m, is about 300 to 370 m wide (Cole and others, 1994); The prehistoric section of the landslide is about 30 m deep and approximately 10 million m3 in volume (Cole and others, 1994). The smaller, historically active portion of the Weeks Creek landslide (fig. 1) is only approximately 500 m long, 200 m wide, and 13 m deep (Cole and others, 1994). Near the landslide, the Santa Cruz Mountains consist of tightly folded, Tertiary sedimentary bedrock materials of the Butano sandstone and San Lorenzo Formations (Eocene through Lower Oligocene). These sedimentary bedrock materials are locally intruded by Oligocene diabase and capped by Oligocene through Miocene basalt of the Mindego Formation (Brabb, 1980; Cole and others, 1994). Within the active landslide, as documented from multiple borings by Cole and others (1994), deeply weathered mudstone and sandstone of the San Lorenzo Formation extends to a depth of about 10 to 13 m, where the active shear zone is located. Beneath this, within the deeper prehistoric landslide, mudstone extends to a depth of about 24 to 32 m and is underlain by strong diabase bedrock. The basal rupture surface of the prehistoric landslide is located near the mudstone/diabase contact (Cole and others, 1994). The historically active section of the Weeks Creek landslide, which is crossed by the La Honda road (California Highway 84, fig. 1), was first noticed to partially move during the great 1906 San Francisco earthquake (Lawson, 1908). It has moved repeatedly over the ensuing years but generally only during wet rainy seasons. For some of these active years, ground cracks and lateral displacements were recorded by local residents Walter Jodicke and Chris Pearson, as well as by U.S. Geological Survey (USGS) personnel. In spring 2006, fresh ground cracks were noted in parts of the prehistoric, previously inactive section of the landslide. In this report, we present daily rainfall measurements from 1973 through 2006 obtained at the landslide site and summarize available observations of slope movement over that period. In addition, we present more detailed observations of rainfall, ground-water pressure, and slope movement for three water years spanning the period 1981-1984. We conclude with some preliminary observations about rainfall and slope movement at this site.
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