Sulfide Electron Microprobe Analyses and Petrography of Mineralized Samples from the Stratabound Sheep Creek Sediment-Hosted Zn-Pb-Ag-Sn Prospect, and SHRIMP U–Pb Zircon Data for Metaigneous Rocks in the Bonnifield Mining District, Healy Quadrangle, Alaska

Identification_Information:

Citation:

Citation_Information:

Originator: Dusel-Bacon, Cynthia (ORCID: 0000-0001-8481-739X)
Originator: Aleinikoff, John N. (ORCID: 0000-0003-3494-6841)
Originator: Paradise, Suzanne (ORCID: 0000-0002-5681-3516)
Originator: Slack, John F. (ORCID: 0000-0001-6600-3130)
Publication_Date: 20230815
Title:

Geospatial_Data_Presentation_Form: tabular digital data
Publication_Information:

Publication_Place: Anchorage, Alaska
Publisher: U.S. Geological Survey, Alaska Science Center

Other_Citation_Details:

Suggested Citation: Dusel-Bacon, C., Aleinikoff, J.N., Paradise, S., Slack, J.F., 2023, Sulfide electron microprobe analyses and petrography of mineralized samples from the stratabound Sheep Creek sediment-hosted Zn-Pb-Ag-Sn prospect, and SHRIMP U–Pb zircon data for metaigneous rocks in the Bonnifield mining district, Healy quadrangle, Alaska: U.S. Geological Survey data release, https://doi.org/10.5066/P9654N1C

Online_Linkage: https://doi.org/10.5066/P9654N1C
Larger_Work_Citation:

Citation_Information:

Originator: U.S. Geological Survey, Alaska Science Center
Publication_Date: 2015
Title:

Geological framework, metallogeny, and critical mineral potential of the broader Yukon-Tanana upland, Alaska

Geospatial_Data_Presentation_Form: website
Series_Information:

Series_Name: Alaska Science Portal
Issue_Identification: 436

Publication_Information:

Publication_Place: Anchorage, Alaska
Publisher: U.S. Geological Survey, Alaska Science Center

Other_Citation_Details:

This is a link to the broader USGS Alaska Science Center research project supported by these data. Users will find a description of the research project and links to associated reports, publications, and data products.

Online_Linkage: https://alaska.usgs.gov/portal/project.php?project_id=436

Description:

Abstract:

This data set contains 99 electron microprobe analyses of cassiterite, chalcopyrite, galena, pyrite, sphalerite, and tetrahedrite from seven Sheep Creek drill core samples and one outcrop; and a table that describes the textures, mineralogy, and rock type of 15 thin sections of Sheep Creek drill core and observations from our study and from drill core logging by industry. These data were used to compare this prospect with others in the Bonnifield district. The data set also contains tables of sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon dates, zircon characteristics (crystal shape, external morphology, internal features, color, aspect ratio, and cathodoluminescence zoning), and 139 U-Th-Pb analyses of the zircons from 11 metaigneous rocks collected during 1997-2005 fieldwork in the Bonnifield mining district, Alaska Range. Our zircon geochronology indicates that volcanogenic massive sulfide deposits in the Bonnifield district are hosted in felsic metavolcanic rocks that yield ages based on weighted averages of 206 Pb/238U ages (± 2-sigma errors) of 362 ± 2 Ma. These rocks overlie the stratigraphic sequence at the Sheep Creek prospect, where metaigneous rocks give ages of 372 ± 4 Ma to 366 ± 4 Ma.

Purpose:

We performed electron microprobe analysis of zinc, lead, silver, and tin and conducted petrographic analysis of thin sections from drill core from 1977 drilling of the Sheep Creek prospect in the Bonnifield mining district to characterize an important massive sulfide occurrence in the Bonnifield mining district, Alaska. These data were compared with comparable mineral chemistry data from massive sulfide deposits elsewhere in the Bonnifield mining district to evaluate the origins of the different deposits. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb geochronology of felsic metaigneous rocks was conducted to determine their ages to help define the age relationships of the regional stratigraphy in the Bonnifield mining district. U-Pb zircon in-situ ion probe geochronology also was used to date the metavolcanic rocks that host massive sulfide mineralization in most of the Bonnifield mining districts and the associated metasedimentary rocks that we propose are the host rocks for the metasedimentary exhalative (Sedex) massive sulfides at the Sheep Creek prospect.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1997
Ending_Date: 2005

Currentness_Reference: observed

Status:

Progress: Complete
Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -148.50
East_Bounding_Coordinate: -147.23
North_Bounding_Coordinate: 64.00
South_Bounding_Coordinate: 63.77

Keywords:

Theme:

Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:ASC549

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: geoscientificInformation

Theme:

Theme_Keyword_Thesaurus: NASA GCMD Earth Science Keyword Thesaurus
Theme_Keyword: Age determinations
Theme_Keyword: Electron microprobe
Theme_Keyword: Igneous rocks
Theme_Keyword: Isotopes
Theme_Keyword: Metamorphic rocks
Theme_Keyword: Mineral chemistry
Theme_Keyword: Radioactive elements
Theme_Keyword: Sulfide petrography
Theme_Keyword: U-Pb geochronology

Theme:

Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: Geology
Theme_Keyword: Geochronology
Theme_Keyword: Isotopic analysis
Theme_Keyword: Radiometric dating
Theme_Keyword: Uranium-lead analysis
Theme_Keyword: Uranium-thorium analysis

Place:

Place_Keyword_Thesaurus: USGS Geographic Names Information System (GNIS)
Place_Keyword: Alaska
Place_Keyword: Bonnifield
Place_Keyword: Healy

Access_Constraints: None
Use_Constraints:

It is requested that the authors, USGS Geology, Minerals, Energy, and Geophysics Science Center, and the USGS Alaska Science Center be cited for any subsequent publications that reference this dataset.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey, Alaska Science Center

Contact_Address:

Address_Type: Mailing and Physical
Address: 4210 University Drive
City: Anchorage
State_or_Province: Alaska
Postal_Code: 99508
Country: USA

Contact_Voice_Telephone: 907-786-7000
Contact_Electronic_Mail_Address: ascweb@usgs.gov

Data_Set_Credit:

The Geology, Minerals, Energy, and Geophysics Science Center in Menlo Park, California, and co-authors from: Geology, Geophysics, and Geochemistry Science Center in Denver, Colorado; Geology, Energy and Minerals Science Center in Reston, Virginia; and from the Geological Survey of Canada, British Columbia are recognized for their support in enabling the collaboration and coordination of the data collection and publication of this project.

Cross_Reference:

Citation_Information:

Originator: Dusel-Bacon, C.
Originator: Aleinikoff, J.N.
Originator: Paradise, S.
Originator: Slack, J.F.
Publication_Date: Unknown
Title:

Sulphide petrology and ore genesis of the stratabound Sheep Creek sediment-hosted Zn-Pb-Ag-Sn prospect, and U–Pb zircon constraints on the timing of magmatism in the northern Alaska Range

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Canadian Journal of Earth Sciences
Issue_Identification: .

Publication_Information:

Publication_Place: online
Publisher: Canadian Journal of Earth Sciences

Other_Citation_Details:

Dusel-Bacon, C., Aleinikoff, J.N., Paradise, S., Slack, J.F., in prep, Sulphide petrology and ore genesis of the stratabound Sheep Creek sediment-hosted Zn-Pb-Ag-Sn prospect, and U–Pb zircon constraints on the timing of magmatism in the northern Alaska Range, Canadian Journal of Earth Sciences

Online_Linkage: .

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Electron microprobe analyses were conducted on polished thin sections at the USGS in Menlo Park, California, and Reston, Virginia. Concentrations of 12 elements (Cu, Pb, As, Fe, S, Zn, Cd, Se, Mn, Ag, Co, and Ni) were determined for all samples, as well as Sb, Hg, and Sn for most, by wavelength-dispersion analysis using a JEOL 8900 Superprobe equipped with five spectrometers. Mineral standards included natural pyrite for calibration of Fe and S; chalcopyrite for Cu and S; galena for Pb; synthetic ZnS for Zn; CdS for Cd; elemental Se for Se; Mn2O3 for Mn; Ag2S for Ag; skutterudite for As and Co; pentlandite for Ni; stibnite for Sb; cinnabar for Hg; and cassiterite for Sn. X-ray intensities were converted to concentrations using a ZAF correction. Accuracy was insured by analyzing materials of known composition.

Zircon was extracted from rock samples using standard mineral separation techniques including crushing and pulverizing, followed by processing over a Wilfley table, through a magnetic separator, and by sinking in methylene iodide to obtain a non-magnetic, heavy mineral concentrate. This process resulted in a fairly pure zircon fraction that sometimes also contained pyrite. Relatively clean zircon with limited imperfections (such as cracks and/or inclusions) were hand-picked under a binocular microscope onto double-sided tape, together with a zircon standard for normalization of isotopic ratios. These grains were mounted in epoxy, ground to about half thickness to expose inner zones using 2400 grit sandpaper, and polished sequentially with 6-µm and 1-µm diamond suspensions.

