North Sister

The northern Chilean and southern Peruvian Andes are full of volcanoes that look stunning - I mean, jaw-dropping details of volcanism litter the landscape. The reason for this is two fold: (1) there is an awful lot of volcanism in the northern Chilean/southern Peruvian Andes (as known as the Central Volcanic Zone) - and has been that way for over 10 million years and (2) it has also been very, very dry in the area (most of which is known as the Altiplano-Puna Plateau) for at least a few millions years as well - it is the home of the Atacama Desert! So, this means you get lots of volcanic…

The latest Eruptions Word of the Day is "Tuya". So, what is a tuya? This is a tuya: A tuya! Click on the image to see a larger version. Image by Erik Klemetti. Alright, well, that doesn't entirely help, does it? Lets look at the feature the arrow indicates. Some observations: (1) It is low and broad. (2) It has a relatively flat top. (3) It is steep-sided. (4) If you look real close, you can see crudely columnar jointing in the some of the outcrops near the top. (5) If you had a piece of it in your hand, you'd know it was a volcano rock (andesite, very rarely you can find bits that are quite…