Explore Subsurface Geology Using Voxel Layers in Three Easy Steps

Ever wonder what lies below the earth’s surface? Now you don’t have to.

We live in a complex 3D world where everything has shape and scale, even the things we can’t see. 3D mapping allows us to view data in a hyper-realistic space and enables us to see what others can’t. In this story, we’ll be exploring how 3D can help us get a better understanding of the geophysical and geothermal properties of our subsurface geology, specifically using Voxel Layers.   

Voxel layers first became available in ArcGIS Pro 2.6 and provide a new way to visualize and understand multidimensional data. They’re a collection of 3D volumetric cubes that store one or more variables and can visualize both qualitative discrete data and quantitative continuous data such as material type, porosity and permeability. Voxel layers are also time enabled, allowing you to view how your data changes over time. They’re very useful for visualizing data that we are unable to physically experience on our own. 

Mineral Bodies and Exploration Potential  

The Rainy River district, located in northern Ontario, contains many gold deposits. The gold is located within layers of volcanic rock and is found in distinct clusters or mineral bodies.  Boreholes can be used to determine the mineral type at specific x,y,z coordinates. In our example, we’re using this information to build a 3D exploratory model of the subsurface geology, painting a clear picture of what’s below the surface.  

3D models like this can help determine exploration potential, decide on areas of focus for exploration efforts, and discover new mineralization. We can also use symbology within the 3D model to isolate the gold body and explore all its facets and perturbances. 

VIDEO: Turn your borehole data into a complete exploratory 3D model in three easy steps. 

1. Interpolate Your Borehole Data Using the Empirical Bayesian Kriging 3D Tool  

The Empirical Bayesian Kriging 3D tool is a geostatistical interpolation tool that uses Empirical Bayesian Kriging methodology to interpolate points in 3D. This tool can be configured to perform Nearest Neighbour interpolation, which is recommend when using qualitative discrete data such as material type. 

The result is a collection of horizontal slices that show the geological properties at a specific depth. The tool also produces a Range Slider, allowing you to jump between depths and view the interpolated predictions for your specified elevation.  

Tip: If your 3D geostatistical layers are offset from your borehole data, change the elevation settings in the layer properties.

2. Combine Your 3D Geostatistical Layers to Create a Voxel Layer Using the GA Layer 3D to NetCDF Tool  

The GA Layer 3D to NetCDF tool is used to export the 3D geostatistical layers created in step 1 to netCDF format. This prepares the layers for visualization as a voxel layer in the local scene. The output of the GA Layer to NetCDF tool is not automatically added to the local scene. To render the subsurface geology voxel layer, you will need to add it to your local scene as a Multidimensional Voxel Layer.

Tip:  When adding the voxel layer to the local scene, you have the option to add it as continuous data or discrete data. Choose discrete when visualizing material type.

Have fun and explore the subsurface geology by rotating your scene. You can change the symbology of your voxel layer to better represent the different material types.

3. Isolate Specific Mineral Types Using Transparency 

Now that your voxel layer has been added to the map, you can explore the subsurface geology within a complete exploratory 3D model. Let’s go a step further and isolate a specific mineral type to view its entire mineral body from any angle. This can be done by symbolizing your voxel layer and selecting specific subsets to be displayed within the local scene.  

Turn off the visibility for any mineral type you don’t want to visualize. Now you have an idea of where each material type is located within the subsurface geology and have a 3D exploratory model to share throughout your organization. 

This post was translated to French and can be viewed here.