Carma A San Juan
Carma San Juan is a Physical Scientist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 15
Mines, Mineral Occurrences, and Mining Districts in the Carlin Area, Nevada Mines, Mineral Occurrences, and Mining Districts in the Carlin Area, Nevada
Sediment hosted gold deposits in Nevada were first mined in the 1960s from open pit mines with large tonnage and low grade resources. Since that time, continuing exploration and discovery have identified extraordinary resources, and together these deposits now form the second-largest gold endowment on Earth, surpassed only by the Witwatersrand Gold Fields of South Africa. The data herein...
Prospect- and Mine-Related Features from U.S. Geological Survey 7.5- and 15-Minute Topographic Quadrangle Maps for the Western United States Prospect- and Mine-Related Features from U.S. Geological Survey 7.5- and 15-Minute Topographic Quadrangle Maps for the Western United States
This data release has been updated in 2017 with a newer version that includes additional states. It is recommended to use the updated data and map services of the new data release located at: https://doi.org/10.5066/F78W3CHG These data are part of a larger USGS project to develop an updated geospatial database of mines, mineral deposits and mineral regions in the United States. Mine and...
Locatable Mineral Assessment Tracts for the U.S. Geological Survey Sagebrush Mineral Resource Assessment Project Locatable Mineral Assessment Tracts for the U.S. Geological Survey Sagebrush Mineral Resource Assessment Project
The polygon (vector) feature class represents locatable mineral resource assessment tracts (tracts of land) associated with the Department of the Interior (DOI) Sagebrush Focal Areas in Montana, Wyoming and Utah, central Idaho, and the Oregon-Nevada-Idaho border area. The mineral resources tracts are geographic areas that were assessed by the U.S. Geological Survey (USGS) and were...
Filter Total Items: 30
Geospatial database for regional environmental assessment of central Colorado. Geospatial database for regional environmental assessment of central Colorado.
In conjunction with the future planning needs of the U.S. Department of Agriculture, Forest Service, the U.S. Geological Survey conducted a detailed environmental assessment of the effects of historical mining on Forest Service lands in central Colorado. Stream sediment, macroinvertebrate, and various filtered and unfiltered water quality samples were collected during low-flow over a...
Authors
Stan E. Church, Carma A. San Juan, David L. Fey, Travis S. Schmidt, Terry L. Klein, Ed H. DeWitt, Richard B. Wanty, Philip L. Verplanck, Katharine A. Mitchell, Monique G. Adams, LaDonna M. Choate, Todor I. Todorov, Barnaby W. Rockwell, Luke McEachron, Michael W. Anthony
Geologic processes influence the effects of mining on aquatic ecosystems Geologic processes influence the effects of mining on aquatic ecosystems
Geologic processes strongly influence water and sediment quality in aquatic ecosystems but rarely are geologic principles incorporated into routine biomonitoring studies. We test if elevated concentrations of metals in water and sediment are restricted to streams downstream of mines or areas that may discharge mine wastes. We surveyed 198 catchments classified as “historically mined” or...
Authors
Travis S. Schmidt, William H. Clements, Richard B. Wanty, Philip L. Verplanck, Stan E. Church, Carma A. San Juan, David L. Fey, Barnaby W. Rockwell, Ed H. DeWitt, Terry L. Klein
Critical tissue residue approach linking accumulated metals in aquatic insects to population and community-level effects Critical tissue residue approach linking accumulated metals in aquatic insects to population and community-level effects
Whole body Zn concentrations in individuals (n = 825) from three aquatic insect taxa (mayflies Rhithrogena spp. and Drunella spp. and the caddisfly Arctopsyche grandis) were used to predict effects on populations and communities (n = 149 samples). Both mayflies accumulated significantly more Zn than the caddisfly. The presence/absence of Drunella spp. most reliably distinguished sites...
Authors
Travis S. Schmidt, William H. Clements, Robert E. Zuellig, Katharine A. Mitchell, Stan E. Church, Richard B. Wanty, Carma A. San Juan, Monique Adams, Paul J. Lamothe
Evaluation of the extent of contamination caused by historical mining in catchments of central Colorado Evaluation of the extent of contamination caused by historical mining in catchments of central Colorado
The U.S. Geological Survey conducted an assessment of stream water and sediment quality in central Colorado, an area of about 54,000 km2. The study area is focused on small tributary catchments in the Rocky Mountains. The Colorado Mineral belt, a northeast-trending mineralized zone that experienced base- and precious-metal mining at the beginning of the late 1800s and early 1900s, cuts...
