New Found Gold Corp V.NFG

Retiredgeo

[diabase1]

A question for you. What's the difference between melanocratic granite and gabbro? Can they look the same in the field? Thanks.

[Retiredgeo]

Melanocratic is a fancy word for dark. A granite is mostly Quartz and feldspars with accessory, Biotite, Augite and Horblende (all three are black minerals).  In rare cases the accessory minerals can become the dominant minerals. A gabbro is mostly Olivine, Feldspar, Augite and Orthopyroxene (both the Augite and Orthopyroxene are dark minerals). When the black/dark minerals are >60% the

[diabase1]

That was a quick response. Thanks a lot. I really appreciate it. I'm reading a drill log that has mostly granite in it, yet there is a strong magnetic response correlating with this 'granite'. Normally granite doesn't give a magnetic response, and that's why I thought of gabbro.

[Retiredgeo]

Magnetite is a rare accessory mineral in granites.  It is far mare common in Anorthosites and mafic rocks like gabbro.  Anorthosites can be considered granitoids even though literally they are not. Drill core logs are of highly variable quality.  Core loggers tend to be junior employees.  "if it has lots of feldspar it is a granite" .  Countertop people use the