Part of NTS Sheets 21A/05, 21B/01, 21B/08 and 21B/09 Nova ... · Kontak, D.J. and Webster, T.L....
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Gulf of St. Lawrence Bay of Fundy Nova Scotia Atlan tic Ocean Sable Island New Brunswick P.E.I. 1 2 4 5 3 60°W 60°W 64°W 64°W 46°N 46°N 44°N 44°N ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! # # ! ^Fnmb ^Fnmb ^Fnme ^Fnme ^Fnmb ^Fnmm ^Fnmm ^Fnme ^Fnme ^Fnmm ^Fnme ^Fnmm ^Fnmm ^Fnme ^Fnme ^Fnme ^Fnmm ^Fnmb ^Fnmb ^Fnmm ^Fnmm ^Fnmb ^Fnme ^Fnmm ^Fnmm ^Fnme ^F nmb ^Fnmm ^Fnmm ^Fnme ^ Fnme Big Pond Little Pond Lac à Isaie Harris Lake Isaacs Lake We Thibault Lake Journeays Lake Long Island Lakes J ourne a ys B k. Bartletts Lake Litt l e B r o o k Li t tl e R iver G i dn e y s Br o o k Bel live a u R i ve r Isa ac s L a k e Bro ok L o n g I sla nd Br o o k R i v iè re G r os s es C oq u e s CRI Q U E D ES C R OS SE C O Q U E S SISS IB O O RI VE R Ohio Tiddville Mink Cove Sandy Cove East Ferry New Edinburgh Central Grove Fre eport Westport Tiverton St. Bernard Little River Church Point Belliveaus Cove W eaver Se ttlement Weymouth Sand Point Birch Point Long Point Boars Head Green Head Long Beach Burns Point South Point North Point Eastern Head Whites Point Second Point Sabean Point Cape F irmain Tommys Beach French Beach Church Point Western Head Harris Bluff Mo unt Shubl ey Ronnies Point Michels Point Cherry Valley Whipple Point Ridge o f Rocks Grand Edd y Point L ighthouse Beach Flour Cove Point French Beach Point Cherry Valley Head Flat Grounds DIG BY N E CK LONG I S LA N D NORTH MOUNTAIN Pointe à Major BRIER ISLAND Cu Fe Fe Cu Cu F e Cu Cu Cu Cu Cu Cu Cu Clay Diatom ite Diatomite Diatomite Diato mite Dia tomite Diatomite Diatomite Diato mite Diato mite Bay of Fundy St Marys Bay L imit of LiDAR Surv e y Not Mapped 2 20 000m E 21 22 23 24 25 26 27 28 29 2 29 000m E 2 30 2 30 31 31 32 32 33 33 34 34 35 35 36 36 37 37 38 38 39 39 2 40 2 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 2 50 2 50 51 51 52 52 53 53 54 54 2 55 000m E 55 56 57 58 59 2 60 61 62 63 2 64 000m E 49 01 000m N 02 03 04 05 06 07 08 09 49 10 11 12 13 14 15 16 17 18 49 18 000m N 49 19 000m N 19 49 20 21 22 23 24 25 26 27 28 29 49 30 31 32 33 34 35 49 36 000m N 66°10'W 66°10'W 66°20'W 66°20'W 66°30'W 66°W 44°30'N 44°20'N 66°30'W 66°W 44°30'N 44°20'N Nova Scotia Department of Natural Resources Mineral Resources Branch 1 0 1 2 3 4 5 km Open File Map ME 2010-8 Bedrock Geology Map of Basaltic Rocks of the North Mountain Formation from Brier Island to Sandy Cove, Part of NTS Sheets 21A/05, 21B/01, 21B/08 and 21B/09, Digby County, Nova Scotia ± 0 100 200 km D.J. Kontak and T.L. Webster Nova Scotia Department of Natural Resources - Mineral Resources Branch Part of NTS Sheets 21A/05, 21B/01, 21B/08 and 21B/09 OFM ME 2010-8 Scale 1:50 000 Crown Copyright © 2010, Province of Nova Scotia, all rights reserved. Halifax, Nova Scotia 2010 Legend Map Notes Dec 17, 2010 Open File Map ME 2010-8 Mineral Resources Branch This is 1 map in a series of 5 bedrock geology maps at a scale of 1:50 000. GIS databases, cartography and reproduction by Angie Ehler, Brian Fisher, John MacNeil and Jeff McKinnon of the Nova Scotia Department of Natural Resources, Geoscience Information Services Section, 2010. The GIS databases and map were developed using ArcGIS® 9.3. Universal Transverse Mercator Projection (UTM), Zone 20, Central Meridian 63°00' West. North American Datum (NAD) 1983 Canadian Spatial Reference System (CSRS) 98. Base and digital data derived from the Nova Scotia Topographic Database (NSTDB), Copyright Her Majesty the Queen in Right of the Province of Nova Scotia. The NSTDB is available from Service Nova Scotia and Municipal Relations (SNSMR), Land Information Services Division (LIS), Nova Scotia Geomatics Centre (NSGC), Amherst, Nova Scotia. Shaded relief image derived from a 5 m LiDAR bare-earth Digital Elevation Model of the North Mountain area, Nova Scotia, DP ME 455, Version 1, 2010. Azimuth of 315° and sun angle of 45°. Compiled by T. Webster. Composite of several individual surveys dating back to 2000. The Annapolis Valley section of the North Mountain was acquired by the Applied Geomatics Research Group with funding from the Canada Foundation for Innovation (2000, 2003, 2004). The Digby Neck, Long Island and Brier Island sections were acquired by the Applied Geomatics Research Group with funding from the Geological Survey of Canada (Atlantic), Natural Resources Canada (2006). Selected References Bay of Fundy New Brunswick Sheet 5 Sheet 3 Sheet 4 Sheet 2 Sheet 1 65°W 65°W 66°W 66°W 45°N 45°N 44°N Cirilli, S., Marzoli, A., Tanner, L., Bertrand, H., Buratti, N., Jourdan, F., Bellieni, G., Kontak, D. and Renne, P. R. 2009: Latest Triassic onset of the Central Atlantic Magmatic Province (CAMP) volcanism in the Fundy Basin (Nova Scotia): new stratigraphic constraints; Earth and Planetary Science Letters, v. 286, p. 514-525. Fisher, B. E. 2006: Nova Scotia drillholes database; Nova Scotia Department of Natural Resources, Digital Product ME 3, Version 4; http://www.gov.ns.ca/natr/meb/download/dp003.asp Hodych, J. P. and Dunning, G. R. 1992: Did the Manicouagan impact trigger end-of- Triassic mass extinction?; Geology, v. 20, no. 1, January, p. 51-54. Keppie, J. D. (compiler) 2000: Geological map of the Province of Nova Scotia; Nova Scotia Department of Natural Resources, Minerals and Energy Branch, Map ME 2000-1, scale 1:500 000. Kontak, D. J. 2002: Internal stratigraphy of the Jurassic North Mountain Basalt, southern Nova Scotia; in Minerals and Energy Branch, Report of Activities 2001, ed. D. R. MacDonald; Nova Scotia Department of Natural Resources, Report ME 2002-1, p. 69-79. Kontak, D. J. 2006a: A geological map of the Jurassic North Mountain Basalt, southern Nova Scotia: a 200 km transect from Cape Split to Brier Island; in Program with Abstracts; The Atlantic Geoscience Society, 32nd Colloquium and Annual Meeting, February 3-4, 2006, Greenwich, Nova Scotia, p. 39. Kontak, D. J. 2006b: Geological map of the North Mountain Basalt from Cape Split to Brier Island, with comments on its resource potential; in Mineral Resources Branch, Report of Activities 2005, ed. D.R. MacDonald; Nova Scotia Department of Natural Resources, Report ME 2006-1, p. 39-66. Kontak, D. J. 2008: On the edge of CAMP: geology and volcanology of the Jurassic North Mountain Basalt, Nova Scotia; Lithos, v. 101, p. 74-101. Kontak, D. J., Dostal, J. and Greenough, J. 2005: Geology and volcanology of the Jurassic North Mountain Basalt, southern Nova Scotia; Geological Association of Canada-Mineralogical Association of Canada, Field Trip Guidebook B3, p. 130. O'Reilly, G. A., Demont, G. J., Fisher, B. E. and Poole, J. C. 2009: Nova Scotia mineral occurrence database; Nova Scotia Department of Natural Resources, Digital Product ME 2, Version 10; http://www.gov.ns.ca/natr/meb/download/dp002.asp Pe-Piper, G. and Miller, L. 2002: Zeolite minerals from the North Shore of the Minas Basin, Nova Scotia; Atlantic Geology, v. 38, p. 11-28. Webster, T. L. 2010: Shaded relief image derived from a 5 m LiDAR bare-earth Digital Elevation Model of the North Mountain area, Digby, Annapolis and Kings Counties, Nova Scotia; Nova Scotia Department of Natural Resources, Digital Product ME 455, Version 1; http://www.gov.ns.ca/natr/meb/download/dp455.asp Webster, T. L., Murphy, J. B. and Gosse, J. C. 2006: Mapping subtle structures with LiDAR: flow units and phreatomagmatic rootless cones in the North Mountain Basalt, Nova Scotia; Canadian Journal of Earth Sciences, v. 43, p. 