Rencontre Formation
The Rencontre Formation (locally pronounced Rown-Counter) is a geological formation just below the Cambrian-Ediacaran boundary in Newfoundland, deposited in a fault-bounded enclosed basin. U-Pb dates obtained just below its base give a maximum age of 552 ± 3 million years ago.
| Rencontre Formation Stratigraphic range: 552–541 Ma[1] (approx) | |
|---|---|
 Outcrops of the Rencontre Formation in Rencountre, NL. | |
| Type | Formation |
| Unit of | (Long Harbour Group, in some schemes - e.g. NL GeoAtlas) |
| Underlies | Chapel Island Fm[2] |
| Overlies | Long Harbour Group - volcanics - in Rencontre, Mooring Cove Formation |
| Thickness | Hundreds of metres[2] |
| Location | |
| Region |  |
| Country | .svg.png.webp){kind=small} |
 Outcrop distribution | |
It is subdivided into five depositional phases, with two subsequent phases in a seven-phase series corresponding to the overlying Chapel Island Formation (900 m thick in this basin) and Random Formation (250 m thick in this basin).[2]
- Phase one - 300 m - conglomerate dominated, some sandstone and minor siltstones
- Phase 2 - 150 m - sands and silts
- Phase 3 - 180 m - silts and minor sands; lower silts are grey-green, glauconitic, wave-rippled and mud-cracked; upper silts becoming red
- Phase 4 - 200 m - coarse sands
- Phase 5 - greater than 200 m - arenites and red silts.
References
- Myrow, P. M. 1995. Neoproterozoic rocks of the Newfoundland Avalon Zone. Precambrian Research, 73:123–136.
- S. A. Smith, R. N. Hiscott, Can. J. Earth Sci. 21, 1379–1392 (1987).
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