Lower Permian brachiopods and molluscs from the upper Jungle Creek Formation, northern Yukon Territory, Canada

A Permian Hydrozoan Mound, Yukon Territory

Canadian Journal of Earth Sciences ◽

10.1139/e71-087 ◽

1971 ◽

Vol 8 (8) ◽

pp. 973-988 ◽

Cited By ~ 14

Author(s):

G. R. Davies

Keyword(s):

Growth Form ◽

Yukon Territory ◽

Source Rocks ◽

Lower Permian ◽

Canal System ◽

Rock Types ◽

System A ◽

Upper Paleozoic ◽

Paleozoic Rocks ◽

Richardson Mountains

A carbonate mound built by the hydrozoan Palaeoaplysina has been found in a poorly-exposed sequence of Lower Permian rocks in the northern Richardson Mountains of the Yukon Territory. Similar hydrozoan mounds have been described from Russia and northwestern United States. The Yukon mound is 12 ft (3.7 m) thick and at least 70 ft (21 m) long. It is underlain by marine siltstones and sandstones, and probably shale. The main mound rock is composed of curved hydrozoan plates enclosed in a bioclastic wackestone matrix, and is overlain successively by tubular–foram packstone and oolitic grainstone. Palaeoaplysina is characterized by a plate-like, laterally-expanding growth form, an internal canal system, a cellular calcareous skeleton, and 'mamelons' on the upper surface of well-preserved plates; 'mamelons' are the principal criterion for placing Palaeoaplysina in the Class Hydrozoa of the coelenterates.The Yukon mound is part of a thick sequence of Lower Permian terrigenous clastic and carbonate rocks deposited on the northern shelf of the ancestral Aklavik Arch. The repetition of similar rock types in the sequence indicates cyclicity, a thesis supported by similarities between the Yukon mound sequence and the Virgilian mound cycles in New Mexico.Lower Permian hydrozoan mounds and associated facies in the Pre-urals of Russia are known oil producers. The possibility exists that hydrozoan mounds, perhaps in multiple cyclic build-ups, may occur in upper Paleozoic rocks in the subsurface of the Yukon Territory. With suitable porosity development and source rocks, these predicted subsurface mounds could become hydrocarbon reservoirs and thus targets for oil exploration.

Download Full-text

Nahoniella, a new name for Yukonella Shi and Waterhouse, 1996 (Spiriferida, Brachiopoda)

Journal of Paleontology ◽

10.1017/s0022336000027268 ◽

1998 ◽

Vol 72 (5) ◽

pp. 935-935 ◽

Cited By ~ 1

Author(s):

G. R. Shi

Keyword(s):

Type Species ◽

New Genus ◽

Upper Triassic ◽

Yukon Territory ◽

Lower Permian ◽

New Name

Shi and Waterhouse (1996, p. 127) proposed a new genus, Yukonella, for a distinctive licharewiinid species (Spiriferida, Brachiopoda) based on well-preserved material from the Lower Permian upper Jungle Creek Formation, northern Yukon Territory, Canada. However, the Editor of the Zoological Record, Mrs. M. Joan Thorne (personal commun., 1997), has kindly informed me that the name Yukonella is preoccupied by an Upper Triassic poriferan genus published by Senowbari-Daryan and Reid (1986, p. 900). I therefore rename the brachiopod genus Nahoniella after the Nahoni Range in the northern Ogilvie Mountains of northern Yukon Territory, Canada, where the type species of the genus, Nahoniella plana (Shi and Waterhouse), was collected.

Download Full-text