Gun River Formation

Last updated
Gun River Formation
Stratigraphic range: Early Silurian (Llandovery)
Type Geological formation
Sub-units
  • Lachute Member
  • Innomée Member
  • Sandtop Member
  • Macgilvray Member
Underlies Menier Formation [1]
Overlies Merrimack Formation [1]
Thickness85 to 100 meters [1]
Location
Region Quebec
Country Canada
Type section
Named bySchuchert and Twenhofel [1]
Year defined1910 [1]

The Gun River Formation is a geologic formation in Quebec. It preserves fossils dating back to the early Silurian period.

Contents

Description

The formation is divided into 4 members (from the base up): the Lachute, Innommée, Sandtop and Macgilvray members. The formation was deposited some 40–80 km offshore from the stable Laurentian craton, underwater at depths of 30 to 60 meters. [1]

Fossil content

Vertebrates

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Conodonts
GenusSpeciesPresenceMaterialNotesImages
Anticostiodus A. fahraeusi Anticosti Island. [2]
A. boltoni Anticosti Island. [2]
Icriodella I. deflectaProbably instead belongs to the Jupiter Formation. [1]

Invertebrates

Brachiopods
GenusSpeciesPresenceMaterialNotesImages
Brachyprion Sandtop and Macgilvray Members. [1] A strophomenid.
Coolinia Sandtop and Macgilvray Members. [1]
Fenestrirostra F. glacialisLowermost part of the formation. [3] A rhynchonellid also found in the Merrimack Formation.
F. pyrrhaLachute Member. [1] A rhynchonellid.
'Gotatrypa''G.' sp.Innommée Member. [1]
Hyattidina Sandtop to Macgilvray Members. [1] An athyrid.
Joviatrypa Uppermost Macgilvray Member. [1]
Kulumbella K. xactaUpper Macgilvray Member. [4] [5] A pentamerid.
Mendacella Innommée Member. [1] A dalmanellid.
Meristina Innommée Member. [1]
Pentamerus P. palaformisTop of the formation (uppermost Macgilvray Member). [1] [4] Also found in the Jupiter Formation.
Stegerhynchus [1]
Stricklandia S. gwelaniTop of the formation (Macgilvray Member). [1] [4] Also found in the Jupiter Formation.
S. sp.Innommée Member. [4] A509 (7 broken valves on a slab). [4] Also found in the uppermost Merrimack Formation.
Sypharatrypa S. sp.Innommée Member. [1]
Bryozoans
GenusSpeciesPresenceMaterialNotesImages
Phaenopora P. superbaAlso found in the Becscie Formation. [6]
Ptilodictya P. canadensisUSNM 143039. [6]
P. sulcataUSNM 143039, 143050; YPM 3063/98, 3063/104. [6]
Corals
GenusSpeciesPresenceMaterialNotesImages
Acidolites A. arctatus [7] A heliolitid.
Brachyelasma [1]
Crassilasma [1]
Helicelasma [1]
Palaearaea Cap aux Goélands (Uppermost Macgilvray Member). [1] Small colonies. [1] The only rugosan coral known from the formation, also found in the Menier formation.
Paleofavosites P. capaxMultiple colonies. [8] A tabulate coral.
Crinoids
GenusSpeciesPresenceMaterialNotesImages
Dendrocrinus [1]
Eumyelodactylus Macgilvray Member. [1]
Laurocrinus Macgilvray Member. [1]
Stupatocrinus Macgilvray Member. [1]
Graptolites
GenusSpeciesPresenceMaterialNotesImages
Paraclimacograptus P. cf. innuitusDeeper water facies of the Sandtop Member. [1]
Sponges
GenusSpeciesPresenceMaterialNotesImages
Camptodictyon [1] A stromatoporoid.
Clathrodictyon [1] A stromatoporoid.

See also

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Copper, Paul; Long, Darrel G. F.; Jin, Jisuo (2012). "The Early Silurian Gun River Formation of Anticosti Island, eastern Canada: A key section for the mid-Llandovery of North America". Newsletters on Stratigraphy. 45 (3): 263. doi:10.1127/0078-0421/2012/0024. ISSN   0078-0421.
  2. 1 2 Zhang, Shunxin; Barnes, Christopher R. (July 2000). "Anticostiodus, a new multielement conodont genus from the Lower Silurian, Anticosti Island, Quebec" . Journal of Paleontology. 74 (4): 662–669. doi:10.1666/0022-3360(2000)074<0662:AANMCG>2.0.CO;2. ISSN   0022-3360. S2CID   59056082.
  3. ↑ Jin, Jisuo; Caldwell, W. G. E.; Copper, Paul (March 1990). "Evolution of the Early Silurian rhynchonellid brachiopod Fenestrirostra in the Anticosti Basin of Quebec". Journal of Paleontology. 64 (2): 214–222. doi:10.1017/s0022336000018370. ISSN   0022-3360. S2CID   132248649.
  4. 1 2 3 4 5 Jin, Jisuo; Copper, Paul. "Late Ordovician and Early Silurian pentamerid brachiopods of Anticosti Island, Québec, Canada". Palaeontographica Canadiana.
  5. ↑ Jin, Jisuo; Copper, Paul (May 1998). "Kulumbella and Microcardinalia (Chiastodoca) new subgenus, Early Silurian divaricate stricklandiid brachiopods from Anticosti Island, eastern Canada". Journal of Paleontology. 72 (3): 441–453. doi:10.1017/s0022336000024185. ISSN   0022-3360. S2CID   132809506.
  6. 1 2 3 "Larger Cryptostome Bryozoa of the Ordovician and Silurian, Anticosti Island, Canada". www.jstor.org. SEPM Society for Sedimentary Geology. JSTOR   1300852 . Retrieved 2022-09-18.
  7. ↑ Dixon, O. A. (January 1986). "The heliolitid coral Acidolites in Ordovician–Silurian rocks of eastern Canada1" . Journal of Paleontology. 60 (1): 26–52. doi:10.1017/S002233600002148X. ISSN   0022-3360. S2CID   130759173.
  8. ↑ Lee, Dong-Jin; Noble, James P. A. (July 1990). "Reproduction and life strategies in the Paleozoic tabulate coral Paleofavosites capax (Billings)" . Lethaia. 23 (3): 257–272. doi:10.1111/j.1502-3931.1990.tb01452.x. ISSN   0024-1164.
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