U–Pb geochronology of zircon was accomplished using the sensitive high resolution ion microprobe-reverse geometry (SHRIMP-RG) instrument at the U.S. Geological Survey/Stanford ion microprobe laboratory at Stanford University. Following the methods described in Williams (1998), SHRIMP analysis consisted of excavating a pit about 25-35 µm in diameter and about 0.5-1 µm in depth. Uranium concentrations are believed to be accurate to ±20%.

References for the U-Pb analysis described above are given in is given in the file included with this data release, Supplemental_Information_Analytical_Methods_Electron_Microprobe_U-Pb_Geochronology.pdf.

Logical_Consistency_Report:

No unexpected values are found in these data. Users should note that the data tables are released in Comma Separated Values format (.csv) which present the data with the correct number of significant figures; however, some software programs may alter the values and truncate trailing zeroes.

Completeness_Report: This data set is complete; no data were omitted.
Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Horizontal position was noted at the time of sample collection on USGS topographic maps with a geodetic reference datum of NAD27. Latitude and longitude values of samples were then converted to geodetic reference datum NAD83, yielding an accuracy of approximately 10 meters.

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Ludwig, K.R.
Publication_Date: 2003
Title:

User's Manual for Isoplot 3.00 : A Geochronological Toolkit for Microsoft Excel

Geospatial_Data_Presentation_Form: document
Series_Information:

Series_Name: Berkeley Geochronology Center Special Publications
Issue_Identification: Special Publication no. 4

Publication_Information:

Publication_Place: online
Publisher: Berkeley Geochronology Center

Other_Citation_Details:

Ludwig, K.R. 2003. User's Manual for Isoplot 3.00 : A Geochronological Toolkit for Microsoft Excel, Berkeley Geochronology Center, Special Publication no. 4

Online_Linkage: https://www.bgc.org/isoplot

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2003

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Ludwig, 2003
Source_Contribution: Software instructions for digital geochronological tools

Source_Information:

Source_Citation:

Citation_Information:

Originator: O'Connor, W.K.
Originator: Dahlin, D.C.
Originator: Warner, J.D.
Publication_Date: 1989
Title:

Characterization of the Sheep Creek Pb-Zn-Ag-Sn prospect, north-central Alaska Range

Geospatial_Data_Presentation_Form: publication
Other_Citation_Details:

O'Connor, W.K., Dahlin, D.C., Warner, J.D., 1989, Characterization of the Sheep Creek Pb-Zn-Ag-Sn Prospect, North-central Alaska Range (Vol. 9256); US Department of the Interior, Bureau of Mines.

Type_of_Source_Media: Digital and/or Hardcopy
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1989

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: O'Connor et al., 1989
Source_Contribution:

Defines anomalous mineralization zone types for the studied area.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Ludwig, K.R.
Publication_Date: 2001
Title: Squid, version 1.02, a user’s manual
Geospatial_Data_Presentation_Form: document
Publication_Information:

Publication_Place: Berkley, California
Publisher: Berkley Geochronology Center

Other_Citation_Details:

Ludwig, K.R., 2001, Squid, version 1.02, a user’s manual: Special Publication 2, Berkeley Geochronology Center

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2001

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Ludwig, 2001
Source_Contribution: Raw data reduction techniques for geochronology

Source_Information:

Source_Citation:

Citation_Information:

Originator: Black, L.P.
Originator: Kamo, S.L.
Originator: Allen, C.M.
Originator: Davis, D.W.
Originator: Aleinikoff, J.N.
Originator: Valley, J.W.
Originator: Mundil, R.
Originator: Campbell, I.H.
Originator: Korsuch, R.J.
Originator: Williams, I.S.
Originator: Foudoulis, C.
Publication_Date: 2004
Title:

Improved 206Pb/238U microprobe geochronology by the monitoring of a trace-element-related matrix effect; SHRIMP, ID–TIMS, ELA–ICP–MS and oxygen isotope documentation for a series of zircon standards

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Chemical Geology
Issue_Identification: 205(1-2):115-140

Publication_Information:

Publication_Place: online
Publisher: Elsevier

Other_Citation_Details:

Black, L.P., Kamo, S.L., Allen, C.M., Davis, D.W., Aleinikoff, J.N., Valley, J.W., Mundil, R., Campbell, I.H., Korsuch, R.J., Williams, I.S., and Foudoulis, C., 2004, Improved 206Pb/238U microprobe geochronology by the monitoring of a trace-element-related matrix effect; SHRIMP, ID–TIMS, ELA–ICP–MS and oxygen isotope documentation for a series of zircon standards: Chemical Geology. 205(1-2):115–140 doi:10.1016/j.chemgeo.2004.01.003

Online_Linkage: https://doi.org/10.1016/j.chemgeo.2004.01.003

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2004

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Black et al., 2004
Source_Contribution: Improved geochronology techniques for SHRIMP

Source_Information:

Source_Citation:

Citation_Information:

Originator: Williams, I.S.
Publication_Date: 1997
Title: U–Th–Pb geochronology by ion microprobe
Geospatial_Data_Presentation_Form: publication
Series_Information:

Series_Name: Reviews in Economic Geology
Issue_Identification: 7:1-35

Publication_Information:

Publication_Place: online
Publisher: GeoScienceWorld

Other_Citation_Details:

Williams, I.S., 1997, U–Th–Pb geochronology by ion microprobe: Reviews in Economic Geology. 7:1–35 doi:10.5382/Rev.07.01

Online_Linkage: https://doi.org/10.5382/Rev.07.01

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1997

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Williams, 1997
Source_Contribution: Ion microprobe procedures in isotope geochronology

Source_Information:

Source_Citation:

Citation_Information:

Originator: Stacey, J.S.
Originator: Kramers, J.D.
Publication_Date: 1975
Title:

Approximation of terrestrial lead isotope evolution by a two-stage model

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Earth and Planetary Science Letters
Issue_Identification: 26(2):207-221

Publication_Information:

Publication_Place: online
Publisher: Elsevier

Other_Citation_Details:

Stacey, J.S., and Kramers, J.D., 1975, Approximation of terrestrial Pb isotope composition by a two-stage model: Earth and Planetary Science Letters 26(2):207–222 doi:10.1016/0012-821X(75)90088-6

Online_Linkage: https://doi.org/10.1016/0012-821X(75)90088-6

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1975

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Stacey and Kramers, 1975
Source_Contribution: Lead isotope correction factors used in geochronologic analyses

Source_Information:

Source_Citation:

Citation_Information:

Originator: Steiger, R.H.
Originator: Jäger, E.
Publication_Date: 1977
Title:

Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Earth and Planetary Science Letters
Issue_Identification: 36(3):359-362

Publication_Information:

Publication_Place: online
Publisher: Elsevier

Other_Citation_Details:

Steiger, R.H., and Jäger, E., 1977, Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology: Earth and Planetary Science Letters 36(3):359–362 doi:10.1016/0012-821X(77)90060-7

Online_Linkage: https://doi.org/10.1016/0012-821X(77)90060-7

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1977

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Steiger and Jäger, 1977
Source_Contribution: Decay constants used in geochronological analyses

Process_Step:

Process_Description:

Samples for U–Pb geochronology were collected during helicopter-supported fieldwork in 1997, 2003, and 2005. Zircon was extracted from rock samples using standard mineral separation techniques including crushing and pulverizing, followed by processing over a Wilfley table, through a magnetic separator, and by sinking in methylene iodide to obtain a non-magnetic, heavy mineral concentrate. This process resulted in a fairly pure zircon fraction that sometimes also contained pyrite. Relatively clean zircon with limited imperfections (such as cracks and/or inclusions) were hand-picked under a binocular microscope onto double-sided tape, together with a zircon standard for normalization of isotopic ratios. These grains were mounted in epoxy, ground to about half thickness to expose inner zones using 2400 grit sandpaper, and polished sequentially with 6-µm and 1-µm diamond suspensions.

Process_Date: 2005

Process_Step:

Process_Description:

U–Pb geochronology of zircon was accomplished using the sensitive high resolution ion microprobe-reverse geometry (SHRIMP-RG) instrument at the U.S. Geological Survey/Stanford ion microprobe laboratory at Stanford University. Following the methods described in Williams (1997), SHRIMP analysis consisted of excavating a pit about 25-35 µm in diameter and about 0.5-1 µm in depth, using a primary oxygen beam at a current of about 4-6 nA. The magnet cycled through the mass stations five times per analysis. Isotopic ratios for the standard zircon were measured every fourth analysis.

