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This dataset is intended to provide seamless, integrated geologic mapping of the U.S. Intermountain West region as a contribution to The National Geologic Map supported by the National Cooperative Geologic Mapping Program of the U.S. Geological Survey. Surficial and bedrock geology are included in this data release as independent datasets at a variable resolution from 1:50,000 to 1:250,000 scale. No original interpretations are presented in this dataset; rather, all interpretive data are assimilated from referenceable publications. Derivative polygon features created for this dataset demonstrate the distribution of SIGMa-GeMS Geologic Provinces derived from the distribution of map units. Initial contributions to...
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Under the direction and funding of the National Cooperative Geologic Mapping Program (NCGMP) with guidance and encouragement from the United States Geological Survey (USGS), there has been a decadal strategic plan in place to call for geologic mapping across the nation. This call has been increasing the need for digital data that has not yet been made available. With such a demand, physical data is being re-released as vector-based, GIS operable data, which is viable as a corporate asset to the USGS. This collection of reports is part of the compilation and synthesis efforts hampered by the distributed nature of subsurface investigations at the USGS and a general lack of cataloging and archiving of 3-D geological...
Categories: Data; Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Almond Formation, Arizona, Baxter Shale, Castlegate Sandstone, Colorado, All tags...
Repeat photography samples were used to analyze how the structure and site-specific distribution of forests may or may not have changed during the past century in the San Juan Mountains, Colorado. Systematic evaluation of 146 photosets was combined with field observations to identify trends in vegetation change. Both conifers and deciduous trees (e.g., aspen) have increased in extent. Forest recovery from large disturbances that occurred during Euro-American settlement contributed substantially to this increase. Trees also encroached into grass/shrublands, but less than half of photosets show tree invasion, and invasion is more common in small grass/shrubland openings interspersed with forest than in large openings....
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This data release presents geologic map data for the bedrock geology of the Blanca Peak, Walsenburg, Trinidad, and Alamosa 30' x 60' quadrangles, Colorado. Geologic mapping incorporates new interpretive contributions and compilation from published geologic map data sources primarily ranging from 1:24,000 to 1:50,000 scale. Much of the geology incorporated from published geologic maps is adjusted based on digital elevation model and natural-color image data sources to improve spatial resolution of the data. Spatial adjustments and new interpretations also eliminate mismatches at source map boundaries. This data set represents only the bedrock geology; deposits of unconsolidated, surficial materials that are typically,...
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This Laser ablation ICPMS U-Pb detrital zircon data set supports mapping and stratigraphic interpretations of the Upper Devonian Ignacio Formation in southwestern Colorado (Silverton area). All samples were collected from a measured stratigraphic section called "Sultan Creek South" located at 37.710010 and -107.67530 (Evans and others, 2019). The Ignacio Formation was previously interpreted as Cambrian, but evidence that it is Devonian includes reexamined fossil data and detrital zircon U-Pb geochronology. The Ignacio Formation has a stratigraphic trend of detrital zircon ages shifting from a single ca. 1.7 Ga age peak to bimodal ca. 1.4 Ga and ca. 1.7 Ga age peaks, which represents local source-area unroofing history....
1. There is mounting evidence that leaf litter typically decomposes more rapidly beneath the plant species it derived from than beneath the different plant species, which has been called home-field advantage (HFA). It has been suggested that this HFA results from the local adaptation of soil communities to decompose the litter that they encounter most often, which probably comes from the plant species above them. 2. To test this hypothesis and to investigate how HFA varies over time and in relation to litter quality, we performed the first detailed assessment of HFA in relation to litter decomposition. We monitored decomposition over time in two reciprocal litter transplant experiments involving three high-elevation...
This reports summarizes work and key findings to date from the Upper RIO Grande Basin SNOwfall Measurement and streamFLOW (RIO-SNO-FLOW) Forecasting Improvement Project conducted from Jan. 1, 2014 through Dec. 31, 2015. The project area was centered over the upper mainstem Rio Grande and Conejos River basins in southern Colorado. This report is organized into 7 chapters that detail the major elements of the project including; a Project Description, NOAA Gap-filling Radar, NASA Airborne Snow Observatory, In-Situ Ground Observations, Distributed Hydrologic Modeling, and Community Engagement. While several follow-on activities are still in progress, a number of conclusions and recommendations have emerged from the...
