GMH reads about Mount Shasta
Mount Shasta (Karuk: Úytaahkoo or "White Mountain")[5][6] is located at the southern end of the Cascade Range in Siskiyou County, California and at 14,179 feet (4,322 m)[1] is the second highest peak in the Cascades and the fifth highest in California. Mount Shasta has an estimated volume of 85 cubic miles (350 km3) which makes it the most voluminous stratovolcano in the Cascade Volcanic Arc.[7][8]
The mountain and its surrounding area are managed by the U.S. Forest Service, Shasta-Trinity National Forest.
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northern California landscape. It rises abruptly and stands nearly
10,000 ft (3,000 m) above the surrounding terrain.[4] On a clear winter day snowy Mount Shasta can be seen from the floor of the valley 140 miles (230 km) south.[9][citation needed] The mountain has attracted the attention of poets,[10] authors,[11] and presidents.[12]
The mountain consists of four overlapping volcanic cones which have
built a complex shape, including the main summit and the prominent satellite cone of 12,330 ft (3,760 m) Shastina,
which has a visibly conical form.
Mount Shasta's surface is relatively free of deep glacial erosion except, paradoxically, for its south side where Sargents Ridge[13] runs parallel to the U-shaped
Avalanche Gulch. This is the largest glacial valley on the volcano,
although it does not presently have a glacier in it. There are seven
named glaciers on Mount Shasta, with the four largest (Whitney, Bolam, Hotlum, and Wintun) radiating down from high on the main summit cone to below 10,000 ft (3,000 m) primarily on the north and east sides.[4]
The Whitney Glacier is the longest and the Hotlum is the most
voluminous glacier in the state of California. Three of the smaller
named glaciers occupy cirques near and above 11,000 ft (3,400 m) on the south and southeast sides, including the Watkins, Konwakiton, and Mud Creek Glaciers.[citation needed]
There are many buried glacial scars on the mountain which were
originally created in recent glacial periods ("ice ages") of the present
Wisconsinian glaciation. Most have since been filled in with andesite lava, pyroclastic flows, and talus from lava domes. Shastina, by comparison, has a fully intact summit crater indicating that Shastina developed after the last ice age.
About 593,000 years ago, andesitic lavas erupted in what is now Mount Shasta's western flank near McBride Spring. Over time, an ancestral Mount Shasta stratovolcano was built to a large but unknown height; sometime between 300,000 and 360,000 years ago the entire north side of the volcano collapsed, creating an enormous landslide or debris avalanche, 6.5 cu mi (27 km3)[14] in volume. The slide flowed northwestward into Shasta Valley, where the Shasta River now cuts through the 28-mile-long (45 km) flow.
What remains of the oldest of Mount Shasta's four cones is exposed at
Sargents Ridge on the south side of the mountain. Lavas from the
Sargents Ridge vent cover the Everitt Hill shield at Mount Shasta's
southern foot. The last lavas to erupt from the vent were hornblende-pyroxene andesites with a hornblende dacite dome at its summit. Glacial erosion has since modified its shape.[citation needed]
The next cone to form is exposed south of Mount Shasta's current
summit and is called Misery Hill. It was formed 15,000 to 20,000 years
ago from pyroxene andesite flows and has since been intruded by a
hornblende dacite dome.[citation needed]
Since then the Shastina cone has been built by mostly pyroxene
andesite lava flows. Some 9,500 years ago, these flows reached about
6.8 mi (10.9 km) south and 3 mi (4.8 km) north of the area now occupied
by nearby Black Butte.
The last eruptions formed Shastina's present summit about a hundred
years later. But before that, Shastina, along with the then forming
Black Butte dacite plug dome complex to the west, created numerous pyroclastic flows that covered 43 sq mi (110 km2), including large parts of what is now Mount Shasta, California and Weed, California.
Diller Canyon (400 ft (120 m) deep and 0.25 mi (400 m) wide) is an
avalanche chute that was probably carved into Shastina's western face by
these flows.[citation needed]
The last to form, and the highest cone, the Hotlum Cone, formed about
8,000 years ago. It is named after the Hotlum glacier on its northern
face; its longest lava flow, the 500 ft-thick (150 m) Military Pass
flow, extends 5.5 mi (8.9 km) down its northwest face. Since the
creation of the Hotlum Cone, a dacite dome intruded the cone and now
forms the summit. The rock at the 600 ft-wide (180 m) summit crater has
been extensively hydrothermally altered by sulfurous hot springs and fumaroles there (only a few examples still remain).[citation needed]
In the last 8,000 years, the Hotlum Cone has erupted at least eight
or nine times. About 200 years ago the last significant Mount Shasta
eruption came from this cone and created a pyroclastic flow, a hot lahar
(mudflow), and three cold lahars, which streamed 7.5 mi (12.1 km) down
Mount Shasta's east flank via Ash Creek. A separate hot lahar went 12 mi
(19 km) down Mud Creek. This eruption was observed by the explorer La Pérouse, from his ship off the California coast, in 1786.[3]
i get so angry sometimes i just punch plankton --Klinotaxis
i get so angry sometimes i just punch plankton --Klinotaxis
i get so angry sometimes i just punch plankton --Klinotaxis
i get so angry sometimes i just punch plankton --Klinotaxis
i get so angry sometimes i just punch plankton --Klinotaxis
i get so angry sometimes i just punch plankton --Klinotaxis
i get so angry sometimes i just punch plankton --Klinotaxis
i get so angry sometimes i just punch plankton --Klinotaxis