Process_Date: 2005

Process_Step:

Process_Description:

Raw data were reduced using Squid 1 (Ludwig 2001) and plotted using Isoplot 3 (Ludwig 2003). Instrument fractionation for 206Pb/238U ages was corrected using zircon standard R33 (419 ± 1 Ma; Black et al. 2004). Weighted averages of selected 206Pb/238U ages were calculated to obtain a crystallization date for each sample. Decay constants are from Steiger and Jäger (1977). Radiogenic ratios were corrected for common Pb using the 204Pb-correction method, based on the Stacey and Kramers (1975) model. More detailed information is given in the files included with this data release, Supplemental information for methods used in U-Pb zircon geochronology, Supplemental_Information_Analytical_Methods_Electron_Microprobe_U-Pb_Geochronology.pdf.

Process_Date: 2005

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Point

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Geographic:

Latitude_Resolution: 0.001
Longitude_Resolution: 0.001
Geographic_Coordinate_Units: Decimal degrees

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983 (NAD 83)
Ellipsoid_Name: Geodetic Reference System 1980 (GRS 80)
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257222

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label:

geology_DataDictionary_Healy_Bonnifield_SheepCreek_DuselBacon.csv

Entity_Type_Definition:

Table describing all fields in the four data tables included in this data package. Includes field names, a brief description of each field, and units of measure, as applicable. The table contains 53 records and is presented in comma separated value (CSV) format.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Table
Attribute_Definition: Filename of the data table the field is found in.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: geology_Bonnifield_UPb_sample_age_location_description
Enumerated_Domain_Value_Definition:

Table with 11 records included with this data package, containing sample information location and type as well as detailed observations and descriptions.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: geology_Bonnifield_UPbZircon_data
Enumerated_Domain_Value_Definition:

Table with 139 records included with this data package, containing sample isotope ratio and concentration information.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: geology_SheepCreek_electron_microprobe_analyses
Enumerated_Domain_Value_Definition:

Table with 99 records included with this data package, containing sample and mineral names with associated weight percent measurements for selected elements.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: geology_SheepCreek_thin_sections
Enumerated_Domain_Value_Definition:

Table with 15 records included with this data package, containing thin section sample identification with detailed observations and descriptions.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Field
Attribute_Definition:

Field name found in data tables included in this data package (single words or concatenated abbreviations that describe the contents of the field).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: Name of each field in the CSV data tables.

Attribute:

Attribute_Label: Description
Attribute_Definition: Brief description of the contents of 'Field'.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: Brief description of the contents of 'Field'.

Attribute:

Attribute_Label: Units
Attribute_Definition: The unit of measurement for applicable data fields.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: N/A
Enumerated_Domain_Value_Definition: N/A = not applicable
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: degrees
Enumerated_Domain_Value_Definition:

degrees = angular unit of measure, expressed as a decimal number

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Mega-annum (Ma)
Enumerated_Domain_Value_Definition: (Ma) Mega-annum = millions of years before present
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: pct
Enumerated_Domain_Value_Definition:

pct = percent, measure of total abundance, expressed in reference to one hundred

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: ppm
Enumerated_Domain_Value_Definition:

ppm = parts per million, measure of mass expressed in reference to one million units

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: wt_pct
Enumerated_Domain_Value_Definition: wt_pct = weight percent, expressed in reference to one hundred
Enumerated_Domain_Value_Definition_Source: Author defined

Detailed_Description:

Entity_Type:

Entity_Type_Label: geology_Bonnifield_UPb_sample_age_location_description.csv
Entity_Type_Definition:

Table containing sample information, location, and type, as well as detailed observations and descriptions of zircon grains. The table contains 11 records and is presented in comma separated value (CSV) format.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Sample_ID
Attribute_Definition: Sample number as collected and assigned in the field.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Unique sample identifier usually consisting of the last two digits of the year collected, abbreviation identifying the collector or location, with a one to three-digit number and possible one to two-letter suffix, some entries are separated within by one or more hyphens. Corresponds to the 'Sample_ID' field in the other tables included with this data package.

