The index map of regional geochemical surveys covering the whole of Canada is available in this OGC WMS service. The map is presented as a single layer. For more information please visit http://geochem.nrcan.gc.ca

Regional stream sediment geochemical data compilation November 2020 Release notes The regional stream sediment geochemical data compilation comprises data for more than 30 000 samples across Yukon. This compilation updates the work of Héon (2003). This new compilation includes results from the reanalysis of more than 24 000 samples; inductively coupled plasma mass spectrometry (ICPMS) analysis provides upgraded detection limits and a broader range of elements relative to previous analytical data. In addition to analytical data, efforts have been made to improve sample location accuracy. The data in this release are organized by analytical method with the geodatabase having six feature classes: RGS_SITE_WATER - site specific physiography and water quality data. These data are unchanged from the original releases. RGS_HEON - the same data as released in Héon (2003) with minor updates to sample location. RGS_AAS - all samples analyzed by atomic absorption spectrometry. Most of these data are superseded by INAA and ICPMS data. RGS_INAA - all samples analyzed by instrumental neutron activation analysis (INAA) and fire assay-neutron activation (FA-NA) analysis. RGS_ICPMS - all samples analyzed by inductively coupled plasma mass spectrometry (ICPMS). RGS_All - includes all AAS, INAA and ICPMS data. Collection of stream sediment samples in Yukon began in 1976 and ended in 2006. Three analytical methods have been used to analyze the minus 0.177 mm fraction (-80 mesh) of these samples: AAS, INNA (and FA-NA) and ICPMS. A simple description of each method is given below. For atomic absorption spectrometry (AAS) a 1 g aliquot is 'partially digested' using Lefort aqua regia or concentrated hot nitric acid. The digestion product is analyzed using an atomic absorption spectrometer. Oxide and silicate minerals are partially digested while some sulphide minerals are erratically volatilized. This means that AAS cannot be used to obtain accurate REE, Ta, Nb, As, Sb, Sn, Hg, Cr, or Au determinations. For instrumental neutron activation analysis ( INAA), aliquots of sieved sediment (the minus 0.177 mm fraction) or milled rock ranging from 5 to 40 g are encapsulated and irradiated in a nuclear reactor before counting the primary gamma radiation induced by the neutron irradiation with a high resolution germanium gamma ray detector. Fire assay-neutron activation (FA-NA) analysis is similar but includes a pre-concentration fire assay step prior to irradiation and analysis. Results for both INAA and FA-NA are similar to those for samples analyses by fusion or other total digestion techniques. Neutron activation detection limits are typically higher than those by acid digestion - ICPMS. Commodity and pathfinder elements such as Au, As, Sb and W have reasonable detection limits by INAA and the data generated are relatively precise. For ICPMS analysis, aliquots of sieved sediment ( the minus 0.177 mm fraction) ranging from 0.5 to 1 g are prepared using a partial digestion technique, typically aqua regia, followed by analysis of dissolution product by ICPMS. Sulphide minerals are completely oxidized and dissolved whereas most oxide and silicate minerals are only partially digested. This means that results produced by partial digestion methods are acceptable for elements such as Ag, As, Mo, Ni, Pb, Sb, Tl, and Zn but values for elements such as Al, Ba, Cr, Fe, P, Sn, Ti, Y, and Zr are likely to not reflect the actual element concentration in a sample. The sample size used for routine RGS sample analysis is too small be representative of Au in the original sample and thus Au by aqua regia digestion - ICPMS has poor precision. Further upgrades to this database are not anticipated. All samples that could be found in the GSC-Ottawa warehouse have been reanalyzed using ICPMS. Any errors or omissions in this database should be reported to the Yukon Geological Survey. Your feedback contributes to improving the accuracy of the geoscience databases for Yukon. Contact: YGSMinerals@yukon.ca ; geology@yukon.ca Distributed from GeoYukon by the Government of Yukon . Discover more digital map data and interactive maps from Yukon's digital map data collection. For more information: geomatics.help@yukon.ca

