Intrusion model example

[vinicius-anp]

Hi,

Is there any example showing a model with a intrusion? I could not find in the examples page on how to model it.

Best regards,

[javoha]

Hi @vinicius-anp,

in order to help we would need a little more information: What kind fo intrusion are wa talking about? What did yiu try so far and where did you encounter problems. iut always helps to provide a sketch so we have an idea what you are aiming for.

Cheers,
Jan

[vinicius-anp]

HI @javoha,

I haven´t tried anything. My study area is a greenstone belt where there are some circular-shaped calc-alkaline intrusions in the basalt unit, so I would like to see how gempy can handle these type of examples (e.g. intrusions with circular/rounded geometry).

Best regards,
Vinicius

[javoha]

Hi again,
it is really hard to evaluate if gempy is suited for this with this little information. I will try to give a general answer:

Gempy does prefer layer stacks and does not have any specific method to model intrusion bodies. Depending on many factors, mainly the shape of your intrusions, their relation to the surrounding strucuture and also the amount of these bodies you want to include in your model it might still be very possible to model with Gempy. The ebst way to evaluate this would be to understand the modeling principles underlying gempy and the structure that is used to define the interaction between structural groups and elements. I would recommend our video tutorial series to get a grasp if you have not already done so.

If a pure gempy solution is not suitable there is also the option to use a gempy model as a basis and either add objects to i or perfom some kind of geostatistical operation within certain units as a post processing step to add intrusion bodies.

I hope this helps, feel free to ask follow-ups if anything is unclear.

Cheers,
Jan

[vinicius-anp]

Hi Jan,

Thank you for your reply. I went through the video series, and they provide a good introduction to GemPy. Apologies if my previous question wasn’t clear. Essentially, I want to create a geomodel based on the following geological map:

The map covers the eastern part of a greenstone belt. However, there is no stratigraphic information available (except for the mine site, which doesn’t apply to the entire area), nor reports on unit thicknesses or structural measurements or faults kinematics.

As you can see, intrusions occur mostly within the basalt unit. My question is whether it’s possible to build a model in GemPy from this map—while making necessary assumptions (e.g., defining unit thicknesses)—and then later convert it into a mesh model to serve as a petrophysical model for constraining my geophysical inversion.

In particular, I’d like to know if GemPy allows inserting intrusions and faults (likely strike-slip in this case) at this stage, before I dive deeper into learning the software.

Best regards,
Vinicius

[javoha]

Hi,
again this might be an unsatisfying answer - but I can't give a clear yes or no if this is generally possible. Some general points. Just working with a map (no depth data) is always tricky, You would also need orientation data for you units which Gempy rewuires. As with every complex strucutral model you might need to somplify some areas or make some manual adjustments. Unit thickness can not be set as input in Gempy.

Inserting intrusions in Gempy is not possible. You could either model them as a new unit on top of you othere units and then just cut it with the topography (this would be fully within GemPy but I cant guarantee you would be satisfied with the result), or just take the gempy solution and add your intrusions as objects (e.g by changing the resulting lithology block or inserting new meshes) afterwards (outside of gempy).

Best regards,
Jan