Authors
Stan E. Church, David L. Fey, Richard B. Wanty, Travis S. Schmidt, T. L. Klein, Barnaby W. Rockwell, Carma A. San Juan
Death Valley regional groundwater flow system, Nevada and California: Hydrogeologic framework and transient groundwater flow model Death Valley regional groundwater flow system, Nevada and California: Hydrogeologic framework and transient groundwater flow model
A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together...
Authors
Wayne Belcher, Frank A. D’Agnese, Grady M. O’Brien, Donald S. Sweetkind, Carma A. San Juan, Randell J. Laczniak, Christopher J. Potter, Heather Putnam, Claudia C. Faunt, Joan B. Blainey, Mary C. Hill, M. S. Bedinger, J. R. Harrill
Predicting risks to aquatic life based on lithologic specific geochemical baselines Predicting risks to aquatic life based on lithologic specific geochemical baselines
No abstract available.
Authors
Travis S. Schmidt, R. B. Wanty, P. L. Verplanck, S. E. Church, C. San Juan, D. Fey, B.W. Rockwell, E.H. deWitt, T. L. Klein
Reconnaissance of weathering rates in alpine catchments of central Colorado, USA Reconnaissance of weathering rates in alpine catchments of central Colorado, USA
No abstract available.
Authors
R.E. Wanty, P. L. Verplanck, C. Bern, T. Todoro, C. San Juan, E.H. deWitt, T. L. Klein, D. Fey, T.S. Schmidt, S. E. Church
Development of a new toxic-unit model for the bioassessment of metals in streams Development of a new toxic-unit model for the bioassessment of metals in streams
Two toxic-unit models that estimate the toxicity of trace-metal mixtures to benthic communities were compared. The chronic criterion accumulation ratio (CCAR), a modification of biotic ligand model (BLM) outputs for use as a toxic-unit model, accounts for the modifying and competitive influences of major cations (Ca2+, Mg2+, Na+, K+, H+), anions (HCO3−, CO32−,SO42−, Cl−, S2−) and...
Authors
Travis S. Schmidt, W.H. Clements, K.A. Mitchell, Stanley E. Church, Richard B. Wanty, David L. Fey, Philip L. Verplanck, Carma A. San Juan
Aquatic ecosystems in Central Colorado are influenced by mineral forming processes and historical mining Aquatic ecosystems in Central Colorado are influenced by mineral forming processes and historical mining
Stream water and sediment toxicity to aquatic insects were quantified from central Colorado catchments to distinguish the effect of geologic processes which result in high background metals concentrations from historical mining. Our sampling design targeted small catchments underlain by rocks of a single lithology, which allowed the development of biological and geochemical baselines...
Authors
T.S. Schmidt, S. E. Church, W.H. Clements, K.A. Mitchell, D. L. Fey, R. B. Wanty, P. L. Verplanck, Juan C.A. San, T. L. Klein, E.H. deWitt, B.W. Rockwell
Environmental effects of hydrothermal alteration and historical mining on water and sediment quality in Central Colorado Environmental effects of hydrothermal alteration and historical mining on water and sediment quality in Central Colorado
The U.S. Geological Survey conducted an environmental assessment of 198 catchments in a 54,000-km2 area of central Colorado, much of which is on Federal land. The Colorado Mineral Belt, a northeast-trending zone of historical base- and precious-metal mining, cuts diagonally across the study area. The investigation was intended to test the hypothesis that degraded water and sediment...
Authors
S. E. Church, D. L. Fey, T. L. Klein, T.S. Schmidt, R. B. Wanty, E.H. deWitt, B.W. Rockwell, Juan C.A. San
Geochemistry of surface water in alpine catchments in central Colorado, USA: Resolving host-rock effects at different spatial scales Geochemistry of surface water in alpine catchments in central Colorado, USA: Resolving host-rock effects at different spatial scales
The US Geological Survey is conducting a study of surface-water quality in the Rocky Mountains of central Colorado, an area of approximately 55,000 km2. Using new and existing geologic maps, the more than 200 rock formations represented in the area were arranged into 17 groups based on lithologic similarity. The dominant regional geologic feature affecting water quality in central...
Authors
R. B. Wanty, P. L. Verplanck, Juan C.A. San, S. E. Church, T.S. Schmidt, D.L. Fey, E.H. deWitt, T. L. Klein
Effects of Mining on the Environment - A National Overview Effects of Mining on the Environment - A National Overview
No abstract available.
