Indian Point Formation

Indian Point Formation
Stratigraphic range: Ludlow epoch ~423–419  Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Formation
Underlies	Archibald Settlement Formation
Lithology
Primary	Sandstone, siltstone, calcarenite
Other	Biostromal limestone, conglomerate, mafic volcanic rock
Location
Coordinates	48°48′N64°30′W / 48.8°N 64.5°W / 48.8; -64.5
Approximate paleocoordinates	26°36′S29°42′W / 26.6°S 29.7°W / -26.6; -29.7
Region	Quebec
Country	Canada
Extent	Gaspe National Park
Indian Point Formation (Canada) Show map of Canada Indian Point Formation (Quebec) Show map of Quebec

The Indian Point Formation is a geologic formation in Quebec. It preserves fossils dating back to the Ludlow epoch of the Silurian period. ^[1]

Description

The Indian Point Formation comprises thin- to thick-bedded, locally fossiliferous, calcareous siltstones, fine-grained sandstones, calcarenites, and minor biostromal limestones, conglomerates, red siltstones, and mafic volcanic rocks. The Indian Point Formation is conformably overlain by within-plate tholeiitic mafic to intermediate flows and flow breccias of the Archibald Settlement Formation, developed as a synsedimentary normal fault in the Late Silurian, based on the presence of polymictic conglomerate beds in a thickened Indian Point section east of the fault. Post-Early Devonian (Acadian) orogenic events have produced open to close folds with northeast-trending axes. ^[2]

Fossil content

The following fossils were reported from the formation: ^{[1] [3]}

Eurypterids

• Waeringopterus sp.

Pterobranchia

• Monograptus nilssoni

See also

• List of fossiliferous stratigraphic units in Quebec
• Bertie Formation, Silurian Lagerstätte in Ontario
• Charlevoix impact structure, Silurian impact structure in Quebec

References

1. Indian Point Formation at Fossilworks.org
2. Eurypterid-associated biota of Indian Point Fmn. in Gaspe National Park at Fossilworks.org
3. Plotnick, 1999

Bibliography

• Plotnick, R. E (1999), Habitat of Llandoverian-Lochkovian eurypterids, in A. J. Boucot, J. D. Lawson (eds.), Paleocommunities - a case study from the Silurian and Lower Devonian, pp. 106–136