that is a "way cool" looking peak. And though I have a minor in geology from a million years ago, I have no idea what that is. Any geologists want to weigh in???
Mount Tom.jpg (4896×4342)
*Damn! I am hopeless at attaching maps and such in an easily accessible manner- sorry.
Above, I've tried to include the best of the geologic maps that I found on the internet. What I learned is that if our "Swarm Dike Peak" is found in formation member: Kd
, then it is described as "Diorite, quartz diorite, and hornblende gabbro
." Further: "includes some hybrid rocks of granodiorite composition.
" On the map the member is shown with a network of pink dashes throughout, and on the same map these are described as follows:
"Felsic dikes and masses, chiefly aplite, pegmatite, and alaskite. Part of dike swarm along Pine Cr. that is marginal to quartz monzonite..
" are also mentioned in this geologic formation.
Now if one of our real geologists would interpret that for us, we might become wiser. I'd like to know the relative ages of the various members /formations. Ie., is the dark rock (the hornblende-gabbro
) a remnant of the much older ancestral Sierra, which has been shot through with the lighter rock, dike material during subsequent uplift of younger granitic plutons, or what? I didn't find the ages of the different fms. yet; I'll keep looking.