GeologyOntario has moved. You will be redirected to the new site in 10 seconds. If you are not immediately redirected please follow the below link to the new GeologyOntario platform. For assistance please contact us.
Ontario Geological Survey
Permanent Link to this Record:
MDI42D10NE00001
| Record Name(s) | Pic Island Nepheline Syenite - 1953, W.C. Arrowsmith Property - 1953, Denison Mines Ltd. Property - 1960 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 1997-Jan-05 |
| Date Last Modified | 2022-Sep-12 |
| Created By | |
| Revised By |
Primary Commodities: Nepheline Syenite
Township or Area: Pic Island Area
Latitude: 48° 42' 25.17" Longitude: -86° 35' 59.87"
UTM Zone: 16 Easting: 529430.917 Northing: 5394961.631 UTM Datum: NAD83
Resident Geologist District: Thunder Bay South
NTS Grid: 42D10NE
Point Location Description: PIC ISLAND
Location Method: Conversion from MDI
Access Description: Pic Island is located 17 km due west of Marathon and 2 km due south of the Coldwell Peninsula. Pic Island is accessible by boat from launches located at Neys Provincial Park and Coldwell Harbour.
PAST: 1953 W.C. Arrowsmith staked 6 claims, TB 45113 to 45118 incl. Thirteen holes totalling 539 feet were drilled. No analyses were conducted. 1960 to R. Preston and L. Gaudreau staked the 1961 eastern half of Pic Island. All interest transferred to Denison Mines Ltd 1976 A. Moses staked 12 claims on Pic Island and transferred all interest to D. Fairbairn. No work was recorded. 1992 A. MacDonnell staked a portion of the Denison Mines property. CURRENT: 1994 A. MacDonnell still holds claims on Pic Island.
Province: Superior
Subprovince: Wawa
Terrane: Wawa-Abitibi
Geological Age: Mesoproterozoic Geochronological Age: 1108 +/- MA Geochron. Age Ref.: (HEAMAN & MACHAD0, 1992)
Dec 07, 2005 (R Degagne) - The general geology of the island has been described by Walker et al. (1992) . The Port Coldwell alkalic complex was emplaced into Archean rocks of the Wawa Subprovince of the Superior Province during the early stages of the Mesoproterozoic Midcontinent Rift at 1108+1 Ma (Heaman and Machado 1992). The complex is located at the north end of the Thiel fault, a zone of faulting that separates grabens with different subsidence history in the rift (Cannon et al. 1989). A north-trending magnetic high occurs between the rocks of the Port Coldwell alkalic complex and those of the Midcontinent Rift beneath Lake Superior (Gupta 1991). Samples of different magmatic suites from the Port Coldwell alkalic complex dated by the U-Pb zircon-baddeleyite method (Heaman and Machado 1992) are all within analytical error.
