R. Randall Schumann
Biography
Education:
B.A., Geography, University of Colorado, 1979
M.S., Geology, Colorado State University, 1985
About Me:
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. 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.
Selected chapters (see Publications tab below for articles and reports):
Schumann, R.R., Gundersen, L.C.S., and Tanner, A.B., 1994, Chapter 6—Geology and occurrence of radon, in Nagda, N.L., ed, Radon: Prevalence, measurement, health risks, and control. American Society for Testing and Materials Manual MNL-15, p. 83-96.
Schumann, R.R., Owen, D.E., and Asher-Bolinder, Sigrid, 1992, Effects of weather and soil characteristics on temporal variations in soil-gas radon concentrations, in Gates, A.E., and Gundersen, L.C.S., eds, Geologic controls on radon: GSA Special Paper 271, p . 65-72.
Science and Products
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...
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...
Schumann, R. Randall; Pigati, Jeffrey S. 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...
Muhs, Daniel R.; Pigati, Jeffrey S.; Schumann, R. Randall; Skipp, Gary L.; Porat, Naomi; DeVogel, Stephen B. 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...
Schumann, R. Randall; Pigati, Jeffrey S. 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...
Schumann, R. Randall; Pigati, Jeffrey S. 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...
Schumann, R. Randall; Zielinski, Robert A.; Otton, James K.; Pantea, Michael P.; Orem, William H. 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...
Schumann, R. Randall; Zielinski, Robert A.; Otton, James K.; Pantea, Michael P.; Orem, William H. 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...
Schumann, R. Randall; Pigati, Jeffery S.; McGeehin, John P. 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....
Muhs, Daniel R.; Simmons, Kathleen R.; Groves, Lindsey T.; McGeehin, John P.; Schumann, R. Randall; Agenbroad, Larry D. 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...
Muhs, Daniel R.; Simmons, Kathleen R.; Schumann, R. Randall; Groves, Lindsey T.; DeVogel, Stephen B.; Minor, Scott A.; Laurel, Deanna 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...
Muhs, Daniel R.; Groves, Lindsey T.; Schumann, R. Randall 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...
Schumann, R. Randall; Minor, Scott A.; Muhs, Daniel R.; Pigati, Jeffery S. Tectonic influences on the preservation of marine terraces: Old and new evidence from Santa Catalina Island, California
The California Channel Islands contain some of the best geologic records of past climate and sea-level changes, recorded in uplifted, fossil-bearing marine terrace deposits. Among the eight California Channel Islands and the nearby Palos Verdes Hills, only Santa Catalina Island does not exhibit prominent emergent marine terraces, though the same...
Schumann, R. Randall; Minor, Scott A.; Muhs, Daniel R.; Groves, Lindsey T.; McGeehin, John P.