| Wordie Creek Formation | |
| Type: | Formation |
| Age: | late Changhsingian–early Dienerian |
| Period: | Induan |
| Prilithology: | Mudstone |
| Otherlithology: | Sandstone, conglomerate |
| Region: | Clavering Ø, Hold with Hope (Kap Stosch), Gauss Halvø, Traill Ø, Jameson Land |
| Country: | Greenland |
| Unitof: | Scoresby Land Group |
| Underlies: | Pingo Dal Formation |
| Overlies: | Schuchert Dal Formation |
The Wordie Creek Formation is an uppermost Permian and Lower Triassic geologic formation in Greenland, outcrops of which are located in Northeast Greenland National Park (until 2008 Tunu County, Danish: Østgrønland, English: East Greenland). In 2017, it was suggested to be raised to group status, as the Wordie Creek Group.[1]
The Lower Triassic sediments in the region were discovered in 1926 independently by James Wordie and Lauge Koch, and the latter named the formation.[1] The rock layers preserve fossils of invertebrates (e.g., ammonoids,[2] gastropods[1]), fishes (coelacanths, ray-finned fish, cartilaginous fish)[3] [4] and temnospondyl amphibians,[5] [6] dating back to the Induan age.[7]
Following Surlyk et al.[1], the Wordie Creek Group is subdivided into two formations, the Kap Stosch Formation and the overlying Godthåb Golf Formation. The Kap Stosch Formation was deposited in relatively deep, partly isolated turbiditic basin, and the Godthåb Golf Formation under relatively shallow marine conditions.
In 1935, Eigil Nielsen[8] recognized five fossil-bearing horizons ("fish zones 1–5")[9] [10] corresponding to three ammonoid zones (in ascending order):
The first two ammonoid zones are Griesbachian in age and the last one is Dienerian in age (Induan). The Kap Stosch Formation corresponds to these three zones. A sixth fossiliferous layer, the "Stegocephalian horizon", is present above, which belongs to the Godthåb Golf Formation (Dienerian). The Hypophiceras triviale ammonoid zone below Nielsen's "fish zones" is dated late Changhsingian.[1]
The Kap Stosch Formation is subdivided into the following eight members (in ascending order):[1]
The Godthåb Golf Formation is not subdivided into members.[1]
A diverse vertebrate fauna composed of temnospondyl amphibians and fishes is known from the formation.[3] [5] [11] Fossil fishes are also known from the Permian Ravnefjeld Formation ("Posidonomya shale") of Greenland.[8]
| Temnospondyls of the Wordie Creek Formation | ||||
|---|---|---|---|---|
| Taxon / Genus | Species | Subunit | Notes | Images |
| Luzocephalus[12] | L. johannsoni | ? | A lydekkerinid stereospondyl, originally described as "Lyrocephalus" | |
| L. kochi | Kap Stosch Formation, Pyramiden Member ("Fish zone 2"), Falkeryg Member ("Fish zone 5") | A lydekkerinid stereospondyl, originally described as "Lyrocephalus" | ||
| L. rapax | Kap Stosch Formation, Falkeryg Member ("Fish zone 5") | A lydekkerinid stereospondyl, originally described as "Lyrocephalus" | ||
| Selenocara[13] | S. groenlandica | Godthåb Golf Formation ("Stegocephalian horizon") | A mastodonsauroid, originally described as Wetlugasaurus groenlandicus | |
| Stoschiosaurus | S. nielseni | Godthåb Golf Formation ("Stegocephalian horizon") | A trematosaurid | |
| Tupilakosaurus | T. heilmani | Kap Stosch Formation, Falkeryg Member ("Fish zone 5") | A tupilakosaurid dvinosaur[14] | |
| Sarcopterygii of the Wordie Creek Formation | ||||
|---|---|---|---|---|
| Taxon / Genus | Species | Subunit | Notes | Images |
| Laugia | L. groenlandica | Kap Stosch Formation, Pyramiden Member ("Fish zones 2–3") | A laugiid coelacanth | |
| Laugia sp. | Kap Stosch Formation ("Fish zone 1") | A laugiid coelacanth | ||
| Sassenia | S. groenlandica | ? | A rhabdodermatid coelacanth[15] that was originally referred to as Sassenia sp. The genus is also known from the Vikinghøgda Formation of Spitsbergen | |
| Whiteia | W. nielseni | ? | A whiteiid coelacanth that was originally described as Whiteia sp. and "undetermined coelacanth". The genus Whiteia had a cosmopolitan distribution during the Triassic | |
| Actinopterygii of the Wordie Creek Formation | ||||
|---|---|---|---|---|
| Taxon / Genus | Species | Subunit | Notes | Images |
| Australosomus | A. kochi | Kap Stosch Formation, Pyramiden Member ("Fish zones 2–4") and Falkeryg Member ("Fish zone 5") | A pholidopleuriform neopterygian. The genus had a cosmopolitan distribution during the Early Triassic epoch | |
| A. simplex | Kap Stosch Formation (Pyramiden Member, "Fish zone 2") | A pholidopleuriform neupterygian. The genus had a cosmopolitan distribution during the Early Triassic epoch | ||
