Christopher Mills
Christopher Mills is a Research Chemist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Research Chemistry
This project develops and maintains state-of-the-art analytical laboratories, expertise, and methods for a broad range of elemental and mineralogical analyses in support of the research priorities of the Mineral Resources Program, USGS, and DOI.
Development of USGS Geochemical Reference Materials
The project focus was the development of traditional and microanalytical reference materials that support USGS geochemical investigations. Development of new microanalytical reference materials allows USGS scientists and outside customers to examine a greater range of sample types while maintaining a high degree of data reliability.
Geochemical Signatures and Environmental Impacts of Ore and Trace Mineralization in the Southern Midcontinent
The overall project objective is a comprehensive analysis of the natural and anthropogenic consequences of extensive ore and trace mineralization in the southern midcontinent of the U.S. with a focus on Missouri. This will be conducted at two scales: 1) landscape and 2) process-level. 1) Landscape scale using geospatial and machine learning techniques to combine multiple geochemical and geologic...
Geochemical Signatures of Covered Mineral Deposits in the Northern Midcontinent
We are evaluating the potential of geochemical prospecting techniques that have shown promise in other covered terranes for mineral exploration in the northern midcontinent of the U.S. Novel components will be added to these methods with the objective of method advancement and improving our understanding of processes controlling the transmission of unique geochemical signatures from buried mineral...
Macro and Micro Analytical Methods Development
The Macro and Micro Analytical Methods Development Project (MMAMD) provides access to the expertise of highly experienced research scientists and state of the art analytical instrumentation to develop new and unique analytical capabilities to solve complex problems beyond routine analysis.
Chemical and isotopic data from wetland pond water samples collected in the Cottonwood Lake Study Area, Stutsman County, North Dakota, USA, 2015–2019
This U.S. Geological Survey data release contains chemical, isotopic, and physical data from wetland pond water samples collected at the Cottonwood Lake Study Area, Stutsman County, North Dakota, USA. Samples were collected monthly during the growing season (April or May through September) in 2015, 2016, 2017, and 2019 and in August 2018. Temperature, specific conductance, and pH were...
Geochemical Analyses of Water, Mine tailings, Fluvial Suspended Sediments, Fluvial Bed Sediments, and Fluvial Flood Deposit Sediments from the Big River and Meramec River Drainage Basins, Missouri
Geochemical data for aqueous, mine tailings, and sediment samples collected from the Big River and Meramec River drainage basins in southeastern Missouri are presented. The Big River drains historical lead, zinc, and barite mining districts, including the Old Lead Belt (OLB). Underground mining in the OLB resulted in large mine-waste chat piles and tailings impoundments that have...
Laboratory data from testing parameters of EPA Method 3060A on Soils Contaminated with Chromium Ore Processing Residue 2013-2016
It has been shown that EPA Method 3060A does not adequately extract Cr(VI) from solids containing chromium ore processing residue (COPR). We systematically tested modifications to prescribed parameters of EPA 3060A towards improving extraction efficiency of Cr(VI) from NIST SRM 2701, a standard COPR-contaminated soil from New Jersey (NJ). The alkaline extraction fluid leached Al, Si, and...
Filter Total Items: 23
Practical guide to measuring wetland carbon pools and fluxes
Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational...