157-176. The information on this map may have come from a variety of government and nongovernment sources. The Nova Scotia Department of Natural Resources does not assume any liability for errors that may occur. This map is intended for use at the published scale of 1:50 000. Disclaimer Kontak, D.J. and Webster, T.L. 2010: Bedrock geology map of basaltic rocks of the North Mountain Formation from Brier Island to Sandy Cove, part of NTS sheets 21A/05, 21B/01, 21B/08 and 21B/09, Digby County, Nova Scotia; Nova Scotia Department of Natural Resources, Mineral Resources Branch, Open File Map ME 2010-8, scale 1:50 000. Recommended Citation This map series shows the extent of the North Mountain Formation, which is a laterally continuous unit of basalt outcropping semicontinuously for about 200 km from Cape Split in the east to Brier Island in the west. The basalt is sandwiched between Triassic age clastic sedimentary rocks of the Blomidon and Scots Bay formations. (Note: The Blomidon Formation is not shown on this map series. See Keppie (2000) for location). The North Mountain Formation consists of three members which are arranged in a conformable, layer-cake stratigraphy dipping gently (2-5°) towards the Bay of Fundy; however, more irregular dips locally occur in the middle member (^Fnmm) owing to the inflation of individual pahoehoe-type flows during formation. Importantly, zeolites are common in the members and in the case of the middle member (^Fnmm) pervasive. Full details of previous work, zeolite occurrences and formation and the physical volcanology are found in the selected references. Descriptive Text Map Series . . . . . . . . . Current Extent . . . . . . . NTS Map Sheets . . . . . 0 20 40 km Symbols * Outcrop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drillhole (after Fisher, 2006) . . . . . . . . . . . . . . . . . . . . Mineral occurrence (Au - gold, Cu - copper, Fe - iron, Mn - manganese, V - vanadium) (after O'Reilly et al., 2009) . . . . . . . . . . . . . . . . . . . Radiometric date (U-Pb zircon; Ma) (after Hodych and Dunning, 1992) . . . . . . . . . Geological contact (defined, assumed) . . . . . Fault (defined) . . . . . . . . . . . . . . . . . . . . LiDAR survey area (Webster, 2010) . . . . . . . Cu U 202±1 Lighthouse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rock in water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arterial highway . . . . . . . . . . . . . . . . . . . Trunk highway . . . . . . . . . . . . . . . . . . . . Collector highway . . . . . . . . . . . . . . . . . . Hard surface road . . . . . . . . . . . . . . . . . . Loose surface/resource access road . . . Trail, footpath, cart track . . . . . . . . . . . . . Railway (active, inactive) . . . . . . . . . . . . Coastline. . . . . . . . . . . . . . . . . . . . . . . . River, stream . . . . . . . . . . . . . . . . . . . . County boundary . . . . . . . . . . . . . . . . . Transmission line (single line) . . . . . . . . . Swamp . . . . . . . . . . . . . . . . . . . . . . . . . . . Lake/ocean . . . . . . . . . . . . . . . . . . . . . . . * Note: Compiled symbols list for map series. All symbols may not appear on each map. 102 4 333 > ! ! ! # # ! MESOZOIC TRIASSIC FUNDY GROUP NORTH MOUNTAIN FORMATION BRIER ISLAND MEMBER (Upper Flow Unit) : this unit ( 150 m) occurs at the top of the basalt sequence, conformable on unit 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 ( 5%) of plagioclase and pyroxene with variable ( 30-40%) amounts of mesostasis in a medium- grained, ophitic-textured host. This unit consists of 1 or 2 flow sheets, has colonnade- style polygonal jointing ( 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. % SiO ) in the form of dykes, amoeboid masses and spectacular segregation pipes (3-60 cm; 10-15/m ) that are sometimes cored by agate and crystalline silica. Rarely veins of silica cut the unit and locally areas of intense silica alteration occur. (Middle Flow Unit) : this unit occurs between the massive and relatively fresher and flows. Due to alteration the unit is recessive and occupies low lying, locally swampy (e.g., Long Island and Brier Island) areas. Significantly, in the eastern part of the mapped area (i.e., Scots Bay) the unit is in contact with the younger Triassic Scots Bay Formation rather than the Brier Island Member. The unit varies in thickness from 20-40 m in the western part of the mapped area to 170 m maximum thickness in the central area; areal exposure varies considerably towards the east. Individual flows are fine grained, dark grey to grey-green and/or red-brown, massive to intensely vesiculated, generally altered and, therefore, very friable. The unit contains multiple (15-20), thin ( 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 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 neptunian dykes of fine-grained, red-brown siliceous material in the upper half of flows indicate a time hiatus between flows. Veins of silica material, including jasper and chalcedony, occur. (Lower Flow Unit) : this unit occurs at the base of the basalts and outcrops extensively on shorelines in the western part of the mapped area, but lesser in inland areas in the central and eastern parts of the mapped area. The basalt is grey-green and dominantly holocrystalline with microcrysts ( 5%) of plagioclase and pyroxene with variable ( 15%) amounts of mesostasis. The contact with the underlying Triassic Blomidon Formation sedimentary rocks, which are altered (i.e., whitish clay material) near the contact, is rarely exposed (e.g., north of Bridgetown, eastern side of Digby Gut). (Note: The Blomidon Formation is not shown on this map series. See Keppie (2000) for location). The top ( 1-5 m) and bottom ( 10-25 cm) of the flow are chilled and vesiculated with the top also locally red-brown due to oxidation. The unit contains well- developed polygonal jointing (i.e., columnar joints 2 m) of colonnade and complex entablature patterns. The upper part of the flow is distinguished by layers (30-50 cm) of vesiculation, now occluded by zeolites, and also by bands (centimetres to 1-3 m) of mafic pegmatite (upper 30-50 m). These sheet-like layers are comb-textured and pyroxene-rich with a granophyric matrix; concordant or discordant rhyolite or granophyre seams ( 3 cm) may also occur. The unit may also contain large (tens of metres wide) circular features, referred to as rootless cones, which are most prevalent in the central and western parts of the mapped area. Fractures cutting the unit are lined with zeolites or silica, or more rarely sedimentary dykes consisting of fine-grained, silica-rich, red-brown material. (^Fnmb) À ^Fnmm À À À (^Fnmm) ^Fnme ^Fnmb À À À (^Fnme) À À À À À 2 2 MARGARETSVILLE MEMBER EAST FERRY MEMBER ^Fnmm ^Fnme ^Fnmb
Transcript of Part of NTS Sheets 21A/05, 21B/01, 21B/08 and 21B/09 Nova ... · Kontak, D.J. and Webster, T.L....
Gulf ofSt. Lawrence
Bay of Fundy
Nova Scotia
Atlantic Ocean
SableIsland
NewBrunswick
P.E.I.
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^Fnmb
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^Fnmm
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^Fnme
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^Fnme
^Fnmm
^Fnmb
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^Fnmm
^Fnmm
^Fnmb
^Fnme
^Fnmm
^Fnmm
^Fnme
^Fnmb
^Fnmm
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^Fnme
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BigPond
Little Pond
Lac à Isaie
Harris Lake
Isaacs Lake
We
ThibaultLake
Journeays Lake
Long Island Lakes
Journeays B
k.
