Does a Caldera Form the Islands of the Four Mountains, Alaska?

Islands of the Four Mountains with volcanoes named.  Image courtesy Quantum Spatial Photo, via Power, et al, Dec 2020 via Volcano Discovery

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Diky Greben and the Kurile Lake Caldera, Kamchatka, Russia

Diky Greben volcanic complex from Kurile Lake. Image courtesy Wiki

TUFF.. TUFA?.. IGNIMBRITE – Pyroclastic Deposits

Erosional structures at Göreme, central Cappadocia Region. The tuff is thought to have been deposited by the Mount Erciyes eruption ~2.6 ma, covering an area of about 20,000 km². This was the last of the series of great Cappadocian ignimbrites. (© Claude Valette, via Wikimedia)

In many descriptions of volcanoes and their eruption histories we stumble upon the terms Tuff, Tufa or Ignimbrite. Most every self-respecting volcano has one or all of them. Generally it becomes obvious from the context that they refer to widespread deposits of volcanic materials. But what exactly is an ignimbrite?, is it different to tuff?, and where do they all come from?

Tuff and ignimbrite are clastic rocks composed of volcanic

Rabaul Caldera – a Most Dangerous System

Tavurvur eruption in Rabaul Caldera. Image courtesy Mountain Forecast.com. https://www.mountain-forecast.com/peaks/Rabaul-caldera

Fisher Caldera, Alaska – The largest Caldera System in the State

Historically Active Volcanoes of Alaska. Image courtesy AVO. https://avo.alaska.edu/images/dbimages/display/1258656665_ak6.jpg

Recent Volcanic Activity in Nevada, USA – Part 2

Mud Springs volcano, Aurora – Bodie volcanic field. Lava flow is andesitic. Photo courtesy NASA Earth Observatory. https://earthobservatory.nasa.gov/IOTD/view.php?id=50493

The Altiplano – Puna Volcanic Complex

Overhead view of Guacha caldera in the Altiplano – Puna Volcanic complex http://volcano.oregonstate.edu/book/export/html/587

The Utah – Nevada Ignimbrite Flareup of 30 Ma

Caliente, Nevada, center of a massive ignimbrite flareup some 30 Ma http://plantsandrocks.blogspot.com/2012_10_01_archive.html

Volcano – a mountain that spits fire? Volcano basics part 2