When most of us think about the impressive geology of the Grand Canyon, our focus is on the ancient rocks. Within the past 1 million years, however, volcanoes have created striking displays in the canyon. Hot lava often flowed down the Colorado River channel for tens of miles; other times, it dammed the river, impounding water behind dams that eventually breached, sometimes releasing catastrophic floods.
Obsidian, smooth and shiny black volcanic glass, has fascinated humans for tens of thousands of years. Researchers believe that humans have a natural reaction to shininess that is tied to an innate need–specifically, water. The Eastern Sierra Nevada is a fabulous place to see dark obsidian, especially in areas where it is swirled and folded together with frothy pale gray pumice..
Geysers, with hot water and steam welling up from deep underground, are mysterious clues to what lies beneath. Yellowstone National Park includes about half of all geysers found on Earth. The Andes Mountains contain a major geyser field, named El Tatio, in northern Chile......I recently dug around for more information about geysers – and I found some that was new news to me and, I think, quite interesting.
The dramatic landscape of Yellowstone National Park, including exploding geysers, bubbling mud volcanoes, and rainbow-colored lakes, all provide hints of the dynamic geologic history of the region. Yellowstone is one of the Earth’s largest volcanic systems, and earthquakes, ground surface movements, and hydrothermal activity in the region are all indications of this volcanism.
The beauty of Mt Rainier masks the fact that it is also an active volcano with a high probability of erupting again in the not-too-distant future....Recently I came across a fascinating blog post called "The Penitentes of Mt Rainier" on a blog site called Volcano Café (https://www.volcanocafe.org/).
Jutting up from the middle of the Pacific Ocean, the Hawaiian Islands are located more than 1,800 miles from the nearest continent. They are also in the center of the Pacific tectonic plate, so the volcanoes that formed these islands have a completely different geologic history from other volcanoes around the Pacific Rim.
Forty years ago, Mount St Helens exploded in a major volcanic eruption. Although this volcano has been quiet recently, it is considered active and could stir back to life anytime. Many other volcanoes in the Pacific Northwest are also active.....
There are five volcanoes in the USA that currently exhibit evidence of increased activity – no eruptions (so far), but numerous small earthquakes and steam plumes – reported by the US Geological Survey for the week beginning April 13, 2020*. The USGS cautions: “Activity could increase with little or no warning …
Did you know that in the time you are reading these words, at least 20 volcanoes are erupting on or close to continents around the Earth? Most of these volcanoes are in a band along the Pacific Rim of Fire, where tectonic plates are smashing together in subduction zones. I love maps, so when I found an excellent one showing....
The volcanic glass obsidian has a rock solid place as a valuable resource in human history. It also has a solid place in fiction, as the Game of Thrones material of Dragonglass found on Westeros [...]
