Great Basin Groundwater Chloride Concentration Map
Table of Contents
IDENTIFICATION_INFORMATION
Citation:
Citation_Information:
Originator: Zehner, R.E., Coolbaugh, M.F., and Shevenell, Lisa
Publication_Date: 20060530
Title: Great Basin Groundwater Chloride Concentration Map
Edition:
Geospatial_Data_Presentation_Form: Map
Publication_Information:
Publication_Place: Reno, Nevada
Publisher: Great Basin Center for Geothermal Energy
Other_Citation_Details:
Zehner, R.E., Coolbaugh, M.F., and Shevenell, Lisa, 2006,
Regional groundwater geochemical trends in the Great Basin:
Implications for Geothermal Exploration, GRC Transactions 2006
Online_Linkage: HTTP://www.unr.edu/Geothermal
Larger_Work_Citation:
Citation_Information:
Originator:
Publication_Date:
Title:
Publication_Information:
Publication_Place:
Publisher:
Online_Linkage:
Description:
Abstract:
Maps of Great Basin groundwater geochemistry show
distinctive regional spatial patterns. Factors affecting
the concentrations of dissolved constituents include
bedrock lithology, location within structural zones,
geothermal systems, and surficial playa deposits and salt
lakes. In
this study, a large geochemical database of ~24,750 Great
Basin groundwater samples from springs and wells was
compiled from multiple sources. These data were uploaded
into a geographic information system (GIS) and used to
produce concentration maps for As, B, Ba, Ca, Cl, F, Fe,
HCO3, K, Li, Mn, Na, SiO2, and SO4. These maps were then
examined to identify geologic factors that might have
influenced their concentration, including the presence of
geothermal systems. A weights-of-evidence statistical
analysis was then performed to assess the correlation
between the concentration maps and a set of ?150o C
geothermal systems.
The results indicate that all 14 constituents correlate to
some degree with geothermal systems. Fluorine, boron,
arsenic, and silica have the highest spatial correlation.
In addition, a subset of the data representing samples with
measured temperatures ?20oC was also analyzed; overall
correlations were lower, but manganese, arsenic, and silica
are still useful indicators. Samples from both the full and
the ?20oC datasets were grouped into statistically
significant populations. Break points for these groups can
be used as a measure of likelihood of a sample having been
influenced by geothermal activity. The study shows that (1)
regional groundwater geochemical patterns exist in the
Great Basin, (2) these patterns can serve as effective
geothermal exploration tools, and (3) a set of
concentrations derived from the weights-of-evidence
analysis may serve as favorability indices indicative of
the influence of geothermal activity on hot and cold
groundwater samples.
Purpose:
Geothermal exploration
Supplemental_Information:
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date:
Ending_Date:
Currentness_Reference:
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -124.9173
East_Bounding_Coordinate: -112.4355
North_Bounding_Coordinate: 43.8948
South_Bounding_Coordinate: 34.5158
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: geochemistry
Theme_Keyword: groundwater
Theme_Keyword: hot spring
Theme_Keyword: chloride
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Arizona
Place_Keyword: California
Place_Keyword: Great Basin
Place_Keyword: Idaho
Place_Keyword: Nevada
Place_Keyword: North America
Place_Keyword: Oregon
Place_Keyword: Utah
Place_Keyword: Western United States
Place_Keyword: Wyoming
Access_Constraints:
None
Use_Constraints:
This spatial information was derived from a variety of
sources. Care was taken in the creation of these themes,
but they are provided "as is". The Great Basin Center for
Geothermal Energy, the University of Nevada, Reno or any of
the data providers cannot accept any responsibility for
errors, omissions, or positional accuracy in the digital
data or underlying records. There are no warranties,
expressed or implied, accompanying this data set.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Great Basin Center for Geothermal Energy
Contact_Person: Richard Zehner
Contact_Position: Research Scientist, Assistant GIS Specialist
Contact_Address:
Address_Type: mailing and physical address
Address: MS 172, University of Nevada Reno
City: Reno
State_or_Province: NV
Postal_Code: 89557
Country: USA
Contact_Voice_Telephone: 775-784-7055
Contact_Facsimile_Telephone: 775-327-5801
Contact_Electronic_Mail_Address: zehner@unr.edu
Hours_of_Service: M-F 8-5
Native_Data_Set_Environment:
ESRI Grid format
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DATA_QUALITY_INFORMATION
Attribute_Accuracy:
Attribute_Accuracy_Report:
Unknown. Data is derived from several sources (NWIS,
Geo-Heat Center, NBMG Geothermal Database) with unknown
sample location and attribute accuracy.