Regional stream sediment geochemical data compilation November 2020 Release notes The regional stream sediment geochemical data compilation comprises data for more than 30 000 samples across Yukon. This compilation updates the work of Héon (2003). This new compilation includes results from the reanalysis of more than 24 000 samples; inductively coupled plasma mass spectrometry (ICPMS) analysis provides upgraded detection limits and a broader range of elements relative to previous analytical data. In addition to analytical data, efforts have been made to improve sample location accuracy. The data in this release are organized by analytical method with the geodatabase having six feature classes: RGS_SITE_WATER - site specific physiography and water quality data. These data are unchanged from the original releases. RGS_HEON - the same data as released in Héon (2003) with minor updates to sample location. RGS_AAS - all samples analyzed by atomic absorption spectrometry. Most of these data are superseded by INAA and ICPMS data. RGS_INAA - all samples analyzed by instrumental neutron activation analysis (INAA) and fire assay-neutron activation (FA-NA) analysis. RGS_ICPMS - all samples analyzed by inductively coupled plasma mass spectrometry (ICPMS). RGS_All - includes all AAS, INAA and ICPMS data. Collection of stream sediment samples in Yukon began in 1976 and ended in 2006. Three analytical methods have been used to analyze the minus 0.177 mm fraction (-80 mesh) of these samples: AAS, INNA (and FA-NA) and ICPMS. A simple description of each method is given below. For atomic absorption spectrometry (AAS) a 1 g aliquot is 'partially digested' using Lefort aqua regia or concentrated hot nitric acid. The digestion product is analyzed using an atomic absorption spectrometer. Oxide and silicate minerals are partially digested while some sulphide minerals are erratically volatilized. This means that AAS cannot be used to obtain accurate REE, Ta, Nb, As, Sb, Sn, Hg, Cr, or Au determinations. For instrumental neutron activation analysis ( INAA), aliquots of sieved sediment (the minus 0.177 mm fraction) or milled rock ranging from 5 to 40 g are encapsulated and irradiated in a nuclear reactor before counting the primary gamma radiation induced by the neutron irradiation with a high resolution germanium gamma ray detector. Fire assay-neutron activation (FA-NA) analysis is similar but includes a pre-concentration fire assay step prior to irradiation and analysis. Results for both INAA and FA-NA are similar to those for samples analyses by fusion or other total digestion techniques. Neutron activation detection limits are typically higher than those by acid digestion - ICPMS. Commodity and pathfinder elements such as Au, As, Sb and W have reasonable detection limits by INAA and the data generated are relatively precise. For ICPMS analysis, aliquots of sieved sediment ( the minus 0.177 mm fraction) ranging from 0.5 to 1 g are prepared using a partial digestion technique, typically aqua regia, followed by analysis of dissolution product by ICPMS. Sulphide minerals are completely oxidized and dissolved whereas most oxide and silicate minerals are only partially digested. This means that results produced by partial digestion methods are acceptable for elements such as Ag, As, Mo, Ni, Pb, Sb, Tl, and Zn but values for elements such as Al, Ba, Cr, Fe, P, Sn, Ti, Y, and Zr are likely to not reflect the actual element concentration in a sample. The sample size used for routine RGS sample analysis is too small be representative of Au in the original sample and thus Au by aqua regia digestion - ICPMS has poor precision. Further upgrades to this database are not anticipated. All samples that could be found in the GSC-Ottawa warehouse have been reanalyzed using ICPMS. Any errors or omissions in this database should be reported to the Yukon Geological Survey. Your feedback contributes to improving the accuracy of the geoscience databases for Yukon. Contact: YGSMinerals@yukon.ca ; geology@yukon.ca Distributed from GeoYukon by the Government of Yukon . Discover more digital map data and interactive maps from Yukon's digital map data collection. For more information: geomatics.help@yukon.ca

Regional stream sediment geochemical data compilation November 2020 Release notes The regional stream sediment geochemical data compilation comprises data for more than 30 000 samples across Yukon. This compilation updates the work of Héon (2003). This new compilation includes results from the reanalysis of more than 24 000 samples; inductively coupled plasma mass spectrometry (ICPMS) analysis provides upgraded detection limits and a broader range of elements relative to previous analytical data. In addition to analytical data, efforts have been made to improve sample location accuracy. The data in this release are organized by analytical method with the geodatabase having six feature classes: RGS_SITE_WATER - site specific physiography and water quality data. These data are unchanged from the original releases. RGS_HEON - the same data as released in Héon (2003) with minor updates to sample location. RGS_AAS - all samples analyzed by atomic absorption spectrometry. Most of