Geology, geochronology, lithogeochemistry and metamorphism of the Holberg-Winter Harbour area, northern Vancouver Island Graham Nixon, Hammack Jean, Fabrice Cordey To cite this version: Graham Nixon, Hammack Jean, Fabrice Cordey. Geology, geochronology, lithogeochemistry and metamorphism of the Holberg-Winter Harbour area, northern Vancouver Island. Geology, geochronol- ogy, lithogeochemistry and metamorphism of the Holberg-Winter Harbour area, northern Vancouver Island, 2011. hal-03275126 HAL Id: hal-03275126 https://hal.archives-ouvertes.fr/hal-03275126 Submitted on 30 Jun 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. BC Geological Survey 47 48 49 550000E 51 52 53 54 55 56 57 58 59 560000E 61 62 63 64 65 66 67 68 69 570000E 71 72 73 74 75 76 77 78 79 580000E 81 82 83 84 85 86 87 88 89 590000E 91 92 GEOSCIENCE MAP 2011-1 Jepther Cape Point Sutil Geology, Geochronology, Lithogeochemistry and Metamorphism 36 36 Weser Island of the Holberg-Winter Harbour Area, Northern Vancouver Island Parts of NTS 092L/05, 12, 13; 102I/08, 09 & 16 35 35 Lemon Loquillilla S kinne Point Cove G.T. Nixon, J.L. Hammack, V.M. Koyanagi, L.D. Snyder, G.J. Payie, A. Panteleyev, N.W.D. Massey, J.V. Hamilton, A.J. Orr, r R.M. Friedman, D.A. Archibald, J.W. Haggart, M.J. Orchard, E.T. Tozer, H.W. Tipper, T.P. Poulton, J. Palfy and F. Cordey 34 34 Creek Heimra Lake 48 PALEONTOLOGY GEOLOGY GEOCHRONOLOGY Irony 39 by by by Creek 32 Gorotisa J.W. HAGGART, M.J. ORCHARD, E.T. TOZER, H.W. TIPPER G.T. NIXON, J.L. HAMMACK, L.D. SNYDER, V.M. KOYANAGI, G.J. PAYIE, R.M. FRIEDMAN (The University of British Columbia) 33 Shuttleworth 33 Point and T.P. POULTON (Geological Survey of Canada) A. PANTELEYEV, N.W.D. MASSEY, J.V. HAMILTON and A.J. ORR D.A. ARCHIBALD (Queen's University) Bight J. PALFY (Hungarian Natural History Museum) (BC Geological Survey) F. CORDEY (University of Lyon) D.A. ARCHIBALD (Queen's University) 32 J.W. HAGGART (Geological Survey of Canada) k 32 e Christensen re Point C 0 24 ek re 31 C 31 kilometres a i l l Scale 1:50 000 y 5 g T 6 g 3 a 0 r B 0 0 0 N INTRUSIVE ROCKS 5630000N LAYERED ROCKS LAYERED ROCKS (Cont'd) U r s i e UPPER CRETACEOUS Lower Jurassic (Hettangian to Sinemurian) LOWER TO MIDDLE JURASSIC (ca. 197.5 to 169.9 Ma) 29 PEGATTEM CREEK SILTSTONE Phyl 29 QUEEN CHARLOTTE GROUP EQUIVALENTS (IN PART) ISLAND PLUTONIC SUITE S Dark grey-green to pale pinkish grey, medium to coarse-grained, equigranular h Cenomanian or Lower Turonian to ?Santonian Dark grey to greenish grey, fossiliferous siltstone and mudstone with minor shaley L C u lJPCs a r sh mudstone; possibly also occurs north of the Holberg-Stranby River fault system granitoid rocks and porphyry; includes gabbro (gb), hornblende±biotite-bearing u e a Lake JI r e r BLUMBERG FORMATION a k t diorite (di), quartz diorite (qdi), granodiorite (gd), plagioclase±hornblende Nissen Bight ie Massive to thinly bedded lithic to arkosic wacke with minor pebble to Upper Triassic (Rhaetian) to possibly Lower Jurassic (Hettangian) porphyry (po) and quartz-plagioclase±biotite porphyry (qpo); combined codes 28 28 indicate a range of common rock types (qdi-gd, quartz diorite - granodiorite) D uKBsn cobble conglomerate a L Phyl Creek Fisherman k ak VOLCANICLASTIC-SEDIMENTARY UNIT o Ursie e t Bay a Lake Interbedded volcaniclastic and sedimentary strata (predominantly submarine): Minor Intrusions TrJBvs Erma uKBcg Massive conglomerate with minor lenses of coarse-grained lithic wacke buff to grey-green, thin to very thickly bedded, calcareous to non-calcareous, volcanic 27 G breccia, lithic and feldspathic wacke, siltstone and limestone, locally coralline; lithic- TERTIARY k 27 C o e Lake r d e crystal tuff, lapilli tuff and reworked equivalents; and minor vitric tuff, pebbly sandstone, e k r Dark to pale grey, rhyolitic dike/sill; plagioclase±hornblende±quartz-phyric; e i k n C Cenomanian to ?Turonian siltstone, and volcaniclastic debris-flow deposits; may include black carbonaceous Tif possibly coeval with Alert Bay volcanic unit C shale, mudstone, siltstone and limestone (locally coralline) equivalent to unit TrJY in re e k SHALE UNIT the Mahatta - Alice Lake area (Geoscience Maps 2011-3 and 2011-4) C 26 re Quartz-feldspar-biotite porphyry; north of the map area e 17 a 26 k m Tipo at Christensen Point r Dark grey, calcareous to non-calcareous siltstone and impure limestone Upper Triassic (Carnian to Rhaetian) E uKs interbedded with subordinate wacke and minor pebble conglomerate (exposure restricted to the north shore of Quatsino Sound) PARSON