Type Locality:

Catoche Point, Port au Choix Peninsula, Bustard Cove to Back Arm, northern Newfoundland (NTS 12 I/11).

Distribution:

The formation is 140 to 160 m thick at Port au Choix Peninsula (NTS 12 I/11) and Bustard Cove (NTS 12 I/14) and 60+ m thick at Boat Harbour and Cape Norman (NTS 2 M/12). It is widely mapped in autochthonous and parautochthonous rocks of the Great Northern Peninsula, Goose Arm (NTS 12 H/4), Humber Arm (NTS 12 G/1) and the Port au Port Peninsula (NTS 12 B/10, 11).

Lithology:

Well-bedded, bioturbated grey limestones with dolomitic mottles. The limestones range from wavy-bedded lime mudstone to lenticular and ripple-marked grainstones. There are some cryptalgal thrombolitic-boundstone mounds hosting sponges and other metazoans at the type section; these are more common near Hare Bay, where they are found in parautochthonous rocks of the Southern Arm Formation (Cooper, 1936; Stouge, 1982). There are some minor dolostone beds. Diagenetic and epigenetic dolostones replace parts of the formation in many sections, including the upper 40 to 60 m of the type section. Dolomitic mottling, stylolites, and laminated drapes are characteristic. Coarser-grained beds may exhibit scoured bases, large ripple marks, and large cross-beds. The limestones are generally fossiliferous, containing trilobites, orthid and inarticulate brachiopods, gastropods, cephalopods, sponges, eocrinoids, ostracods, and receptaculites. The limestones accumulated mostly in an open subtidal shelf environment.

Relationship:

The Catoche Formation conformably overlies the Boat Harbour and Isthmus Bay formations at Port au Choix, Bustard Cove, Boat Harbour, and the Port au Port Peninsula. The base is placed at the first rubbly limestone bed lying upon a mudcracked, shaly, dolomite lime mudstone. The upper boundary is conformable, being placed at the last limestone bed or diagenetic dolostone below bedded, pale grey to green, syngenetic dolostone and shale of the Aguathuna formation. Strata equivalent to the Catoche, in Hare Bay, belong to the Southern Arm Formation. The St. George Group, as defined by Knight (1983a), includes, in ascending order, the Watts Bight (informal), Boat Harbour (informal), Catoche, Aguathuna (informal) formations and also includes the Corner Brook Formation, the Brent Island Limestone and Southern Arm Formation.

History:

Rocks of the Catoche Formation, as outlined here, span divisions F to K of Richardson (Logan et al., 1863) whose divisions were followed by Schuchert and Dunbar (1934) and Johnson (1939). The formation was first named by Kluyver (1975). The present definition includes Kluyver's original Catoche Formation and his overlying Port au Choix Formation (diagenetic dolomites of Knight, 1978), which replace the top of the limestone sequence. This definition is followed by Knight (1980b), Pratt (1981), Pratt and James (1982), and Knight and Boyce (1984).

Other Citations:

James et al., 1980; Knight, 1980a; Lane, 1984; Pratt, 1981.

References:

Boyce, W.D., 1979. Further developments in western Newfoundland Cambrian-Ordovician biostratigraphy, pp. 7-10: in R.V. Gibbons (ed.), Report of Activities for 1978; Newfoundland Department of Mines and Energy, Mineral Development Division, Report 79-1, 205 p.

Boyce, W.D., 1983. Preliminary Ordovician trilobite biostratigraphy of the Eddies Cove West-Port au Choix area, western Newfoundland, pp. 11-15: in M.J. Murray et al. (eds.), Current Research: New-foundland Department of Mines and Energy, Mineral Development Division, Report 83-1, 228 p.

Cooper, J.R., 1936. Geology of the southern half of the Bay of Islands igneous complex; Newfoundland Department of Natural Resources, Geological Section, Bulletin 4, 62 p.

Cumming, L M., 1967b. Clonograptus from the St. George Formation, Newfoundland, pp. 61-63: in S.E. Jenness (ed.), Report of Activities, Part B; Geological Survey of Canada, Paper 67-1, 92 p.

