Service: Structure detection reveals pronounced and subtle edges in data

Structure detection service post image

LIFE can be messy and the process of doing a decent manual interpretation of mineral exploration data is no exception. A good way to cut through an information tangle is to employ map layers displaying your data's structural networks.

These structure maps let you to look at the geological features in your area of interest with more clarity — and let you make more-informed decisions about the features' location, importance and morphology.

Not only do these structure maps help you pin down the locations of faults and contacts, but they also provide peace of mind that such features are corroborated by what's observed in the geospatial evidence.

This approach has two benefits: (1) it ensures that the manual interpretation incorporates the expert knowledge of the human beings working on the map, and (2) at the same time, the available physical, chemical, radiometric, and topographic data are being respected.

If the right balance is struck, this approach is not a compromise but a way to gain the best of both worlds.

It marries the speed of computer vision-assisted interpretation and the common sense, experience and realism of expert interpreters.

Structure detection service figure showing example results over Sentinel-2 ternary imageFIGURE: Very fine-scale geological belt-parallel structures detected, in vectorized form (thin black lines) co-displayed with a Sentinel-2 ternary image (constructed from original open-access data made available by the European Space Agency). The area shown in this figure contains the Nebo-Babel site within the broader Musgrave Province case study, which we present in further detail in subsequent figures below. The tightly concentric fingerprint-like feature in the east is the Saturn Pluton. This image is an example of how one might combine structure detection results with other data types to help gain further geological and mineral exploration insight at given locales of potential interest. To view a larger version, click on either the image or this text link.

Case study: Musgrave Province, Western Australia

To provide a feel for how this approach looks in action, we'll use some publicly available magnetic data for a portion of the Musgrave Province that's situated in Western Australia.

The Musgrave Province, positioned at the junction of the West Australian Craton, the North Australia Craton, and the South Australia Craton, is dominated by voluminous mafic-ultramafic and felsic meta-igneous domains.

The province hosted the long-lived intracontinental Ngaanyatjarra Rift created during the mantle plume-related 1085-1040 Ma Giles Event. [1] This rift is thought to be somewhat analogous to North America's Mid-Continental Rift system.

The series of figures below (see Figures 1 to 27) show how computer vision-extracted structures can be informative during a manual interpretation.

For our case study, we extracted structural features (faults, lithological boundaries, and other types of contacts) with wavelengths of 50m, 100m, 200m, 400m, 800m, 1600m, and 6400m. In other words, we looked at fine-scale structures through to relatively large-scale structures across the area of interest we selected.

Now, let's permit the images below to speak for themselves. We're presenting an illustrative subset (the 400m-scale results) of the full range of scales of structure detection results we obtained. Results such as these can augment existing pre-competitive geological mapping. [2]

The area of interest includes the geological features of the Nebo-Babel intrusion (host to a magmatic nickel-copper-PGE sulfide deposit), the Blackstone Range, the Saturn Pluton, the Tollu Pluton, the Mount Aloysius antiform, the Mount Holt raft, the Jameson Range, Murray Range, Bell Rock Range, and Hinckley Range.

Note that the images appearing here are small and relatively low-resolution, to fit the purpose of presenting them online.

References

[1] H.M. Howard, M. Werner, R.H. Smithies, P.M. Evins, C.L. Kirkland, D.E. Kelsey, M. Hand, A. Collins, F. Pirajno, M.T.D. Wingate, W.D. Maier and T. Raimondo (2011) "The geology of the west Musgrave Province and the Bentley Supergroup: A field guide", Geological Survey of Western Australia, Record 2011/4, 116 pages.

[2] In the western Musgrave Province, see for example: H.M. Howard, R.H. Smithies, R. Quentin de Gromard, P.M. Evins and M. Werner (2016) "Geological interpretation of the west Musgrave Province (1:250,000)", Geological Survey of Western Australia.

Structure detection service figure 1FIGURE 1: Reduced-to-the-pole (RTP) magnetic data for the case study area, the western Musgrave Province, Western Australia. This dataset was sourced from the Geological Survey of Western Australia. To view a larger version, click on either the image or this text link.

Structure detection service figure 2FIGURE 2: Results of total structure detection of features with a minimum wavelength of 400m for the western Musgrave Province case study area of interest. The warm color palette shows low values as yellows, moderate values as oranges, and high values as reds. To view a larger version, click on either the image or this text link.