Bartletts Lake
Little Brook
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Tiddville
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EastFerry
NewEdinburgh
CentralGrove
Freeport
Westport
Tiverton
St. Bernard
LittleRiver
ChurchPoint
BelliveausCove
WeaverSettlement
Weymouth
Sand Point
Birch Point
LongPoint
BoarsHead
GreenHead
Long Beach
Burns Point
SouthPoint
NorthPoint
EasternHead
WhitesPoint
SecondPoint
SabeanPoint
CapeFirmain
TommysBeach
French Beach
ChurchPoint
WesternHead
HarrisBluff
MountShubley
Ronnies Point
Michels Point
CherryValley
WhipplePoint
Ridge of Rocks
Grand EddyPoint
LighthouseBeach
Flour CovePoint
French Beach Point
Cherry ValleyHead
FlatGrounds
DIGBY NECK
LONG ISLAND
NORTH MOUNTAIN
Pointe à Major
BRIER ISLAND
Cu
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ClayDiatomite
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B a y o f F u n d y
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66°10'W
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44°30'N44°20'N
66°30'W
66°W
44°30'N
44°20'N
Nova Scotia Department of Natural ResourcesMineral Resources Branch
1 0 1 2 3 4 5 km
Open File Map ME 2010-8
Bedrock Geology Map of Basaltic Rocks of theNorth Mountain Formation from Brier Island to Sandy Cove,
Part of NTS Sheets 21A/05, 21B/01, 21B/08 and 21B/09,Digby County, Nova Scotia
± 0 100 200 km
D.J. Kontak and T.L. Webster
Nova Scotia Department of Natural Resources - Mineral Resources BranchPart of NTS Sheets 21A/05, 21B/01, 21B/08 and 21B/09 OFM ME 2010-8
Scale 1:50 000
Crown Copyright © 2010, Province of Nova Scotia, all rights reserved.
Halifax, Nova Scotia2010
Legend
Map Notes
Dec 17, 2010
Open File Map ME 2010-8
Mineral Resources Branch
This is 1 map in a series of 5 bedrock geology maps at a scale of 1:50 000.
GIS databases, cartography and reproduction by Angie Ehler, Brian Fisher, JohnMacNeil and Jeff McKinnon of the Nova Scotia Department of Natural Resources,Geoscience Information Services Section, 2010. The GIS databases and map weredeveloped using ArcGIS® 9.3.
Universal Transverse Mercator Projection (UTM), Zone 20, Central Meridian 63°00'West.
North American Datum (NAD) 1983 Canadian Spatial Reference System (CSRS) 98.
Base and digital data derived from the Nova Scotia Topographic Database (NSTDB),Copyright Her Majesty the Queen in Right of the Province of Nova Scotia. TheNSTDB is available from Service Nova Scotia and Municipal Relations (SNSMR),Land Information Services Division (LIS), Nova Scotia Geomatics Centre (NSGC),Amherst, Nova Scotia.
Shaded relief image derived from a 5 m LiDAR bare-earth Digital Elevation Model ofthe North Mountain area, Nova Scotia, DP ME 455, Version 1, 2010. Azimuth of 315°and sun angle of 45°. Compiled by T. Webster. Composite of several individualsurveys dating back to 2000. The Annapolis Valley section of the North Mountain wasacquired by the Applied Geomatics Research Group with funding from the CanadaFoundation for Innovation (2000, 2003, 2004). The Digby Neck, Long Island and BrierIsland sections were acquired by the Applied Geomatics Research Group withfunding from the Geological Survey of Canada (Atlantic), Natural Resources Canada(2006).
Selected References
B a y o f F u n d y
NewBrunswick
Sheet 5
Sheet 3
Sheet 4
Sheet 2
Sheet 1
65°W
65°W
66°W
66°W
45°N45°N
44°N
Cirilli, S., Marzoli, A., Tanner, L., Bertrand, H., Buratti, N., Jourdan, F., Bellieni, G.,Kontak, D. and Renne, P. R. 2009: Latest Triassic onset of the Central AtlanticMagmatic Province (CAMP) volcanism in the Fundy Basin (Nova Scotia): newstratigraphic constraints; Earth and Planetary Science Letters, v. 286, p. 514-525.
Fisher, B. E. 2006: Nova Scotia drillholes database; Nova Scotia Department ofNatural Resources, Digital Product ME 3, Version 4;http://www.gov.ns.ca/natr/meb/download/dp003.asp
Hodych, J. P. and Dunning, G. R. 1992: Did the Manicouagan impact trigger end-of-Triassic mass extinction?; Geology, v. 20, no. 1, January, p. 51-54.
Keppie, J. D. (compiler) 2000: Geological map of the Province of Nova Scotia; NovaScotia Department of Natural Resources, Minerals and Energy Branch, Map ME2000-1, scale 1:500 000.
Kontak, D. J. 2002: Internal stratigraphy of the Jurassic North Mountain Basalt,southern Nova Scotia; in Minerals and Energy Branch, Report of Activities 2001, ed.D. R. MacDonald; Nova Scotia Department of Natural Resources, Report ME 2002-1,p. 69-79.
