Montayne, Simone
Wypych, Alicja
Freeman, L.K.
Griesel, G.A.
2019
Petrographic observations of rocks collected in the Bonnifield mining district, Fairbanks A-1, Fairbanks A-2, Healy D-1, and Healy D-2 quadrangles, Alaska
report and digital data
Raw Data File
RDF 2019-1
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
4 p.
http://doi.org/10.14509/30171
Mineral Resources Section personnel from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a geologic field mapping survey in the eastern part of the Bonnifield mining district in the Fairbanks A-1 and A-2 and the Healy D-1 and D-2 quadrangles. The map area contains several significant polymetallic sulfide prospects and transects three metamorphic assemblages, which include the Healy Schist, Keevy Peak Formation, and the Totatlanika Schist. The fieldwork (June 16 through July 18, 2008) augments publically available information critical to building an understanding of Alaska's geology and is part of an integrated program of airborne geophysical surveys followed by geologic mapping. This raw data release provides petrographic thin section observations of 264 samples from the East Bonnifield Project rock collection. Project staff examined thin sections to better distinguish rock units, assist with evaluating the structural and stratigraphic relationships among the various lithologies, and to determine suitability for lithogeochemical and geochronological analysis. Observations in the data tables include lithologic classification, texture, mineral crystal structure, and mineral components. Users can access the complete report and digital data from the DGGS website: http://doi.org/10.14509/30171.
Mineral Resources Section personnel from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a geologic field mapping survey in the eastern part of the Bonnifield mining district in the Fairbanks A-1 and A-2 and the Healy D-1 and D-2 quadrangles. The map area contains several significant polymetallic sulfide prospects and transects three metamorphic assemblages, which include the Healy Schist, Keevy Peak Formation, and the Totatlanika Schist. The fieldwork (June 16 through July 18, 2008) augments publically available information critical to building an understanding of Alaska's geology and is part of an integrated program of airborne geophysical surveys followed by geologic mapping. Specifically, this mapping provides geologic context for geophysical surveys conducted in 2006 (Burns and others, 2016).
>bonnifield-tx-rock-descriptions: petrographic thin section lithology observations
>bonnifield-tx-mineral-descriptions: petrographic thin section mineral observations
2008
2018
ground condition
None planned
-147.829220
-147.165490
64.067800
63.840900
ISO 19115 Topic Category
geoscientificInformation
Alaska Division of Geological & Geophysical Surveys
Bedrock
Bedrock Geology
Exploration
Geologic
Geology
Igneous
Igneous Rocks
Metamorphic
Metamorphic Minerals
Metamorphic Rocks
Metasedimentary Rocks
Metavolcanic rocks
Mineral Composition
Mineral Resources
Mineralogy
Minerals
Petrogenesis
Petrographic
Petrography
Petrology
Rocks
Alaska Division of Geological & Geophysical Surveys
Bonnifield Mining District
Chute Creek
Coal Creek
Dry Creek
Glacier Creek
Glory Creek
Kansas Creek
Mystic Creek
Newman Creek
Red Mountain
Red Mountain Creek
Rogers Creek
Sheep Creek
Slate Creek
Slide Creek
Smallwood Creek
Snow Mountain Gulch
Threemile Creek
Waugaman Mountain
Wood River
Alaska Division of Geological & Geophysical Surveys
Healy Schist
Keevy Peak Formation
Totatlanika Schist
This report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
Alaska Division of Geological & Geophysical Surveys
Metadata Manager
mailing and physical
3354 College Road
Fairbanks
AK
99709-3707
USA
(907)451-5020
(907)451-5050
dggspubs@alaska.gov
8 am to 4:30 pm, Monday through Friday, except State holidays
The Eastern Bonnifield Mining District Project is part of the Alaska Airborne Geophysical/Geological Mineral Inventory Program, which was funded by the Alaska State Legislature and managed by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. Partial funding for the geologic mapping, thin section preparation, and geochemical analyses was also provided through the State of Alaska General Fund and the U.S. Geological Survey STATEMAP Program under award number 08HQAG0051.
Athey, J.E.
Seitz, S.S.
DGGS Staff
2017
Geologic Photos of Alaska
Digital Data Series
DDS 14
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
http://doi.org/10.14509/29735
Benowitz, J.A.
Layer, P.W.
Freeman, L.K.
2011
40Ar/39Ar ages from the east Bonnifield geologic map area, Fairbanks A-1, Fairbanks A-2, Healy D-1, and Healy D-2 quadrangles, Alaska
Raw Data File
RDF 2011-2 v. 1.1
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
22 p
http://doi.org/10.14509/22482
Burns, L.E.
Fugro Airborne Surveys Corp.
Stevens Exploration Management Corp.
Graham, G.R.C.
Emond, A.M.