these data are superseded by INAA and ICPMS data. RGS_INAA - all samples analyzed by instrumental neutron activation analysis (INAA) and fire assay-neutron activation (FA-NA) analysis. RGS_ICPMS - all samples analyzed by inductively coupled plasma mass spectrometry (ICPMS). RGS_All - includes all AAS, INAA and ICPMS data. Collection of stream sediment samples in Yukon began in 1976 and ended in 2006. Three analytical methods have been used to analyze the minus 0.177 mm fraction (-80 mesh) of these samples: AAS, INNA (and FA-NA) and ICPMS. A simple description of each method is given below. For atomic absorption spectrometry (AAS) a 1 g aliquot is 'partially digested' using Lefort aqua regia or concentrated hot nitric acid. The digestion product is analyzed using an atomic absorption spectrometer. Oxide and silicate minerals are partially digested while some sulphide minerals are erratically volatilized. This means that AAS cannot be used to obtain accurate REE, Ta, Nb, As, Sb, Sn, Hg, Cr, or Au determinations. For instrumental neutron activation analysis ( INAA), aliquots of sieved sediment (the minus 0.177 mm fraction) or milled rock ranging from 5 to 40 g are encapsulated and irradiated in a nuclear reactor before counting the primary gamma radiation induced by the neutron irradiation with a high resolution germanium gamma ray detector. Fire assay-neutron activation (FA-NA) analysis is similar but includes a pre-concentration fire assay step prior to irradiation and analysis. Results for both INAA and FA-NA are similar to those for samples analyses by fusion or other total digestion techniques. Neutron activation detection limits are typically higher than those by acid digestion - ICPMS. Commodity and pathfinder elements such as Au, As, Sb and W have reasonable detection limits by INAA and the data generated are relatively precise. For ICPMS analysis, aliquots of sieved sediment ( the minus 0.177 mm fraction) ranging from 0.5 to 1 g are prepared using a partial digestion technique, typically aqua regia, followed by analysis of dissolution product by ICPMS. Sulphide minerals are completely oxidized and dissolved whereas most oxide and silicate minerals are only partially digested. This means that results produced by partial digestion methods are acceptable for elements such as Ag, As, Mo, Ni, Pb, Sb, Tl, and Zn but values for elements such as Al, Ba, Cr, Fe, P, Sn, Ti, Y, and Zr are likely to not reflect the actual element concentration in a sample. The sample size used for routine RGS sample analysis is too small be representative of Au in the original sample and thus Au by aqua regia digestion - ICPMS has poor precision. Further upgrades to this database are not anticipated. All samples that could be found in the GSC-Ottawa warehouse have been reanalyzed using ICPMS. Any errors or omissions in this database should be reported to the Yukon Geological Survey. Your feedback contributes to improving the accuracy of the geoscience databases for Yukon. Contact: YGSMinerals@yukon.ca ; geology@yukon.ca Distributed from GeoYukon by the Government of Yukon . Discover more digital map data and interactive maps from Yukon's digital map data collection. For more information: geomatics.help@yukon.ca

Regional stream sediment geochemical data compilation November 2020 Release notes The regional stream sediment geochemical data compilation comprises data for more than 30 000 samples across Yukon. This compilation updates the work of Héon (2003). This new compilation includes results from the reanalysis of more than 24 000 samples; inductively coupled plasma mass spectrometry (ICPMS) analysis provides upgraded detection limits and a broader range of elements relative to previous analytical data. In addition to analytical data, efforts have been made to improve sample location accuracy. The data in this release are organized by analytical method with the geodatabase having six feature classes: RGS_SITE_WATER - site specific physiography and water quality data. These data are unchanged from the original releases. RGS_HEON - the same data as released in Héon (2003) with minor updates to sample location. RGS_AAS - all samples analyzed by atomic absorption spectrometry. Most of these data are superseded by INAA and ICPMS data. RGS_INAA - all samples analyzed by instrumental neutron activation analysis (INAA) and fire assay-neutron activation (FA-NA) analysis. RGS_ICPMS - all samples analyzed by inductively coupled plasma mass spectrometry (ICPMS). RGS_All - includes all AAS, INAA and ICPMS data. Collection of stream sediment samples in Yukon began in 1976 and ended in 2006. Three analytical methods have been used to analyze the minus 0.177 mm fraction (-80 mesh) of these samples: AAS, INNA (and FA-NA) and ICPMS. A simple description of each method is given below. For