Kontak, D. J. 2006a: A geological map of the Jurassic North Mountain Basalt,southern Nova Scotia: a 200 km transect from Cape Split to Brier Island; in Programwith Abstracts; The Atlantic Geoscience Society, 32nd Colloquium and AnnualMeeting, February 3-4, 2006, Greenwich, Nova Scotia, p. 39.
Kontak, D. J. 2006b: Geological map of the North Mountain Basalt from Cape Splitto Brier Island, with comments on its resource potential; in Mineral ResourcesBranch, Report of Activities 2005, ed. D.R. MacDonald; Nova Scotia Department ofNatural Resources, Report ME 2006-1, p. 39-66.
Kontak, D. J. 2008: On the edge of CAMP: geology and volcanology of the JurassicNorth Mountain Basalt, Nova Scotia; Lithos, v. 101, p. 74-101.
Kontak, D. J., Dostal, J. and Greenough, J. 2005: Geology and volcanology of theJurassic North Mountain Basalt, southern Nova Scotia; Geological Association ofCanada-Mineralogical Association of Canada, Field Trip Guidebook B3, p. 130.
O'Reilly, G. A., Demont, G. J., Fisher, B. E. and Poole, J. C. 2009: Nova Scotiamineral occurrence database; Nova Scotia Department of Natural Resources,Digital Product ME 2, Version 10;http://www.gov.ns.ca/natr/meb/download/dp002.asp
Pe-Piper, G. and Miller, L. 2002: Zeolite minerals from the North Shore of the MinasBasin, Nova Scotia; Atlantic Geology, v. 38, p. 11-28.
Webster, T. L. 2010: Shaded relief image derived from a 5 m LiDAR bare-earthDigital Elevation Model of the North Mountain area, Digby, Annapolis and KingsCounties, Nova Scotia; Nova Scotia Department of Natural Resources, DigitalProduct ME 455, Version 1; http://www.gov.ns.ca/natr/meb/download/dp455.asp
Webster, T. L., Murphy, J. B. and Gosse, J. C. 2006: Mapping subtle structures withLiDAR: flow units and phreatomagmatic rootless cones in the North MountainBasalt, Nova Scotia; Canadian Journal of Earth Sciences, v. 43, p. 157-176.
The information on this map may have come from a variety of government andnongovernment sources. The Nova Scotia Department of Natural Resources doesnot assume any liability for errors that may occur. This map is intended for use at thepublished scale of 1:50 000.
Disclaimer
Kontak, D.J. and Webster, T.L. 2010: Bedrock geology map of basaltic rocks of theNorth Mountain Formation from Brier Island to Sandy Cove, part of NTS sheets21A/05, 21B/01, 21B/08 and 21B/09, Digby County, Nova Scotia; Nova ScotiaDepartment of Natural Resources, Mineral Resources Branch, Open File Map ME2010-8, scale 1:50 000.
Recommended Citation
This map series shows the extent of the North Mountain Formation, which is alaterally continuous unit of basalt outcropping semicontinuously for about 200 kmfrom Cape Split in the east to Brier Island in the west. The basalt is sandwichedbetween Triassic age clastic sedimentary rocks of the Blomidon and Scots Bayformations. (Note: The Blomidon Formation is not shown on this map series. SeeKeppie (2000) for location). The North Mountain Formation consists of threemembers which are arranged in a conformable, layer-cake stratigraphy dipping gently(2-5°) towards the Bay of Fundy; however, more irregular dips locally occur in themiddle member (^Fnmm) owing to the inflation of individual pahoehoe-type flowsduring formation. Importantly, zeolites are common in the members and in the case ofthe middle member (^Fnmm) pervasive. Full details of previous work, zeoliteoccurrences and formation and the physical volcanology are found in the selectedreferences.
Descriptive Text
Map Series . . . . . . . . .
Current Extent . . . . . . .
NTS Map Sheets . . . . .
0 20 40 km
Symbols *
Outcrop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drillhole (after Fisher, 2006) . . . . . . . . . . . . . . . . . . . .
Mineral occurrence (Au - gold, Cu - copper, Fe - iron, Mn - manganese, V - vanadium)(after O'Reilly et al., 2009) . . . . . . . . . . . . . . . . . . .
Radiometric date (U-Pb zircon; Ma)(after Hodych and Dunning, 1992) . . . . . . . . .
Geological contact (defined, assumed) . . . . .
Fault (defined) . . . . . . . . . . . . . . . . . . . .
