St.Amable Sill/Varennes

Thanks again to László and Elsy Horváth for taking me there - nice place to collect ! And naturally - for information and specimens, too.

St.Amable Sill is an intrusion between the towns of St.Amable and Varennes in Québec, about 20 km ENE of Montreal (andabout 20 km WNW of Mt.St.Hilaire). It is related to the Monteregian alkaline rocks, and it is the most extensive and thickest sill in this complex. The age may be betwenn 80 and 145 million years. The sill, which lays upon a black shale, has a very distinct contact zone of up to 2,5m. The sill rock can best be described as a nepheline syenite. Within the sill there are horizontal zones of mineralized vugs and cavities in the upper portion, and tiny cavities in the central portion. Rarely there are pod-like areas rich in vugs and cavities of hydrothermal origin. Boths types of cavities yield lots of interesting minerals.

The first description dates from 1942, the first quarrying started in 1959. As in MSH, the quarrying history is pretty complicated, today mining is done in the Demix quarry (yes, same company as in MSG until 1981) in a flat open pit of about 1,5x0,9 km. Peter Tarassoff was the first to discover unusual minerals in cavitis in 1962. In 1991 the authors mentioned below started a comprehensive study of the St.Amable-Sill.



Mineral list:

Aegirine
Albite
Amphibole grp.
Analcime
Anatase
Ancylite-(Ce)
Ancylite-(La)
Aragonite
Arfvedsonite
Arsenopyrite
Astrophyllite
Bastnaesite-(Ce)
Birnessite
Calciohilairite
Calcite
Carbonate-fluorapatite
Catapleiite
Celestine
Cerussite
Chabazite
Chlorite grp.
Cordylite-(Ce)
Cryolite
Dawsonite
Dolomite
Donnayite-(Y)
Doyleite
Elpidite
Epididymite
Epistolite
Erdite
Eudialyte
Fluorapatite
Fluorite
Franconite
Gaidonnayite
Galena
Gibbsite
Gmelinite
Goethite
Gypsum
Halotrichite
Hematite
Hilairite
Hochelagaite
Jarosite
Kaolinite grp.
Kukharenkoite-(Ce)
Labuntsovite
Lavenite
Lemoynite
Loellingite
Lorenzenite
Lueshite
Magadiite
Makatite
Mangan-neptunite
Marcasite
Microcline
Monazite-(Ce)
Montmorillonite
Muscovite
Natrolite
Nenadkevichite
Nepheline
Opal
Paranatrolite
Pectolite
Polylithionite
Quartz
Pyrite
Pyrrhotite
Rhabdophane-(Ce)
Rhodochrosite
Rinkite
Sazhinite-(Ce)
Serandite
Shkatulkalite
Siderite
Smectite grp.
Sodalite
Sphalerite
Strontianite
Synchisite-(Ce)
Terskite
Tetranatrolite
Thomsenolite
Thornasite
Titanite
Todorokite
Tuperssuatsiaitie
Varennesite
Villiaumite
Vuonnemite
Woodruffite
Wulfenite
Yofortierite
Zakharovite
Zircon

VUK1 (silicate)
VUK3 (oxid/hydroxide)
VUK6 (silicate)
VUK7 (silicate)
VUK8 (silicate)
VUK9 (silicate)
VUK11 (carbonate)




&Suggested reading:
Horváth,L, E.Pfenninger-Horváth, R.A.Gault, P.Tarassoff: Mineralogy of the Saint-Amable Sill, Varennes and Saint-Amable, Québec. The Mineralogical Record, 29(1998), 3, 83-117


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