Highlights of the Multi-Year (2013-2018) Bonavista Peninsula Bedrock Mapping Project

Andrea Mills

The Geological Survey resumed bedrock mapping of the Bonavista Peninsula in 2013, building upon previous work conducted in the early 2000s. The project, now nearing completion, involved compilation of all previous work, as well as new structural, geochemical and geochronological studies to gain a better understanding of the geology of the peninsula. Rocks of particular interest on the Bonavista Peninsula include ash-covered marine turbidites that host biota, ancient glacial deposits, diverse volcanic assemblages as well as slates and cupriferous rocks having potential economic significance.

Discovery Aspiring Geopark Incorporated, in collaboration with Government of Labrador and the Atlantic Canada Opportunities Agency (ACOA), continues its efforts to have parts of the Bonavista Peninsula recognized as an UNESCO Global Geopark to highlight its geological and paleontological importance. Significant aspects of the Geopark include Ediacaran biota similar to those at the Mistaken Point Ecological Reserve.

Other notable rocks include glacigenic diamictite, called the Trinity facies, which has been correlated with the Gaskiers Formation (Conception Group of the Avalon Peninsula) through U-Pb (TIMS) geochronology. Correlation of these two map units has major implications for stratigraphic interpretations of the Avalon Terrane, highlighting the need for revision of existing compilation maps. Volcanic rocks, while mainly spatially restricted to the western part of the peninsula, also include (in the Robinhood Bay area) spectacular exposures of peperite – a rock formed by the intrusion and mingling of volcanic rock into unconsolidated, wet sediment.

Economically significant rocks on the peninsula include the Blue Point, Copper Gulch and Tickle Cove (among other) copper prospects. These showings are hosted by reduced horizons within the terrestrial redbeds of the Crown Hill Formation, and were discovered in the early 2000s during exploration for sedimentary-hosted stratiform copper deposits. Of further economic significance is the slate of the Bonavista Formation (Adeyton Group) in the Keels area, which was quarried in the 1990s.

53°30'0"W 53°20'0"W 53°10'0"W 53°0'0"W 48°45'N 48°45'N AVALON EAST BASIN

SYMBOLS NEOPROTEROZOIC SIGNAL HILL GROUP Geological contact (approximate, inferred)...... GIBBET HILL FORMATION ...... ST. JOHN'S GROUP RENEWS HEAD FORMATION Fault (Sense of displacement unknown)...... FERMEUSE FORMATION (undivided) Back Cove Member Thrust fault (, Paleozoic, ornaments on hanging wall side)...... Cape Bonavista 48 TREPASSEY FORMATION Green Dextral fault (inferred)...... Island Port Union Member 52 Catalina Member Anticline (Precambrain, Paleozoic), Syncline (Precambrian, Paleozoic)...... CONCEPTION GROUP Bedding (tops known, unknown, vertical, overturned)...... MISTAKEN POINT FORMATION 30 36 Murphy's Cove Member Spillars Point 18 Mineral occurrence...... 25 32 Goodland Point Member

26 14 Lance Cove 48°40'N 76 59 10 Cable John DROOK FORMATION 20 Cove Bayleys Spillers Cove 15 Cove Shepherd Point Member 10 Spillars 8 Cape L'Argent Cove Argent Bonavista Hill AVALON WEST BASIN Bonavista B O N A V I S T A B A Y Harbour CAMBRIAN

238 23 Elliston GREEN RIDGE Cove ADEYTON GROUP 58 21 BONAVISTA FORMATION

Black Head 235 230 Elliston estern W Head RANDOM FORMATION 75 RIDGE RANDOM FORMATION (undivided) Slate quarry Danson Maberly D e e p C o v e 33 Cove 20 27 10 55 BURNT 25 Blue Point (Cu) 15 NEOPROTEROZOIC 13 10 24 46 GROUP Keels 238 Cu Cu Broad Cove Broad CROWN HILL FORMATION (terrestrial facies) 20 Duntara Head 25 B L A C K H E A D Newmans Birchy Cove Western Head facies Tickle Cu Cove Cove 34 16 Cu Copper Gulch (Cu) Tickle Cove facies 48°35'N Trinity facies 19 10 29 25 Red Cliff facies 19 diamictite 21 B A Y Amherst 10 45 Broad Head facies Cove 19 Pigeon Gulch facies Kings Cove Kings Cove Middle Duntara Harbour facies Wolf Head Amherst Cove 48 41 Red Cliff Knights 40 70 ROCKY HARBOUR FORMATION (shelf facies) 30 26 Point Wolf 16 Cove Upper 70 Brook Point facies 48 44 Amherst Cove 28 Little 20 Kings Cove Lighthouse facies 10 25 235 Catalina 40 Kings Cove North facies Open Knights 12 5 Rolling Cove 20 230 Hall Cove 14 18 40 Monk Bay facies 75 Stock Cove Middle Amherst Cove facies 7 30 Monk 235 Birchy Cove facies 237 Pb 34 5 Bay Burnt 14 Point 15 45 Trinity facies 55 235 Hodderville 8 40 42 41 5 Jones Pond facies 29 Plate Cove 48 East Ediacaran Cape Bonavista facies 44 Catalina 10 Plate Cove facies 236 fossils Plate Cove 14 13 15 25 Catalina Harbour Green BIG HEAD FORMATION (slope to rise facies) Port Island 25 Union BIG HEAD FORMATION (undivided) 48°30'N 24 48°30'N 53°0'0"W 53°30'0"W 53°20'0"W 53°10'0"W Dam Pond Member Bedrock geology map of the Bonavista area (NTS 2C/11)

Plate 2. Laminated dropstone diamictite of the Trinity facies, Plate 1. Charniodiscus specimen from Little Catalina area. New Bonaventure.

Plate 4. Blue Point copper prospect; note gossanous unit within reduced beds Plate 3. Peperite from the Robinhood Bay area. (Blue Point horizon) of the Crown Hill Formation.