|Author:||Goutier et al., in preparation|
|Reference section:||Representative outcrops of unit nAfer1 are located along the Sakami River in NTS sheet 33G01. One of the reference outcrops along this river segment is outcrop 2012-QD-2049. It was sampled for U-Pb isotopic dating in 2017. Representative outcrops of unit nAfer2 outcrop on the south shore of Goose Lake in sheet 33G01.|
|Type area:||Sheet 33G01, where this suite covers a large area.|
|Geological province:||Superior Province|
|Geological subdivision:||Opinaca Subprovince|
|Lithology:||Hornblende-biotite-magnetite quartz monzodiorite, quartz monzonite and monzonite, K-feldspar porphyritic, diorite, tonalite and monzodiorite|
Table des matières
The Féron Suite was described during the work of 2012 in sheets 33G01, 33G02 and 33H04 (Goutier et al., in preparation). The Frégate Pluton has been associated with it and, since its age is known, this has led to the first dating of the Féron Suite (Augland et al., 2016). The mapping work of Gigon and Goutier (2017) expanded this suite in sheets 33H02 and 33H03. The work in 2016 (Goutier, 2018) allowed for the identification of new occurrences of the Féron Suite in sheets 33F01, 33G04 and 33G05. From this work, the belongingness of certain intrusions of the Bezier Suite to the Féron Suite is also changed in sheets 33G05 and 33G06. Units in the Féron Suite are restricted to the Opinaca Subprovince. UnitnAfer3 (the only polygon in sheet 33G01 created in 2012) has been joined to unit nAfer2 (Goutier, 2018).
Unit nAfer1 consists of a group of quartz monzodiorite, monzodiorite, quartz monzonite and hornblende, biotite and magnetite monzonite, usually K-feldspar porphyritic and granite intruded. The rock is grey, porphyritic and foliated. The characteristic minerals are hornblende (5-30%), biotite (5-20%) and magnetite (<5%). Outcrops are characterized by K-feldspar ranging in size from 0.5 to 3 cm and representing 5 to 20% of the minerals. Locally observed are diopside (15% of the minerals on one of the outcrops), hypersthene, titanite and pyrite. The rock is sometimes altered in hematite, epidote or chlorite. Various types of fusiform enclaves of various lithologies are found throughout the outcrops. Foliated diorite enclaves are decimatric and contain hornblende, biotite and magnetite, while hornblendite enclaves are centimetric, foliated and finely grained with magnetite, and amphibolite enclaves are centimetric and fine-grained (Goutier et al., in preparation).
Unit nAfer2 is an assemblage of diorite, tonalite and monzodiorite whose main intrusion is to the southwest of sheet 33G01. Diorite, tonalite and monzodiorite contain biotite (<20%), hornblende (<15%), magnetite and locally hypersthene and chlorite. In thin section, plagioclase is anti-perthitic and accessory minerals are apatite and zircon. The rock is heterogeneous and has light grey patina and fresh surface. The mineralogical assemblage of the rocks in sheet 33G01 is migmatized, as shown in the tonalitic mobilisate. A weak foliation is indicative of low deformation. Some fine-grained hornblendite enclaves were observed in the diorite; they contain diopside, magnetite and biotite. This unit is cut by decimetric intrusions of coarse-grained pegmatitic granite.
The Féron Suite is shown in sheets 33F01, 33F02, 33G01, 33G02, 33G04, 33G05, 33H02, 33H03 and 33H04. This suite covers a total area of approximately 685 km², of which 633 km² (92.4%) is unit nAfer1 and 52 km² (7.6%) is unit nAfer2. Some intrusions belonging to the Bezier Suite were reassigned to the Féron Suite because they were not in direct contact with rocks of the La Grande Subprovince.
The Féron Suite most likely extends southward in sheet 33B, where it is believed to correspond to unit AOAN2 of Simard and Gosselin (1999). Unit AOAN2 unit also has a strong magnetic signature.
In 2017, outcrop 2012-QD-2049 was sampled for U-Pb isotpic dating (nAfer1). Results to come.
|Isotopic System||Mineral||Crystallization Age (Ma)||(+)||(-)||Reference(s)|
|U-Pb||Zircon||2710.4||2.4||2.4||Augland et al., 2016 (Frégate Pluton)|
|U-Pb||Zircon||2702.4||2.7||2.7||David, personal communication, 2018|
The Féron Suite is intrusive in the Laguiche Complex, especially in units nAlgi2a, Algi3a and Algi4a. It is cut by dykes from the Vieux Comptoir Granitic Suite and diabases from the Mistassini Dyke Swarm and the Lac Esprit Dykes.
Does not apply.