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R. Randall Schumann

I am currently a geologist in the Geosciences and Environmental Change Science Center in Denver, Colorado, conducting studies on the effects of climate change on landscape dynamics in coastal and fluvial environments.

I began my career at the USGS in 1980 with research focusing on fluvial geomorphology and sedimentology of anastomosing river channels; wetland hydrology; surficial uranium deposits; and the geology and geochemistry of radon in rocks and soils.  I received the Department of Interior's Superior Service Award for my work on radon. I was a member of the Central Publications Group from 1995-1997 and was coordinator of computer support, GIS, and web services for the Earth Surface Processes Team from 1997-2000.  I served as Team Chief Scientist (Center Director) of the Earth Surface Processes Team from 2002-2008 and was director of the National Ice Core Laboratory from 2007-2008.
 

 

 

 

Education and Certifications

  • M.S., Geology, Colorado State University, 1985

  • B.A., Geography, University of Colorado, 1979

Science and Products

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Coral reef and overlying marine deposits a few meters above sea level, south of Kaena Point, Hawaii

Geologic Records of High Sea Levels

This project studies past high sea levels on coastlines that preserve fossil coral reefs or marine terraces. We ascertain the magnitudes of sea-level high stands by field mapping, stratigraphic measurements, and precise elevation measurements. Geochronology is accomplished by radiocarbon dating of mollusks (for Holocene-to-last-glacial deposits), uranium-series dating of corals (for high-sea...
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Climate Research and Development Program, Geosciences and Environmental Change Science Center
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Geologic Records of High Sea Levels

This project studies past high sea levels on coastlines that preserve fossil coral reefs or marine terraces. We ascertain the magnitudes of sea-level high stands by field mapping, stratigraphic measurements, and precise elevation measurements. Geochronology is accomplished by radiocarbon dating of mollusks (for Holocene-to-last-glacial deposits), uranium-series dating of corals (for high-sea...
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Stratigraphic, geochemical, and hydrologic data for the Boston Peak wetland, Larimer County, CO, USA

Comprehensive sampling of peat, underlying lakebed sediments, and coexisting waters of a naturally uraniferous montane wetland are combined with hydrologic measurements to define the important controls on uranium (U) supply and uptake. The major source of U to the wetland is groundwater flowing through locally fractured and faulted granite gneiss of Proterozoic age. Dissolved U concentrations in f
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Geosciences and Environmental Change Science Center

Map showing radon potential of rocks and soils in Fairfax County, Virginia

Since 1984, indoor radon has gained national attention as a significant health hazard in the United States. Radon is a colorless, odorless, radioactive gas derived from uranium by radioactive decay. The U.S. Environmental Protection Agency (EPA) now projects that 5,000 to 20,000 lung-cancer deaths per year may be attributed to the long-term exposure to indoor radon and its radioactive decay produc
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The marine terraces of Santa Cruz Island, California: Implications for glacial isostatic adjustment models of last-interglacial sea-level history

Glacial isostatic adjustment (GIA) models hypothesize that along coastal California, last interglacial (LIG, broadly from ~130 to ~115 ka) sea level could have been as high as +11 m to +13 m, relative to present, substantially higher than the commonly estimated elevation of +6 m. Areas with low uplift rates can test whether such models are valid. Marine terraces on Santa Cruz Island have previousl
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Testing glacial isostatic adjustment models of last-interglacial sea level history in the Bahamas and Bermuda

Part of the spatial variation in the apparent sea-level record of the last interglacial (LIG) period is due to the diverse response of coastlines to glacial isostatic adjustment (GIA) processes, particularly where coastlines were close to the Laurentide Ice Sheet during the past two glacial periods. We tested modeled LIG paleo-sea levels on New Providence Island (NPI), Bahamas and Bermuda by inves
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Fluvial sedimentary history of Arlington Canyon, Channel Islands National Park, California

Arlington Canyon, in the northwest part of Santa Rosa Island, Channel Islands National Park, California, has been the setting for important scientific discoveries over the past half century, including the oldest human remains in North America, several vertebrate fossil sites, and purported evidence of a catastrophic extinction event at the end of the Pleistocene. The canyon is filled with alluvial
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Quaternary sea-level history and the origin of the northernmost coastal aeolianites in the Americas: Channel Islands National Park, California, USA