Attribute:

Attribute_Label: Mean_206Pb_238U_age_Ma
Attribute_Definition:

U-Pb crystallization age of sample based on mean of weighted averages of 206Pb/238U ages, in millions of years.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 57.3
Range_Domain_Maximum: 372.0
Attribute_Units_of_Measure: (Ma) Mega-annum, or millions of years before present

Attribute:

Attribute_Label: Mean_206Pb_238U_age_2sig_unc_Ma
Attribute_Definition:

U-Pb crystallization age 2-sigma uncertainty of sample based on weighted averages of 206Pb/238U ages in millions of years.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.4
Range_Domain_Maximum: 4.0
Attribute_Units_of_Measure: (Ma) Mega-annum, or millions of years before present

Attribute:

Attribute_Label: Grains_used_in_age_calc
Attribute_Definition:

Number of grains used in calculation of weighted average of Mean_206Pb_238U_age_Ma field.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 7
Range_Domain_Maximum: 14

Attribute:

Attribute_Label: MSWD
Attribute_Definition:

Mean square of weighted deviates for calculated value in Mean_206Pb_238U_age_Ma field.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.079
Range_Domain_Maximum: 2.3

Attribute:

Attribute_Label: Map_location_index
Attribute_Definition:

Letter to denote location of sample on figure 2 of Dusel-Bacon and others, Canadian Journal of Earth Sciences, 2023.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset are unique alphabetic identifiers associated with a specific sample location outlined.

Attribute:

Attribute_Label: Sample_description
Attribute_Definition: Description of dated rock sample
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values present in this dataset include physical descriptions of rock samples collected, often with some location and stratigraphic association information.

Attribute:

Attribute_Label: Whole_rock_SiO2_wt_pct
Attribute_Definition:

Weight percent of SiO2 in whole-rock dated sample normalized to 100% on an anhydrous basis.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 70.24
Range_Domain_Maximum: 80.80
Attribute_Units_of_Measure: (wt_pct) weight percent

Attribute:

Attribute_Label: Latitude_NAD83
Attribute_Definition: Sample collection latitude in degrees north, datum NAD83.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 63.7788
Range_Domain_Maximum: 63.9980
Attribute_Units_of_Measure: decimal degrees
Attribute_Measurement_Resolution: 0.0001

Attribute:

Attribute_Label: Longitude_NAD83
Attribute_Definition: Sample collection longitude in degrees west, datum NAD83.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -148.493
Range_Domain_Maximum: -147.2395
Attribute_Units_of_Measure: decimal degrees
Attribute_Measurement_Resolution: 0.0001

Attribute:

Attribute_Label: Healy_15min_ quad
Attribute_Definition:

Number of the specific 1:63,360-scale quadrangle within the 1:250,000-scale Healy quadrangle, Alaska

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset only include the following: "D-1", "D-2", or "D-3".

Attribute:

Attribute_Label: Crystal_shape
Attribute_Definition: Crystal shape of separated zircons.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset include only "Euhedral", "Euhedral-subhedral", and "Euhedral-subhedral-anhedral".

Attribute:

Attribute_Label: External_morphology
Attribute_Definition: External morphology of separated zircons.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset include only "blocky", "prismatic", and "prismatic-blocky".

Attribute:

Attribute_Label: Internal_features
Attribute_Definition: Internal features of separated zircons.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset include descriptions of types of fractures and inclusions noted during observation and analyses of the sample material. This a free text field.

Attribute:

Attribute_Label: Color
Attribute_Definition: Colors of separated zircons noted.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset include only "tan", "colorless", or "tan-colorless".

Attribute:

Attribute_Label: Aspect_ratio
Attribute_Definition: Length-to-width ratio of separated zircons.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset are two numbers separated by a hyphen. The numbers represent the range of the length-to-width ratio of separated zircons.

Attribute:

Attribute_Label: CL_zoning
Attribute_Definition:

Zoning types in separated zircons observed in cathodoluminescence.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: oscillatory; concentric
Enumerated_Domain_Value_Definition: Zoning observed was both oscillatory and concentric.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: oscillatory; parallel
Enumerated_Domain_Value_Definition: Zoning observed was both oscillatory and parallel.
Enumerated_Domain_Value_Definition_Source: Author defined

Detailed_Description:

Entity_Type:

Entity_Type_Label: geology_Bonnifield_UPbZircon_data.csv
Entity_Type_Definition:

Table containing sample information and type with concentrations and ratios of lead, thorium, and uranium from zircon grains. The table contains 139 records and is presented in comma separated value (CSV) format.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Sample_ID
Attribute_Definition:

Sample field number or drill core number from Anderson Mountain 1998 drill hole No. 02 with down-hole depth of 252 meters as measured from the hole collar.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Attribute:

Attribute_Label: Mineral
Attribute_Definition: Name of the mineral analyzed.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: The only value in this dataset is 'zircon'.