Authors
Sheel Bansal, Irena F. Creed, Brian Tangen, Scott D. Bridgham, Ankur R. Desai, Ken Krauss, Scott C Neubauer, Gregory Noe, Donald O. Rosenberry, Carl C. Trettin, Kimberly Wickland, Scott T. Allen, Ariane Arias-Ortiz, Anna R. Armitage, Dennis Baldocchi, Kakoli Banerjee, David Bastviken, Peter Berg, Matthew J. Bogard, Alex T. Chow, William H. Conner, Christopher Craft, Courtney Creamer, Tonya Delsontro, Jamie Duberstein, Meagan J. Eagle, M. Siobhan Fennessey, Sarah A. Finkelstein, Mathias Goeckede, Sabine Grunwald, Meghan Halibisky, Ellen R. Herbert, Mohammad Jahangir, Olivia Johnson, Miriam C. Jones, Jeffrey Kelleway, Sarah Knox, Kevin D. Kroeger, Kevin Kuehn, David Lobb, Amanda Loder, Shizhou Ma, Damien Maher, Gavin McNicol, Jacob Meier, Beth A. Middleton, Christopher T. Mills, Purbasha Mistry, Abhijith Mitra, Courtney Mobilian, Amanda M. Nahlik, Sue Newman, Jessica O'Connell, Patty Oikawa, Max Post van der Burg, Charles A Schutte, Chanchung Song, Camille Stagg, Jessica Turner, Rodrigo Vargas, Mark Waldrop, Markus Wallin, Zhaohui Aleck Wang, Eric Ward, Debra A. Willard, Stephanie A. Yarwood, Xiaoyan Zhu
By
Ecosystems Mission Area, Water Resources Mission Area, Ecosystems Land Change Science Program, Florence Bascom Geoscience Center, Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science Center, Northern Prairie Wildlife Research Center, Wetland and Aquatic Research Center , Woods Hole Coastal and Marine Science Center
Lessons learned from wetlands research at the Cottonwood Lake Study Area, Stutsman County, North Dakota, 1967–2021
Depressional wetlands in the Prairie Pothole Region of North America have a long history of investigation owing to their importance in maintaining migratory-bird populations, especially waterfowl. One area of particularly intensive study is the Cottonwood Lake study area in Stutsman County, North Dakota. Studies at the Cottonwood Lake study area began in 1967 and continue through the...
Authors
David M. Mushet, Ned H. Euliss, Donald O. Rosenberry, James W. LaBaugh, Sheel Bansal, Zeno F. Levy, Owen P. McKenna, Kyle McLean, Christopher T. Mills, Brian P. Neff, Richard D. Nelson, Matthew J. Solensky, Brian Tangen
Using stream-side groundwater discharge for geochemical exploration in mountainous terrain
Groundwater chemistry has been predominantly used in geochemical exploration studies to identify mineralized targets concealed under transported cover in areas with gentle topography. Another potentially valuable ap-plication that has received little attention is using groundwater chemistry to identify deposits concealed within mountain ridges. A number of geochemical exploration studies...
Authors
Andrew H. Manning, Jean Morrison, Richard Wanty, Christopher T. Mills
The Pothole Hydrology-Linked Systems Simulator (PHyLiSS)—Development and application of a systems model for prairie-pothole wetlands
The North American Prairie Pothole Region covers about 770,000 square kilometers of the United States and Canada (including parts of 5 States and 3 provinces: North Dakota, South Dakota, Montana, Minnesota, Iowa, Saskatchewan, Manitoba, and Alberta). The Laurentide Ice Sheet shaped the landscape of the region about 12,000 to 14,000 years ago. The retreat of the ice sheet left behind low...
Authors
Owen P. McKenna, David M. Mushet, Eric J. Scherff, Kyle McLean, Christopher T. Mills
Using halogens (Cl, Br, I) to understand the hydrogeochemical evolution of drought-derived saline porewater beneath a prairie wetland
Numerous closed-basin prairie wetlands throughout the Prairie Pothole Region (PPR) of North America maintain moderate surface pond salinities (total dissolved solids [TDS] from 1 to 10 g L− 1) under semiarid climate by accumulation of gypsum and saline lenses of sulfate-rich porewater (TDS > 10 g L− 1) in wetland sediments during droughts. In order to understand the hydrogeochemical...
Authors
Zeno F. Levy, Christopher T. Mills, Zunli Lu, Martin B. Goldhaber, Donald O. Rosenberry, David M. Mushet, Laura K. Lautz, Xiaoli Zhou, Donald I. Siegel
Modifications to EPA Method 3060A to Improve Extraction of Cr(VI) from Chromium Ore Processing Residue-Contaminated Soils
It has been shown that EPA Method 3060A does not adequately extract Cr(VI) from chromium ore processing residue (COPR). We modified various parameters of EPA 3060A toward understanding the transformation of COPR minerals in the alkaline extraction and improving extraction of Cr(VI) from NIST SRM 2701, a standard COPR-contaminated soil. Aluminum and Si were the major elements dissolved...
