Eastern Sierra South of Mammoth
It was raining in June Lake and Mammoth on Wednesday morning, but the further south we drove, the better the weather. In this shot of the Eastern Sierra, you can see some reddish rocks. This is the remnant of volcanic rock that spewed over the granite mountains.
More than 100 million years ago, granite formed deep underground. The range started to uplift 4 million years ago, and erosion by glaciers exposed the granite and formed the light-colored mountains and cliffs that make up the range. The uplift caused a wide range of elevations and climates in the Sierra, which are reflected by the presence of five life zones.
In the Cretaceous, a subduction zone formed at the edge of the continent; an oceanic plate started to dive beneath the North American plate. Magma formed through the subduction of the ancient Farallon Plate rose in plumes (plutons) deep underground, their combined mass forming what is called the Sierra Nevada batholith. These plutons formed at various times, from 115-million to 87-million years ago. The earlier plutons formed in the western half of the Sierra, while the later plutons formed in the eastern half of the Sierra. By 65-million years ago, the proto-Sierra Nevada had been worn down to a range of rolling low mountains, a few thousand feet high.
Twenty million years ago, crustal extension associated with the Basin and Range Province caused extensive volcanism in the Sierra.[18] About 4-million years ago, the Sierra Nevada started to form: a block of crust between the Coast Range and the Basin and Range Province started to tilt to the west. Rivers started cutting deep canyons on both sides of the range. The Earth's climate cooled, and ice ages started about 2.5-million years ago. Glaciers carved out characteristic U-shaped canyons throughout the Sierra. The combination of river and glacier erosion exposed the uppermost portions of the plutons emplaced millions of years before, leaving only a remnant of metamorphic rock on top of some Sierra peaks.
In this shot of the Eastern Sierra the reddish rocks are remnants of that volcanic rock.
Uplift of the Sierra Nevada continues today, especially along its eastern side. This uplift causes large earthquakes, such as the Lone Pine earthquake of 1872.
Eastern Sierra South of Mammoth
It was raining in June Lake and Mammoth on Wednesday morning, but the further south we drove, the better the weather. In this shot of the Eastern Sierra, you can see some reddish rocks. This is the remnant of volcanic rock that spewed over the granite mountains.
More than 100 million years ago, granite formed deep underground. The range started to uplift 4 million years ago, and erosion by glaciers exposed the granite and formed the light-colored mountains and cliffs that make up the range. The uplift caused a wide range of elevations and climates in the Sierra, which are reflected by the presence of five life zones.
In the Cretaceous, a subduction zone formed at the edge of the continent; an oceanic plate started to dive beneath the North American plate. Magma formed through the subduction of the ancient Farallon Plate rose in plumes (plutons) deep underground, their combined mass forming what is called the Sierra Nevada batholith. These plutons formed at various times, from 115-million to 87-million years ago. The earlier plutons formed in the western half of the Sierra, while the later plutons formed in the eastern half of the Sierra. By 65-million years ago, the proto-Sierra Nevada had been worn down to a range of rolling low mountains, a few thousand feet high.
Twenty million years ago, crustal extension associated with the Basin and Range Province caused extensive volcanism in the Sierra.[18] About 4-million years ago, the Sierra Nevada started to form: a block of crust between the Coast Range and the Basin and Range Province started to tilt to the west. Rivers started cutting deep canyons on both sides of the range. The Earth's climate cooled, and ice ages started about 2.5-million years ago. Glaciers carved out characteristic U-shaped canyons throughout the Sierra. The combination of river and glacier erosion exposed the uppermost portions of the plutons emplaced millions of years before, leaving only a remnant of metamorphic rock on top of some Sierra peaks.
In this shot of the Eastern Sierra the reddish rocks are remnants of that volcanic rock.
Uplift of the Sierra Nevada continues today, especially along its eastern side. This uplift causes large earthquakes, such as the Lone Pine earthquake of 1872.