Attribute:

Attribute_Label: Analysis_ID
Attribute_Definition:

Analysis number as assigned by Aleinikoff during analysis; ion microprobe grain and spot number.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset are a concatenation of portions of the 'Sample_ID', a hyphen, and one- or two-digit grain number followed by a single digit spot number on that grain.

Attribute:

Attribute_Label: 204Pb_206Pb_ratio
Attribute_Definition:

Measured ratio of 204Pb/206Pb; negative numbers may result from counting statistics.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -0.000218
Range_Domain_Maximum: 0.001460

Attribute:

Attribute_Label: 207Pb_206Pb_ratio
Attribute_Definition: Measured ratio of 207Pb/206Pb.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0468
Range_Domain_Maximum: 0.0926

Attribute:

Attribute_Label: Pct_comm_206Pb
Attribute_Definition:

Percentage of 206Pb that is of common (not radiogenic) origin; negative numbers may result from counting statistics.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -0.47
Range_Domain_Maximum: 2.59
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: U_ppm
Attribute_Definition: Concentration of uranium, in parts per million.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 107
Range_Domain_Maximum: 4300
Attribute_Units_of_Measure: parts per million (ppm)

Attribute:

Attribute_Label: Th_U_ratio
Attribute_Definition:

Calculated ratio of thorium concentration divided by uranium concentration.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.04
Range_Domain_Maximum: 0.99

Attribute:

Attribute_Label: 206Pb_238U_age_Ma
Attribute_Definition:

Calculated 206Pb/238U age, in Mega-annum, or millions of years. Decay constants from Steiger and Jäger (1977).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 56.0
Range_Domain_Maximum: 1443.3
Attribute_Units_of_Measure: (Ma) Mega-annum, or millions of years before present

Attribute:

Attribute_Label: 206Pb_238U_age_unc_Ma
Attribute_Definition:

1-sigma uncertainty of the 206Pb/238U age, in Mega-annum, or millions of years.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.3
Range_Domain_Maximum: 15.2
Attribute_Units_of_Measure: (Ma) Mega-annum, or millions of years before present

Attribute:

Attribute_Label: 206Pb_238U_ratio
Attribute_Definition:

206Pb/238U isotopic ratio; radiogenic ratios, corrected for common Pb using the 204Pb-correction method, based on the Stacey and Kramers (1975) model.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 3.98
Range_Domain_Maximum: 114.53

Attribute:

Attribute_Label: 206Pb_238U_unc_pct
Attribute_Definition: 1-sigma uncertainty of the 206Pb/238U ratio, in percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.5
Range_Domain_Maximum: 4.0
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: 207Pb_206Pb_ratio
Attribute_Definition:

207Pb/206Pb isotopic ratio; radiogenic ratios corrected for common Pb using the 204Pb-correction method, based on the Stacey and Kramers (1975) model

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0416
Range_Domain_Maximum: 0.0918

Attribute:

Attribute_Label: 207Pb_206Pb_unc_pct
Attribute_Definition: 1-sigma uncertainty of the 207Pb/206Pb ratio, in percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.7
Range_Domain_Maximum: 8.9
Attribute_Units_of_Measure: percent

Detailed_Description:

Entity_Type:

Entity_Type_Label: geology_SheepCreek_electron_microprobe_analyses.csv
Entity_Type_Definition:

Table containing sample and mineral names with associated microprobe weight percent measurements for selected elements. The table contains 99 records and is presented in comma separated value (CSV) format.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Sample_ID
Attribute_Definition:

Sample field number or drill core number from Sheep Creek 1977 drill hole No. 1; last 3 digits give down-hole depth in meters as measured from the hole collar (for example SC77-1-75.6).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Sample identifier usually consisting of the last two digits of the year collected, abbreviation identifying the collector or location, with a one to three-digit number and possible one to two-letter suffix, some entries are separated within by one or more hyphens. May correspond to the 'Sample_ID' field in other tables included with this data package.