Authors
Christopher T. Mills, Carleton R. Bern, Ruth E. Wolf, Andrea L. Foster, Jean Morrison, William Benzel
Abundant carbon substrates drive extremely high sulfate reduction rates and methane fluxes in Prairie Pothole Wetlands
Inland waters are increasingly recognized as critical sites of methane emissions to the atmosphere, but the biogeochemical reactions driving such fluxes are less well understood. The Prairie Pothole Region (PPR) of North America is one of the largest wetland complexes in the world, containing millions of small, shallow wetlands. The sediment pore waters of PPR wetlands contain some of...
Authors
Paula Martins, David W. Hoyt, Sheel Bansal, Christopher T. Mills, Malak Tfaily, Brian Tangen, Raymond Finocchiaro, Michael D. Johnston, Brandon C. McAdams, Matthew J. Solensky, Garrett J. Smith, Yu-Ping Chin, Michael J. Wilkins
Changes in pond water levels and surface extent due to climate variability alter solute sources to closed-basin Prairie-Pothole wetland ponds, 1979 to 2012
Wetter conditions beginning in 1993 resulted in marked changes in water levels and surface extent of prairie-pothole region wetland ponds, including closed-basin wetlands in the Cottonwood Lake area of North Dakota, U.S.A. Pond water levels after 1993 were consistently 0.5 to 2 m higher than during 1979–1993 (≤ 1 m deep) in wetlands lacking surface or substantial groundwater outlets, and...
Authors
James W. LaBaugh, David M. Mushet, Donald O. Rosenberry, Ned H. Euliss, Martin B. Goldhaber, Christopher T. Mills, Richard D. Nelson
Controls on the geochemical evolution of Prairie Pothole Region lakes and wetlands over decadal time scales
One hundred sixty-seven Prairie Pothole lakes, ponds and wetlands (largely lakes) previously analyzed chemically during the late 1960’s and early to mid-1970’s were resampled and reanalyzed in 2011–2012. The two sampling periods differed climatically. The earlier sampling took place during normal to slightly dry conditions, whereas the latter occurred during and immediately following...
Authors
Martin B. Goldhaber, Christopher T. Mills, David M. Mushet, R. Blaine McCleskey, Jennifer Rover
The use of amino acid indices for assessing organic matter quality and microbial abundance in deep-sea Antarctic sediments of IODP Expedition 318
The Adélie Basin, located offshore of the Wilkes Land margin, experiences unusually high sedimentation rates (~ 2 cm yr− 1) for the Antarctic coast. This study sought to compare depthwise changes in organic matter (OM) quantity and quality with changes in microbial biomass with depth at this high-deposition site and an offshore continental margin site. Sediments from both sites were...
Authors
Stephanie A Carr, Christopher T. Mills, Kevin W Mandernack
Chemical and biotic characteristics of prairie lakes and large wetlands in south-central North Dakota—Effects of a changing climate
The climate of the prairie pothole region of North America is known for variability that results in significant interannual changes in water depths and volumes of prairie lakes and wetlands; however, beginning in July 1993, the climate of the region shifted to an extended period of increased precipitation that has likely been unequaled in the preceding 500 years. Associated changing...
Authors
David M. Mushet, Martin B. Goldhaber, Christopher T. Mills, Kyle I. McLean, Vanessa M. Aparicio, R. Blaine McCleskey, JoAnn M. Holloway, Craig A. Stockwell
Weathering and transport of chromium and nickel from serpentinite in the Coast Range ophiolite to the Sacramento Valley, California, USA
A soil geochemical study in northern California was done to investigate the role that weathering and transport play in the regional distribution and mobility of geogenic Cr and Ni, which are both potentially toxic and carcinogenic. These elements are enriched in ultramafic rocks (primarily serpentinite) and the soils derived from them (1700–10,000 mg Cr per kg soil and 1300–3900 mg Ni...
