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.

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?

Mount Damavand, Iran – The Original Mount Doom?

Mount Damavand http://outdooruae.com/persian-volcanoes-mount-damavand/

Volcano & Verdelho – PICO – Azores Part 5

Aerial view eastwards and into the crater of Mt. Pico, with the cone Piquinho rising another seventy meters. (© Herbert Terra, via Panoramio)

Pico volcano is the youngest in the Azores islands, a kid of just 6000 years. Although it hasn’t been playing with fire in the last few centuries, in a geological time scale he and his siblings have been constantly active during the Holocene. The Island of Pico in the Central Azores group presents 173 square miles of most diverse volcanic landscape – dotted with crater lakes and marshes, with extensive lava fields and caves. It is the most important natural reserve of the Azores. The coast of Pico is dominated by steep slopes with fantastic viewpoints, lava arches and vineyards. Some of the local wines that should be tasted by any visiting volcanoholic are “Magma”, “Basalto” or “Terras d’ Lava” 😉 .

Unzen Conduit Drilling Project

Drilling completion day! (Photo: ICDP, Image of the day – 2004/07/07)

POÁS – Exciting Times for a Volcano (& Updates)

Image from RSN webcam on 17 April 2017

I know, it’s exciting times for volcanoholics when a volcano starts playing up but if you live at the foot of same edifice you might not feel quite as much excitement and hope it might soon go away… Notwithstanding, you might as well be interested what the thing on your doorstep is up to. Some background for this volcano can be found on our post “Poás” from Oct. 2015.

Where the World Smells of Nutmeg – BANDA API

Banda Api southern lava flow seen from Lonthor village. (© Welly W, via tripadviser.com)

The lovely smell might change for a more sulfurous one – at least if recent forecasts of volcanic gas emissions or even an eruption of Banda Api come true…

The Socorro Magma Body – The Next Big Thing?

Desert sky over Socorro County, NM. http://www.socorronm.org/things-to-do-in-socorro-new-mexico/

The Rio Grande Rift in New Mexico is a failed rift in North America, a rift that did not complete the separation of North America and the growth of a new sea between the two sides.

Basaltic…? Felsic…? Porphyritic…? Confusion!

Felsite quarry at Mount Ararat (© en.ararat-stone.com)

That’s how I felt at times reading interesting things about volcanoes but had to skip those -ic words. So, I am trying to give you a simple overview on rock types produced by volcanoes… I can already hear the experts groan: omg, “petrology” and “simple” are the two most antagonistic terms in the world! 😉 Nevertheless, I know all too well our typical skip-and-jump motion when it comes to different lavas, just let’s try and achieve a broad understanding about what volcanoes bring up from the depth.