Logical_Consistency_Report:
Completeness_Report:
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: Zehner, R.E., Coolbaugh, M.F., and Shevenell, Lisa
Publication_Date: 20060530
Title: Regional Groundwater Geochemical Trends in the Great Basin
Implications for Geothermal Exploration
Edition:
Geospatial_Data_Presentation_Form: map
Publication_Information:
Publication_Place: Reno, NV
Publisher: Great Basin Center for Geothermal Energy
Other_Citation_Details:
Online_Linkage: HTTP://www.unr.edu/Geothermal
Larger_Work_Citation:
Citation_Information:
Originator:
Publication_Date:
Title:
Publication_Information:
Publication_Place:
Publisher:
Online_Linkage:
Source_Scale_Denominator:
Type_of_Source_Media:
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date:
Ending_Date:
Source_Currentness_Reference:
Source_Citation_Abbreviation:
Source_Contribution:
Process_Step:
Process_Description:
The data set was constructed using groundwater geochemical
data (springs and wells) from three sources: (1) the
National Water Information System ("NWIS", USGS, 2005),
which includes cold temperature springs and wells along
with the former GEOTHERM database, (2) the Nevada Bureau of
Mines and Geology's geothermal database
(http: HTTP://www.nbmg.unr.edu/geothermal/gthome.htm), and (3)
the Geo-Heat Center's Western Geothermal Database (Reed et
al., 1983; Boyd, 2002). Spring and well samples within a
100 km radius of the Great Basin were used so that outside
values would form a continuous concentration surface right
up to the Great Basin boundary. Not all samples were
analyzed for all constituents; few of the samples were
analyzed for all 14 constituents that were examined. The
data were first screened to remove surface water samples.
Next, a histogram analysis was performed that identified an
approximate log-normal distribution for all elements.
Consequently, the [natural] log of concentration of the 14
cations/anions was calculated. The sample values of each
constituent at each site were then averaged: for the NWIS
data in its one-to-many format, sample data was averaged
for each location of the site table; for the Geo-Heat and
NBMG data sets, samples having identical location
coordinates were averaged. Finally, the three data sets
were spatially screened for duplicate samples, which were
removed. The final table contains data from 24,769
aggregate geochemical samples from both hot and cold
springs and wells, summarized in Table 1. Of these, 8,780
samples have reported temperatures of >20oC and probably
have been influenced by geothermal activity. A subset of
data containing 10,713 records from samples with measured
temperatures ?20oC was also made. These two files were then
loaded into a GIS for analysis.
The log-normalized point data were interpolated over the
Great Basin using an inverse distance weighting (IDW)
method (neighbors = 12, power = 2) to generate a set of
concentration maps. Maps were produced for As, B, Ba, Ca,
Cl, F, Fe, HCO3, K, Li, Na, Mn, SO4, and SiO2. The sample
density of some cations (As, Ba, Fe, Li, Mn) was limited
over portions of the Great Basin; areas greater than 50 km
from the nearest sample site were not considered in the
analysis and appear as blank areas on the maps.
The IDW interpolation method estimates values between
points using a 'nearest neighbors' approach, which does not
take into account hydrologic factors such as basin
boundaries, faults, or low-permeability rock units. Since
deep-seated geothermal systems operate primarily below the
region of near-surface groundwater flow, this approach is
probably warranted for the analysis of regional groundwater
trends. The smoothness of the concentration gradients on
most of the maps attests to the relative uniformity of
sample concentrations at the regional scale.
Source_Used_Citation_Abbreviation:
Process_Date:
Source_Produced_Citation_Abbreviation:
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Organization: Great Basin Center for Geothermal Energy
Contact_Person: Richard Zehner
Contact_Position: Research Scientist, Assistant GIS Specialist
Contact_Address:
Address_Type: mailing and physical address
Address: MS 172, University of Nevada Reno
City: Reno
State_or_Province: NV
Postal_Code: 89557
Country: USA
Contact_Voice_Telephone: 775-784-7055
Contact_Facsimile_Telephone: 775-327-5801
Contact_Electronic_Mail_Address: zehner@unr.edu
Hours_of_Service: M-F 8-5
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SPATIAL_DATA_ORGANIZATION_INFORMATION
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Grid Cell
Row_Count: 2071
Column_Count: 2001
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SPATIAL_REFERENCE_INFORMATION
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: Lambert Conformal Conic
Lambert_Conformal_Conic:
Standard_Parallel: 33.000000
Standard_Parallel: 45.000000
Longitude_of_Central_Meridian: -119.000000
Latitude_of_Projection_Origin: 0.000000
False_Easting: 0.000000
False_Northing: 0.000000
Standard_Parallel: 33.000000
Standard_Parallel: 45.000000
Longitude_of_Central_Meridian: -119.000000
Latitude_of_Projection_Origin: 0.000000
False_Easting: 0.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: Row and column
Coordinate_Representation:
Abscissa_Resolution:
Ordinate_Resolution:
Planar_Distance_Units: Meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1927
Ellipsoid_Name: Clarke 1866
Semi-major_Axis: 6378206.4000000
Denominator_of_Flattening_Ratio: 294.98
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ENTITY_AND_ATTRIBUTE_INFORMATION
Overview_Description:
Entity_and_Attribute_Overview:
Cell size = 500 m; units are natural log of concentration.
