Mount Chiginagak

Mount Chiginagak sits some 600 km southwest of Anchorage, roughly situated on the Alaska Peninsula between Aniakchak and the Katmai Volcanic Complex.  It is a single peak that tops out at just over 2,200 M.  The peak itself is composed primarily of andesitic and pyroclastic layers.  It also has basalt lava flows with some evidence…

The Katmai Volcanic Complex

First an appropriately weasel-worded disclaimer….. The Katmai Volcanic Complex is one of the most complex, interconnected volcanic structures in the US. Within an area of 300 km2, it has five major stratovolcanoes, a caldera, and a dome marking the site of the largest eruption in the 20th Century – the Katmai – Novarupta eruption of…

An introduction to igneous rocks – Part 1

What is an igneous rock? It’s hard, may be pale or nearly black, but what’s in it? This entry is aimed as a brief introduction to igneous mineralogy/petrology to the ‘beginners’ and it may be useful to have available a mineralogy and/or petrology text, see the ‘Books’ below the title bar. An igneous rock is…