Last modified:
Translation of original French
| Author: | Daigneault and Allard, 1990 |
| Age: | Neoarchean |
| Reference section: | None |
| Type area: | Outcrops primarily in the David Lake area (southwestern portion of the NTS sheet 32G16) |
| Geological province: | Superior Province |
| Geological subdivision: | Abitibi Subprovince |
| Lithology: | Mafic to ultramafic intrusive rocks |
| Type: | Lithodemic |
| Rank: | Lithodeme |
| Status: | Informal |
| Use: | Active |
Background
The peridotitic subzone was established by Daigneault and Allard (1990) and included in the “Lower Series”. It now represents an informal lithodeme of the Lac Doré Lower Unit (Leclerc et al., 2017).
Description
The peridotitic subzone is characterized by a succession of rhythmic layers of peridotite, pyroxenite and gabbro. On a total magnetic field map, it corresponds to a positive magnetic anomaly (Daigneault and Allard, 1990; Keating and D’Amours, 2010).
Thickness and Distribution
The peridotitic subzone outcrops on the northern flank of the Chibougamau Anticline, particularly in the David Lake area. A small ovoid mass (300 m x 400 m) is also known south of Clark Lake, and a number of E-W-oriented lenses appear in the Marguerite Island area (northeastern portion of sheet 32G16).
Dating
None.
Stratigraphic Relationship(s)
The peridotitic subzone is interstratified within the anorthositic zone and forms a horizon 5 to 10 m thick (Daigneault and Allard, 1990).
Paleontology
Does not apply.