Authors
S. E. Church, T.S. Schmidt, C. A. San Juan, G.S. Plumlee
Science and Products
Filter Total Items: 15
Mines, Mineral Occurrences, and Mining Districts in the Carlin Area, Nevada Mines, Mineral Occurrences, and Mining Districts in the Carlin Area, Nevada
Sediment hosted gold deposits in Nevada were first mined in the 1960s from open pit mines with large tonnage and low grade resources. Since that time, continuing exploration and discovery have identified extraordinary resources, and together these deposits now form the second-largest gold endowment on Earth, surpassed only by the Witwatersrand Gold Fields of South Africa. The data herein...
Prospect- and Mine-Related Features from U.S. Geological Survey 7.5- and 15-Minute Topographic Quadrangle Maps for the Western United States Prospect- and Mine-Related Features from U.S. Geological Survey 7.5- and 15-Minute Topographic Quadrangle Maps for the Western United States
This data release has been updated in 2017 with a newer version that includes additional states. It is recommended to use the updated data and map services of the new data release located at: https://doi.org/10.5066/F78W3CHG These data are part of a larger USGS project to develop an updated geospatial database of mines, mineral deposits and mineral regions in the United States. Mine and...
Locatable Mineral Assessment Tracts for the U.S. Geological Survey Sagebrush Mineral Resource Assessment Project Locatable Mineral Assessment Tracts for the U.S. Geological Survey Sagebrush Mineral Resource Assessment Project
The polygon (vector) feature class represents locatable mineral resource assessment tracts (tracts of land) associated with the Department of the Interior (DOI) Sagebrush Focal Areas in Montana, Wyoming and Utah, central Idaho, and the Oregon-Nevada-Idaho border area. The mineral resources tracts are geographic areas that were assessed by the U.S. Geological Survey (USGS) and were...
Filter Total Items: 30
Geospatial database for regional environmental assessment of central Colorado. Geospatial database for regional environmental assessment of central Colorado.
In conjunction with the future planning needs of the U.S. Department of Agriculture, Forest Service, the U.S. Geological Survey conducted a detailed environmental assessment of the effects of historical mining on Forest Service lands in central Colorado. Stream sediment, macroinvertebrate, and various filtered and unfiltered water quality samples were collected during low-flow over a...
Authors
Stan E. Church, Carma A. San Juan, David L. Fey, Travis S. Schmidt, Terry L. Klein, Ed H. DeWitt, Richard B. Wanty, Philip L. Verplanck, Katharine A. Mitchell, Monique G. Adams, LaDonna M. Choate, Todor I. Todorov, Barnaby W. Rockwell, Luke McEachron, Michael W. Anthony
Geologic processes influence the effects of mining on aquatic ecosystems Geologic processes influence the effects of mining on aquatic ecosystems
Geologic processes strongly influence water and sediment quality in aquatic ecosystems but rarely are geologic principles incorporated into routine biomonitoring studies. We test if elevated concentrations of metals in water and sediment are restricted to streams downstream of mines or areas that may discharge mine wastes. We surveyed 198 catchments classified as “historically mined” or...
Authors
Travis S. Schmidt, William H. Clements, Richard B. Wanty, Philip L. Verplanck, Stan E. Church, Carma A. San Juan, David L. Fey, Barnaby W. Rockwell, Ed H. DeWitt, Terry L. Klein
Critical tissue residue approach linking accumulated metals in aquatic insects to population and community-level effects Critical tissue residue approach linking accumulated metals in aquatic insects to population and community-level effects
Whole body Zn concentrations in individuals (n = 825) from three aquatic insect taxa (mayflies Rhithrogena spp. and Drunella spp. and the caddisfly Arctopsyche grandis) were used to predict effects on populations and communities (n = 149 samples). Both mayflies accumulated significantly more Zn than the caddisfly. The presence/absence of Drunella spp. most reliably distinguished sites...
Authors
Travis S. Schmidt, William H. Clements, Robert E. Zuellig, Katharine A. Mitchell, Stan E. Church, Richard B. Wanty, Carma A. San Juan, Monique Adams, Paul J. Lamothe
Evaluation of the extent of contamination caused by historical mining in catchments of central Colorado Evaluation of the extent of contamination caused by historical mining in catchments of central Colorado
The U.S. Geological Survey conducted an assessment of stream water and sediment quality in central Colorado, an area of about 54,000 km2. The study area is focused on small tributary catchments in the Rocky Mountains. The Colorado Mineral belt, a northeast-trending mineralized zone that experienced base- and precious-metal mining at the beginning of the late 1800s and early 1900s, cuts...
