An exciting part of being a PhD student is being surrounded by new ideas and technology that pushes forward your field of study. On an undergraduate geology field trip to Freycinet National Park, Tasmania, I was part of a team in conjunction with our new TMVC hub (i.e. ARC Industrial Transformation Research Hub, Transforming the Mining Value Chain) at the University of Tasmania, to teach the undergraduate students geological mapping.
What was different about this was that we integrated high-resolution photographs taken from an aerial drone with a mapping technique used in mineral exploration and ore deposit studies. Are exercise took place on a beautiful outcrop near Bluestone Bay, Freycinet Peninsula, Tasmania, Australia.
Mapping and drones
Geology is very much an observational-based science. While many branches of the science focus on observation on a microscopic scale, it is critical to first understand what the bigger picture is. The best way to record these observations is by creating a geological map of the rocks you are interested in. In fact, it was just the 200th anniversary of the first ever geological map by William Smith in 1815 (this “map that changed the world”). The technique of geological mapping hasn’t changed a whole lot since then, but new technologies like Unmanned Aerial Vehicles (UAVs; i.e., drones) are being used to create the most detailed 3-D photos of the outcrops ever.
On a recent field trip for the 2nd year geology undergraduate students, we went to Freycinet Peninsula, on the east coast of Tasmania, to teach them about the rocks that make up the peninsula, and how to do geological mapping. One of the professors in the Geology department at the University of Tasmania, Dr. Michael Roach, has been very active with capturing 3-D spatially referenced geological outcrops. The main purpose is to have a representation of key geological outcrops for teaching to students (check out www.AusGeol.org for a virtual library of Australia’s geology). The UAV was flown over the area ahead of time so we had the high-resolution maps ready to deploy.
Bridging the Old with the New
A small area was chosen for detailed mapping, with a high-resolution photograph as a base layer. Instead of just mapping the usual rock units (lithotypes) and structures (…which are beautiful, note the fault offsetting the pink dyke in the centre of the photo…), we also mapped hydrothermal alteration and mineralization. This is very important when it comes to mineral exploration, as the hydrothermal fluids that create veins and alter rocks over a wide area are usually associated with (or are the same) hydrothermal fluids that cause mineralization and ore deposition (i.e. gold, copper). A colour-coated mapping style was used, known as “Anaconda” mapping, which basically is mapping of different alteration assemblages (Einaudi, 1997).
That is, if a hydrothermal fluid passed through or nearby a rock, the original minerals will because altered with depletion or addition of different elements. These are visible in the rocks, as when you look at primary minerals their properties (i.e. colour, hardness, appearance, etc.), differ from what they originally were.
Final thoughts
The aid of a high-resolution base layer makes mapping prominent geological features fantastic, and it allows you to keep thinking about the big picture while you take your hand lens, hammer and notebook out to understand the details. For the interest of future students doing this exercise I shouldn’t reveal the final geological map, but there were some good-looking maps by the students and lots of enthusiasm to go around (a good chunk coming from us, the demonstrators…).
Mapping alteration and veins systematically in the field allows you to start to see the more prospective areas on the map while you are still on the ground, and have a better understanding of the prospective areas associated with hydrothermal fluid flow. Overall it was a successful exercise in integrating an old technique with new technology, something that will no doubt be used going forward!
-Stephanie
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Hi , my name is marco, i am a geology , and i found your post very interesting , i want use some techniques
with drones to evaluate risk geology like , landslides and floods, in chancamayo , cusco , peru , your post was very
inspired me alot, i am a native spanish speaker , sorry for my mistakes , regards
marcos
That ‘s great.
I want to detect the hydrothermal alterations with my hand made UAV.
As you know these alterations are detectable by remote sensing with satellite images.
My question is: what the advantage(s) of using UAV (kind of photogrammetry ) to determine hydrothermal alteration compare to the using of satellite images?
Please kindly send a copy of your response to my Email: h_shahsavany@yahoo.com
Regards
Hi Hashem, I will send an email response to you as well, but yes, it would be very neat to do alteration mapping on UAV, such as with remote sensing satellites. The main limitation at the moment is the size of the devices that collects spectral information compared to the weight the drone can carry. But technology is developing fast so it is only a matter of time before this is very doable. Cheers, Stephanie.
Excellent technique to map magmatic structures. I was last week doing drone-assisted maps on glaciar pavements in Gredos (Central Spain). Fantastic results. These maps offer a fundamental intermediate scale between standard photographs (meter) to geological maps (100 m). Middle scale maps contain fundamental information for interpretation of geological structures in granites.
Hi Antonio. Thanks for the comment and reading my blog. Yes I definitely agree with you that the high-resolution 3D mapping results in very useful information for interpretation of geological structures. It is a very neat tool to have as a geologist. Cool to hear that you have been doing some of this drone-assisted mapping yourself too! All the best, Stephanie.
That’s cool stuff. Geological mapping is easier and more effective with this technology. Must be pretty exciting for the geology field. I can see lots of potential, like the study of tectonics — something I’ve always been interested in and can’t find enough study of. I would think someday we would be better able to anticipate shifts and the anomalies that come with. Like the earthquake in Haiti was followed by the one in Christchurch. Could we possibly know someday?
Anyway, enjoyed the post and looking forward to hearing from you again! Have fun and tell everyone HELLO!
No, wait. It was Haiti, CHILI, then Christchurch. I did that wrong. Dopey me.
Hello,
Yes it is a very cool new technology to use in geology indeed. As for tectonics, there are scientist working on way to better predict major earthquakes, but it is still very tricky and not yet a reality. We do have are probabilities of earthquakes based on the geological record and current tectonic reconstructions, but the accuracy is more like decades to centuries, rather than day and minutes. Hopefully one day we can predict earthquakes, I look forward to that as well, would be very cool science I imagine. Thanks for reading my blog, cheers!
Stephanie