Structure detection service figure 3FIGURE 3: Results of total structure detection of features with a minimum wavelength of 400m for the western Musgrave Province case study area of interest. Results are shown over the top of the area's grayscale RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 4FIGURE 4: Results of total structure detection of features with a minimum wavelength of 400m for the western Musgrave Province case study area of interest. Results are colored according to the dominant orientation azimuth detected (red means N-trending, magenta means NNE-trending, purple means NE-trending, blue means ENE trending, cyan means E-trending, green means ESE-trending, yellow-green means SE-trending, and gold means SSE-trending). Results are shown over the top of the area's grayscale RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 5FIGURE 5: Results of total structure detection of features with a minimum wavelength of 400m for the western Musgrave Province case study area of interest, this time as vectorized results (black lines). Results are shown over the area's RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 6FIGURE 6: Results of total structure detection of features with a minimum wavelength of 400m for the western Musgrave Province case study area of interest, this time as vectorized results (black lines). Results are shown over the area's colored-up geology polygons (sourced from the Geological Survey of Western Australia). To view a larger version, click on either the image or this text link.

Structure detection service figure 7FIGURE 7: Results showing intersections among the 400m minimum-wavelength total structures detected for the western Musgrave Province case study area of interest. The warm color palette shows low values as yellows, moderate values as oranges, and high values as reds. To view a larger version, click on either the image or this text link.

Structure detection service figure 8FIGURE 8: Results showing intersections among the 400m minimum-wavelength total structures detected for the western Musgrave Province case study area of interest. Results are shown over the top of the area's grayscale RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 9FIGURE 9: Vectorized version of results (red polygons) showing the strongest intersections occurring within the 400m minimum-wavelength total structure network detected for the western Musgrave Province case study area of interest. Results are shown over the top of the area's grayscale RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 10FIGURE 10: Vectorized version of results (red polygons) showing the strongest intersections among the 400m minimum-wavelength total structures detected for the western Musgrave Province case study area of interest. Results are co-displayed with the vectorized version of total structure network detected at the same scale (black lines). All of this is shown over the area's RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 11FIGURE 11: Vectorized version of results (red polygons) showing the strongest intersections among the 400m minimum-wavelength total structures detected for the western Musgrave Province case study area of interest. Results are co-displayed with the vectorized version of total structure network detected at the same scale (black lines). All of this is shown over the area's colored-up geology polygons (sourced from the Geological Survey of Western Australia). To view a larger version, click on either the image or this text link.

Structure detection service figure 12FIGURE 12: North-trending and NNE-trending structure present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. To view a larger version, click on either the image or this text link.

Structure detection service figure 13FIGURE 13: North-trending and NNE-trending structure present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. Results are in vectorized form (black lines) and are shown over the area's RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 14FIGURE 14: Northeast-trending and ENE-trending structure present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. To view a larger version, click on either the image or this text link.

Structure detection service figure 15FIGURE 15: Northeast-trending and ENE-trending structure present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. Results are in vectorized form (black lines) and are shown over the area's RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 16FIGURE 16: East-trending and ESE-trending structure present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. To view a larger version, click on either the image or this text link.

Structure detection service figure 17FIGURE 17: East-trending and ESE-trending structure present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. Results are in vectorized form (black lines) and are shown over the area's RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 18FIGURE 18: Southeast-trending and SSE-trending structure present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. To view a larger version, click on either the image or this text link.

Structure detection service figure 19FIGURE 19: Southeast-trending and SSE-trending structure present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. Results are in vectorized form (black lines) and are shown over the area's RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 20FIGURE 20: Geological belt-parallel structures present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. To view a larger version, click on either the image or this text link.

Structure detection service figure 21FIGURE 21: Geological belt-parallel structures present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. Results are shown over the top of the area's grayscale RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 22FIGURE 22: Geological belt-parallel structures present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. Results are in vectorized form (black lines) and are shown over the area's RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 23FIGURE 23: Geological belt-parallel structures present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest, this time as vectorized results (black lines). Also shown are the original yellow-through-red structures, to supply additional context. Results are shown over the area's colored-up geology polygons (sourced from the Geological Survey of Western Australia). To view a larger version, click on either the image or this text link.

Structure detection service figure 24FIGURE 24: Geological belt-crossing structures present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. To view a larger version, click on either the image or this text link.

Structure detection service figure 25FIGURE 25: Geological belt-crossing structures present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. Results are shown over the top of the area's grayscale RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 26FIGURE 26: Geological belt-crossing structures present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest. Results are in vectorized form (black lines) and are shown over the area's RTP grid. To view a larger version, click on either the image or this text link.

Structure detection service figure 27FIGURE 27: Geological belt-crossing structures present within the detected 400m-scale total structure network for the western Musgrave Province case study area of interest, this time as vectorized results (black lines). Also shown are the original yellow-through-red structures, to supply additional context. Results are shown over the area's colored-up geology polygons (sourced from the Geological Survey of Western Australia). To view a larger version, click on either the image or this text link.