EARLY JURASSIC (PLIENSBACHIAN) BIVALVE AND BRACHIOPOD FAUNA FROM THE PENINSULAR TERRANE, SOUTHERN TALKEETNA MOUNTAINS, ALASKA - PALEOBIOGEOGRAPHIC SIGNATURE AND TECTONIC SIGNIFICANCE
Here we investigate a North
American Jurassic locality with a high diversity brachiopod and bivalve fauna. This
Early Jurassic (Pliensbachian) bivalve and brachiopod
fauna is from the Talkeetna Formation, Hicks Creek
area, southern
Eighteen bivalve taxa are identified, representing fifteen genera and subgenera: Parallelodontidae: Grammatodon costulatus (Leanza); Ostreidae: Gryphaea dilobotes Duff, Gryphaea sp.; Neitheidae: Weyla alata (Buch) and Weyla (Lywea) unca (Philippi); Pachycardiidae: ?Trigonodus sp. (probably gen. nov.) and Cardinioides sp. (probably nov. sp.); Kalenteridae: Kalentera sp. (nov. sp.); Trigoniidae: Trigonia (T.) cf. prora Fursich & Heinze, Vaugonia literata (Young & Bird); Family Astartidae: Coelastarte excavata (J. de C. Sowerby); Cardiniidae: Cardinia hybrida (J. Sowerby), Protocardia cf. truncata (J. de C. Sowerby), Protocardia striatula (J. de C. Sowerby); Quenstedtiidae: Quenstedtia sp., Tancrediidae: Tancredia (T.) gibbosa Lycett; Pholadomiidae: Pholadomya sp., Pleuromyidae: Pleuromya uniformis (J. Sowerby).
The
brachiopod fauna includes: terebratulids referred to Lobothyris; ovate zeillerids
comparable to Cincta; medium-sized biplicate terebratulids; and spiriferids referred to Callospiriferina
tumida (Von Buch).
Sandy and Blodgett (2000) recorded Callospiriferina
tumida (Von Buch) from
the Talkeetna Formation, Peninsular Terrane, south-central
The bivalve and brachiopod fauna is consistent with a mid latitude paleogeographic setting for the Peninsular Terrane during the Pliensbachian.
Acknowledgement: Thanks to Curvin Metzler for making these collections available for study and to Dr. Cristina Panaiotu for analyzing bivalve shell microstructure.