Canadian Journal of Earth Sciences Upper Cambrian and Lower Ordovician conodont biostratigraphy and revised lithostratigraphy, Boothia Peninsula, Nunavut Journal: Canadian Journal of Earth Sciences Manuscript ID cjes-2020-0006.R1 Manuscript Type: Article Date Submitted by the 31-Mar-2020 Author: Complete List of Authors: Zhang, Shunxin; Canada-Nunavut Geoscience Office, upper Cambrian, Lower Ordovician, conodont biostratigraphy, Boothia Keyword: Peninsula Draft Is the invited manuscript for consideration in a Special Not applicable (regular submission) Issue? : https://mc06.manuscriptcentral.com/cjes-pubs Page 1 of 55 Canadian Journal of Earth Sciences Upper Cambrian and Lower Ordovician conodont biostratigraphy and revised lithostratigraphy, Boothia Peninsula, Nunavut Shunxin Zhang Canada - Nunavut Geoscience Office, PO Box 2319, 1106 Inuksugait IV, 1st floor, Iqaluit, Nunavut X0A 0H0, Canada; [email protected] Draft Correspondence author: Shunxin Zhang PO Box 2319, 1106 Inuksugait IV, 1st floor, Iqaluit, Nunavut X0A 0H0, Canada; Phone: (867) 975-4579 Fax: (867) 979-0708 Email: [email protected] Natural Resources Canada (NRCan) contribution number: 20190339 Abstract The strata exposed along Lord Lindsay River on southern Boothia Peninsula were previously named the Netsilik Formation, and then recognized as the Turner Cliffs Formation; the interpretation of the age and correlation was based on limited data. New detailed field 1 https://mc06.manuscriptcentral.com/cjes-pubs Canadian Journal of Earth Sciences Page 2 of 55 investigation at 23 localities along the section resulted in the discovery of over 640 identifiable conodont specimens, with 35 species representing 16 genera, among which a new species, Rossodus? boothiaensis n. sp., is recognized. Five North American standard conodont zone/subzone-equivalent faunas are documented from the section, namely the Hirsutodontus hirsutus Subzone-equivalent, Cordylodus angulatus, Rossodus manitouensis, Acodus deltatus/Oneotodus costatus and Oepikodus communis zones-equivalent faunas. These faunas enable a new understanding of the age and stratigraphic position of the Netsilik and Turner Cliffs formations on southern Boothia Peninsula. The Netsilik Formation can be correlated to the lower member (except for the lowest part) and upper member of the Turner Cliffs Formation; the previously unmeasured upper part of the section can be associated with the lower Ship Point Formation. Based on the new conodont Draftdata, these three units are dated as early Age 10, late Cambrian to middle Tremadocian, Early Ordovician; late Tremadocian, Early Ordovician; and early Floian, Early Ordovician, respectively. This study fills a gap in upper Cambrian and Lower Ordovician biostratigraphy on Boothia Peninsula, and links the regional biostratigraphy to that of Laurentia. Keywords: upper Cambrian; Lower Ordovician; conodont biostratigraphy; Boothia Peninsula Introduction Boothia Peninsula, a large peninsula extending from Nunavut's northern mainland into the Canadian Arctic, is about 32 300 km2, located at the northernmost tip of mainland Canada, and separated from Somerset Island by Bellot Strait. Geologically, the peninsula is formed with a central spine of Precambrian metamorphic rocks, flanked by lowlands of Paleozoic carbonate 2 https://mc06.manuscriptcentral.com/cjes-pubs Page 3 of 55 Canadian Journal of Earth Sciences and sandstone units (Fig. 1). Its important tectonic and geographic location makes it key for understanding the Paleozoic stratigraphy and evolution of the Boothia Uplift. Almost no geological information about Paleozoic rocks from the Boothia region existed until the Geological Survey of Canada began systematic studies in the Arctic Islands in 1947. Fortier (1948) provided a general description of the geological structure and the physiography of the region. Fraser (1958) described the distribution of the crystalline Precambrian basement and the overlying Paleozoic rocks on Boothia Isthmus in some detail. A brief stratigraphic and structural report, partially including Boothia Peninsula, was published as a result of Operation Prince of Wales in 1962 (Blackadar and Christie 1963). In the course of this operation, Christie (1963) examined the stratigraphy of the Paleozoic rocks on Boothia Peninsula, and established three stratigraphic units including BoothiaDraft Felix (Middle Cambrian), Netsilik (Lower Ordovician) and Franklin Strait (Ordovician and Silurian) formations. However, all these three formations were abandoned and replaced by the well-established stratigraphic units of the Arctic Islands including Turner Cliffs, Ship Point, Bay Fiord, Thumb Mountain, Irene Bay and Allen Bay formations by Miall and Kerr (1980) and Stewart (1987) (Fig. 2). Given these