Part of NTS Sheets 21A/05, 21A/12, 21A/13, 21B/08 and 21B/09 Nova Scotia Department of Natural Resources - Mineral Resources Branch OFM ME 2010-9 44°40'N 66°W 65°50'W 251000mE 52 53 54 55 56 57 58 59 260 61 62 63 64 65 66 67 68 69 270 71 72 73 74 75 76 77 78 79 280 81 82 83 84 85 86 287000mE N N 000m 000m 48 49 65 Legend 49 A n MESOZOIC D 47 n a i g p 64 b o y l i s C TRIASSIC C o u o n u t n y t y FUNDY GROUP NORTH MOUNTAIN FORMATION 46 63 BRIER ISLAND MEMBER (Upper Flow Unit) (^Fnmb) : this unit ( À 150 m) occurs at the ^Fnmb top of the basalt sequence, conformable on unit ^Fnmm and outcrops extensively on the northern shorelines except in the central part of the mapped area where it is notably absent. The basalt is massive, dark grey to grey-green with microcrysts (À 5%) of plagioclase and pyroxene with variable (À 30-40%) amounts of mesostasis in a medium- 45 grained, ophitic-textured host. This unit consists of 1 or 2 flow sheets, has colonnade- 62 style polygonal jointing (À 1 m) and, at the base, inclined pipe vesicles occur. The lower 10-20 m locally (e.g., Morden, Margaretsville) contains felsic material (ca. 65-74 wt. % SiO2 ) in the form of dykes, amoeboid masses and spectacular segregation pipes (3-60 cm; 10-15/m2 ) that are sometimes cored by agate and crystalline silica. Rarely veins of silica cut the unit and locally areas of intense silica alteration occur. 44 61 65°40'W MARGARETSVILLE MEMBER (Middle Flow Unit) (^Fnmm) : this unit occurs between the ^Fnmm massive and relatively fresher^Fnme and ^Fnmb flows. Due to alteration the unit is recessive and occupies low lying, locally swampy (e.g., Long Island and Brier Island) d y areas. Significantly, in the eastern part of the mapped area (i.e., Scots Bay) the unit is in n contact with the younger Triassic Scots Bay Formation rather than the Brier Island F u Member. The unit varies in thickness from À20-40 m in the western part of the mapped 43 f area to À170 m maximum thickness in the central area; areal exposure varies o 4960 y considerably towards the east. Individual flows are fine grained, dark grey to grey-green a and/or red-brown, massive to intensely vesiculated, generally altered and, therefore, very B friable. The unit contains multiple (15-20), thin (À 15-20 m), geometrically complex flow sheets with abundant, zonally-arranged vesicles (e.g., pipes, vesicle cylinders and sheets) which are mostly occluded with different zeolite phases (locally 20-30% by volume) and lesser silica and micaceous material. In thicker flows the cores or lower parts 42 59 can be massive and rarely exhibit columnar jointing. Abundant field evidence (e.g., flow lobes, stacked lobes, vesicle zonation, tumuli) indicates this is a compound flow unit consisting of abundant inflated pahoehoe flow sheets. Red-brown oxidized tops and ^Fnmm Fleet Brook neptunian dykes of fine-grained, red-brown siliceous material in the upper half of flows ^Fnmb indicate a time hiatus between flows. Veins of silica material, including jasper and Head S chalcedony, occur. l o 41 a Green n k 58 s o EAST FERRY MEMBER (Lower Flow Unit) (^Fnme): this unit occurs at the base of the Point o B Point B r Cu ^Fnme r o basalts and outcrops extensively on shorelines in the western part of the mapped area, B o Prim g o s a k but lesser in inland areas in the central and eastern parts of the mapped area. The basalt e r i t l r ^Fnmm Condons B a is grey-green and dominantly holocrystalline with microcrysts (À 5%) of plagioclase and r h o C Point Shag o pyroxene with variable (À 15%) amounts of mesostasis. The contact with the underlying k Cliffs Triassic Blomidon Formation sedimentary rocks, which are altered (i.e., whitish clay ^Fnmb 49 40 material) near the contact, is rarely exposed (e.g., north of Bridgetown, eastern side of 57 ^Fnmm F Bogart Digby Gut). (Note: The Blomidon Formation is not shown on this map series. See Keppie l e Lake e (2000) for location). The top (ÀÀ 1-5 m) and bottom ( 10-25 cm) of the flow are chilled and Tommys t M B Mill Cove i ^Fnmb Point c vesiculated with the top also locally red-brown due to oxidation. The unit contains well- m r o Point o developed polygonal jointing (i.e., columnar joints 