Authors
Jean Morrison, Martin B. Goldhaber, Christopher T. Mills, George N. Breit, Robert L. Hooper, JoAnn M. Holloway, Sharon F. Diehl, James F. Ranville
Science and Products
Research Chemistry
This project develops and maintains state-of-the-art analytical laboratories, expertise, and methods for a broad range of elemental and mineralogical analyses in support of the research priorities of the Mineral Resources Program, USGS, and DOI.
Development of USGS Geochemical Reference Materials
The project focus was the development of traditional and microanalytical reference materials that support USGS geochemical investigations. Development of new microanalytical reference materials allows USGS scientists and outside customers to examine a greater range of sample types while maintaining a high degree of data reliability.
Geochemical Signatures and Environmental Impacts of Ore and Trace Mineralization in the Southern Midcontinent
The overall project objective is a comprehensive analysis of the natural and anthropogenic consequences of extensive ore and trace mineralization in the southern midcontinent of the U.S. with a focus on Missouri. This will be conducted at two scales: 1) landscape and 2) process-level. 1) Landscape scale using geospatial and machine learning techniques to combine multiple geochemical and geologic...
Geochemical Signatures of Covered Mineral Deposits in the Northern Midcontinent
We are evaluating the potential of geochemical prospecting techniques that have shown promise in other covered terranes for mineral exploration in the northern midcontinent of the U.S. Novel components will be added to these methods with the objective of method advancement and improving our understanding of processes controlling the transmission of unique geochemical signatures from buried mineral...
Macro and Micro Analytical Methods Development
The Macro and Micro Analytical Methods Development Project (MMAMD) provides access to the expertise of highly experienced research scientists and state of the art analytical instrumentation to develop new and unique analytical capabilities to solve complex problems beyond routine analysis.
Chemical and isotopic data from wetland pond water samples collected in the Cottonwood Lake Study Area, Stutsman County, North Dakota, USA, 2015–2019
This U.S. Geological Survey data release contains chemical, isotopic, and physical data from wetland pond water samples collected at the Cottonwood Lake Study Area, Stutsman County, North Dakota, USA. Samples were collected monthly during the growing season (April or May through September) in 2015, 2016, 2017, and 2019 and in August 2018. Temperature, specific conductance, and pH were...
Geochemical Analyses of Water, Mine tailings, Fluvial Suspended Sediments, Fluvial Bed Sediments, and Fluvial Flood Deposit Sediments from the Big River and Meramec River Drainage Basins, Missouri
Geochemical data for aqueous, mine tailings, and sediment samples collected from the Big River and Meramec River drainage basins in southeastern Missouri are presented. The Big River drains historical lead, zinc, and barite mining districts, including the Old Lead Belt (OLB). Underground mining in the OLB resulted in large mine-waste chat piles and tailings impoundments that have...
Laboratory data from testing parameters of EPA Method 3060A on Soils Contaminated with Chromium Ore Processing Residue 2013-2016
It has been shown that EPA Method 3060A does not adequately extract Cr(VI) from solids containing chromium ore processing residue (COPR). We systematically tested modifications to prescribed parameters of EPA 3060A towards improving extraction efficiency of Cr(VI) from NIST SRM 2701, a standard COPR-contaminated soil from New Jersey (NJ). The alkaline extraction fluid leached Al, Si, and...
Filter Total Items: 23
Practical guide to measuring wetland carbon pools and fluxes
Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational...