atomic absorption spectrometry (AAS) a 1 g aliquot is 'partially digested' using Lefort aqua regia or concentrated hot nitric acid. The digestion product is analyzed using an atomic absorption spectrometer. Oxide and silicate minerals are partially digested while some sulphide minerals are erratically volatilized. This means that AAS cannot be used to obtain accurate REE, Ta, Nb, As, Sb, Sn, Hg, Cr, or Au determinations. For instrumental neutron activation analysis ( INAA), aliquots of sieved sediment (the minus 0.177 mm fraction) or milled rock ranging from 5 to 40 g are encapsulated and irradiated in a nuclear reactor before counting the primary gamma radiation induced by the neutron irradiation with a high resolution germanium gamma ray detector. Fire assay-neutron activation (FA-NA) analysis is similar but includes a pre-concentration fire assay step prior to irradiation and analysis. Results for both INAA and FA-NA are similar to those for samples analyses by fusion or other total digestion techniques. Neutron activation detection limits are typically higher than those by acid digestion - ICPMS. Commodity and pathfinder elements such as Au, As, Sb and W have reasonable detection limits by INAA and the data generated are relatively precise. For ICPMS analysis, aliquots of sieved sediment ( the minus 0.177 mm fraction) ranging from 0.5 to 1 g are prepared using a partial digestion technique, typically aqua regia, followed by analysis of dissolution product by ICPMS. Sulphide minerals are completely oxidized and dissolved whereas most oxide and silicate minerals are only partially digested. This means that results produced by partial digestion methods are acceptable for elements such as Ag, As, Mo, Ni, Pb, Sb, Tl, and Zn but values for elements such as Al, Ba, Cr, Fe, P, Sn, Ti, Y, and Zr are likely to not reflect the actual element concentration in a sample. The sample size used for routine RGS sample analysis is too small be representative of Au in the original sample and thus Au by aqua regia digestion - ICPMS has poor precision. Further upgrades to this database are not anticipated. All samples that could be found in the GSC-Ottawa warehouse have been reanalyzed using ICPMS. Any errors or omissions in this database should be reported to the Yukon Geological Survey. Your feedback contributes to improving the accuracy of the geoscience databases for Yukon. Contact: YGSMinerals@yukon.ca ; geology@yukon.ca Distributed from GeoYukon by the Government of Yukon . Discover more digital map data and interactive maps from Yukon's digital map data collection. For more information: geomatics.help@yukon.ca

Regional stream sediment geochemical data compilation November 2020 Release notes The regional stream sediment geochemical data compilation comprises data for more than 30 000 samples across Yukon. This compilation updates the work of Héon (2003). This new compilation includes results from the reanalysis of more than 24 000 samples; inductively coupled plasma mass spectrometry (ICPMS) analysis provides upgraded detection limits and a broader range of elements relative to previous analytical data. In addition to analytical data, efforts have been made to improve sample location accuracy. The data in this release are organized by analytical method with the geodatabase having six feature classes: RGS_SITE_WATER - site specific physiography and water quality data. These data are unchanged from the original releases. RGS_HEON - the same data as released in Héon (2003) with minor updates to sample location. RGS_AAS - all samples analyzed by atomic absorption spectrometry. Most of these data are superseded by INAA and ICPMS data. RGS_INAA - all samples analyzed by instrumental neutron activation analysis (INAA) and fire assay-neutron activation (FA-NA) analysis. RGS_ICPMS - all samples analyzed by inductively coupled plasma mass spectrometry (ICPMS). RGS_All - includes all AAS, INAA and ICPMS data. Collection of stream sediment samples in Yukon began in 1976 and ended in 2006. Three analytical methods have been used to analyze the minus 0.177 mm fraction (-80 mesh) of these samples: AAS, INNA (and FA-NA) and ICPMS. A simple description of each method is given below. For atomic absorption spectrometry (AAS) a 1 g aliquot is 'partially digested' using Lefort aqua regia or concentrated hot nitric acid. The digestion product is analyzed using an atomic absorption spectrometer. Oxide and silicate minerals are partially digested while some sulphide minerals are erratically volatilized. This means that AAS cannot be used to obtain accurate REE, Ta, Nb, As, Sb, Sn, Hg, Cr, or Au determinations. For instrumental neutron activation analysis ( INAA), aliquots of sieved sediment (the minus 0.177 mm fraction) or milled rock ranging from 5 to 40 g are encapsulated and irradiated