limited earlier studies and the uncertain age assignments and stratigraphic relationships between the Boothia Peninsula and other areas in the Arctic region, new data, particularly fossil evidence, are needed to understand the Paleozoic stratigraphy on Boothia Peninsula, and to provide evidence for supporting revisions of the stratigraphic nomenclature and correlations to the other areas in the Arctic region, as well as linkage to the Laurentian biostratigraphic framework. In order to meet this objective, the field investigation on Paleozoic stratigraphy on Boothia Peninsula was carried by the author in 2018, based on which this present 3 https://mc06.manuscriptcentral.com/cjes-pubs Canadian Journal of Earth Sciences Page 4 of 55 paper focuses on the upper Cambrian and Lower Ordovician stratigraphy and conodont biostratigraphy on the peninsula. Paleozoic stratigraphic units on Boothia Peninsula The Boothia Felix versus the Turner Cliffs formations The Boothia Felix Formation was established by Christie (1973) for about 110 m thick sandy dolostone and sandstone with thin beds of intraformational conglomerates. This formation was assigned to the middle Cambrian based on trilobites with an upper Cambrian disconformity between the Boothia Felix and overlying Netsilik formations (Christie 1973; Fig. 2). The lithology of the Boothia Felix FormationDraft was considered to be similar to that of the Turner Cliffs Formation of the Arctic Islands, and the latter was later used in preference to the Boothia Felix Formation (Miall and Kerr 1980; Fig. 2). The Boothia Felix Formation was correlated to the lower part of the lower member of the Turner Cliffs Formation (Stewart 1987; Fig. 2). The Netsilik versus the Turner Cliffs formations The Netsilik Formation was erected by Christie (1973) taking Lord Lindsay River (Fig. 3) as the type section for about 150 m of thin-bedded, dark to greenish grey weathering sandstone and sandy and shaly dolostone. At the type section, ten units were measured in the Netsilik Formation. Based on graptolite and trilobite fossils, this formation was assigned to the Lower Ordovician (Christie 1973). However, the Netsilik Formation was abandoned by Miall and Kerr (1980), because 1) complete sections of the formation have nowhere been seen in stratigraphic contact, and the relationship between the Netsilik and underlying Boothia Felix 4 https://mc06.manuscriptcentral.com/cjes-pubs Page 5 of 55 Canadian Journal of Earth Sciences formations is problematic; and 2) the Early Ordovician fossils of Netsilik Formation were only collected from upper part of the formation. Therefore, the Netsilik Formation is confined to the lower part of the Lower Ordovician and overlaps the age range of the Turner Cliffs Formation; part or all of the Boothia Felix and Netsilik formations were combined into the Turner Cliffs Formation (Miall and Kerr 1980; Fig. 2). Further, both Boothia Felix and Netsilik formations were together correlated to the lower member of Turner Cliffs Formation (Stewart 1987; Fig. 2). To make the stratigraphic classification and correlation clear, it is necessary to review the definition of the Turner Cliffs and Ship Point formations. At the type locality on the west shore of Admiralty Inlet on Baffin Island, the Turner Cliffs Formation was divided into six members, in ascending order: 1) edgewise conglomerate; 2) lower sandstone; 3) second edgewise conglomerate; 4) thin-bedded argillaceousDraft dolostone; 5) third edgewise conglomerate and 6) upper sandstone (Lemon and Blackadar 1963). The Ship Point Formation at its type locality on the east shore of Baillarge Bay, northern Baffin Island, was originally defined for nearly 300 m of thick bedded to massive dolostone with minor argillaceous and sandy beds lying above the Turner Cliffs Formation (Blackadar 1956; Lemon and Blackadar 1963). It was redefined by Trettin (1975) to include the original “upper sandstone member” (Lemon and Blackadar 1963) of the Turner Cliffs Formation as member A of the Ship Point Formation and the original Ship Point Formation as member B. Since then, this “upper sandstone member” has been accepted as member A or unit 1 of Ship Point Formation in the Foxe Basin area (e.g. Sanford 1977; Sanford and Grant 2000; Dewing and Nowlan 2012; Zhang 2013, 2018). However, because of the different stratigraphic-structural province, these definitions were not employed by Miall and Kerr (1980) and Stewart (1987) for Somerset Island and the Boothia Peninsula. 5 https://mc06.manuscriptcentral.com/cjes-pubs Canadian Journal of Earth Sciences Page 6 of 55 On Somerset Island and Boothia Peninsula, based on Miall and Kerr (1980) and Stewart (1987) (Fig. 2), the Turner Cliffs Formation is divided into lower and upper members. The lower member