Authors
Sheel Bansal, Irena F. Creed, Brian Tangen, Scott D. Bridgham, Ankur R. Desai, Ken Krauss, Scott C Neubauer, Gregory Noe, Donald O. Rosenberry, Carl C. Trettin, Kimberly Wickland, Scott T. Allen, Ariane Arias-Ortiz, Anna R. Armitage, Dennis Baldocchi, Kakoli Banerjee, David Bastviken, Peter Berg, Matthew J. Bogard, Alex T. Chow, William H. Conner, Christopher Craft, Courtney Creamer, Tonya Delsontro, Jamie Duberstein, Meagan J. Eagle, M. Siobhan Fennessey, Sarah A. Finkelstein, Mathias Goeckede, Sabine Grunwald, Meghan Halibisky, Ellen R. Herbert, Mohammad Jahangir, Olivia Johnson, Miriam C. Jones, Jeffrey Kelleway, Sarah Knox, Kevin D. Kroeger, Kevin Kuehn, David Lobb, Amanda Loder, Shizhou Ma, Damien Maher, Gavin McNicol, Jacob Meier, Beth A. Middleton, Christopher T. Mills, Purbasha Mistry, Abhijith Mitra, Courtney Mobilian, Amanda M. Nahlik, Sue Newman, Jessica O'Connell, Patty Oikawa, Max Post van der Burg, Charles A Schutte, Chanchung Song, Camille Stagg, Jessica Turner, Rodrigo Vargas, Mark Waldrop, Markus Wallin, Zhaohui Aleck Wang, Eric Ward, Debra A. Willard, Stephanie A. Yarwood, Xiaoyan Zhu
By
Ecosystems Mission Area, Water Resources Mission Area, Ecosystems Land Change Science Program, Florence Bascom Geoscience Center, Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science Center, Northern Prairie Wildlife Research Center, Wetland and Aquatic Research Center , Woods Hole Coastal and Marine Science Center
Lessons learned from wetlands research at the Cottonwood Lake Study Area, Stutsman County, North Dakota, 1967–2021
Depressional wetlands in the Prairie Pothole Region of North America have a long history of investigation owing to their importance in maintaining migratory-bird populations, especially waterfowl. One area of particularly intensive study is the Cottonwood Lake study area in Stutsman County, North Dakota. Studies at the Cottonwood Lake study area began in 1967 and continue through the...
Authors
David M. Mushet, Ned H. Euliss, Donald O. Rosenberry, James W. LaBaugh, Sheel Bansal, Zeno F. Levy, Owen P. McKenna, Kyle McLean, Christopher T. Mills, Brian P. Neff, Richard D. Nelson, Matthew J. Solensky, Brian Tangen
Using stream-side groundwater discharge for geochemical exploration in mountainous terrain
Groundwater chemistry has been predominantly used in geochemical exploration studies to identify mineralized targets concealed under transported cover in areas with gentle topography. Another potentially valuable ap-plication that has received little attention is using groundwater chemistry to identify deposits concealed within mountain ridges. A number of geochemical exploration studies...
Authors
Andrew H. Manning, Jean Morrison, Richard Wanty, Christopher T. Mills
The Pothole Hydrology-Linked Systems Simulator (PHyLiSS)—Development and application of a systems model for prairie-pothole wetlands
The North American Prairie Pothole Region covers about 770,000 square kilometers of the United States and Canada (including parts of 5 States and 3 provinces: North Dakota, South Dakota, Montana, Minnesota, Iowa, Saskatchewan, Manitoba, and Alberta). The Laurentide Ice Sheet shaped the landscape of the region about 12,000 to 14,000 years ago. The retreat of the ice sheet left behind low...
Authors
Owen P. McKenna, David M. Mushet, Eric J. Scherff, Kyle McLean, Christopher T. Mills
Using halogens (Cl, Br, I) to understand the hydrogeochemical evolution of drought-derived saline porewater beneath a prairie wetland
Numerous closed-basin prairie wetlands throughout the Prairie Pothole Region (PPR) of North America maintain moderate surface pond salinities (total dissolved solids [TDS] from 1 to 10 g L− 1) under semiarid climate by accumulation of gypsum and saline lenses of sulfate-rich porewater (TDS > 10 g L− 1) in wetland sediments during droughts. In order to understand the hydrogeochemical...
Authors
Zeno F. Levy, Christopher T. Mills, Zunli Lu, Martin B. Goldhaber, Donald O. Rosenberry, David M. Mushet, Laura K. Lautz, Xiaoli Zhou, Donald I. Siegel
Modifications to EPA Method 3060A to Improve Extraction of Cr(VI) from Chromium Ore Processing Residue-Contaminated Soils
It has been shown that EPA Method 3060A does not adequately extract Cr(VI) from chromium ore processing residue (COPR). We modified various parameters of EPA 3060A toward understanding the transformation of COPR minerals in the alkaline extraction and improving extraction of Cr(VI) from NIST SRM 2701, a standard COPR-contaminated soil. Aluminum and Si were the major elements dissolved...
