In ASPECT, compositional fields are used to represent geological layers in the real world, and their initial thickness is limited by manually input parameters in the ‘Subsection Initial composition model’. However, in most cases, both the layer’s shape and thickness will change over time, for instance, the lithosphere is deformed by compression. Therefore, i would like to know how to calcualte the thickness at different timestep of a specific compositional field. Ideally, use ‘Postprocess’ to output the results for subsequent calculation.
Assuming a compositional field named ‘lower_crust’, I think 'get_geometry_model().depth(position) ’ should be used, it seems that the key point to this problem is how to accurately locate the ‘position’ in the lower_crust, so, any suggestions?