| A. aff. simplex | Kap Stosch Formation, Falkeryg Member ("Fish zone 5") | A pholidopleuriform neupterygian. The genus had a cosmopolitan distribution during the Early Triassic epoch | ||
| A. pholidopleuroides | Kap Stosch Formation (Pyramiden Member, "Fish zone 2") | A pholidopleuriform neupterygian. The genus had a cosmopolitan distribution during the Early Triassic epoch | ||
| Birgeria | B. groenlandica | Kap Stosch Formation, Pyramiden Member ("Fish zone 2"), Falkeryg Member ("Fish zone 5") | A birgeriid. The genus had a cosmopolitan distribution during the Triassic | |
| Bobasatrania | B. groenlandica | Kap Stosch Formation, Pyramiden Member ("Fish zones 2–3") | A bobasatraniform[16] The genus had a cosmopolitan distribution during the Triassic | |
| Bobasatrania sp. | Nebalopok Member | A bobasatraniform. One of the few Permian occurrences of the genus | ||
| Boreosomus | B. piveteaui | Kap Stosch Formation, Pyramiden Member ("Fish zones 2–4"), Falkeryg Member ("Fish zone 5") | A ptycholepid. The genus had a cosmopolitan distribution during the Early Triassic epoch | |
| Broughia | B. perleididoides | Kap Stosch Formation, Pyramiden Member ("Fish zone 3"), Falkeryg Member ("Fish zone 5") | A parasemionotiform neopterygian | |
| Helmolepis | H. gracilis | Kap Stosch Formation, Pyramiden Member ("Fish zones 2–4") | A platysiagid neopterygian. The genus had a cosmopolitan distribution during the Early Triassic[17] | |
| Ospia | O. whitei | Kap Stosch Formation, Pyramiden Member ("Fish zone 3"), Falkeryg Member ("Fish zone 5") | A parasemionotiform neopterygian | |
| Pteronisculus | P. arcticus | Kap Stosch Formation, Pyramiden Member ("Fish zone 2") | A rhadinichthyid or turseoid, It was originally described as Glaucolepis arctica, but later referred to the genus Pteronisculus because the genus name Glaucolepis is preoccupied | |
| P. aldingeri | Kap Stosch Formation, Pyramiden Member ("Fish zones 2 and 4") | A rhadinichthyid or turseoid, It was originally described as Glaucolepis aldingeri, but later referred to the genus Pteronisculus because the genus name Glaucolepis is preoccupied | ||
| P. gunnari | Kap Stosch Formation, Pyramiden Member ("Fish zones 2?–3") | A rhadinichthyid or turseoid, It was originally described as Glaucolepis gunnari, but later referred to the genus Pteronisculus because the genus name Glaucolepis is preoccupied | ||
| P. magnus | Kap Stosch Formation, Falkeryg Member ("Fish zone 5") | A rhadinichthyid or turseoid, It was originally described as Glaucolepis magna, but later referred to the genus Pteronisculus because the genus name Glaucolepis is preoccupied | ||
| P. stensioei | Kap Stosch Formation, Falkeryg Member ("Fish zone 5") | A rhadinichthyid or turseoid, It was originally described as Glaucolepis stensioei, but later referred to the genus Pteronisculus because the genus name Glaucolepis is preoccupied | ||
| Pteronisculus sp. | Kap Stosch Formation, Pyramiden Member ("Fish zones 2–4"), Godthåb Golf Formation ("Stegocephalian horizon") | A rhadinichthyid or turseoid, It was originally referred to the genus Glaucolepis, a homonym of Pteronisculus | ||
| Saurichthys | S. aff. dayi | Kap Stosch Formation, Pyramiden Member ("Fish zone 2"), Falkeryg Member ("Fish zone 5")[18] | A saurichthyiform with a dense squamation | |
| S. cf. ornatus[19] | Kap Stosch Formation, Falkeryg Member ("Fish zone 5") | A three-dimensionally preserved skull of a saurichthyiform, which was analyzed using μCT-aided tomography[20] | ||
| Teffichthys | T. stoschiensis | Kap Stosch Formation, Pyramiden Member ("Fish zones 2–4"), Falkeryg Member ("Fish zone 5") | A perleidiform neopterygian. It was originally described as Perleidus stoschiensis,. Early Triassic species of Perleidus were subsequently referred to the genus Teffichthys[21] | |
| Chondrichthyes of the Wordie Creek Formation | ||||
|---|---|---|---|---|
| Taxon / Genus | Species | Subunit | Notes | Images |
| Polyacrodus | P. claveringensis | Kap Stosch Formation, Pyramiden Member ("Fish zone 2") | A polyacrodontid hybodontiform shark. Known from isolated teeth and partial skeletons with fin spines | |
| Nemacanthus? | N.? sp. | "Fish zone 1" | Fin spines of the Nemacanthus-type | |
| Edestidae | Gen. et sp. indet | Kap Stosch Formation, Pyramiden Member ("Fish zone 2") | Symphyseal tooth whorl of a eugeneodontid holocephalian | |
| Hybodontiformes | Gen. et sp. indet | "Fish zone 1" | Fin spines of the Hybodus/Acrodus-type | |