R. Randall Schumann
I am a Geologist Emeritus 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, director of the National Ice Core Laboratory from 2007-2008, and Center Director of GECSC 2018-2020. I retired from USGS in 2022 but I am pleased and honored to continue pursuing my research interests as a Scientist Emeritus.
Education and Certifications
M.S., Geology, Colorado State University, 1985
B.A., Geography, University of Colorado, 1979
Science and Products
Filter Total Items: 39
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
Authors
Daniel R. Muhs, Kathleen R. Simmons, R. Randall Schumann, Lindsey T. Groves, Stephen B. DeVogel, Scott A. Minor, Deanna Laurel
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
Authors
Daniel R. Muhs, Lindsey T. Groves, R. Randall Schumann
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
Authors
R. Randall Schumann, Scott A. Minor, Daniel R. Muhs, Jeffery S. Pigati
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 terrace-forming processes that acted on the other Ch
Authors
R. Randall Schumann, Scott A. Minor, Daniel R. Muhs, Lindsey T. Groves, John P. McGeehin
Sea-level history of past interglacial periods: New evidence from uranium-series dating of corals from Curaçao, Leeward Antilles islands
Curaçao has reef terraces with the potential to provide sea-level histories of interglacial periods. Ages of the Hato (upper) unit of the “Lower Terrace” indicate that this reef dates to the last interglacial period, Marine Isotope Stage (MIS) 5.5. On Curaçao, this high sea stand lasted at least 8000 yr (~ 126 to ~ 118 ka). Elevations and age of this reef show that late Quaternary uplift rates on
Authors
Daniel R. Muhs, John M. Pandolfi, Kathleen R. Simmons, R. Randall Schumann
Sea-level history during the Last Interglacial complex on San Nicolas Island, California: implications for glacial isostatic adjustment processes, paleozoogeography and tectonics
San Nicolas Island, California has one of the best records of fossiliferous Quaternary marine terraces in North America, with at least fourteen terraces rising to an elevation of ~270 m above present-day sea level. In our studies of the lowest terraces, we identified platforms at 38-36 m (terrace 2a), 33-28 m (terrace 2b), and 13-8 m (terrace 1). Uranium-series dating of solitary corals from these
Authors
Daniel R. Muhs, Kathleen R. Simmons, R. Randall Schumann, Lindsey T. Groves, Jerry X. Mitrovica, Deanna Laurel
Sea-level history of the past two interglacial periods: New evidence from U-series dating of reef corals from south Florida
As a future warm-climate analog, much attention has been directed to studies of the Last Interglacial period or marine isotope substage (MIS) 5.5, which occurred ∼120,000 years ago. Nevertheless, there are still uncertainties with respect to its duration, warmth and magnitude of sea-level rise. Here we present new data from tectonically stable peninsular Florida and the Florida Keys that provide e
Authors
Daniel R. Muhs, Kathleen Simmons, R. Randall Schumann, R. B. Halley
The origin and paleoclimatic significance of carbonate sand dunes deposited on the California Channel Islands during the last glacial period
No abstract available.
Authors
Daniel R. Muhs, Gary Skipp, R. Randall Schumann, Donald L. Johnson, John P. McGeehin, Jossh Beann, Joshua Freeman, Timothy A. Pearce, Zachary Muhs Rowland
Uranium in surface waters and sediments affected by historical mining in the Denver West 1:100,000 Quadrangle, Colorado
Geochemical sampling of 82 stream waters and 87 stream sediments within mountainous areas immediately west of Denver, Colorado, was conducted by the U.S. Geological Survey in October 1994. The primary purpose was to evaluate regionally the effects of geology and past mining on the concentration and distribution of uranium. The study area contains uranium- and thorium-rich bedrock, numerous nonecon
Authors
Robert A. Zielinski, James K. Otton, R. Randall Schumann, Laurie Wirt
2007 Rocky Mountain section Friends of the Pleistocene field trip - Quaternary geology of the San Luis basin of Colorado and New Mexico, September 7-9, 2007
Prologue
Welcome to the 2007 Rocky Mountain Cell Friends of the Pleistocene Field Trip, which will concentrate on the Quaternary geology of the San Luis Basin of Colorado and New Mexico. To our best knowledge, Friends of the Pleistocene (FOP) has never run a trip through the San Luis Basin, although former trips in the region reviewed the 'Northern Rio Grande rift' in 1987 and the 'Landscape Hi
Authors
Michael N. Machette, Mary-Margaret Coates, Margo L. Johnson
Geologic and climatic controls on the radon emanation coefficient
Geologic, pedologic, and climatic factors, including radium content, grain size, siting of radon parents within soil grains or on grain coatings, and soil moisture conditions, determine a soil's emanating power and radon transport characteristics. Data from field studies indicate that soils derived from similar parent rocks in different regions have significantly different emanation coefficients d
Authors
R. R. Schumann, L.C.S. Gundersen
Geology and occurrence of radon
The accumulation of radon indoors is commonly due to movement of radon from adjacent soil and rock into a building foundation through joints, utility openings, cracks, or porous block walls. When air pressure inside the building is lower than that in the soil, pressure-driven flow of radonbearing soil gas can occur (see Chapter 2). Whether or not an indoor radon problem results depends on: (1) the
