A: by Sri Pramod Kumar, AMD
Structural analysis and interpretations, field mapping give clear ideas
A: by Sri Om Prakash Somani, MSPL
In the field we have to closely examine cross cutting relations of intrusions. Wherever the cross cutting is not available then rock dating may help to understand this.
Mineral Exploration Academy 
On behalf of Saurabh Priyadarshi, GeoExplorers
“…Its all about petrogenesis where new rocks cut into the old rocks. The veins or dykes are an example of intrusion of one ore body into another. Details may be read in any book having Petrogenesis as a titled chapter…”
LikeLike
On behalf of Dr.V.Ganeshan, former Director, GSI
“…Remobilised, recrystallised minerals may form, it may have imprints on them which can be deciphered from ore microscopy/SEM EDX studies. The general orientation of mineral grains would have been affected by the later intruded solution / material out of new mineral/ ores may crystallize and which ma show intergrowth / over growth / or enclose the earlier formed ones and show different orientation of crystallization. This effect will be more in the contact zone on either side of the body of intrusion—sometimes show baking effect, partial melting and recrystallisation may infer through colour, grain size variations through megascopically or microscopically, and show propylitic altered zone, intensely oxidised zone and highly weathered nature are noticeable in such areas than the adjoining country rocks…”
LikeLike