Authors
Stan E. Church, David L. Fey, Richard B. Wanty, Travis S. Schmidt, T. L. Klein, Barnaby W. Rockwell, Carma A. San Juan
Death Valley regional groundwater flow system, Nevada and California: Hydrogeologic framework and transient groundwater flow model Death Valley regional groundwater flow system, Nevada and California: Hydrogeologic framework and transient groundwater flow model
A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together...
Authors
Wayne Belcher, Frank A. D’Agnese, Grady M. O’Brien, Donald S. Sweetkind, Carma A. San Juan, Randell J. Laczniak, Christopher J. Potter, Heather Putnam, Claudia C. Faunt, Joan B. Blainey, Mary C. Hill, M. S. Bedinger, J. R. Harrill
Predicting risks to aquatic life based on lithologic specific geochemical baselines Predicting risks to aquatic life based on lithologic specific geochemical baselines
No abstract available.
Authors
Travis S. Schmidt, R. B. Wanty, P. L. Verplanck, S. E. Church, C. San Juan, D. Fey, B.W. Rockwell, E.H. deWitt, T. L. Klein
Reconnaissance of weathering rates in alpine catchments of central Colorado, USA Reconnaissance of weathering rates in alpine catchments of central Colorado, USA
No abstract available.
Authors
R.E. Wanty, P. L. Verplanck, C. Bern, T. Todoro, C. San Juan, E.H. deWitt, T. L. Klein, D. Fey, T.S. Schmidt, S. E. Church
Development of a new toxic-unit model for the bioassessment of metals in streams Development of a new toxic-unit model for the bioassessment of metals in streams
Two toxic-unit models that estimate the toxicity of trace-metal mixtures to benthic communities were compared. The chronic criterion accumulation ratio (CCAR), a modification of biotic ligand model (BLM) outputs for use as a toxic-unit model, accounts for the modifying and competitive influences of major cations (Ca2+, Mg2+, Na+, K+, H+), anions (HCO3−, CO32−,SO42−, Cl−, S2−) and...
Authors
Travis S. Schmidt, W.H. Clements, K.A. Mitchell, Stanley E. Church, Richard B. Wanty, David L. Fey, Philip L. Verplanck, Carma A. San Juan
Aquatic ecosystems in Central Colorado are influenced by mineral forming processes and historical mining Aquatic ecosystems in Central Colorado are influenced by mineral forming processes and historical mining
Stream water and sediment toxicity to aquatic insects were quantified from central Colorado catchments to distinguish the effect of geologic processes which result in high background metals concentrations from historical mining. Our sampling design targeted small catchments underlain by rocks of a single lithology, which allowed the development of biological and geochemical baselines...
Authors
T.S. Schmidt, S. E. Church, W.H. Clements, K.A. Mitchell, D. L. Fey, R. B. Wanty, P. L. Verplanck, Juan C.A. San, T. L. Klein, E.H. deWitt, B.W. Rockwell
Environmental effects of hydrothermal alteration and historical mining on water and sediment quality in Central Colorado Environmental effects of hydrothermal alteration and historical mining on water and sediment quality in Central Colorado
The U.S. Geological Survey conducted an environmental assessment of 198 catchments in a 54,000-km2 area of central Colorado, much of which is on Federal land. The Colorado Mineral Belt, a northeast-trending zone of historical base- and precious-metal mining, cuts diagonally across the study area. The investigation was intended to test the hypothesis that degraded water and sediment...
Authors
S. E. Church, D. L. Fey, T. L. Klein, T.S. Schmidt, R. B. Wanty, E.H. deWitt, B.W. Rockwell, Juan C.A. San
Geochemistry of surface water in alpine catchments in central Colorado, USA: Resolving host-rock effects at different spatial scales Geochemistry of surface water in alpine catchments in central Colorado, USA: Resolving host-rock effects at different spatial scales
The US Geological Survey is conducting a study of surface-water quality in the Rocky Mountains of central Colorado, an area of approximately 55,000 km2. Using new and existing geologic maps, the more than 200 rock formations represented in the area were arranged into 17 groups based on lithologic similarity. The dominant regional geologic feature affecting water quality in central...
Authors
R. B. Wanty, P. L. Verplanck, Juan C.A. San, S. E. Church, T.S. Schmidt, D.L. Fey, E.H. deWitt, T. L. Klein
Effects of Mining on the Environment - A National Overview Effects of Mining on the Environment - A National Overview
No abstract available.
Authors
S. E. Church, T.S. Schmidt, C. A. San Juan, G.S. Plumlee