2016
Bonnifield mining district electromagnetic and magnetic airborne geophysical survey data compilation
Geophysical Report
GPR 2016-1
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
2 sheets
http://doi.org/10.14509/29557
DGGS Staff
2016
Geologic Materials Center Inventory
Digital Data Series
DDS 11
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
http://doi.org/10.14509/29550
DGGS Staff
Seitz, S.S.
Reioux, D.A.
Blessington, M.J.
Jozwik, Diana
Mulliken, K.M.
2017
Alaska Geochemistry
Digital Data Series
DDS 15
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
http://doi.org/10.14509/29770
Freeman, L.K.
Newberry, R.J.
Andrew, J.E.
Szumigala, D.J.
Werdon, M.B.
Athey, J.E.
Burns, L.E.
2013
Geologic setting of syngenetic and epigenetic deposits in the eastern Bonnifield mining district, Alaska (presentation): Alaska Miners Association, 22nd Annual Biennial Mining Conference, March 9-13, 2010
Poster and Presentation
Freeman, L.K. and others, 2013
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
25 p
http://doi.org/10.14509/25279
Freeman, L.K.
Newberry, R.J.
Werdon, M.B.
Szumigala, D.J.
Andrew, J.E.
Athey, J.E.
2016
Preliminary bedrock geologic map data for the eastern Bonnifield mining district, Fairbanks and Healy quadrangles, Alaska
Preliminary Interpretive Report
PIR 2016-3
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
6 p
http://doi.org/10.14509/29661
Freeman, L.K.
Werdon, M.B.
Szumigala, D.J.
Andrew, J.E.
Newberry, R.J.
Athey, J.E.
2009
Geochemical, major-oxide, minor-oxide, trace-element and carbon data from rocks collected in 2008 in the eastern Bonnifield mining district, Fairbanks and Healy quadrangles, Alaska
Raw Data File
RDF 2009-1 v. 1.2
Fairbanks, Alaska, United States
Alaska Division of Geological & Geophysical Surveys
69 p
http://doi.org/10.14509/20041
This publication is PRELIMINARY in nature and meant to allow release of field observations and initial interpretations of geologic features. It has undergone limited technical review but does not necessarily conform to DGGS editorial standards. Interpretations contained in this publication are subject to change. Observations in the data tables include lithologic classification, texture, mineral crystal structure and development sequence, and mineral components. Mineral and component modal percentages are visual estimates. The primary focus of this work was to aid in distinguishing igneous, volcaniclastic metasedimentary rocks, and volcaniclastic metavolcanic rocks, consequently the level of detail varies from cursory to comprehensive. Although the classifications and descriptions have been lightly edited for spelling and consistency, the descriptions are typically freeform text written to note key features and highlight uncertainties that may warrant subsequent investigation. Users may notice sample numbering discrepancies throughout various Bonnifield Project publications. DGGS staff have completed significant work over the duration of the project to assimilate data from various sources into comprehensive division-wide databases. In conjunction with loading the Bonnifield data into the Geologic Materials Center Inventory and Alaska Geochemistry databases, staff identified and, when possible, corrected sample labeling inconsistencies. Error correction required certain assumptions, and it is possible, particularly in cases where multiple lithologies were collected from a single outcrop, that published geochemical results and thin section observations tied to a given sample number may not correspond to the same rock. The data tables in this publication list both the sample numbers written on each thin section and the standardized numbers used by the division databases.
not applicable
This data release is complete.
Location coordinates were collected using hand-held GPS units (no differential correction was applied). Estimated position errors calculated by the GPS units were a minimum of 3 meters. At many locations the horizon was limited by steep topography, resulting in positional errors of more than 100 meters. Waypoints were downloaded from the GPS units into the project database, merged with related information, and converted from UTM (Universal Transverse Mercator) to geographic coordinates. Location coordinates are based on the NAD27 datum (North American Datum of 1927).
Sample collection - Mineral Resources Section personnel from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a geologic field mapping survey in the eastern part of the Bonnifield mining district in the Fairbanks A-1 and A-2 and the Healy D-1 and D-2 quadrangles (June 16 through July 18, 2008). The samples selected for petrographic observation either generally represent outcrop lithology or contain significant lithologic features.
2008
Sample preparation - Thin section billets were cut using a diamond-blade tile saw; foliated and lineated rocks were cut so that the examination surface is perpendicular the rock fabric. Many of the rocks were fragile and required either significant gluing or vacuum impregnation to prepare billets. The billets were used to create standard petrographic thin-sections. Thin section billets were mounted on glass slides, hand ground to 30 microns, and finished with a 600 mesh grit. A few thin sections of mineralized rocks were left uncovered and polished for use in reflected light ore microscopy.
2008
Petrographic observation - Using basic polarized light microscopy, project staff examined thin sections to identify mineral content, investigate textural relationships, and determine suitability for further geochemical and geochronological analysis. A polarizing reflected light microscope was used on the polished thin sections containing sulfide minerals.
