Conodont Colour and Thermal Maturity of the Late Triassic Kunga Group, Queen Charlotte Islands, British Columbia

Abstract. The Gökdere Formation of the Alakircay Nappe (Antalya Nappes) mainly consists of cherty limestone and limestone with calciturbidite intercalations. Moderately to well-preserved radiolarians were obtained from the Gökcam section of the Gökdere Formation located to the west of Antalya City, southwestern Turkey. The radiolarians of the Gökdere Formation obtained in this study are comparable to the faunas described from the Queen Charlotte Islands, British Columbia and the Antalya Nappes, southwestern Turkey. The age range of the radiolarians is late Early Norian to early Middle Norian based on the co-occurrence of Capnodoce serisa, Harsa siscwaiensis, Xiphosphaera fistulata and an associated fauna. Three species (Nodocapnuchosphaera altineri, Renzium whalenae and Enoplocampe(?) norica) and one subspecies (Kinyrosphaera helicata goekcamensis) are defined as new.

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Late Triassic-Early Jurassic Calcareous Nannofossils of the Queen Charlotte Islands, British Columbia

Journal of Micropalaeontology ◽

10.1144/jm.11.2.177 ◽

1992 ◽

Vol 11 (2) ◽

pp. 177-188 ◽

Cited By ~ 5

Author(s):

Paul R. Bown

Keyword(s):

British Columbia ◽

North America ◽

Mediterranean Area ◽

Lower Jurassic ◽

Late Triassic ◽

Time Interval ◽

Calcareous Nannofossils ◽

Low Latitude ◽

Queen Charlotte Islands ◽

Northwest Europe

Abstract. Sediments of the Kunga and Maude groups (Early Norian-Aalenian) from the Queen Charlotte Islands, British Columbia, have yielded the first records of early Mesozoic calcareous nannofossils in North America. These occurrences are the only record of Triassic nannofossils away from the recent discoveries in the Tethyan area (Austria, Indonesia, and the northwestern Australian margin). The nannofossil assemblages from the Queen Charlotte Islands are generally poor to moderately preserved, with species diversities typical for this time interval (2–10 species). The assemblages are comparable to those from northwest Europe, for the Lower Jurassic, and to those from Austria, Indonesia, and the Australian margin, for the Upper Triassic. They show compatible stratigraphical ranges, allowing the application of existing biostratigraphical zonations. Palaeobiogeographical interpretations are inconclusive and fail to positively confirm a low latitude (Tethyan) position for the Queen Charlotte Islands, as indicated by macrofossil data. However, Triassic nannofossil assemblages have yet to be described from high palaeolatitude locations. In addition, certain features of the Lower Jurassic assemblages may indicate Tethyan affinities but also distinguish these assemblages from those which have been previously documented. These features include the absence of Schizosphaerella punctulata, which occurs abundantly in the circum-Mediterranean region and was previously thought to be “cosmopolitan” in distribution; and the absence of Mitrolithus jansae which characterizes “Tethyan” assemblages in the circum-Mediterranean area. The Queen Charlotte Islands results are compared with new nannofossil data from Argentina, Timor and North America.

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