| Rock Type | Rank | Composition | Texture | Relationship | Syenite | 1 | Amp Ne Syenite | Medium Grained, Brecciated | Host |
|---|---|---|---|---|
| Syenite | 2 | Ne Syenite | Host | |
| Syenite | 3 | Amp Qtz Syenite | Host |
Dec 07, 2005 (R Degagne) - The Port Coldwell alkalic complex consists of a variety of felsic syenites and gabbroic rocks (Figure 19.2). Mitchell and Platt (1977, 1978) subdivided the Port Coldwell alkalic complex into 3 centres of alkalic magmatism emplaced by cauldron subsidence associated with major faults. CHEMICAL ANALYSIS: Sample No. IM-92-045: 62.7 SiO2, 20.0 Al2O3, 1.47 Fe2O3, 0.18 MgO, 1.66 CaO, 7.57 Na2O, 4.71 K2O, 0.11 TiO2, 0.14 P2O5, 0.03 MnO, 0.03 Cr2O3. Sample No. IM-92-046: 59.2 SiO2, 19.7 Al2O3, 2.88 Fe2O3, 0.85 MgO, 2.59 CaO, 7.47 Na2O, 4.51 K2O, 0.30 TiO2, 0.22 P2O5, 0.07 MnO, <0.01 Cr2O3. Sample No. IM-92-047: 62.2 SiO2, 19.6 Al2O3, 2.08 Fe2O3, 0.46 MgO, 1.98 CaO, 6.68 Na2O, 5.40 K2O, 0.21 TiO2, 0.17 P2O5, 0.05 MnO, 0.01 Cr2O3. Sample No. IM-92-048: 61.9 SiO2, 18.5 Al2O3, 2.57 Fe2O3, 0.58 MgO, 1.70 CaO, 6.05 Na2O, 6.11 K2O, 0.40 TiO2, 0.24 P2O5, 0.06 MnO, 0.01 Cr2O3. Sample No. IM-92-049: 56.6 SiO2, 19.6 Al2O3, 3.80 Fe2O3, 2.04 MgO, 5.68 CaO, 5.10 Na2O, 3.91 K2O, 0.41 TiO2, 0.78 P2O5, 0.07 MnO, <0.01 Cr2O3. Sample No. IM-92-050: 58.4 SiO2, 22.5 Al2O3, 0.79 Fe2O3, 0.26 MgO, 4.59 CaO, 6.34 Na2O, 3.67 K2O, 0.12 TiO2, 0.31 P2O5, 0.01 MnO, <0.01 Cr2O3. Sample No. IM-92-051: 58.5 SiO2, 21.5 Al2O3, 2.16 Fe2O3, 0.84 MgO, 4.80 CaO, 6.05 Na2O, 3.90 K2O, 0.26 TiO2, 0.45 P2O5, 0.04 MnO, <0.01 Cr2O3. Sample No. IM-92-052: 58.9 SiO2, 20.4 Al2O3, 2.77 Fe2O3, 0.78 MgO, 3.57 CaO, 5.71 Na2O, 5.64 K2O, 0.31 TiO2, 0.34 P2O5, 0.07 MnO, <0.01 Cr2O3. Sample No. IM-92-053: 60.2 SiO2, 21.0 Al2O3, 1.46 Fe2O3, 0.23 MgO, 1.54 CaO, 6.95 Na2O, 6.67 K2O, 0.05 TiO2, 0.07 P2O5, 0.05 MnO, 0.01 Cr2O3. Analyses by Lakefield Research.
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Nepheline | Economic | Ore | ||||
| 1 | Amphibole | Economic | Gangue | ||||
| 2 | Quartz | Economic | Gangue | ||||
| 3 | Biotite | Economic | Gangue | ||||
| 4 | Apatite | Economic | Gangue | ||||
| 5 | Zeolite | Economic | Gangue | ||||
| 6 | Feldspar | Economic | Gangue | ||||
| 7 | Olivine | Economic | Gangue |
Dec 07, 2005 (R Degagne) - Walker et al. (1993) described the different phases of the nepheline syenites: There are 2 areas of amphibole nepheline syenite within the Port Coldwell alkalic complex: 1 centred over Pic Island and the other between Little Pic River and Red Sucker Cove within the western part of the complex. Both areas are typified by a texturally variable suite of syenite types with gradational contacts. The variation is complicated by brecciation and assimilation resulting from the intrusion of a second phase of heterogeneous amphibole nepheline syenite and later amphibole quartz syenite. The amphibole nepheline syenite is white to black, medium grained with variable proportions of nepheline, amphibole, biotite, apatite and zeolites. Locally, the nepheline syenite is well layered with melanocratic nepheline syenite grading into mesocratic syenite. The melanocratic layers locally contain olivine. At the margins of the main nepheline syenite unit are additional textural varieties of nepheline syenite. These textural varieties include a white to pink mesocratic nepheline-amphibole syenite with stubby euhedral-amphibole prisms and white to pink, mesocratic nepheline syenite with interstitial amphibole and euhedral lath to columnar feldspar. A second phase of heterogeneous amphibole nepheline syenite intrudes the nepheline syenite described in the previous paragraph and exhibits a variety of textures. These result from brecciation and assimilation of older nepheline syenite and alkaline gabbro. Further complexity is a result of mixing with mafic magma.