in a nuclear reactor before counting the primary gamma radiation induced by the neutron irradiation with a high resolution germanium gamma ray detector. Fire assay-neutron activation (FA-NA) analysis is similar but includes a pre-concentration fire assay step prior to irradiation and analysis. Results for both INAA and FA-NA are similar to those for samples analyses by fusion or other total digestion techniques. Neutron activation detection limits are typically higher than those by acid digestion - ICPMS. Commodity and pathfinder elements such as Au, As, Sb and W have reasonable detection limits by INAA and the data generated are relatively precise. For ICPMS analysis, aliquots of sieved sediment ( the minus 0.177 mm fraction) ranging from 0.5 to 1 g are prepared using a partial digestion technique, typically aqua regia, followed by analysis of dissolution product by ICPMS. Sulphide minerals are completely oxidized and dissolved whereas most oxide and silicate minerals are only partially digested. This means that results produced by partial digestion methods are acceptable for elements such as Ag, As, Mo, Ni, Pb, Sb, Tl, and Zn but values for elements such as Al, Ba, Cr, Fe, P, Sn, Ti, Y, and Zr are likely to not reflect the actual element concentration in a sample. The sample size used for routine RGS sample analysis is too small be representative of Au in the original sample and thus Au by aqua regia digestion - ICPMS has poor precision. Further upgrades to this database are not anticipated. All samples that could be found in the GSC-Ottawa warehouse have been reanalyzed using ICPMS. Any errors or omissions in this database should be reported to the Yukon Geological Survey. Your feedback contributes to improving the accuracy of the geoscience databases for Yukon. Contact: YGSMinerals@yukon.ca ; geology@yukon.ca Distributed from GeoYukon by the Government of Yukon . Discover more digital map data and interactive maps from Yukon's digital map data collection. For more information: geomatics.help@yukon.ca

Regional stream sediment geochemical data compilation November 2020 Release notes The regional stream sediment geochemical data compilation comprises data for more than 30 000 samples across Yukon. This compilation updates the work of Héon (2003). This new compilation includes results from the reanalysis of more than 24 000 samples; inductively coupled plasma mass spectrometry (ICPMS) analysis provides upgraded detection limits and a broader range of elements relative to previous analytical data. In addition to analytical data, efforts have been made to improve sample location accuracy. The data in this release are organized by analytical method with the geodatabase having six feature classes: RGS_SITE_WATER - site specific physiography and water quality data. These data are unchanged from the original releases. RGS_HEON - the same data as released in Héon (2003) with minor updates to sample location. RGS_AAS - all samples analyzed by atomic absorption spectrometry. Most of these data are superseded by INAA and ICPMS data. RGS_INAA - all samples analyzed by instrumental neutron activation analysis (INAA) and fire assay-neutron activation (FA-NA) analysis. RGS_ICPMS - all samples analyzed by inductively coupled plasma mass spectrometry (ICPMS). RGS_All - includes all AAS, INAA and ICPMS data. Collection of stream sediment samples in Yukon began in 1976 and ended in 2006. Three analytical methods have been used to analyze the minus 0.177 mm fraction (-80 mesh) of these samples: AAS, INNA (and FA-NA) and ICPMS. A simple description of each method is given below. For atomic absorption spectrometry (AAS) a 1 g aliquot is 'partially digested' using Lefort aqua regia or concentrated hot nitric acid. The digestion product is analyzed using an atomic absorption spectrometer. Oxide and silicate minerals are partially digested while some sulphide minerals are erratically volatilized. This means that AAS cannot be used to obtain accurate REE, Ta, Nb, As, Sb, Sn, Hg, Cr, or Au determinations. For instrumental neutron activation analysis ( INAA), aliquots of sieved sediment (the minus 0.177 mm fraction) or milled rock ranging from 5 to 40 g are encapsulated and irradiated in a nuclear reactor before counting the primary gamma radiation induced by the neutron irradiation with a high resolution germanium gamma ray detector. Fire assay-neutron activation (FA-NA) analysis is similar but includes a pre-concentration fire assay step prior to irradiation and analysis. Results for both INAA and FA-NA are similar to those for samples analyses by fusion or other total digestion techniques. Neutron activation detection limits are typically higher than those by acid digestion - ICPMS. Commodity and pathfinder elements such as Au, As, Sb and W have reasonable detection limits