Geology and lithogeochemistry of the Fyre lake copper-cobalt-gold sulphide-magnetite deposit, southeastern Yukon

The Fyre Lake sulphide-magnetite deposit is located in the Finlayson Lake massive sulphide district in the Yukon-Tanana terrane, southeastern Yukon. It is hosted by quartz-chlorite-actinolite schist derived from (probable) Devono-Mississippian-aged mafic volcanic rocks. Overlying the deposit are intercalated metasedimentary and metavolcanic rocks. This mixed sequence is, in turn, overlain by a thick sequence of graphitic phyllite. The deposit consists of three northwest-trending stratiform lenses comprising massive and semi-massive sulphide and magnetite iron formation. Pyrite is the dominant sulphide mineral in the deposit, with lesser amounts of pyrrhotite, chalcopyrite, and locally, sphalerite. The sulphide mineralization is copper and cobalt-rich and locally contains significant concentrations of zinc and gold. It has low to trace amounts of lead, barium, arsenic, antimony, tin and selenium. Lithogeochemical results indicate that the host mafic metavolcanic rocks are strongly depleted of light rare-earth elements (LREE) and high field strength elements (HFSE), and contain elevated levels of MgO, Ni and Cr. SiO2 in the host rocks ranges from 53 to 58%. Chemically, the mafic metavolcanic rocks are similar to boninitic rocks found in some suprasubduction zone ophiolites such as those at Cyprus. The primitive boninitic chemistry of the host metavolcanic rocks implies that they originated as melts from a depleted mantle in a rifted setting. The presence of felsic metasedimentary rocks below, within and overlying the host metavolcanic rocks suggests that the Fyre Lake deposit was formed in or near a mature tectonic setting, possibly a continental arc or an evolved island arc. The host mafic metavolcanic rocks are chemically distinct from other mafic and intermediate metavolcanic rocks that outcrop on the Fyre Lake property. A clastic metavolcanic rock unit lies stratigraphically below the deposit. It consists of fragmental LREE and HFSE-enriched transitional subalkaline basalts. Other discontinuous bodies of metavolcaniclastic and metaflow rocks occur stratigraphically above and peripheral to the Fyre Lake deposit. These are enriched in LREE and Th, and relatively depleted in Nb, Ta and Ti, and generally display the chemical features of transitional basalts and andesites erupted in a continental arc or evolved island arc setting.

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• Yukon Geological Survey publication metadataHTML
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• Science and Technology
• ygs-import
• ygs-import-20250711
• ygs-publications
• yukon-geological-survey

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Field	Value
Last Updated	October 20, 2025, 02:23 (UTC)
Created	October 20, 2025, 02:23 (UTC)
Domain / Topic Domain or topic of the dataset being cataloged.
Title Title for the Dataset.	Geology and lithogeochemistry of the Fyre lake copper-cobalt-gold sulphide-magnetite deposit, southeastern Yukon
Description A description of the dataset.	The Fyre Lake sulphide-magnetite deposit is located in the Finlayson Lake massive sulphide district in the Yukon-Tanana terrane, southeastern Yukon. It is hosted by quartz-chlorite-actinolite schist derived from (probable) Devono-Mississippian-aged mafic volcanic rocks. Overlying the deposit are intercalated metasedimentary and metavolcanic rocks. This mixed sequence is, in turn, overlain by a thick sequence of graphitic phyllite. The deposit consists of three northwest-trending stratiform lenses comprising massive and semi-massive sulphide and magnetite iron formation. Pyrite is the dominant sulphide mineral in the deposit, with lesser amounts of pyrrhotite, chalcopyrite, and locally, sphalerite. The sulphide mineralization is copper and cobalt-rich and locally contains significant concentrations of zinc and gold. It has low to trace amounts of lead, barium, arsenic, antimony, tin and selenium. Lithogeochemical results indicate that the host mafic metavolcanic rocks are strongly depleted of light rare-earth elements (LREE) and high field strength elements (HFSE), and contain elevated levels of MgO, Ni and Cr. SiO2 in the host rocks ranges from 53 to 58%. Chemically, the mafic metavolcanic rocks are similar to boninitic rocks found in some suprasubduction zone ophiolites such as those at Cyprus. The primitive boninitic chemistry of the host metavolcanic rocks implies that they originated as melts from a depleted mantle in a rifted setting. The presence of felsic metasedimentary rocks below, within and overlying the host metavolcanic rocks suggests that the Fyre Lake deposit was formed in or near a mature tectonic setting, possibly a continental arc or an evolved island arc. The host mafic metavolcanic rocks are chemically distinct from other mafic and intermediate metavolcanic rocks that outcrop on the Fyre Lake property. A clastic metavolcanic rock unit lies stratigraphically below the deposit. It consists of fragmental LREE and HFSE-enriched transitional subalkaline basalts. Other discontinuous bodies of metavolcaniclastic and metaflow rocks occur stratigraphically above and peripheral to the Fyre Lake deposit. These are enriched in LREE and Th, and relatively depleted in Nb, Ta and Ti, and generally display the chemical features of transitional basalts and andesites erupted in a continental arc or evolved island arc setting.
Tags / Keywords Keywords/tags categorizing the dataset.	Science and Technology ygs-import ygs-import-20250711 ygs-publications yukon-geological-survey
Format (CSV, XLS, TXT, PDF, etc) File format of the dataset.
Dataset Size Dataset size in megabytes.
Metadata Identifier Metadata identifier – can be used as the unique identifier for catalogue entry
Published Date Published date of the dataset.	2011-04-04
Time Period Data Span (start date) Start date of the data in the dataset.
Time Period Data Span (end date) End date of time data in the dataset.
GeoSpatial Area Data Span A spatial region or named place the dataset covers.

