Gun River Formation

Gun River Formation
Stratigraphic range: Early Silurian (Llandovery)
TypeGeological formation
Sub-units
  • Lachute Member
  • Innomée Member
  • Sandtop Member
  • Macgilvray Member
UnderliesMenier Formation[1]
OverliesMerrimack Formation[1]
Thickness85 to 100 meters[1]
Location
RegionQuebec
CountryCanada
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.

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 taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Conodonts
Genus Species Presence Material Notes Images
Anticostiodus A. fahraeusi Anticosti Island.[2]
A. boltoni Anticosti Island.[2]
Icriodella I. deflecta Probably instead belongs to the Jupiter Formation.[1]

Invertebrates

Brachiopods
Genus Species Presence Material Notes Images
Brachyprion Sandtop and Macgilvray Members.[1] A strophomenid.
Coolinia Sandtop and Macgilvray Members.[1]
Fenestrirostra F. glacialis Lowermost part of the formation.[3] A rhynchonellidalso found in the Merrimack Formation.
F. pyrrha Lachute 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. xacta Upper Macgilvray Member.[4][5] A pentamerid.
Mendacella Innommée Member.[1] A dalmanellid.
Meristina Innommée Member.[1]
Pentamerus P. palaformis Top of the formation (uppermost Macgilvray Member).[1][4] Also found in the Jupiter Formation.
Stegerhynchus [1]
Stricklandia S. gwelani Top 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
Genus Species Presence Material Notes Images
Phaenopora P. superba Also found in the Becscie Formation.[6]
Ptilodictya P. canadensis USNM 143039.[6]
P. sulcata USNM 143039, 143050; YPM 3063/98, 3063/104.[6]
Corals
Genus Species Presence Material Notes Images
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. capax Multiple colonies.[8] A tabulate coral.
Crinoids
Genus Species Presence Material Notes Images
Dendrocrinus [1]
Eumyelodactylus Macgilvray Member.[1]
Laurocrinus Macgilvray Member.[1]
Stupatocrinus Macgilvray Member.[1]
Graptolites
Genus Species Presence Material Notes Images
Paraclimacograptus P. cf. innuitus Deeper water facies of the Sandtop Member.[1]
Sponges
Genus Species Presence Material Notes Images
Camptodictyon [1] A stromatoporoid.
Clathrodictyon [1] A stromatoporoid.

See also

References

  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae 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. ^ a b 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. ^ a b c d e 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. ^ a b c "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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