| Rank | Classification |
|---|---|
| 1 | Magmatic |
| Shape | Length | Thickness | Depth | Strike | Dip | Plunge | Trend | Age | Reference |
|---|---|---|---|---|---|---|---|---|---|
| Irregular |
Date: Jan 05, 1997
Geologist: R Degagne
Notes: Visited in September, 1993 by P. Hinz | R. M. Landry (OGS OFR 5889, 1994) ECONOMIC FEATURES: Walker et al. (1993) says the following about the nepheline syenites potential: The nepheline syenites within the Port Coldwell alkalic complex have been examined by Denison Mines Limited in 1960 as a potential source for nepheline. The results indicated that the nepheline had too high an iron content to be of economic value (Puskas 1967). This may be due to the zeolite and hematite crystallization in the nepheline syenites during postcrystallization alteration. Based on the results of the present study, nepheline occurs in 2 different units; amphibole nepheline syenite and heterogeneous amphibole nepheline syenite. The distribution of these rock types has been outlined, and samples of each of the different varieties have been taken by the Resident Geologist's Office in order to determine the modal abundance of nepheline in the rocks. It is anticipated that with the analytical results, it will be possible to isolate the areas that are the best targets for evaluating the potential of nepheline as an industrial mineral within the Port Coldwell alkalic complex. COMMENTS/RECOMMENDATIONS: Although the geochemical results are interesting, they are not good enough to warrant development on the island. Logistical problems of developing on an island, roughness of the terrain and the possibility that the island will be added to Neys Provincial Park, indicate that the nepheline syenite will probably never be extracted.
Book - Industrial Minerals Geologist's Files, Thunder Bay
Publication Number: Date:
Author:
Publisher Name:
Location: Thunder Bay RGP
File - Schreiber-Hemlo Resident Geologist Mineral Deposit Files, Thunder Bay office
Publication Number: Min Dep Date:
Author:
Publisher Name:
Location: Thunder Bay RGP
Map - Port Coldwell area, District of Thunder Bay
Publication Number: P0114 Scale: 1:31,680 Date: 1997
Author: Puskas F.P.
Publisher Name: Ontario Dept. of Mines
Location:
Map - Precambrian Geology, Port Coldwell Complex, West Half
Publication Number: P3232 Scale: 1:20,000 Date: 1993
Author: Walker E.C., Sutcliffe R.H., Shaw C.S.J., Shore G.T., Penczak R.S.
Publisher Name: Ontario Geological Survey
Location:
MonoMap - Geology of the Port Coldwell area, District of Thunder Bay
Publication Number: OFR5014 Date: 1997
Author: Puskas F.P.
Publisher Name: Ontario Dept. of Mines
Location:
Mono - Industrial Mineral Occurrences and Deposits in Northwest Ontario
Publication Number: OFR5889 Page: 97-98 Date: 1994
Author: Hinz P., Landry R.M.
Publisher Name: Ontario Geological Survey
Location:
Article - Geology of the Coldwell alkaline complex
Publication Number: MP157.018 Page: 107-116 Date: 1998
Author: Walker E.C., Sutcliffe R.H., Shaw C.S.J., Shore G.T.
Publisher Name: Ontario Geological Survey
Location:
Article - Geology of the Port Coldwell alkalic complex
Publication Number: MP160.019 Page: 108-119 Date: 1997
Author: Walker E.C., Sutcliffe R.H., Shaw C.S.J., Shore G.T., Penczak R.S.
Publisher Name: Ontario Geological Survey
Location:
We are continuously updating our assessment file / technical report information. If you notice errors in the data, please contact us.
Please review our Terms of Use agreement for this data product.
For detailed information regarding this mineral record please contact the Thunder Bay South Resident Geologist District Office