by INAA and the data generated are relatively precise. For ICPMS analysis, aliquots of sieved sediment ( the minus 0.177 mm fraction) ranging from 0.5 to 1 g are prepared using a partial digestion technique, typically aqua regia, followed by analysis of dissolution product by ICPMS. Sulphide minerals are completely oxidized and dissolved whereas most oxide and silicate minerals are only partially digested. This means that results produced by partial digestion methods are acceptable for elements such as Ag, As, Mo, Ni, Pb, Sb, Tl, and Zn but values for elements such as Al, Ba, Cr, Fe, P, Sn, Ti, Y, and Zr are likely to not reflect the actual element concentration in a sample. The sample size used for routine RGS sample analysis is too small be representative of Au in the original sample and thus Au by aqua regia digestion - ICPMS has poor precision. Further upgrades to this database are not anticipated. All samples that could be found in the GSC-Ottawa warehouse have been reanalyzed using ICPMS. Any errors or omissions in this database should be reported to the Yukon Geological Survey. Your feedback contributes to improving the accuracy of the geoscience databases for Yukon. Contact: YGSMinerals@yukon.ca ; geology@yukon.ca Distributed from GeoYukon by the Government of Yukon . Discover more digital map data and interactive maps from Yukon's digital map data collection. For more information: geomatics.help@yukon.ca

A location line is defined as a straight line opened or indicated throughout between No. 1 and No. 2 location posts of a mineral claim and joining them. Distributed from GeoYukon by the Government of Yukon . Discover more digital map data and interactive maps from Yukon's digital map data collection. For more information: geomatics.help@yukon.ca

This dataset represents lithogeochemistry of Saskatchewan samples. This dataset represents lithogeochemistry of Saskatchewan samples. This dataset represents the exhaustive mapping and sampling program of the Athabasca Group between 1975 and 1981 by the Saskatchewan Geological Survey (SGS), the results of which are contained in Ramaekers (1990). These samples are now stored at the Ministry of Energy and Resources, Subsurface Geological Laboratory in Regina, Saskatchewan. A selection of these samples was chosen to help characterize the background geochemical signature of the Athabasca Group and to identify anomalous regions. A total of 837 samples were chosen. All samples in this data set were processed at the Geoanalytical Laboratories at the Saskatchewan Research Council (SRC) in Saskatoon, Saskatchewan, an ISO/IEC 17025:2005 certified facility (i.e., meets the General Requirements for the Competence of Mineral Testing and Calibration Laboratories). Samples were crushed, split, agate ground, and then run with Sandstone Exploration Package ICPMS 1. The package produces three separate analysis types: inductively coupled plasma mass spectroscopy (ICP MS) partial digestion for trace elements; ICP MS total digestion for trace elements; and ICP–Optical Emission Spectrometry (ICP–OES) total digestion for major and minor elements. Details and detection limits are available on the SRC’s website. ICP total digestion: a 0.250 g pulp is gently heated in a mixture of ultrapure HF/HNO3/HClO4until dry and the residue dissolved in dilute ultrapure HNO3; ICP MS total digestion: a 0.250 g pulp is gently heated in a mixture of ultrapure HF/HNO3/HClO4until dry and the residue dissolved in dilute ultrapure HNO3; ICP MS partial digestion: a 2.00 g pulp is digested with 2.25 ml of 8:1 ultrapure HNO3:HCl for 1 hour at 95° C; Detection limits are from the SRC's 2011 Analytical Fee Schedule; null values indicate that elements are below the detection limit. NOTE: Attribute data headings ending with TD indicate Total Digestion, those ending with PD indicate Partial Digestion. Majors oxides are in percent; all other elements are in ppm. **Please Note – All published Saskatchewan Geological Survey datasets, including those available through the Saskatchewan Mining and Petroleum GeoAtlas, are sourced from the Enterprise GIS Data Warehouse. They are therefore identical and share the same refresh schedule. 

The Yukon Territory is underlain by a great variety of rock types ranging in age from Early Proterozoic to Recent and representing diverse environments including epicratonic basins, subsiding shelves, foreland basins, island arcs and deep ocean basins. Episodes of compressional and extensional deformation, transcurrent faulting, metamorphism and plutonism further complicate the map pattern. This complex geological record has been described in terms of the interactions of several terranes (large parts of the earth's crust which preserve a common geological record) with each other and with the margin of ancestral North America.