+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

Systematics and paleoecology of norian late triassic bivalves from a tropical island arc wallowa terrane oregon usa

Systematics and paleoecology of norian late triassic bivalves from a tropical island arc wallowa terrane oregon usa

Journal of Paleontology 61(4 SUPPL): 1-83

Early Norian silicified bivalves from Hells Canyon in the Wallowa terrane of northeastern Oregon are part of a rich molluscan biota associated with a tropical island arc. The Hells Canyon locality preserves lenses of silicified shells formed as tempestites in a shallow subtidal carbonate environment. These shell assemblages are parautochthonous and reflect local, rather than long-distance, transport. Silicification at this locality involved small-scale replacement of original calcareous microstructures, or small-scale replacement of neomorphosed shells, without an intervening phase of moldic porosity. This incremental replacement of carbonate by silica contrasts markedly with void-filling silicification textures reported previously from silicified Permian bivalve assemblages. The bivalve paleoecology of this site indicates a suspension feeding biota existing on and within the interstices of coral-spongiomorph thickets, and inhabiting laterally adjacent substrates of peloidal carbonate sand. The bivalve fauna is ecologially congruent with the reef-dwelling molluscs associated with Middle Triassic sponge-coral buildups in the Cassian Formation of the Dolomites [Italy] (Fuersich and Wendt, 1977). Hells Canyon is a particularly important early Norian locality because of the diversity of substrate types and because the site includes many first occurrences of bivalves in the North American Cordillera. These first occurrences include the first documentation of the important epifaunal families Pectinidae and Terquemiidae in Triassic rocks of the North American Cordillera. The large number of biogeographic and geochronologic range extensions discovered in this single tropical Norian biota indicates that use of literature-based range data for Late Triassic bivalves may be very hazardous. Many bivalve taxa formerly thought to have gone extinct in Karnian time have now been documented from Norian strata in this arc terrane. These range extensions, coupled with the high bivalve species richness of the Hells Canyon site, suggest that the Karnian mass extinction in several literature-based compilations may be an artifact of incomplete sampling. Even for the Norian, present compilations of molluscan extinction may have an unacceptably large artifactual component. Thirty-five bivalve taxa from the Hells Canyon locality are discussed. Of these, seven are new: the mytilid Mysidiella cordillerana n. sp., the limacean Antiquilima vallieri n. sp., the true oyster Liostrea newelli n. sp., the pectinacean CRENAMUSSIUM concentricum n. gen. and sp., the unioid Cardinioides josephus n. sp., the trigoniacean ERUGONIA canyonensis n. gen. and sp., and the carditacean Palaeocardita silberlingi n. sp.

(PDF 0-2 workdays service: $29.90)

Accession: 006574489

Download citation: RISBibTeXText

Related references

New neritopsoidean gastropods (Neritimorpha) from the Late Triassic (Late Carnian - Early Norian) of the Wallowa Terrane, northeastern Oregon. Mitteilungen aus dem Geologisch-Palaeontologischen Institut der Universitaet Hamburg. Oktober; 87: 55-71, 2003

Stratigraphic occurrence and paleoecology of halobiid bivalves from the type Martin Bridge Limestone (Upper Triassic), Wallowa Terrane, Oregon. Abstracts with Programs - Geological Society of America 22(6): 38, 1990

Late Triassic silicified bivalves of the Martin Bridge Formation, Wallowa-Seven Devils terrane; taphonomy, paleoecology, paleozoogeography. Abstracts - SEPM Midyear Meeting 1: 59-60, 1984

Late Triassic (Late Norian) gastropods from the Wallowa Terrane (Idaho, USA). Palaeontologische Zeitschrift 78(2): 361-416, 2004

A Norian Late Triassic ichthyosaur from the Martin Bridge Limestone, Wallowa Mountains, Oregon. U S Geological Survey Professional Paper, 41-51 No. 1435, 1986

Delphinulopsidae, a new neritopsoidean gastropod family from the Upper Triassic upper Carnian or lower Norian of the Wallowa Terrane, northeastern Oregon. Journal of the Czech Geological Society = Casopis Ceske Geologicke Spolecnosti 46(3-4): 307-318, 2001

Late Triassic gastropods from the Martin Bridge Formation (Wallowa Terrane) of northeastern Oregon and their paleogeographic significance. Neues Jahrbuch fuer Geologie und Palaeontologie Abhandlungen. April; 2281: 83-100, 2003

Late Triassic Carnian-Norian mixed carbonate-volcaniclastic facies of the Olds Ferry Terrane, eastern Oregon and western Idaho. Geological Society of America 442, 2008

Late Triassic bivalves of the Martin Bridge Limestone, Hells Canyon, Oregon; taphonomy, paleoecology, paleozoogeography. U S, 1986

Late Triassic bivalves of the Martin Bridge Limestone, Hells Canyon, Oregon: taphonomy, paleoecology and paleozoogeography. U S Geological Survey Professional Paper: 7-21 (1435), 1986

Triassic corals and spongiomorphs from Hells Canyon, Wallowa terrane, Oregon. Journal of Paleontology, 636: 800-819, 1989

Triassic corals and spongiomorphs from hells canyon wallowa terrane oregon usa. Journal of Paleontology 63(6): 800-819, 1989

On the occurrence of Spinidelphinulopsis whaleni (Gastropoda) in the Late Triassic (early Norian) Cornwallis Limestone, Kuiu Island, Southeastern Alaska (Alexander Terrane) and its paleobiogeographic significance. Bulletin of Geosciences (Praha) 76(4): 235-242, 2001

Analysis and interpretation of a Triassic-aged reef complex, Wallowa Terrane, northeastern Oregon. Abstracts with Programs - Geological Society of America 38(5): 21, 2006

Biogeographic complexity in Triassic bivalves of the Wallowa terrane, northwestern United States oceanic islands, not continents provide the best analogues. Geology (Boulder): 1512: 1126-1129, 1987