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These data include snow depth and snow water equivalence (SWE) for the 2022 and 2023 water years during 16 separate field campaigns. The field area is comprised of 311 surveyed points in, on the perimeter of, and surrounding six forest openings next to Coal Creek off Coal Bank Pass in the San Juan Mountains in Southwest Colorado, USA. These measurements were taken to look at the relationship between snow accumulation and snow melt patterns between forest gaps of various sizes, and forest edges of various sizes (edge of forest gaps). Canopy metrics, including canopy height, total gap area, mean distance to canopy, canopy closure, leaf area index, non-directional edginess, canopy edginess with a southern aspect, and...
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Album caption: Hinsdale Co, Colo. Index card: Wood Mountain arête, elevation 13,600' feet. San Juan Mountains. Hinsdale County, Colorado. August 3, 1971.
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Album caption: Bog-Picayne Gulch. Index card: General view of Bog in Picayne Gulch. San Juan Mountains. San Juan County, Colorado. July 19, 1972.
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Hydrologic reconnaissance of Mineral Creek near Silverton, Colo., was conducted from June 25-27, 2020. Both banks of Mineral Creek and the adjacent hillsides were walked, starting near the ghost town of Chattanooga and proceeding downstream to the confluence of Mineral Creek with the Middle Fork of Mineral Creek. The purpose of this reconnaissance was to identify areas of emergent groundwater on the right (EGR) and left (EGL) banks, a task that was accomplished by following observed surface flows (seeps and springs) upgradient to the point at which they emanated from the subsurface. Coordinates, using a handheld global positioning system (GPS) device, and photographs were obtained at these locations of emergent...
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Album caption: San Juan Co, Colo. Index card: The U-shaped valley of Cunningham Creek. San Juan Mountains. San Juan County, Colorado. July 27, 1971.
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Multispectral remote sensing data acquired by the Landsat 8 Operational Land Imager (OLI) sensor were analyzed using a new, automated technique to generate a map of exposed mineral and vegetation groups in the western San Juan Mountains, Colorado and the Four Corners Region of the United States (Rockwell and others, 2021). Spectral index (e.g. band-ratio) results were combined into displayed mineral and vegetation groups using Boolean algebra. New analysis logic has been implemented to exploit the coastal aerosol band in Landsat 8 OLI data and identify concentrations of iron sulfate minerals. These results may indicate the presence of near-surface pyrite, which can be a potential non-point source of acid rock drainage....
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Album caption: Ouray Co, Colo. Index card: Gilpin Peak and arête, elevation 13,694 feet. San Juan Mountains. Ouray County, Colorady. August 14, 1971.
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Album caption and index card: View to west from Handies' Peak, including view of cirque. San Juan Mountains, Colorado. Hinsdale and San Juan Counties, Colorado. June 27, 1972.
The Rosa mule deer (Odocoileus hemionus) migrate an average of 45 miles from northwest New Mexico to southwest Colorado. Their winter range is located in the upper San Juan Basin, east of the Navajo Reservoir, and is dominated by pinyon juniper woodlands and sagebrush grasslands. The Rosa herd utilize three distinct areas as summer range: the lower elevation Valle Seco, consisting primarily of ponderosa pine woodland and big sagebrush shrubland, and the higher elevation North and South San Juan Mountains, consisting of ponderosa pine and aspen-mixed woodlands. The herd collectively migrate northeast from their winter range for around 12 miles before a second route branches off the main corridor, with these individuals...
The Pagosa Springs geologic map is of the 7.5-minute quadrangle of the same name. It is located in southwestern Colorado, USA and shows the town of Pagosa Springs. The mapped area is southwest of the San Juan volcanic mountains (Oligocene) and north of the San Juan Basin. All bedrock units exposed in the map area are Upper Cretaceous in age except a minor canyon outcrop of Upper Jurassic rock. Pre-Holocene Quaternary age deposits are mainly alluvial gravels and outwash on terraces. Structure is simple: shale and sandstone beds dip at low angles east to northeast as a broad limb of the north-northwest striking Archuleta Anticline. Three geologic cross sections controlled by drill holes are included and depict Mesozoic...
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Album caption: Minnie Gulch. Index card: U-shaped valley of Minnie Gulch. San Juan Mountains. San Juan County, Colorado. July 22, 1972.
