Mineral system proxies
The Mineral system proxies page is included in EIS Wizard to implement a Mineral systems approach for mineral exploration in EIS QGIS Plugin. You can utilize the collected information about mineral system proxies to prepare data for modelling in a knowledge-driven fashion.
How you decide which proxies you prepare will likely be a combination of different factors: The importance of the proxy, what data you have available and which proxies you assume will be the most important for your specific study. Currently, only IOCG mineral system has been implemented by EIS project members and is shipped with the plugin. If you want to extend the given IOCG mineral system with additional proxies or create a completely new mineral system for your needs, it is possible through custom mineral systems and custom proxies.
The Mineral system proxies view is the first page you see when you open EIS Wizard. The view helps you to prepare data for modeling based on a mineral system and relevant proxies.
First, select the mineral system at the top of the view (1). The default options are
- IOCG
- Li-Pegmatites (planned but not implemented yet)
- Co-VMS (planned but not implemented yet)
After selecting a mineral system, choose the scale of the study area (2), as relevancy of proxies vary by study scale. Changing the scale updates the importance of each available proxy represented by the color of the "*" (asterisk) symbol before each proxy name. Red marks high importance, orange moderate importance and green low importance. The available scales are
- Regional
- Camp
- Deposit
Below the Mineral system and Study scale drop-down menus there is a list of proxies for the selected system, divided into tabs for each mineral system component (3) which are
- Source
- Active/structural pathways
- Depositional processes
- Mineralisation, remobilization, modification.
EIS QGIS Plugins gives the option to use custom mineral systems and proxies to be as extendable and flexible as possible. To create, delete, import or export a new mineral system, press the Configure mineral system button (5). When you add a new mineral system, you can either initialize it as empty or copy all proxies from another system. When you export your mineral system, it is saved a .json file that can be imported by other users.
To configure proxies of the selected custom mineral system (the default mineral systems of the plugin cannot be modified – if you wish to extend them, create a copy and modify the copy), click the Configure proxies button (6). The buttons shows a menu that allows you to define a proxy, add/import proxy from another system, edit an existing proxy and delete a proxy. Selecting any of these items opens a new dialog with options and inputs relevant to the action.
By pressing the Process button (4) on the right side of a proxy, the proxy view is changed to proxy processing view. There are currently 2 different workflows (both of them have their own pages) that are mapped to the proxies:
- Compute distance to features
- Interpolate (optional) + Compute distance to anomaly
Distance to features (also known as Distance computation in EIS Processing) tool is used to compute distance to vector features such as points, lines or polygons.
First in the Input section, select the input vector layer (1) and optionally set the maximum distance (2) up to which the distances are computed. In the Output section, you can set a save path (3) for the output raster. If left empty, the output raster is a temporary layer which can be saved later (Note that if you exit QGIS without saving the temporary layer, you will lose it!). Before computing the distances you need to decide whether the pixel size and extent of the output raster (4) are set manually or computed from a base raster. Once the parameters are set, press Run to begin processing. If you want to cancel the computation, press Cancel. Once the computation has finished, the produced output raster is loaded as a layer in you QGIS project. You can return to the Proxies view by clicking the Back button.
Distance to anomaly is a workflow step that needs an input raster. If you have a vector dataset that you need to rasterize, you can interpolate it first before moving to the Distance to anomaly step.
In the Input section, select the input vector layer (1) and attribute (2) on which you want to perform interpolation. Then, in the Method settings section, select either of the two interpolation methods (3), inverse distance weighting (IDW) and kriging, and set the parameters (4) or use the default ones.
Anomaly can be defined as values higher or lower than a threshold, when one threshold value is given. It is also possible to provide two threshold values, when anomaly is defined either as in-between or outside these values.
If you started the workflow by interpolating, the input raster (1) will be your interpolation result raster automatically. In the Method settings section, you select the threshold criterion (2) and its value(s) (3). Additionally, you can select a maximum distance (4), similarly to Distance to features.