Field	Value
Access category Type of access granted for the dataset (open, closed, service, etc).
License License used to access the dataset.	Open Government Licence - Yukon
Limits on use Limits on use of data.
Location Location of the dataset.	https://open.canada.ca/data/en/dataset/2a36f1c7-48e3-4c81-9517-f0ce3b68500a
Data Service Data service for accessing a dataset.
Owner Owner of the dataset.	Government of Yukon | Gouvernement du Yukon
Contact Point Who to contact regarding access?	Yukon Geological Survey
Contact Point Email The email to contact regarding access?
Publisher Publisher of the dataset.
Publisher Email Email of the publisher.	[email protected]
Author Author of the dataset.
Author Email Email of the author.
Accessed At Date the data and metadata was accessed.

Field	Value
Identifier Unique identifier for the dataset.
Language Language(s) of the dataset
Link to dataset description A URL to an external document describing the dataset.
Persistent Identifier Data is identified by a persistent identifier.
Globally Unique Identifier Data is identified by a persistent and globally unique identifier.
Contains data about individuals Does the data hold data about individuals?
Contains data about identifiable individuals Does the data hold identifiable data about individual?
Contains Indigenous Data Does the data hold data about Indigenous communities?
Portal Type Platform type of the source portal.

Field	Value
Version Version of the datatset	None
Source Source of the dataset.	None
Version notes Version notes about the dataset.
Is version of another dataset Link to dataset that it is a version of.
Other versions Link to datasets that are versions of it.
Provenance Text Provenance Text of the data.
Provenance URL Provenance URL of the data.
Temporal resolution Describes how granular the date/time data in the dataset is.
GeoSpatial resolution in meters Describes how granular (in meters) geospatial data is in the dataset.
GeoSpatial resolution (in regions) Describes how granular (in regions) geospatial data is in the dataset.

Field	Value
Indigenous Community Permission Who holds the Indigenous Community Permission. Who to contact regarding access to a dataset that has data about Indigenous communities.
Community Permission Community permission (who gave permission).
The Indigenous communities the dataset is about Indigenous communities from which data is derived.

Field	Value
Number of data rows If tabular dataset, total number of rows.
Number of data columns If tabular dataset, total number of unique columns.
Number of data cells If tabular dataset, total number of cells with data.
Number of data relations If RDF dataset, total number of triples.
Number of entities If RDF dataset, total number of entities.
Number of data properties If RDF dataset, total number of unique properties used by the triples.
Data quality Describes the quality of the data in the dataset.
Metric for data quality A metric used to measure the quality of the data, such as missing values or invalid formats.

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