Along most of the Pacific Coast of North America, sand dunes are dominantly silicate-rich. On the California Channel Islands, however, dunes are carbonate-rich, due to high productivity offshore and a lack of dilution by silicate minerals. Older sands on the Channel Islands contain enough carbonate to be cemented into aeolianite. Several generations of carbonate aeolianites are present on the Cali
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Climate Research and Development Program, Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

Reply to the discussion of Pinter et al. on ‘Fluvial system response to late Pleistocene-Holocene sea-level change on Santa Rosa Island, Channel Islands National Park, California’ by Schumann et al. (2016)

We appreciate the thoughtful discussion offered by Pinter et al. (2017) because it gives us an opportunity to elucidate some of the main points of our study, address some apparent misinterpretations, and recapitulate one of our conclusions. Pinter et al.’s discussion emphasizes and reinforces some of the important concepts we presented but also raises questions regarding specific aspects of our st
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Climate Research and Development Program, Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

Late Quaternary fluvial history of Santa Cruz Island, California, USA

The geologic history of fluvial systems on Santa Cruz Island (SCI) is complex, involving responses to both allogenic and autogenic forcings. During periods of low or lowering sea level, canyons on the island were eroded and sediment was transported off the island onto the exposed marine shelf. When sea level rose, streams aggraded, building a sedimentary wedge that progressed from the shelf upstre
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Geosciences and Environmental Change Science Center

Uranium delivery and uptake in a montane wetland, north-central Colorado, USA

Comprehensive sampling of peat, underlying lakebed sediments, and coexisting waters of a naturally uraniferous montane wetland are combined with hydrologic measurements to define the important controls on uranium (U) supply and uptake. The major source of U to the wetland is groundwater flowing through locally fractured and faulted granite gneiss of Proterozoic age. Dissolved U concentrations in f
By
Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

Fluvial system response to late Pleistocene-Holocene sea-level change on Santa Rosa Island, Channel Islands National Park, California

Santa Rosa Island (SRI) is one of four east-west aligned islands forming the northern Channel Islands chain, and one of the five islands in Channel Islands National Park, California, USA. The island setting provides an unparalleled environment in which to record the response of fluvial systems to major changes of sea level. Many of the larger streams on the island occupy broad valleys that have be
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Climate Research and Development Program, Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

Late Quaternary sea-level history and the antiquity of mammoths (Mammuthus exilis and Mammuthus columbi), Channel Islands NationalPark, California, USA

Fossils of Columbian mammoths (Mammuthus columbi) and pygmy mammoths (Mammuthus exilis) have been reported from Channel Islands National Park, California. Most date to the last glacial period (Marine Isotope Stage [MIS] 2), but a tusk of M. exilis (or immature M. columbi) was found in the lowest marine terrace of Santa Rosa Island. Uranium-series dating of corals yielded ages from 83.8 ± 0.6 ka to
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Climate Research and Development Program, Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

Coastal tectonics on the eastern margin of the Pacific Rim: Late Quaternary sea-level history and uplift rates, Channel Islands National Park, California, USA

The Pacific Rim is a region where tectonic processes play a significant role in coastal landscape evolution. Coastal California, on the eastern margin of the Pacific Rm, is very active tectonically and geomorphic expressions of this include uplifted marine terraces. There have been, however, conflicting estimates of the rate of late Quaternary uplift of marine terraces in coastal California, parti
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Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

Interpreting the paleozoogeography and sea level history of thermally anomalous marine terrace faunas: A case study from the the last interglacial complex of San Clemente Island, California

Marine invertebrate faunas with mixtures of extralimital southern and extralimital northern faunal elements, called thermally anomalous faunas, have been recognized for more than a century in the Quaternary marine terrace record of the Pacific Coast of North America. Although many mechanisms have been proposed to explain this phenomenon, no single explanation seems to be applicable to all localiti
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Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

Landscapes of Santa Rosa Island, Channel Islands National Park, California

Santa Rosa Island (SRI) is the second-largest of the California Channel Islands. It is one of 4 east–west aligned islands forming the northern Channel Islands chain, and one of the 5 islands in Channel Islands National Park. The landforms, and collections of landforms called landscapes, of Santa Rosa Island have been created by tectonic uplift and faulting, rising and falling sea level, landslides
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Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

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