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A database of geologic map of Three Sisters Volcanic Cluster as described in the original abstract: The geologic map represents part of a late Quaternary volcanic field within which scores of eruptions have taken place over the last 50,000 years, some as recently as ~1,500 years ago. No rocks of early Pleistocene (or greater) age crop out within the map area, although volcanic and derivative sedimentary rocks of Miocene and Pliocene age are widespread to the east and west and are certainly buried beneath the younger volcanic field. Of the 145 volcanic map units described herein, only 22 are certainly older than late Pleistocene (>126 ka), and 12 are postglacial (<15 ka). The oldest unit identified yields an age...
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In 1968, the Missouri Geological Survey (MGS) established the Operation Basement program to address three objectives: a) to obtain drill hole and underground mining data relative to the structure and composition of the buried Precambrian basement; b) to expand mapping in the Precambrian outcrop area and conduct research related to Precambrian geology and mineral resources; and c) to publish the results of the first two objectives in the Contribution to Precambrian Geology series (Kisvarsanyi, 1976). The database presented here represents the first of those objectives. It was originally compiled in close cooperation with exploration and mining companies operating in Missouri, who provided drillhole data, core and...
Categories: Data; Types: Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, Shapefile; Tags: Adair County, Andrew County, Atchison County, Audrain County, Barry County, All tags...
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This is a database of the geologic map of the Lassen Peak, Chaos Crags, and Upper Hat Creek volcanic area as described in the original abstract: The Lassen Peak, Chaos Crags, and Upper Hat Creek map area lies near the southern end of the Cascade Range in northern California. The map area includes parts of the three elements that together form the Lassen volcanic center: the Lassen dacitic dome field, the Central Plateau andesitic lava field, and the underlying deeply eroded and partly altered Brokeoff andesitic stratocone. The Lassen volcanic center is the southernmost active long-lived center of the present-day Cascades volcanic arc. This geologic map contributes to understanding the youngest major volcanic events...
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This data release is a geochemical data set from the reanalysis of 23 rock and 85 sediment samples collected between 1966 and 1970 by the U.S. Geological Survey (USGS) for a series of studies investigating the mineral resources of the Idaho Primitive Area (Cater et al., 1973). The samples are from the upper Middle Fork Salmon River and the South Fork Salmon River, including the tributaries of East Fork of the South Fork and Porphyry Creek. The overall objective of this study is to characterize the regional impact of legacy mining for the Frank Church - River of No Return Wilderness Area. In 1980 the U. S. Congress passed the Central Idaho Wilderness Act which combined the Idaho Primitive Area, the Salmon Rivers...
Categories: Data; Types: Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, Shapefile; Tags: Automatic Creek, Beansnapper Creek, Bear Creek, Big Chief Creek, Big Cottonwood Creek, All tags...
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This geodatabase contains all the geologic map information for the Geologic Map of the San Juan caldera cluster, southwestern Colorado and is part of U.S. Geological Survey Geologic Investigations Map Series I-2799. The San Juan Mountains are the largest erosional remnant of a composite volcanic field that covered much of the southern Rocky Mountains in middle Tertiary time. The San Juan field consists mainly of intermediate-composition lavas and breccias, erupted about 35-30 Ma from scattered central volcanoes (Conejos Formation) and overlain by voluminous ash-flow sheets erupted from caldera sources. In the central San Juan Mountains, eruption of at least 8,800 km3 of dacitic-rhyolitic magma as nine major ash...


    map background search result map search result map Operation Basement: Missouri Precambrian Sample Database Database for the Geologic Map of the Lassen Peak, Chaos Crags, and Upper Hat Creek Area, California Database for the Geologic Map of Three Sisters Volcanic Cluster, Cascade Range, Oregon Database for the geologic map of the central San Juan caldera cluster, southwestern Colorado Geochemical reanalysis of rock and sediment samples from the Middle Fork and South Fork of the Salmon River collected in the mid-1960s through the early 1970s as part of the Idaho Primitive Area studies Database for the Geologic Map of the Lassen Peak, Chaos Crags, and Upper Hat Creek Area, California Database for the Geologic Map of Three Sisters Volcanic Cluster, Cascade Range, Oregon Database for the geologic map of the central San Juan caldera cluster, southwestern Colorado Geochemical reanalysis of rock and sediment samples from the Middle Fork and South Fork of the Salmon River collected in the mid-1960s through the early 1970s as part of the Idaho Primitive Area studies Operation Basement: Missouri Precambrian Sample Database