{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Karl S. Kellogg", "hasEmail": "mailto:kkellogg@usgs.gov"}, "description": "This 1:50,000-scale geologic map represents a compilation\nof the most recent geologic studies of the upper Arkansas\nRiver valley, between Leadville and Salida, Colorado. The\nvalley is structurally controlled by an extensional fault\nsystem that forms part of the prominent northern Rio Grande\nrift, an intra-continental region of crustal extension.  This\nwork also incorporates new detailed geologic mapping of\npoorly understood areas within the map area and reinterprets\npreviously studied areas, aided by lidar data that covers 59\npercent of the map area. The mapped region extends into the\nProterozoic metamorphic and intrusive rocks in the Sawatch\nRange west of the valley and the Mosquito Range to the east.\nPaleozoic rocks are preserved along the crest of the Mosquito\nRange, but most of them have been eroded from the Sawatch Range.\nNumerous new isotopic ages (U-Pb zircon ages for the intrusive\nProterozoic and some Tertiary rocks adjacent to the valley and\n40Ar/39Ar ages for the Late Cretaceous to Oligocene intrusive\nand extrusive rocks) better constrain the timing of both\nProterozoic and Late Cretaceous to early Tertiary intrusive\nevents.  The U-Pb ages document widespread ~1,440-Ma granitic\nplutonism north of Buena Vista that produced batholiths that\nintruded an older suite of ~1,760-Ma metamorphic rocks\nand ~1,700-Ma plutonic rocks.  As a result of extension\nduring the Neogene and possibly latest Paleogene, the graben\nunderlying the valley is filled with thick basin-fill deposits\n(Dry Union Formation and older sediments), which occupy two\nsub-basins, separated by a bedrock high near the small town\nof Granite.  The Dry Union Formation has undergone deep\nerosion since the late Miocene or early Pliocene.  During the\nPleistocene, ongoing steam incision by the Arkansas River and\nits major tributaries has been interrupted by periodic\naggradation. From Leadville south to Salida as many as 7\nmapped alluvial depositional units, which range in age from\nearly to late Pleistocene, record periodic aggradational events\nalong these streams that are commonly associated with\ndeposition of glacial outwash or bouldery glacial-flood\ndeposits.  Many previously unrecognized Neogene and Quaternary\nfaults, some of the latter with possible Holocene displacement,\nhave been identified on lidar imagery.  This imagery has also\npermitted more accurate remapping of glacial, fluvial, and\nmass-movement deposits and has aided in the determination of\ntheir relative ages.  Recently published 10Be cosmogenic\nsurface-exposure ages, coupled with new geologic mapping, have\nrevealed the timing and rates of late Pleistocene deglaciation.\nGlacial dams that impounded the Arkansas River at Clear Creek\nand possibly at Pine Creek failed at least 3 times during the\nmiddle and late Pleistocene, resulting in catastrophic floods\nand deposition of enormous boulders and bouldery alluvium\ndownstream; at least two failures occurred during the late\nPleistocene during the Pinedale glaciation.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/F75B00XQ", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.5910ab8fe4b0e541a03ac85f.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_5910ab8fe4b0e541a03ac85f", "keyword": ["207Pb/206Pb zircon age", "40Ar/39Ar age", "Arkansas River", "Balltown", "Balltown placer gold mining areas", "Belden Formation", "Belle of Granite Mine", "Big Union Creek", "Bishop ash", "Black Cloud Mine", "Black Mountain", "Browns Canyon", "Browns Canyon Formation", "Browns Canyon fluorspar mining district", "Browns Creek", "Buckskin Gulch", "Buena Vista", "Buffalo Creek", "Buffalo Peaks", "Bull Lake age", "Bull Lake glaciation", "Cache Creek", "California Gulch", "California Mine", "Cambrian", "Cenozoic", "Centerville", "Chaffee County", "Chaffee Group", "Chalk Creek", "Clear Creek", "Clear Creek Reservoir", "Colorado", "Cottonwood Creek", "Cretaceous", "Devonian", "Dotsero