LiDAR survey area (Webster, 2010) . . . . . . .
Cu
U 202±1
Lighthouse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rock in water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Arterial highway . . . . . . . . . . . . . . . . . . .
Trunk highway . . . . . . . . . . . . . . . . . . . .
Collector highway . . . . . . . . . . . . . . . . . .
Hard surface road . . . . . . . . . . . . . . . . . .
Loose surface/resource access road . . .
Trail, footpath, cart track . . . . . . . . . . . . .
Railway (active, inactive) . . . . . . . . . . . .
Coastline. . . . . . . . . . . . . . . . . . . . . . . .
River, stream . . . . . . . . . . . . . . . . . . . .
County boundary . . . . . . . . . . . . . . . . .
Transmission line (single line) . . . . . . . . .
Swamp . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lake/ocean . . . . . . . . . . . . . . . . . . . . . . .
* Note: Compiled symbols list for map series. All symbols may not appear on each map.
102
4
333
>
! ! !
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MESOZOIC
TRIASSIC
FUNDY GROUP
NORTH MOUNTAIN FORMATION
BRIER ISLAND MEMBER (Upper Flow Unit) : this unit ( 150 m) occurs at the top of the basalt sequence, conformable on unit 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 ( 5%) of plagioclase and pyroxene with variable ( 30-40%) amounts of mesostasis in a medium-grained, ophitic-textured host. This unit consists of 1 or 2 flow sheets, has colonnade-style polygonal jointing ( 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. % SiO ) in the form of dykes, amoeboid masses and spectacular segregation pipes (3-60 cm; 10-15/m ) that are sometimes cored by agate and crystalline silica. Rarely veins of silica cut the unit and locally areas of intense silica alteration occur.
(Middle Flow Unit) : this unit occurs between the massive and relatively fresher and flows. Due to alteration the unit is recessive and occupies low lying, locally swampy (e.g., Long Island and Brier Island) areas. Significantly, in the eastern part of the mapped area (i.e., Scots Bay) the unit is in contact with the younger Triassic Scots Bay Formation rather than the Brier Island Member. The unit varies in thickness from 20-40 m in the western part of the mapped area to 170 m maximum thickness in the central area; areal exposure varies considerably towards the east. Individual flows are fine grained, dark grey to grey-green and/or red-brown, massive to intensely vesiculated, generally altered and, therefore, very friable. The unit contains multiple (15-20), thin ( 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 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 neptunian dykes of fine-grained, red-brown siliceous material in the upper half of flows indicate a time hiatus between flows. Veins of silica material, including jasper and chalcedony, occur.
(Lower Flow Unit) : this unit occurs at the base of the basalts and outcrops extensively on shorelines in the western part of the mapped area, but lesser in inland areas in the central and eastern parts of the mapped area. The basalt is grey-green and dominantly holocrystalline with microcrysts ( 5%) of plagioclase and pyroxene with variable ( 15%) amounts of mesostasis. The contact with the underlying Triassic Blomidon Formation sedimentary rocks, which are altered (i.e., whitish clay material) near the contact, is rarely exposed (e.g., north of Bridgetown, eastern side of Digby Gut). (Note: The Blomidon Formation is not shown on this map series. See Keppie (2000) for location). The top ( 1-5 m) and bottom ( 10-25 cm) of the flow are chilled and vesiculated with the top also locally red-brown due to oxidation. The unit contains well-developed polygonal jointing (i.e., columnar joints 2 m) of colonnade and complex entablature patterns. The upper part of the flow is distinguished by layers (30-50 cm) of vesiculation, now occluded by zeolites, and also by bands (centimetres to 1-3 m) of mafic pegmatite (upper 30-50 m). These sheet-like layers are comb-textured and pyroxene-rich with a granophyric matrix; concordant or discordant rhyolite or granophyre seams ( 3 cm) may also occur. The unit may also contain large (tens of metres wide) circular features, referred to as rootless cones, which are most prevalent in the central and western parts of the mapped area. Fractures cutting the unit are lined with zeolites or silica, or more rarely sedimentary dykes consisting of fine-grained, silica-rich, red-brown material.
(^Fnmb) À^Fnmm
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(^Fnmm)^Fnme ^Fnmb
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(^Fnme)
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22
MARGARETSVILLE MEMBER
EAST FERRY MEMBER
^Fnmm
^Fnme
^Fnmb