Attribute:

Attribute_Label: Mineral
Attribute_Definition:

Mineral phase analyzed on electron microprobe in polished thin section of sample.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: cst
Enumerated_Domain_Value_Definition: cst = cassiterite
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: cp
Enumerated_Domain_Value_Definition: cp = chalcopyrite
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: gn
Enumerated_Domain_Value_Definition: gn = galena
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: py
Enumerated_Domain_Value_Definition: py = pyrite
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: sp
Enumerated_Domain_Value_Definition: sp = sphalerite
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: td
Enumerated_Domain_Value_Definition: td = tetrahedrite
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Cu_wt_pct
Attribute_Definition: Concentration of copper (Cu), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 39.349
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Pb_wt_pct
Attribute_Definition: Concentration of lead (Pb), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 87.457
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: As_wt_pct
Attribute_Definition: Concentration of arsenic (As), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 2.063
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Fe_wt_pct
Attribute_Definition: Concentration of iron (Fe), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 47.261
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: S_wt_pct
Attribute_Definition: Concentration of sulphur (S), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 54.425
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Zn_wt_pct
Attribute_Definition: Concentration of zinc (Zn), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 66.062
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Cd_wt_pct
Attribute_Definition: Concentration of cadmium (Cd), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 0.325
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Se_wt_pct
Attribute_Definition: Concentration of selenium (Se), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 0.066
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Mn_wt_pct
Attribute_Definition: Concentration of manganese (Mn), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 0.053
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Ag_wt_pct
Attribute_Definition: Concentration of silver (Ag), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 1.393
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Co_wt_pct
Attribute_Definition: Concentration of cobalt (Co), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 0.119
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Sb_wt_pct
Attribute_Definition: Concentration of antimony (Sb), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 24.493
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Ni_wt_pct
Attribute_Definition: Concentration of nickel (Ni), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 0.164
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Hg_wt_pct
Attribute_Definition: Concentration of mercury (Hg), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 0.1
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Sn_wt_pct
Attribute_Definition: Concentration of tin (Sn), in weight percent.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 80.923
Attribute_Units_of_Measure: weight percent

Attribute:

Attribute_Label: Total_wt_pct
Attribute_Definition: Total analysis of all phases analyzed in weight percent
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 79.422
Range_Domain_Maximum: 102.945
Attribute_Units_of_Measure: weight percent

Detailed_Description:

Entity_Type:

Entity_Type_Label: geology_SheepCreek_thin_sections.csv
Entity_Type_Definition:

Table containing sample information and detailed observations and descriptions of thin sections derived from samples. The table contains 15 records and is presented in comma separated value (CSV) format.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Thin_sections_sample_ID
Attribute_Definition:

Polished thin section sample number made from Sheep Creek 1997 drill hole No. 1 with down-hole depth in meters as measured from the hole collar (for example SC77-1-31.4)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset follow conventions for 'Sample_ID' in 'geology_SheepCreek_electron_microprobe_analyses.csv' with down-hole depth in meters as measured from the hole collar (for example SC77-1-31.4).

Attribute:

Attribute_Label: Petrographic_description
Attribute_Definition:

Petrographic description made by Dusel-Bacon of thin section. Bimodal refers to having 2 different grain sizes.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset include a more generalized description of the type of rock fabric and may also include specific grain types and size indications as noted by the observer; this is a free text field.

Attribute:

Attribute_Label: Sulfides_observed
Attribute_Definition:

Sulfide minerals observed macroscopically in drill core and (or) microscopically in thin section.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset are proper mineral names of sulfide minerals observed in sample, or the notation 'no sulfides'.

Attribute:

Attribute_Label: Rock_description
Attribute_Definition: Rock description, as determined in our study.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset include more specific mineral and grain types and descriptions; this is a free text field.

Attribute:

Attribute_Label: Anomalous_mineralization_zones
Attribute_Definition:

Zones are those in defined in O'Connor and others, 1989, Characterization of the Sheep Creek Pb-Zn-Ag-Sn prospect, north-central Alaska Range. U.S. Bureau of Mines Report of Investigations 9256, 15 p.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this dataset reference mineralization zones 1 or 2 as defined in O'Connor and others (1989) and a relation to those zones using descriptors such as 'above' or 'between'.

Attribute:

Attribute_Label: Drill_core_description
Attribute_Definition:

Description of drill core interval logged by John S. Phillips and Jay W. Hammitt, Bear Creek Mining Company, Spokane office, 1977.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Values in this field are relevant text notations taken from drill core logs as noted above; this is a free text field.

Sulfide Electron Microprobe Analyses and Petrography of Mineralized Samples from the Stratabound Sheep Creek Sediment-Hosted Zn-Pb-Ag-Sn Prospect, and SHRIMP U–Pb Zircon Data for Metaigneous Rocks in the Bonnifield Mining District, Healy Quadrangle, Alaska

Metadata: