[Palaeontology, Vol. 56, Part 2, 2013, pp. 359–379] LATE ORDOVICIAN BRACHIOPODS FROM EASTERN NORTH GREENLAND: EQUATORIAL OFFSHORE MIGRATION OF THE RED RIVER FAUNA by CHRISTIAN M. Ø. RASMUSSEN Center for Macroecology, Evolution and Climate, and Nordic Center for Earth Evolution (NordCEE), Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark; e-mail:
[email protected] Typescript received 29 February 2012; accepted in revised form 11 July 2012 Abstract: Late Ordovician rhynchonelliformean brachio- Washington Land, it indicates that the upper boundary of pods, typical of the North American Red River fauna, are the Cape Calhoun Formation is considerably younger than found sporadically in the Børglum River Formation of the previous estimates, reaching into the uppermost Katian Centrum Sø area, Kronprins Christian Land, eastern North (middle Cautleyan–Rawtheyan). The Cape Calhoun Forma- Greenland. The geographical distribution of this characteris- tion correlates with the upper member of the Børglum River tic brachiopod fauna is thus extended to the easternmost Formation and further demonstrates that the Hiscobeccus extremity of the Laurentian craton. The assemblage compares fauna was widespread in Laurentian marginal settings of specifically with the Hiscobeccus brachiopod fauna, based on North Greenland. Even though the Hiscobeccus fauna was key taxa such as notably Hiscobeccus gigas (Wang, 1949), and pan-continental during the late Katian (Richmondian), it indicates a late Katian age for this part of the succession. For possesses a strong provincial signal during the later Ordovi- the first time, this typically inland, shallow-water fauna is cian. The new occurrences indicate that this fauna extended found associated with genera like Bimuria, suggesting a tran- to the north-eastern margin of the Laurentian Craton.