2010
point
0.00001
0.00001
decimal degrees
North American Datum of 1927
Clarke 1866
6378206.40000000037
294.978698199999997
bonnifield-tx-rock-descriptions.csv, bonnifield-tx-rock-descriptions-metadata.csv
petrographic thin section lithology observations
Alaska Division of Geological & Geophysical Surveys (DGGS)
bonnifield-tx-rock-descriptions
thin_section_id
The label printed on the thin section slide. Primary key used to uniquely identify each thin section record
this report
string
dggs_sample_number
The sample number assigned in the field to identify the sample, modified to DGGS standard format. Generic example of a sample identifier: YYAAA999X: YY=last two digits of the year the sample was collected, AAA=geologist's initials (one to three characters), 999=unique station number, X= optional alpha character which indicates that multiple samples were collected at a given location or that multiple observations were recorded in the project database. This number is used to identify corresponding records in the DGGS geochemistry and GMC inventory databases
this report
string
dggs_field_station_number
The number assigned in the field to uniquely identify the outcrop location and description; station numbers have been modified to DGGS standard format. Generic example of a sample identifier: YYAAA999X: YY=last two digits of the year the sample was collected, AAA=geologist's initials (one to three characters), 999=unique station number. This number is used to identify corresponding records in the DGGS geochemistry and GMC inventory databases
this report
string
latitude_nad27
Latitude, decimal degrees, NAD27 datum
this report
double
longitude_nad27
Longitude, decimal degrees, NAD27 datum
this report
double
observer
Geologist who observed and described the sample
this report
string
observation_date
The observation date
this report
date
rock_name
General rock name based on mineral composition and textures
this report
string
thin_section_remarks
Freeform text written to briefly describe key lithologic features and highlight uncertainties
this report
string
texture_keywords
Comma delimited list of keywords used to note observed textures
this report
string
texture_remarks
Freeform text written to briefly describe key texture features and highlight uncertainties
this report
string
matrix_remarks
Freeform text written to briefly describe matrix/groundmass and highlight uncertainties
this report
string
matrix_size_mm
The average grain size of the matrix, measured in mm
this report
double
mineralization_flag
Flag to indicate presence or lack of mineralization features
this report
string
alteration_flag
Flag to identify rocks that may be too altered for whole rock analysis. 'Undetermined' indicates the rock was altered, but the degree of alteration could not be assigned
this report
string
overprinting_alteration
Characteristics or mineralogy of overprinting alteration
this report
string
overprinting_structures
Characteristics of overprinting structures
this report
string
label_error_flag
Flag to identify samples or records where the thin section label differs from the most likely associated sample and field station. Because there is not an exact match, there is some possibility that the locations for these samples and links to related data may be incorrect
this report
string
bonnifield-tx-mineral-descriptions.csv, bonnifield-tx-mineral-descriptions-metadata.csv
petrographic thin section mineral observations
Alaska Division of Geological & Geophysical Surveys (DGGS)
bonnifield-tx-mineral-descriptions
thin_section_id
The label printed on the thin section slide. Foreign key used to relate mineral observation records to thin section observation records
this report
string
mineral
Mineral name, NULL values indicate that the observer could not confidently identify the mineral
this report
string
modal_abundance_pct
Visually estimated modal abundance of mineral (percent)
this report
string
mineral_shape
Mineral shape
this report
string
mineral_size_mm
The average size of the mineral, measured in mm
this report
double
mineral_remarks
Freeform text written to briefly describe key observations and highlight uncertainties
this report
string
tectonic_timing
Inferred timing of mineral origination relative to tectonic deformation. Inferences are based on foliation, strain shadows, extinction patterns, and other observations
this report
string
mineral_sequence_flag
Flag to differentiate primary and secondary minerals
this report
string
mineral_replaced
The primary mineral (or mineral class) that is replaced by the secondary mineral
this report
string
pct_primary_mineral_replaced
The percentage of the primary mineral that is altered to the secondary mineral
this report
double
Alaska Division of Geological & Geophysical Surveys
Metadata Manager
mailing and physical
3354 College Road
Fairbanks
AK
99709-3707
USA
(907)451-5020
(907)451-5050
dggspubs@alaska.gov
8 am to 4:30 pm, Monday through Friday, except State holidays
RDF 2019-1
The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount.
Contact DGGS for current pricing
report and digital data
http://doi.org/10.14509/30171
Free download
20190408
Alaska Division of Geological & Geophysical Surveys
Simone Montayne
Metadata Manager
mailing and physical
3354 College Road
Fairbanks
AK
99709-3707
USA
(907)451-5020
(907)451-5050
dggspubs@alaska.gov
8 am to 4:30 pm, Monday through Friday, except State holidays
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998
If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys.
http://www.dggs.alaska.gov/metadata/dggs.ext
dggs metadata extensions