
REGIONAL GEOLOGY OF EASTERN LABRADOR (EASTERN MAKKOVIK AND GRENVILLE PROVINCES) Michael gabbro 1426 ± 6 Ma Pinwarian Pegmatite 1499 +8/-7 Ma Labradorian & Grenvillian Granodiorite/tonalite gneiss 1658 ± 5 Ma (zircon) 978 ± 4 Ma (titanite) Labradorian Quartz diorite 1654 ± 5 Ma C.F. Gower Memoir 4 St. John’s Newfoundland and Labrador 2019 REGIONAL GEOLOGY OF EASTERN LABRADOR (EASTERN MAKKOVIK AND GRENVILLE PROVINCES) C.F. Gower Memoir 4 St. John’s, Newfoundland 2019 AVAILABILITY Portions of this publication are available for free download through GEOFILES https://gis.geosurv.gov.nl.ca/minesen/geofiles/ or obtained from Geoscience Publications and Information, Geological Survey, Department of Natural Resources, Government of Newfoundland and Labrador, P.O. Box 8700, St. John’s, NL, Canada A1B 4J6 ([email protected]). TERMS OF USE The purchaser or end user agrees not to provide a digital reproduction or copy of this product to a third party. Derivative products should acknowledge the source of the data. TERMS OF USE FOR DATA View the licence agreement for data at https://opendata.gov.nl.ca/public/opendata/page/?page-id=licence DISCLAIMER The Geological Survey, a division of the Department of Natural Resources (the “authors and publish- ers”), retains the sole right to the original data and information found in any product produced. The authors and publishers assume no legal liability or responsibility for any alterations, changes or misrep- resentations made by third parties with respect to these products or the original data. Furthermore, the Geological Survey assumes no liability with respect to digital reproductions or copies of original prod- ucts or for derivative products made by third parties. Please consult with the Geological Survey in order to ensure originality and correctness of data and/or products. Recommended citation: Gower, C.F. 2019: Regional geology of eastern Labrador (eastern Makkovik and Grenville provinces). Government of Newfoundland and Labrador, Department of Natural Resources, Geological Survey, St. John’s, Memoir 4, 654 pages. [Geofile LAB/1752] ISBN: 978-1-55146-697-2 Charles F. Gower, Emeritus Geoscientist Regional Geology Section, Department of Natural Resources Government of Newfoundland and Labrador P.O. Box 8700, St. John’s, NL, Canada A1B 4J6 FRONTISPIECE Although not all encompassing, the image captures some of the key events (U–Pb zircon dates) in the geological history of the Grenville Province in eastern Labrador. Late Paleoproterozoic Labradorian granitoid rocks are intrud- ed by Early Mesoproterozoic Pinwarian pegmatite and then mid-Mesoproterozoic Michael gabbro. Pre-Grenvillian history is well displayed because Grenvillian effects were modest at this outcrop. Grenvillian orogenesis is expressed by boudinage of the Michael gabbro (outside frame of image), accentuation of fabric in Labradorian granitoid rocks, and U–Pb titanite age. See Plate 10.2 for more detail. CONTENTS Page ABSTRACT . xxx ACKNOWLEDGMENTS. xxxii CHAPTER 1 – INTRODUCTION 1.1 LOCATION . 1 1.2 PHYSIOGRAPHY . 1 1.3 INFRASTRUCTURE AND LAND USE. 4 1.3.1 HIGHWAYS . 4 1.3.1.1 Trans-Labrador Highway . 4 1.3.1.2 Secondary Road Access . 5 1.3.1.3 Possible Highway from Northwest River to Postville . 5 1.3.2 PARKS . 5 1.3.2.1 Mealy Mountains National Park. 5 1.3.2.2 Provincial Parks and Reserves . 5 1.3.3 HYDROELECTRICITY. 5 CHAPTER 2 – PREVIOUS MAPPING 2.1 EXPLORER STAGE (1860–1890). 7 2.2 GOVERNMENT SURVEY COASTAL MAPPING STAGE (1895–1960) . 7 2.3 GEOLOGICAL SURVEY OF CANADA MAPPING STAGE (1960–1975) . 9 2.4 TARGETED GEOLOGICAL MAPPING STAGE (1975–1979) . 11 CHAPTER 3 – SYSTEMATIC 1:100 000-SCALE MAPPING OF EASTERN LABRADOR 3.1 MDA I (1979–1981) . 13 3.2 COOPERATIVE MINERALS PROGRAM (1982–1983). 13 3.3 MDA II (1984–1989) . 15 3.4 MDA III (1991–1995) . 15 3.5 PROVINCIAL FUNDING (1996–2000) . 15 3.6 PROVINCIAL FUNDING (POST 2000). 15 3.7 COMMENTS REGARDING MAPPING. 15 CHAPTER 4 – PREVIOUS OTHER (NON-MAPPING) GEOLOGICAL STUDIES 4.1 REGIONAL REVIEWS AND ‘BEYOND EASTERN LABRADOR’ CORRELATIONS . 17 4.2. GEOCHRONOLOGY . 17 4.2.1 K–Ar AND Ar–Ar. 17 4.2.1.1 K–Ar . 17 4.2.1.2 Ar–Ar . 18 4.2.2 Rb–Sr. 18 4.2.3 Sm–Nd. 19 4.2.4 U–Pb . 19 4.3 GEOPHYSICS. 20 4.3.1 MAGNETIC . 20 4.3.2 GRAVITY . 20 i Page 4.3.3 SEISMIC. 20 4.3.4 PALEOMAGNETIC . 21 4.4 IGNEOUS PETROLOGY . 21 4.5 METAMORPHIC PETROLOGY. 22 4.6 STRUCTURAL, TECTONIC AND GEODYNAMIC STUDIES. 22 4.7 POST-GRENVILLIAN SUPRACRUSTAL ROCKS. 22 4.8 SURFICIAL DEPOSITS . 23 CHAPTER 5 – INTRODUCTION TO REGIONAL GEOLOGY 5.1 MAKKOVIK PROVINCE. 25 5.2 GRENVILLE PROVINCE. 27 5.2.1 ‘EAGLE RIVER’ (LATE MAKKOVIKIAN) OROGENESIS (1810–1775 Ma) . 28 5.2.2 LABRADORIAN OROGENESIS (1710–1600 Ma) . 28 5.2.3 PINWARIAN OROGENESIS (1520–1460 Ma) . 35 5.2.4 POST-PINWARIAN–PRE-GRENVILLIAN EVENTS (1460–1090 Ma) . 35 5.2.5 GRENVILLIAN OROGENESIS (1090–985 Ma) AND LATE- TO POST-GRENVILLIAN EVENTS (985–920 Ma) . 35 5.2.6 NEOPROTEROZOIC AND PHANEROZOIC EVENTS . ..
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