Did you know there are three types of volcano? If you didn't, research using one of our favourite volcano sites and find out the difference. Once you understand the difference, can you locate each type of volcano on three different continents? When you have, post your answer in a comment below.
4 comments:
Three Main Types of Volcanoes and Utah Volcanoes
by Sandra Eldredge
Three Main Types of Volcanoes*
The three main types of volcanoes differ in shape, size, and make-up; the differences partly result from the different types of eruptions.
Volcano Type Volcano Shape Volcano Size Volcano Materials Eruption Type Utah Example
Cinder Cone
Steep conical hill with straight sides
Small
less than 300m high
cinders
Explosive
Diamond Cinder Cone,
Washington County
Shield Volcano
Very gentle slopes; convex upward (shaped like a warrior’s shield)
Large
over 10s of kms across
fluid lava flows (basalt)
Quiet
Cedar Hill,
Box Elder County
Stratovolcano
Gentle lower slopes, but steep upper slopes; concave upward
Large
1-10 km in diameter
numerous layers of lava and pyroclastics
Explosive
Mount Belknap,
Tushar Mountains, Paiute County
Selected volcanoes/volcanic areas in Utah mentioned in text.
Teachers:
Volcanoes
Landforms
of Utah (ppt)
Utah Volcanoes
Utah contains the three main types of volcanoes. The following is a brief introduction to Utah's volcanoes; only several of numerous volcanoes are mentioned.
Stratovolcanoes
Stratovolcanoes erupted in western Utah between about 40 to 25 million years ago. At this time, Utah was closer to a continental-oceanic plate boundary where an oceanic plate (Farallon) was subducting underneath the North American continental plate. Stratovolcanoes are found at these types of plate boundaries.
Stratovolcano - Mount Rainer and Mt. St. Helens (left background) rise above the surrounding landscape in Washington. These are a few of the active volcanoes in the Cascade Range. Mt. St. Helens boasts the most recent eruption (1980).
Photo credit: Marli Miller, Earth Science World Image Bank.
Today’s active stratovolcanoes include those in the Cascade Range in Washington, Oregon, and California where an oceanic plate (Juan de Fuca) is subducting underneath the North American continental plate.
Two examples of Utah’s stratovolcanoes are Mount Belknap in the Tushar Mountains and Monroe Peak on the Sevier Plateau.
Because these volcanoes are old and have been extensively eroded, it is difficult to distinguish the original volcano shapes.
Shield Volcanoes and Cinder Cones
Shield volcanoes and cinder cones started to erupt about 12 million years ago after plate motions and resulting crustal forces changed.
Compressional forces had eased, and the crust started to stretch between the Wasatch Range in Utah and the Sierra Nevada Range in California. This extension created splintered zones in the Earth’s crust where magma rose to the surface creating shield volcanoes and cinder cones.
Shield Volcano - Cedar Hill, located north of Great Salt Lake, bears a resemblance to several Hawaiian shield volcanoes. The volcano is approximately 1,150,000 years old. Cinder Cone - Diamond Cinder Cone is one of several cinder cones near St. George in Washington County, Utah. The cone is approximately 27,000 years old.
The most recent volcanic activity in Utah occurred about 600 years ago in the Black Rock Desert (Millard County).
Source : http://geology.utah.gov/utahgeo/geo/volcanoes/volcano_type.htm
come on no one is answering the tricky question
Active:Mona Loa
Dormant:Mount Fugi
Exinct:Deccan Traps
I just did man.
Post a Comment