Authors
R. Randall Schumann, Linda C. Gundersen, A. B. Tanner
Science and Products
Filter Total Items: 39
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
Authors
Daniel R. Muhs, Kathleen R. Simmons, R. Randall Schumann, Lindsey T. Groves, Stephen B. DeVogel, Scott A. Minor, Deanna Laurel
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
Authors
Daniel R. Muhs, Lindsey T. Groves, R. Randall Schumann
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
Authors
R. Randall Schumann, Scott A. Minor, Daniel R. Muhs, Jeffery S. Pigati
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 terrace-forming processes that acted on the other Ch
Authors
R. Randall Schumann, Scott A. Minor, Daniel R. Muhs, Lindsey T. Groves, John P. McGeehin
Sea-level history of past interglacial periods: New evidence from uranium-series dating of corals from Curaçao, Leeward Antilles islands
Curaçao has reef terraces with the potential to provide sea-level histories of interglacial periods. Ages of the Hato (upper) unit of the “Lower Terrace” indicate that this reef dates to the last interglacial period, Marine Isotope Stage (MIS) 5.5. On Curaçao, this high sea stand lasted at least 8000 yr (~ 126 to ~ 118 ka). Elevations and age of this reef show that late Quaternary uplift rates on
Authors
Daniel R. Muhs, John M. Pandolfi, Kathleen R. Simmons, R. Randall Schumann
Sea-level history during the Last Interglacial complex on San Nicolas Island, California: implications for glacial isostatic adjustment processes, paleozoogeography and tectonics
San Nicolas Island, California has one of the best records of fossiliferous Quaternary marine terraces in North America, with at least fourteen terraces rising to an elevation of ~270 m above present-day sea level. In our studies of the lowest terraces, we identified platforms at 38-36 m (terrace 2a), 33-28 m (terrace 2b), and 13-8 m (terrace 1). Uranium-series dating of solitary corals from these
Authors
Daniel R. Muhs, Kathleen R. Simmons, R. Randall Schumann, Lindsey T. Groves, Jerry X. Mitrovica, Deanna Laurel
Sea-level history of the past two interglacial periods: New evidence from U-series dating of reef corals from south Florida
As a future warm-climate analog, much attention has been directed to studies of the Last Interglacial period or marine isotope substage (MIS) 5.5, which occurred ∼120,000 years ago. Nevertheless, there are still uncertainties with respect to its duration, warmth and magnitude of sea-level rise. Here we present new data from tectonically stable peninsular Florida and the Florida Keys that provide e
Authors
Daniel R. Muhs, Kathleen Simmons, R. Randall Schumann, R. B. Halley
The origin and paleoclimatic significance of carbonate sand dunes deposited on the California Channel Islands during the last glacial period
No abstract available.
Authors
Daniel R. Muhs, Gary Skipp, R. Randall Schumann, Donald L. Johnson, John P. McGeehin, Jossh Beann, Joshua Freeman, Timothy A. Pearce, Zachary Muhs Rowland
Uranium in surface waters and sediments affected by historical mining in the Denver West 1:100,000 Quadrangle, Colorado
Geochemical sampling of 82 stream waters and 87 stream sediments within mountainous areas immediately west of Denver, Colorado, was conducted by the U.S. Geological Survey in October 1994. The primary purpose was to evaluate regionally the effects of geology and past mining on the concentration and distribution of uranium. The study area contains uranium- and thorium-rich bedrock, numerous nonecon
Authors
Robert A. Zielinski, James K. Otton, R. Randall Schumann, Laurie Wirt
2007 Rocky Mountain section Friends of the Pleistocene field trip - Quaternary geology of the San Luis basin of Colorado and New Mexico, September 7-9, 2007
Prologue
Welcome to the 2007 Rocky Mountain Cell Friends of the Pleistocene Field Trip, which will concentrate on the Quaternary geology of the San Luis Basin of Colorado and New Mexico. To our best knowledge, Friends of the Pleistocene (FOP) has never run a trip through the San Luis Basin, although former trips in the region reviewed the 'Northern Rio Grande rift' in 1987 and the 'Landscape Hi
Authors
Michael N. Machette, Mary-Margaret Coates, Margo L. Johnson
Geologic and climatic controls on the radon emanation coefficient
Geologic, pedologic, and climatic factors, including radium content, grain size, siting of radon parents within soil grains or on grain coatings, and soil moisture conditions, determine a soil's emanating power and radon transport characteristics. Data from field studies indicate that soils derived from similar parent rocks in different regions have significantly different emanation coefficients d
Authors
R. R. Schumann, L.C.S. Gundersen
Geology and occurrence of radon
The accumulation of radon indoors is commonly due to movement of radon from adjacent soil and rock into a building foundation through joints, utility openings, cracks, or porous block walls. When air pressure inside the building is lower than that in the soil, pressure-driven flow of radonbearing soil gas can occur (see Chapter 2). Whether or not an indoor radon problem results depends on: (1) the
Authors
R. Randall Schumann, Linda C. Gundersen, A. B. Tanner