Authors
Christopher T. Mills, Carleton R. Bern, Ruth E. Wolf, Andrea L. Foster, Jean Morrison, William Benzel
Abundant carbon substrates drive extremely high sulfate reduction rates and methane fluxes in Prairie Pothole Wetlands
Inland waters are increasingly recognized as critical sites of methane emissions to the atmosphere, but the biogeochemical reactions driving such fluxes are less well understood. The Prairie Pothole Region (PPR) of North America is one of the largest wetland complexes in the world, containing millions of small, shallow wetlands. The sediment pore waters of PPR wetlands contain some of...
Authors
Paula Martins, David W. Hoyt, Sheel Bansal, Christopher T. Mills, Malak Tfaily, Brian Tangen, Raymond Finocchiaro, Michael D. Johnston, Brandon C. McAdams, Matthew J. Solensky, Garrett J. Smith, Yu-Ping Chin, Michael J. Wilkins
Changes in pond water levels and surface extent due to climate variability alter solute sources to closed-basin Prairie-Pothole wetland ponds, 1979 to 2012
Wetter conditions beginning in 1993 resulted in marked changes in water levels and surface extent of prairie-pothole region wetland ponds, including closed-basin wetlands in the Cottonwood Lake area of North Dakota, U.S.A. Pond water levels after 1993 were consistently 0.5 to 2 m higher than during 1979–1993 (≤ 1 m deep) in wetlands lacking surface or substantial groundwater outlets, and...
Authors
James W. LaBaugh, David M. Mushet, Donald O. Rosenberry, Ned H. Euliss, Martin B. Goldhaber, Christopher T. Mills, Richard D. Nelson
Controls on the geochemical evolution of Prairie Pothole Region lakes and wetlands over decadal time scales
One hundred sixty-seven Prairie Pothole lakes, ponds and wetlands (largely lakes) previously analyzed chemically during the late 1960’s and early to mid-1970’s were resampled and reanalyzed in 2011–2012. The two sampling periods differed climatically. The earlier sampling took place during normal to slightly dry conditions, whereas the latter occurred during and immediately following...
Authors
Martin B. Goldhaber, Christopher T. Mills, David M. Mushet, R. Blaine McCleskey, Jennifer Rover
The use of amino acid indices for assessing organic matter quality and microbial abundance in deep-sea Antarctic sediments of IODP Expedition 318
The Adélie Basin, located offshore of the Wilkes Land margin, experiences unusually high sedimentation rates (~ 2 cm yr− 1) for the Antarctic coast. This study sought to compare depthwise changes in organic matter (OM) quantity and quality with changes in microbial biomass with depth at this high-deposition site and an offshore continental margin site. Sediments from both sites were...
Authors
Stephanie A Carr, Christopher T. Mills, Kevin W Mandernack
Chemical and biotic characteristics of prairie lakes and large wetlands in south-central North Dakota—Effects of a changing climate
The climate of the prairie pothole region of North America is known for variability that results in significant interannual changes in water depths and volumes of prairie lakes and wetlands; however, beginning in July 1993, the climate of the region shifted to an extended period of increased precipitation that has likely been unequaled in the preceding 500 years. Associated changing...
Authors
David M. Mushet, Martin B. Goldhaber, Christopher T. Mills, Kyle I. McLean, Vanessa M. Aparicio, R. Blaine McCleskey, JoAnn M. Holloway, Craig A. Stockwell
Weathering and transport of chromium and nickel from serpentinite in the Coast Range ophiolite to the Sacramento Valley, California, USA
A soil geochemical study in northern California was done to investigate the role that weathering and transport play in the regional distribution and mobility of geogenic Cr and Ni, which are both potentially toxic and carcinogenic. These elements are enriched in ultramafic rocks (primarily serpentinite) and the soils derived from them (1700–10,000 mg Cr per kg soil and 1300–3900 mg Ni...
Authors
Jean Morrison, Martin B. Goldhaber, Christopher T. Mills, George N. Breit, Robert L. Hooper, JoAnn M. Holloway, Sharon F. Diehl, James F. Ranville