Fortey, R.A., 1979. Early Ordovician trilobites from the Catoche Formation (St. George Group), western Newfoundland, in, in Contributions to Canadian paleontology; Geological Survey of Canada, Bulletin 321, pp. 61-114.

James, N.P., Klappa, C.F., Skevington, D., and Stevens, R.K., 1980. Trip 13: Cambro-Ordovician of west Newfoundland - sediments and faunas: Field Trip Guidebook, Annual Meeting, Geological and Mineralogical Associations of Canada, Halifax, 88 p.

Johnson, H., 1939. Geology of western Newfoundland; Newfoundland Department of Mines and Energy, Unpublished report, 127 p.

Kluyver, H.M., 1975. Stratigraphy of the Ordovician St. George Group in the Port-au-Choix Area, Western Newfoundland; Canadian Journal of Earth Sciences = Journal Canadien des Sciences de la Terre, vol. 12, no. 4 (April), pp. 589-594.

Knight, I. and Boyce, W.D., 1984. Geological mapping of the Port Saunders and (12 I/11), St. John Island (12 I/14) and parts of the Torrent River (12 I/10) Bellburns (12 I/6) map sheets, northwestern Newfoundland, in, M.J. Murray et al. (eds.), Current Research; Newfoundland Department of Mines and Energy, Mineral Development Division, Report 84-1, pp. 114-123.

Knight, I., 1978. Platformal sediments on the Great Northern Peninsula stratigraphic studies and geological mapping of the north St. Barbe district, pp. 140-150: in R.V. Gibbons (ed.) Report of Activities for 1977; Newfoundland Department of Mines and Energy, Mineral Development Division, Report 78-1, 184 p.

Knight, I., 1980a. Geological mapping of parts of the Eddies Cove, Salmon River and adjacent map-areas, pp. 1-9: in C.F. O'Driscoll and R.V. Gibbons (eds.), Report of Activities for 1979; Newfound-land Department of Mines and Energy, Report 80-1, 264 p.

Knight, I., 1980b. Cambro-Ordovician carbonate stratigraphy of western Newfoundland; sedimentaiton, diagenesis and zinc-lead mineralization: Newfoundland Department of Mines and Energy, Mineral Development Division, Paper given at 82nd CIMM Meeting, Open File 1154, 43 p.

Knight, I., 1983a. Geology of the Carboniferous Bay St. George Subbasin. Map 82-001. In Geology of the Carboniferous Bay St. George Subbasin, Western Newfoundland. Government of Newfoundland and Labrador, Department of Mines and Energy, Mineral Development Division, Memoir 1, 382 pages. GS# NFLD/1314.

Lane, T.E., 1984. Preliminary classification of carbonate breccias, Newfoundland Zinc Mines, Daniel's Harbour, Newfoundland; in, R.G. Blackadar et al (eds.), Current Research, Part A; Geological Survey of Canada, Paper 84-1A, pp. 505-512.

Logan, W.E., Murray, A., Sterry Hunt, T., and Billings, E., 1863. Geology of Canada: Geological Survey of Canada, Report of Progress from its commencement to 1863, 983 p.

Pratt, B.R. and James, N.P., 1982. Cryptalgal-metazoan bioherms of Early Ordovician age in the St. George Group, western Newfoundland: Sedimentology, vol. 29, pp. 543-569.

Pratt, B.R., 1981. Stromatolitic framework of carbonate mud mounds: American Association of Petroleum Geologists Bulletin, vol. 65, p. 974.

Schuchert, C. and Dunbar, C.O., 1934. Stratigraphy of western Newfoundland; Geological Society of America, Memoir 1, 123 p.

Stouge, S., 1982. Preliminary conodont biostratigraphy and correlation of Lower to Middle Ordovician carbonates of the St. George Group, Great Northern Peninsula, Newfoundland: Newfoundland Department of Mines and Energy, Mineral Development Division, Report 82-3, 59 p.