Formation", "Dry Union Formation", "Dry Union Gulch", "Dyer Dolomite", "Eagle County", "Eagle River", "East Fork Arkansas River", "Eddy Creek", "Elephant Rock", "Eocene", "Fremont County", "Fremont Dolomite", "Front Range", "Garfield", "Garfield Mine", "Garfield mining district", "Gordon Mine", "Granite", "Granite mining district", "Granite placer gold mining areas", "Harding Sandstone", "Hayden Gulch", "Holocene", "Homestake Reservoir", "Iowa Gulch", "Johnson Village", "Kerber Formation", "Lake County", "Lake Creek", "Langhoff Gulch", "Lava Creek B ash", "Leadville", "Leadville Limestone", "Leadville mining district", "Lilly Mine", "London Mine", "Malta", "Manitou Dolomite", "Manitou Dolomite, Taylor Pass Member", "Maroon Formation", "Maroon Formation, Coffman Member", "Maroon Formation, evaporite facies", "Maysville", "Mesoproterozoic", "Mesozoic rocks", "Minturn Formation", "Miocene", "Mississippian", "Morrison Creek", "Mosquito Range", "Mount Aetna", "Mount Antero", "Mount Antero mining district", "Mount Princeton", "Mount Shavano", "Mount Yale", "Neogene", "Oligocene", "Paleocene", "Paleogene", "Paleoproterozoic", "Paleozoic", "Paleozoic rocks", "Park County", "Parting Sandstone", "Pennsylvanian", "Permian", "Pine Creek", "Pinedale age", "Pinedale glaciation", "Pitkin County", "Pleistocene", "Pliocene", "Poncha Springs", "Proterozoic rocks", "Quaternary", "Quaternary deposits", "Rio Grande rift", "Riverside", "Rock Creek", "Ruby Mine", "Ruby Mountain", "San Juan Mountains", "Sangre de Cristo Range", "Sawatch Quartzite", "Sawatch Range", "Sedalia Mine", "Sedalia copper-zinc mining district", "South Arkansas River", "South Park", "South Platte River", "Squaw Creek", "St. Kevin mining district", "Sugar Loaf mining district", "Sugarloaf Mountain", "Tennessee Creek", "Tertiary", "Tertiary rocks", "Triad Ridge", "Trout Creek", "Trout Creek Pass", "Trout Creek paleovalley", "Tumble Creek", "Turquoise Lake", "Twin Lakes Reservoir", "Twin Lakes mining district", "Two Bits mining district", "USA", "USGS:5910ab8fe4b0e541a03ac85f", "United States", "Western Alma mining district", "Weston Pass", "Weston Pass mining district", "Yankee Blade Mine", "alluvial deposits", "alluvium", "andesite", "artificial-fill deposits", "augen gneiss", "basalt", "basin-fill deposits", "breccia", "colluvium", "copper", "cosmogenic surface-exposure age", "dacite", "debris flow", "debris-flow deposits", "diamicton", "diorite", "eolian deposits", "fan deposits", "fault", "faulting", "fluorspar", "fluvial deposits", "gabbro", "glacial deposits", "glacial flood deposits", "glacial flood gravel", "glaciofluvial deposits", "gneiss", "gold", "graben", "granite", "granitic gneiss", "granodiorite", "gravel", "hydrologic hazards", "hypabyssal rhyolite", "intrusive rock", "lahar deposit", "lamprophyre", "landslide deposits", "latite", "lava", "lead", "leucogranite", "leucogranite gneiss", "lidar imagery", "man-made deposits", "mass-movement deposits", "mass-movement hazards", "metabasalt", "metagabbro", "metaigneous rocks", "metasedimentary rocks", "metavolcanic rocks", "microtonalite", "mine", "mine-waste deposits", "mineral deposits", "mining district", "monzodiorite", "monzogranite", "monzonite", "mud-flow deposits", "neotectonics", "ore", "outwash", "outwash gravel", "peat deposits", "pegmatite", "periglacial", "placer gold", "placer-tailings deposits", "porphyry", "pre-Bull Lake age", "pre-Bull Lake glaciation", "quartz diorite", "quartz latite", "quartzite", "rhyodacite", "rhyolite", "rift", "rock-glacier deposits", "sackungen", "sand and gravel resources", "scarp", "schist", "sedimentary rocks", "seismic hazards", "silver", "smelter-slag deposits", "soil", "surficial deposits", "talus deposits", "till", "tuff", "volcanic ash", "volcanic breccia", "volcanic rock", "weathering", "wetland deposits", "zinc"], "modified": "2022-08-29T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-106.50000, 38.50000, -105.92200, 39.37500", "theme": ["geospatial"], "title": "Data release for the geologic map of the upper Arkansas River valley region, north-central Colorado"}