BAY FORMATION Medium grey to black, thinly laminated to medium bedded, impure limestone, EARLY(?) JURASSIC 25 Cenomanian? uTrP Godkin 25 calcareous to non-calcareous mudstone, siltstone and shale intercalated with Dark grey-green diabase to medium-grained gabbro sill; coeval 32 variable proportions of grey-green lithic feldspathic/tuffaceous wacke, minor JBid Ra Lake Lake Dark grey to grey-green and brownish grey siltstone, shale and greywacke; with Bonanza Group volcanism; dp, plagioclase porphyritic variety ne crystal-lithic tuff and reworked equivalents, volcaniclastic breccia and debris- ll uKQs locally fossiliferous of the flow deposits, and rare vitric tuff, pebbly sandstone and conglomerate; 36 Mountains shale locally yields abundant thin-shelled bivalves (Halobia sp., Monotis sp.); Medium grey, aphanitic to plagioclase-phyric rhyolite intrusion; JBif coeval with Bonanza Group volcanism 24 C limestone locally contains rare algal structures; may include coralline limestone re 24 LOWER CRETACEOUS ek Brownie (Sutton limestone equivalent in part; see below) near the top of the succession Nahshutti Ge Upper Valanginian to Barremian orgie Lake Lake Rannell LONGARM FORMATION EQUIVALENTS Sutton limestone equivalent: thin (<10m) unit of pale to medium grey, MAP SYMBOLS Lake Lake k massive reefoid limestone near the top of the Parson Bay Formation; 23 ee Greenish to brownish grey, thinly bedded to massive sandstone, siltstone, 22 Cr 23 contains silicified corals and other fossils; likely equivalent in part to 46 lKL mudstone, pebble conglomerate and minor coal; locally fossiliferous Geological contact, defined 21 Sutton limestone in the Cowichan Lake area, southern Vancouver Island Fi Lm i sh utt erm sh 40 Geological contact, approximate a Na Dark grey-green, basaltic tuff-breccia, crystal-lithic lapilli tuff and debris-flow n 56 30 UPPER TRIASSIC TO MIDDLE JURASSIC 45 uTrPvmc breccia; aphanitic to coarsely clinopyroxene-plagioclase±olivine-phyric Geological contact, inferred 22 67 57 22 BONANZA GROUP - NORTH OF HOLBERG FAULT 68 82 Creek Steeply dipping fault, defined h Lower (?Hettangian) to Middle (Bajocian) Jurassic 54 ug R P uTrPpmc Dark grey-green basaltic pillowed flows, pillow breccia and debris-flow breccia 63 iv 54 68 Isle HOLBERG VOLCANIC UNIT Steeply dipping fault, approximate er 28 40 45 45 71 28 35 72 30 Lake Undivided basaltic to rhyolitic flows, volcaniclastic and sedimentary rocks 21 21 Steeply dipping fault, inferred S 57 35 lmJH t 37 36 to the north of the map area Dark grey-green, andesitic tuff-breccia, lapilli tuff and debris-flow breccia; 39 24 30 uTrPvia plagioclase-hornblende-phyric Reverse fault, approximate (teeth on upper plate) 80 Tsulquate River 5620000N 85 Mainly dark grey-green to medium grey, basaltic to andesitic flows and Reverse fault, inferred (teeth on upper plate) M mJHm volcaniclastic rocks including plagioclase-hornblende-phyric andesite, UPPER TRIASSIC a r 36 70 85 Unconformity, approximate y plagioclase-clinopyroxene-phyric basalt-andesite with sparse hornblende 24 5620000N megacrysts (~1cm), tuff-breccia, lapilli tuff and reworked equivalents; minor VANCOUVER GROUP 36 sedimentary rocks including volcanic breccia, wacke, siltstone, mudstone Unconformity, inferred 22 C 35 15 35 and shale; locally may include minor rhyolitic flows and tuffs Upper Triassic (Carnian to Lower Norian) re 75 Limit of mapping e 30 k QUATSINO FORMATION 19 35 80 19 80 85 Medium grey to grey-green, aphanitic to feldspar-phyric, rhyolitic to dacitic AC Medium to pale grey, thinly bedded to massive micritic limestone and locally bioclastic Line of vertical cross-section 22 28 50 mJHf flows, flow domes and/or pyroclastic rocks including flow and pyroclastic Brink 46 53 uTrQ limestone; minor silica replacement and chert nodules; rare laminated interbeds, oolitic k 42 22 breccia, welded to non-welded crystal-lithic lapilli tuff with carbonized wood Outcrop examined ee Lake Kains layers and algal structures; locally fossiliferous Cr 45 fragments; may locally include thin interbedded volcanic breccia and wacke, 47 74 38 58 Lake and minor basaltic to andesitic flows 18 90 18 Outcrop too small to show at map scale 36 60 20 43 20 k Upper Triassic (Carnian; possibly Middle Triassic (Ladinian) at the base) 57 24 Cree l 86 75 Brownish to greenish grey, laminated to medium-bedded, feldspathic Structure el 29 s 20 62 26 KARMUTSEN FORMATION s 25 46 mJHs volcanic wacke and pebbly sandstone locally cross-bedded with organic- 30 86 u 25 R ins rich horizons; and dark grey to