The data set was constructed using groundwater geochemical
data (springs and wells) from three sources: (1) the
National Water Information System ("NWIS", USGS, 2005),
which includes cold temperature springs and wells along
with the former GEOTHERM database, (2) the Nevada Bureau of
Mines and Geology's geothermal database
(http: HTTP://www.nbmg.unr.edu/geothermal/gthome.htm), and (3)
the Geo-Heat Center's Western Geothermal Database (Reed et
al., 1983; Boyd, 2002). Spring and well samples within a
100 km radius of the Great Basin were used so that outside
values would form a continuous concentration surface right
up to the Great Basin boundary. Not all samples were
analyzed for all constituents; few of the samples were
analyzed for all 14 constituents that were examined. The
data were first screened to remove surface water samples.
Next, a histogram analysis was performed that identified an
approximate log-normal distribution for all elements.
Consequently, the [natural] log of concentration of the 14
cations/anions was calculated. The sample values of each
constituent at each site were then averaged: for the NWIS
data in its one-to-many format, sample data was averaged
for each location of the site table; for the Geo-Heat and
NBMG data sets, samples having identical location
coordinates were averaged. Finally, the three data sets
were spatially screened for duplicate samples, which were
removed. The final table contains data from 24,769
aggregate geochemical samples from both hot and cold
springs and wells, summarized in Table 1. Of these, 8,780
samples have reported temperatures of >20oC and probably
have been influenced by geothermal activity. A subset of
data containing 10,713 records from samples with measured
temperatures ?20oC was also made. These two files were then
loaded into a GIS for analysis.
The log-normalized point data were interpolated over the
Great Basin using an inverse distance weighting (IDW)
method (neighbors = 12, power = 2) to generate a set of
concentration maps. Maps were produced for As, B, Ba, Ca,
Cl, F, Fe, HCO3, K, Li, Na, Mn, SO4, and SiO2. The sample
density of some cations (As, Ba, Fe, Li, Mn) was limited
over portions of the Great Basin; areas greater than 50 km
from the nearest sample site were not considered in the
analysis and appear as blank areas on the maps.
The IDW interpolation method estimates values between
points using a 'nearest neighbors' approach, which does not
take into account hydrologic factors such as basin
boundaries, faults, or low-permeability rock units. Since
deep-seated geothermal systems operate primarily below the
region of near-surface groundwater flow, this approach is
probably warranted for the analysis of regional groundwater
trends. The smoothness of the concentration gradients on
most of the maps attests to the relative uniformity of
sample concentrations at the regional scale.
The log normalized values in each concentration map were
split into 27 equally ranked categories and colored from
red to blue, with the hottest colors corresponding to the
highest concentrations.
Entity_and_Attribute_Detail_Citation:
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DISTRIBUTION_INFORMATION
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Great Basin Center for Geothermal Energy
Contact_Person: Richard Zehner
Contact_Position: Research Scientist, Assistant GIS Specialist
Contact_Address:
Address_Type: mailing and physical address
Address: MS 172, University of Nevada Reno
City: Reno
State_or_Province: NV
Postal_Code: 89557
Country: USA
Contact_Voice_Telephone: 775-784-7055
Contact_Facsimile_Telephone: 775-327-5801
Contact_Electronic_Mail_Address: zehner@unr.edu
Hours_of_Service: M-F 8-5
Resource_Description:
Distribution_Liability:
This spatial information was derived from a variety of
sources. Care was taken in the creation of these themes,
but they are provided "as is". The Great Basin Center for
Geothermal Energy, the University of Nevada, Reno or any of
the data providers cannot accept any responsibility for
errors, omissions, or positional accuracy in the digital
data or underlying records. There are no warranties,
expressed or implied, accompanying this data set.
Standard_Order_Process:
Non-Digital_Form:
Download directly from http: HTTP://www.unr.edu/Geothermal/datalist.html
Fees: None
Ordering_Instructions:
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METADATA_REFERENCE_INFORMATION
Metadata_Date: 20060531
Metadata_Review_Date:
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Great Basin Center for Geothermal Energy
Contact_Person: Richard Zehner
Contact_Position: Research Scientist, Assistant GIS Specialist
Contact_Address:
Address_Type: Mailing and physical address
Address: MS 172, University of Nevada Reno
City: Reno
State_or_Province: NV
Postal_Code: 89557
Country: USA
Contact_Voice_Telephone: 775-784-7055
Contact_Facsimile_Telephone: 775-327-5801
Contact_Electronic_Mail_Address: zehner@unr.edu
Hours_of_Service: M-F 8-5
Metadata_Standard_Name: FGDC CSDGM
Metadata_Standard_Version: FGDC-STD-001-1998
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