2 m) of colonnade and complex a Johnson k c ^Fnmm B k entablature patterns. The upper part of the flow is distinguished by layers (30-50 cm) of ^Fnmb B k r Hill ^Fnmb o ls Bay Fleet 39 B l vesiculation, now occluded by zeolites, and also by bands (centimetres to 1-3 m) of mafic o u T r b k View Lake 56 o n r U ^Fnme pegmatite (upper 30-50 m). These sheet-like layers are comb-textured and pyroxene-rich Theriaults n u n T Gu llivers V Culloden G k o o with a granophyric matrix; concordant or discordant rhyolite or granophyre seams (À 3 Point o C r Burns ' Head ^Fnme B O s cm) may also occur. The unit may also contain large (tens of metres wide) circular Point Y Zeolite ^Fnmm ne ^Fnmm r B o features, referred to as rootless cones, which are most prevalent in the central and h T G Battery I rook western parts of the mapped area. Fractures cutting the unit are lined with zeolites or B Victoria D Point Worcester p u silica, or more rarely sedimentary dykes consisting of fine-grained, silica-rich, red-brown c 38 Van Beach Lake os r Thornes material. Tassel C 55 IN Cove TH MOUN TA Lake ^Fnme ^Fnmb R NO U 202±1 k Indian Kaolinite o ro Lynchs ke B ^Fnmb Gullivers Bur Mountain Beach Cove Karsdale Fe Port Pollys ^Fnmm Wade 37 Point McWhinnies k 54 Post oo Mount er Br Handspik Point Mountain Pleasant Beamans Rattling Upper ^Fnmm Fe Mountain Beach Point Lower ^Fnme Hendersons > Smalls > > Black Point CK Seawall NE ^Fnmm Lake Mountain k Y Point Jasper o Hi B o ll IG Br D k 36 n o ^Fnmb o o Roxville Symbols * s r 53 n t B > h h g o > Hai Waterford J > Outcrop . > > Centreville ^Fnme G r if Fe fi Lighthouse n > Drillhole (after Fisher, 2006) . B ro ^Fnme The Road o k k Seawall o Mineral occurrence (Au - gold, Cu - copper, o 35 r Fe - iron, Mn - manganese, V - vanadium) ^Fnmm Rossway B H Lake t k 52 Cu s o o Midway o o l (after O'Reilly et al., 2009) . P r d B s s w d d o u r Radiometric date (U-Pb zircon; Ma) t U 202±1 Fe B h B (after Hodych and Dunning, 1992) . idway k e M Lak ^Fnme Annapolis Basin Geological contact 34 Green (defined, assumed) . 51 Seabrook Point Fault (defined) . Red Head LiDAR survey area (Webster, 2010) . F e Digby Broo k Not Mapped Shipyards derson Hen 33 Point Shaws # 4950 #! Bear Point Lighthouse . Island Rock in water . > Cornwallis Arterial highway . 102 ! Park ! ! Clementsport See 44°40'N ly B Trunk highway . 4 32 roo ! 44°30'N k M 49 o Collector highway . 333 ! Pinkneys o y s a Robinsons e Point D B ! R Hard surface road . e D Point e i s p i v B Deep B t e y S P m o u r r r ! m o Loose surface/resource access road . y a a r Brook o c d r i e k M t Bear River y s Jordantown h s Marshalltown B B t ! C B Guinea o Station k Trail, footpath, cart track . ! 31 S Au v k k e ! ! ! 48 ! ! ! ! ! ! Railway (active, inactive) . Brighton ! Not Mapped ! ! Coastline. Y Joggin o ! u ! Bridge n River, stream . W g ! N a s Waldeck ! l Waldeck N s B ! East County boundary . h 000m r o B ! 000m 30 o ! Acaciaville ! r rvey o u k S !!! 49 ! R 47 ! iDA Transmission line (single line) . o mit of L 49 ! i ! L k Barton ! R ! Swamp . ! 260000mE 61 62 63 64 65 66 67 68 69 270 71 72 73 74 75 76 77 78 79 280 81 82 83 84 85 86 87 88 89 290 91 92 93 94 295000mE Lake/ocean . 66°W 44°30'N 65°50'W 65°40'W * Note: Compiled symbols list for map series. All symbols may not appear on each map. Map Notes Descriptive Text Nova Scotia Department of Natural Resources Selected References Mineral Resources Branch 64°W 60°W 66°W 65°W This is 1 map in a series of 5 bedrock geology maps at a scale of 1:50 000. This map series shows the extent of the North Mountain Formation, which is a Cirilli, S., Marzoli, A., Tanner, L., Bertrand, H., Buratti, N., Jourdan, F., Bellieni, G., Kontak, D. J. 2006b: Geological map of the North Mountain Basalt from Cape Split Open File Map ME 2010-9 laterally continuous unit of basalt outcropping semicontinuously for about 200 km Kontak, D. and Renne, P. R. 2009: Latest Triassic onset of the Central Atlantic to Brier Island, with comments on its resource potential; in Mineral Resources New Gulf of GIS databases, cartography and reproduction by Angie Ehler, Brian Fisher, John from Cape Split in the east to Brier Island in the west.