Fire severity, frequency, and extent are expected to change dramatically in coming decades in response to changing climatic conditions, superimposed on the adverse cumulative effects of various human-related disturbances on ecosystems during the past 100 years or more. To better gauge these expected changes, knowledge of climatic and human influences on past fire regimes is essential. We characterized the temporal and spatial properties of fire regimes in ponderosa pine forests of the southern San Juan Mountains of southwestern Colorado by collecting 175 fire-scarred tree samples from nine sites across a wide range of topographic settings. All tree rings and fire scars were dated using standard dendrochronological...
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La Botica is positioned on a topographic bench sharply inset into the gentle eastern slope of the high San Juan Mountains and perched ~70-80 meters above La Jara Creek (fig. 1), a tributary to the Rio Grande. Quaternary surface processes have modified the Tertiary bedrock deposits that underlie La Botica to shape the physical environment. Bedrock deposits consist of Oligocene to Pliocene volcanic and sedimentary deposits related to the Rio Grande rift and the San Juan volcanic locus of the Southern Rocky Mountains volcanic field. Bedrock deposits are mildly deformed by normal faulting and eastward tilting related to the onset of extensional deformation in the Oligocene and formation of the San Luis Basin. Bedrock...


map background search result map search result map San Juan Mountains, Colorado. Wood Mountain arête, elevation 13,600 feet. 1971. San Juan Mountains, Colorado. Gilpin Peak and arête, elevation 13,694 feet.1971. View to west from Handies Peak. San Juan Mountains. Hinsdale and San Juan Counties, Colorado. 1972. San Juan Mountains, Colorado. Bog in Picayne Gulch. 1972. San Juan Mountains, Colorado. U-shaped valley of Minnie Gulch. 1972. Data Release for the Geologic Map of the Pagosa Springs 7.5' Quadrangle, Archuleta County, Colorado U-Pb detrital zircon data for: lower Paleozoic sedimentary rocks near Silverton, CO USA Digital map of iron sulfate minerals, other mineral groups, and vegetation of the San Juan Mountains, Colorado, and Four Corners Region derived from automated analysis of Landsat 8 satellite data Hydrologic reconnaissance to identify areas of emergent groundwater, Mineral Creek, near Silverton, Colorado, June 2020 Geologic setting and geomorphic history of the La Botica area, south-central Colorado Migration Stopovers of Mule Deer in the Rosa Herd in New Mexico Collection of digital structure contour maps from previously published USGS studies Snow Measurements in Specific Canopy Structure Regimes for the 2022-2023 Water Years, North of Coal Creek, San Juan Mountains, Colorado, USA Seamless Integrated Geologic Map Database of the Intermountain West: Contributions to The National Geologic Map Bedrock geologic map database for the Blanca Peak, Walsenburg, Trinidad, and Alamosa 30' x 60' quadrangles, Colorado Geologic setting and geomorphic history of the La Botica area, south-central Colorado Snow Measurements in Specific Canopy Structure Regimes for the 2022-2023 Water Years, North of Coal Creek, San Juan Mountains, Colorado, USA Data Release for the Geologic Map of the Pagosa Springs 7.5' Quadrangle, Archuleta County, Colorado San Juan Mountains, Colorado. Bog in Picayne Gulch. 1972. San Juan Mountains, Colorado. U-shaped valley of Minnie Gulch. 1972. San Juan Mountains, Colorado. Gilpin Peak and arête, elevation 13,694 feet.1971. San Juan Mountains, Colorado. Wood Mountain arête, elevation 13,600 feet. 1971. View to west from Handies Peak. San Juan Mountains. Hinsdale and San Juan Counties, Colorado. 1972. Migration Stopovers of Mule Deer in the Rosa Herd in New Mexico Bedrock geologic map database for the Blanca Peak, Walsenburg, Trinidad, and Alamosa 30' x 60' quadrangles, Colorado Seamless Integrated Geologic Map Database of the Intermountain West: Contributions to The National Geologic Map Digital map of iron sulfate minerals, other mineral groups, and vegetation of the San Juan Mountains, Colorado, and Four Corners Region derived from automated analysis of Landsat 8 satellite data Collection of digital structure contour maps from previously published USGS studies