Bridge River Cones facts for kids
Quick facts for kids Bridge River Cones |
|
|---|---|
| Highest point | |
| Elevation | 2,500 m (8,200 ft) |
| Geography | |
| Location | Upper Bridge River, British Columbia, Canada |
| Parent range | Pacific Ranges |
| Geology | |
| Age of rock | Holocene |
| Mountain type | Volcanic field |
| Volcanic arc/belt | Canadian Cascade Arc Garibaldi Volcanic Belt |
| Last eruption | Unknown, possibly younger than 500 |
The Bridge River Cones are a group of small volcanoes and volcanic features. They are also known as the Lillooet Cones or Salal Creek Cones. This volcanic area is found in British Columbia, Canada. It is about 40 kilometers (25 miles) west of the town of Gold Bridge.
These cones are located near the Lillooet Icecap. They sit in an area with mountain passes. These passes connect the Bridge River in the south with the Lord River in the north. The Lord River flows towards the Taseko Lakes.
What are the Bridge River Cones?
The Bridge River Cones are part of a volcanic field. A volcanic field is an area with many small volcanoes and lava flows. These volcanoes are not all connected to one big magma chamber. Instead, they have separate vents.
The cones are made of two types of volcanic rock. These are called trachybasalt and basalt. These rocks are formed from cooled lava.
Oldest Volcanoes
One of the oldest volcanoes in this field is Sham Hill. It is a steep-sided volcanic plug. A volcanic plug is like a stopper in an old volcano's vent. Sham Hill is about 60 meters (200 feet) tall.
Scientists used a method called potassium-argon dating to find its age. Sham Hill is about one million years old. Its top is smooth and covered with rocks left by glaciers. These rocks are called glacial erratics.
Another old part of the field is the Salal Glacier volcanic complex. This area is between 0.97 and 0.59 million years old. It has layers of ash and thin lava flows. Some lava flows are very thick, up to 100 meters (330 feet). They formed when lava flowed into ice.
Younger Volcanoes
Tuber Hill is a small stratovolcano. It is about 0.6 million years old. This volcano formed when the valleys nearby were filled with ice. Lava flows from Tuber Hill sometimes met glaciers. This created lakes from melted ice.
In these lakes, special volcanic materials were deposited. These include hyaloclastite and tuff. Hyaloclastite forms when hot lava shatters in water. Tuff is rock made from volcanic ash.
The newest volcanic rocks in the Bridge River field are found east of Tuber Hill. These are basalt flows that filled valleys. Scientists are not sure of their exact age. However, they think these flows are less than 1,500 years old. This is because they sit on top of loose glacial dirt.
