| Age | Early Silurian (Llandovery) |
|---|---|
| Namedby | Schuchert and Twenhofel[1] |
| Year ts | 1910[1] |
| Region | Quebec |
| Country | Canada |
| Subunits |
|
| Underlies | Menier Formation[1] |
| Overlies | Merrimack Formation[1] |
| Thickness | 85 to 100 meters[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
| 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
- ^ 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
- ^ 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
- ^ 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
- ^ Jin, Jisuo & Copper, Paul. "Late Ordovician and Early Silurian pentamerid brachiopods of Anticosti Island, Québec, Canada". Palaeontographica Canadiana
- ^ 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
- ^ "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.
- ^ 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
- ^ 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
- ((Various Contributors to the Paleobiology Database)). "Fossilworks: Gateway to the Paleobiology Database". Archived 25 March 2022 at the Wayback Machine. Retrieved 17 December 2021.