GRANITE…, SYENITE…, DOLERITE… INTRUSIONS (1)

INTRUSIONS PART 1:  INTRUSIVE IGNEOUS ROCKS

Stone Mountain is a part of the Spruce Pine plutonic suite in North Carolina, U.S.. Petrologically, “the marginal phases are fine- to medium-grained muscovite-biotite tonalite to granodiorite, and the interior of the pluton is largely medium- to coarse-grained leucocratic muscovite-biotite quartz monzonite to granite”. Not that complicated, or is it? (© Nathan Lyons)

Magma is intruded somewhere deep down, it stays down there, it cools down there, never to be seen for the next couple of million years – why should anybody care about it? Well, as we’ll see, in many places it DID come up. In fact, a good percentage of Earth’s surface is made up of intrusive rocks.

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1999 – 2001 Eruption Sequence in the Gakkel Ridge

Gakkel Ridge across the Arctic Ocean basin https://www.researchgate.net/figure/284359093_fig1_Fig-1-The-study-area-is-the-Gakkel-ridge-Dotted-line-divides-the-Gakkel-Ridge-into

A PRECIOUS VOLCANO – KUDRYAVIY (KURIL ISLANDS)

Medvezhia volcanic complex (© kkv1970, via Wikimapia)

Sometimes I browse satellite images on WorldView to see what “my” volcanoes are up to. The other day I noticed a thermal anomaly on “Medvezhia”, Iturup Island, Kuriles. So I went back to look at every day of May and found that a red spot had shown on eight days in May, sometimes two spots, practically on most days the mountain wasn’t covered in thick clouds. Could that be a glowing hot lava dome, degassing, with an eruption to come, or a small one going on already?