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Modern-day regional mapping training in the Aussie Outback

Jun 22, 2016

Recently the CET, with the help of the Geological Survey of Western Australia designed and implemented a regional mapping training unit in typical Australian bush conditions.  During the trip geoscientists from Greenland learnt all of the aspects involved in the state of the art production of a regional geological map by combining remote sensing, airborne geophysical and field observation data. The CET staff shared their knowledge of mapping geological processes through time as well as the importance of these processes in the formation of mineral deposits. In the end, the participants produced a geological map where they could record multiple deformation events, associated with different grades of metamorphism and several stages of magmatic activity.

Figure 1. From where to there and back again.

The CET multidisciplinary team included a structural geologist, geophysicist, remote sensing and regolith landform specialist and computer scientist, illustrating how people with different expertise work together to get the best value out of available data. Students (Heta Lampinen and Lara Ramos) joined the group as a part of their PhD training and research in the Capricorn Orogen. The Geological Survey of Western Australia (GSWA) recognized the importance of regional mapping in promoting mineral exploration in Western Australia and decided to support the efforts of the government of Greenland in setting up a geological survey that will be able to provide the same standard of services to mineral exploration industry in Greenland.  The successful completion of the training was only possible thanks to the field support offered by the GSWA (Fig. 7. and Fig.8.) for the trip as well as complimentary workshops and training for the visiting geologists illustrating the GSWA's world class in house database formats and mapping systems.

​Figure 2. Schematic geological map outlining areas to be mapped as part of the field trip in the Padbury Basin of the Capricorn Orogen.

Throughout the field trip, the participants were encouraged to use remote sensing and airborne geophysical data (Fig. 4. and Fig.6.) to guide the planned fieldwork, and could clearly see the benefits of this type of data in regions with scarce outcrop. In Greenland airborne magnetic and gravity will surely be employed in the mapping of geological structures under the cover of ice and snow while remote sensing datasets may provide information in regions that are difficult to reach. The CET staff discussed the various types of datasets in terms of the pre-processing and the application of filters that can enhance the subsequent interpretation.  All of the participants followed the general guide of digital geological mapping where portable ruggedized field computers are used together with a GIS package to store, display, and query all of the datasets directly in the field.  The interpretations made from geophysical data were verified in the field through observations made at the outcrop scale. The students were then able to map out different lithological units according to their response and appearance in the digital data.  One of the aims of the course was to teach how we can understand the structural framework and the geological overprinting relationships at each outcrop. This understanding can then be utilized not only during the map production but also for planning of subsequent areas to ground truth, and gap analyses that can lead to sampling for geochemical or geochronological studies (Fig.5.). As a part of the training the geologists were demonstrated how to collect geological, geochemical, and geochronological samples and keep a standardized record.

After the fieldwork was finished GIS map production using geodatabase editing workflow was demonstrated. Such map production provides additional control on the data integrity and consistency. Apart from the GIS training, CET staff also demonstrated the use of the Integrated Exploration platform that can be employed in the interpretation of geophysical and remote sensing data during the mapping process. The CET geophysics crew provided additional insights on the use of geophysical modelling and available processing of geophysical data in Geosoft’s Oasis Montaj. The whole training was successfully finished after three weeks of hard work and all of our Greenland colleagues left back for home safely surviving the unusually stormy weather that Perth offered them during their last weekend in Australia.​

Figure 3. Dr. Sandra Occhipinti’s morning briefing of the Robinson Range map sheet geology before a mapping exercise at the Bryah-Padbury Basin (photo: Heta Lampinen).

Figure 4. Dr. Sandra Occhipinti (CET) and Helene Heide-Jørgensen (Geological Survey of Greenland, Nuuk) accessing digital resources through Motion tablets while PhD student Lara Ramos follows the discussion (photo: Heta Lampinen).

Figure 5. Dr. Mark Lindsay extracting a hand sample for geochronology and geochemical analysis from the Padbury Basin (photo: Heta Lampinen).

Figure 6. Dr. Sandra Occhipinti demonstrating the use of remote sensing maps (Landsat 8 band combination 7, 5, 2 in this case) in extrapolating observations to regional scale structural interpretations in geological maps (photo: Heta Lampinen).

Figure 7. The sleeping arrangements at the Capricorn Orogen Fieldtrip (photo: Heta Lampinen).

Figure 8. Happy Capricorn Orogen mapping fieldtrip participants decorating the Geological Survey of Western Australia’s field vehicle. Top from left to right: Helene Heide-Jørgensen, Heta Lampinen, bottom row left to right: David Nathan, Lara Ramos, Anette Juul-Nielsen, Sandra Occhipinti, Vaclav Metelka and Mark Lindsay (photo: Mark Lindsay).