Geophysical Data Set 1074
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ONTARIO GEOLOGICAL SURVEY Geophysical Data Set 1074 Ontario Airborne Geophysical Surveys Magnetic and Gamma-Ray Spectrometric Data Renfrew Area by Ontario Geological Survey 2014 Ontario Geological Survey Ministry of Northern Development and Mines Willet Green Miller Centre, 933 Ramsey Lake Road, Sudbury, Ontario P3E 6B5 Canada © Queen’s Printer for Ontario, 2014 Contents CREDITS .................................................................................................................................................... iii DISCLAIMER ............................................................................................................................................ iii CITATION .................................................................................................................................................. iii NOTE ......................................................................................................................................................... iii 1. Introduction .................................................................................................................................................. 1 2. Survey Location and Specifications ............................................................................................................ 1 2.1. Survey Location ............................................................................................................................... 1 2.2. Survey Specifications ...................................................................................................................... 1 3. Aircraft, Equipment and Personnel ........................................................................................................... 3 4. Data Acquisition ........................................................................................................................................... 4 4.1. Acquistion Summary ....................................................................................................................... 4 4.2. Pre-survey Tests and Calibrations ................................................................................................... 5 5. Data Compilation and Processing .............................................................................................................. 5 5.1. Personnel ......................................................................................................................................... 5 5.2. Base Maps ....................................................................................................................................... 6 5.3. Processing of the Magnetic Data ..................................................................................................... 6 5.4. Processing of Radiometric Data ...................................................................................................... 12 5.5. Processing of the Positioning and Altitude Data ............................................................................. 19 6. Final Products .............................................................................................................................................. 19 7. Quality Assurance and Quality Control .................................................................................................... 23 7.1. Survey Contractor ............................................................................................................................ 23 7.2. QA/QC Geophysicist ....................................................................................................................... 26 7.3. Ministry of Northern Development and Mines ................................................................................ 27 8. References ..................................................................................................................................................... 27 Appendix A. Test and Calibration Results ..................................................................................................... 29 Appendix B. Archive Definitions ..................................................................................................................... 58 Appendix C. Operational Reports ................................................................................................................... 65 FIGURES 1. Geology of the Renfrew survey area; survey boundaries shown in black ................................................... 2 2. Ontario master aeromagnetic grid. The outline for the sample data set to be levelled, using the Vickers survey area as the example, is shown ............................................................................................ 8 3. Difference grid (difference between survey grid and master grid), using the Vickers survey as the example ....................................................................................................................................................... 9 4. Difference grid after application of non-linear filtering and rotation, using the Vickers survey as the example ....................................................................................................................................................... 10 5. Level correction grid, using the Vickers survey as the example ................................................................. 10 ii CREDITS List of accountabilities and responsibilities. • Jack Parker, Senior Manager, Earth Resources and Geoscience Mapping Section, Ontario Geological Survey (OGS), Ministry of Northern Development and Mines (MNDM) – accountable for the geophysical survey projects, including contract management • Edna Mueller-Markham, Senior Consulting Geophysicist, Paterson, Grant & Watson Limited (PGW), Toronto, Ontario, Geophysicist under contract to MNDM – responsible for the airborne geophysical survey project management, quality assurance (QA) and quality control (QC) • Tom Watkins, Manager, Publication Services Unit, GeoServices Section, Ontario Geological Survey, MNDM – managed the project-related hard-copy products • Desmond Rainsford, Geophysicist, Earth Resources and Geoscience Mapping Section, Ontario Geological Survey – responsible for initial quality assurance (QA), quality control (QC) and project-related digital products • Goldak Airborne Surveys, Saskatoon, Saskatchewan – data acquisition and data compilation DISCLAIMER To enable the rapid dissemination of information, this digital data has not received a technical edit. However, every possible effort has been made to ensure the accuracy of the information presented in this report and the accompanying data; however, the Ontario Ministry of Northern Development and Mines does not assume liability for errors that may occur. Users should verify critical information. CITATION Parts of this publication may be quoted if credit is given. It is recommended that reference to this publication be made in the following form: Ontario Geological Survey 2014. Survey report on Renfrew area, 70p. [PDF document]; in Ontario airborne geophysical surveys, magnetic and gamma-ray spectrometric data, grid and profile data (ASCII and Geosoft® formats) and vector data, Renfrew area, Ontario Geological Survey, Geophysical Data Set 1074. NOTE Users of OGS products are encouraged to contact those Aboriginal communities whose traditional territories may be located in the mineral exploration area to discuss their project. iii iv Report on the Renfrew Area Airborne Geophysical Survey 1. Introduction The airborne survey contract was awarded through a Request for Proposal and Contractor Selection process. The system and contractor selected for the survey area were judged on many criteria, including the following: • applicability of the proposed system to the local geology and potential deposit types • aircraft capabilities and safety plan • experience with similar surveys • QA/QC plan • capacity to acquire the data and prepare final products in the allotted time • price-performance 2. Survey Location and Specifications 2.1. SURVEY LOCATION The Renfrew survey area is located within the Central Metasedimentary Belt of the Grenville Province. The simplified geology is shown in Figure 1. The north and eastern parts of the area are underlain primarily by metamorphosed carbonate rocks comprising mainly marbles, calc-silicate gneiss with minor mafic and felsic gneiss. Large (up to 15 km) plutonic bodies, with granitic, dioritic and tonalitic compositions, are intruded into these rocks. The northwest corner of the survey area is occupied by granitic gneisses belonging to the Central Gneiss Belt. Sinistral strike-slip deformation has been noted in the area; a later ductile deformational event has also been identified along with a subsequent dextral thrusting event. Each of these deformational episodes appears to have been associated with syenitic to granitic magmatism. Strongly potassic alteration, with concentrations of up to 11.5% K2O, has also been noted in the area. 2.2. SURVEY SPECIFICATIONS The Renfrew area survey specifications and tolerances are as follows: a) Traverse-line spacing and direction • flight-line spacing is 200 m • the survey area was flown with lines oriented at 150°/330° (relative to UTM grid). The distance between adjacent flight lines will not exceed 1.25 times the line spacing for a distance of more than 1 km along any flight line. b) Control-line spacing and direction • at regular 2000 m intervals,