America's Volcanic Past
|"Though few people in the United States may actually experience an erupting volcano, the evidence for earlier volcanism is preserved in many rocks of North America. Features seen in volcanic rocks only hours old are also present in ancient volcanic rocks, both at the surface and buried beneath younger deposits." -- Excerpt from: Brantley, 1994|
Volcanic Highlights and Features:
|[NOTE: This list is just a sample of various Lava Bed features or events and is by no means inclusive. All information presented here was gathered from other online websites and each excerpt is attributed back to the original source. Please use those sources in referencing any information on this webpage, and please visit those websites for more information on the Geology of the Lava Beds.]|
For a million years the volcano has spewed forth lava, gases,
and cinders, creating what seems to be
an inhospitable landscape. Yet the youngest cinder cones - 1,000 years old -
are covered by vegetation
that provides food and shelter for wildlife.
This area of northern California has a history of volcanism.
The legacy of those times - and it should not
be assumed that all volcanic activity is a thing of the past -
is all around. Cinder cones, shield volcanoes,
stratovolcanoes, lava tubes, both Pahoehoe (smooth and ropy)
and Aa (rough and clinker-like) lava,
spatter cones, and chimneys are all a part of this legacy.
Excerpts from: U. S. National Park Service, Lava Beds National Monument Website, 2001
|Callahan Lava Flow|
Callahan Lava Flow:1
Slightly more andesitic lava erupted about 1100 years ago to form the blocky Callahan lava flow (sometimes known as the Black lava flow), a portion of which covers the southwestern part of Lava Beds National Monument; this flow erupted from Cinder Butte, located just outside the monument boundary. The Callahan flow is the youngest lava flow in the monument. Covering all the flows is a thin layer of white pumice fragments that formed as fallout from explosive eruptions about a thousand years ago when Glass Mountain and Little Glass Mountain erupted high on the slopes of Medicine Lake volcano.
|Captain Jack's Stronghold|
Captain Jack's Stronghold:1
Volcanic eruptions on the Medicine Lake shield volcano have created an incredibly rugged landscape punctuated by cinder cones, lava flows, spatter cones, lava tube caves and pit craters. During the Modoc War of 1872-1873, the Modoc Indians used these tortuous lava flows to their advantage. Under the leadership of Captain Jack, the Modocs took refuge in "Captain Jack's Stronghold," a natural lava fortress. From this base a group of 53 fighting men and their families held off U. S. Army forces numbering up to twenty times their strength for five months. Visitors can tour both the geologic and historic wonders of this unusual landscape.
The latest cinder cone to erupt is Cinder Butte, occurring 1110 years ago, plus or minus 60 years. Cinder Butte forms a conspicuous landmark for park visitors, especially in winter when its treeless slopes are commonly covered with a dusting of snow.
Fleener Chimneys, Black Crater,
Ross Chimneys, The Devil's Homestead
Fleener Chimneys, Black Crater, Ross Chimneys:1
Spatter cones are another formation that can occur in association with shield volcanoes. Blobs of lava are thrown up through the break in the earth's crust. The lava is very thick and pasty, taking the shape of whatever it coats. A chimney may eventually be formed. An excellent example of a spatter cone is at Fleener Chimneys, 150 feet deep. Black Crater and Ross Chimneys are also spatter cones.
Fleener Chimneys and Black Crater:1
Picnic tables and a wheelchair accessible toilet are available at Fleener Chimneys. Fleener Chimneys and Black Crater are castle-like formations created by globs of molten lava which piled up on top of each other. Varying textures and colors will delight photographers.
Fleener Chimneys and The Devil's Homestead:1
Fleener Chimneys has a picnic area shaded by western juniper trees. The picnic tables were constructed by members of the CCC; the logs were obtained at Oregon Caves National Monument and the rocks were gathered locally. This spatter cone was created by globs of molten lava piling on top of each other. A fifty-foot hole is left in the center giving it a chimney-like effect. The chimneys are the source of the tremendous aa flow called The Devil's Homestead. The eruption occurred between 2,000 and 8,000 years ago.
|Lava Tubes and Lava Tube Caves|
Lava Tubes and Lava Tube Caves:1
Perhaps one of the most striking volcanic features in Lava Beds is the phenomenon of lava tube caves. Lava tubes are not particularly unusual in a volcanic area nor is their formation difficult to explain or understand. Nearly 200 caves have been counted within the monument making this formation an especially prominent feature. When lava pours from a volcano it is hot, about 1800 degrees Fahrenheit. The outer edges and surface of the flow cool rapidly, however, and begin to slow down and harden. This outside layer acts as an insulating material while the rest of the flow beneath it remains hot and fast-moving. The flow continues on, somewhat like a river that keeps flowing even though the surface has frozen over. When the eruption stops and the river of lava drains, a tunnel or tube (the outer shell) is left. Lava tubes can lie atop one another, the result of subsequent flows. Many of the tubes here were formed about 30,000 years ago after an eruption at Mammoth Crater on the southern boundary.
Mammoth Crater, on the southern boundary of the monument, erupted about 30,000 years ago. There was such a tremendous outpouring of lava, that it covered the entire monument from the crater to Tule Lake, forming most of the 435 known lava tube caves in the monument.
Mammoth Crater, Modoc Crater, and Bearpaw Butte, and Related Lava Tube Caves:1
About two-thirds of the basalt exposed in Lava Beds National Monument erupted from Mammoth Crater and related vents, including Modoc Crater and Bearpaw Butte. The basaltic lava was transported out to the northern and northeastern parts of the monument where Canby's cross, Captain Jack's Stronghold, and Hospital Rock are located, via lava tubes. Where empty, these tubes form caves, such as Balcony, Boulevard, Merrill, Skull, and Fern. The caves along Cave Loop Drive are located in lava tubes that transported basalt of Mammoth Crater to the east, to Craig Cave and beyond. This very large eruption produced at least one cubic mile of basaltic lava in less than a hundred years. The date of the eruption is unknown but almost certainly took place less than 100,000 years ago.
You step into the past when you view the carvings in the cliff at Petroglyph Point. This formation was created when a cinder cone erupted from the floor of ancient Tule Lake to form an island. Early people paddled out in boats to carve these pictures into the soft rock. Waves undercut the base of the cliff where the petroglyphs are carved. Wind, rain, and ice have enlarged gas bubbles and faults, creating many cracks and crannies. These natural nesting sites are filled with barn owls, cliff swallows, hawks, prairie falcons, and many other birds who find an abundant supply of food nearby. A brochure is available at the site to help you better understand the significance of the area. You will long remember your visit to this special place.
Cinder cones are easily eroded so please stay on the established trails and don't take shortcuts. Frothy lava, cooled in the air, created the large cinder cones throughout the monument. Schonchin Butte's .75 mile trail leads you to a panoramic view from the historic fire lookout. The lookout is staffed from June to September. Children of all ages can earn a Junior Fire Lookout badge. Butte is a geological word for any landform that sticks up abruptly, but cinder cone is a more descriptive geological way of describing this landmark of the monument. Erupting more than 30,000 years ago, it spewed ash and cinders into the air much like a can of soda when shaken. A lava spatter rampart is at the very top. From the lookout panoramic views of the Medicine Lake volcano, Mount Shasta, Mount McLoughlin, the Clear Lake Hills and the Warner Mountains can be viewed and photographed. On a really clear day, you can even see the south rim of Crater Lake. Below the butte, lava flows and collapses are easy to pick out in the landscape. This alone is reason enough to make the climb.
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