9: Sierra Nevada
- Page ID
- 20343
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Introduction
The Sierra Nevada range of California has a complex geologic history that spans 210 million years. While the majority of what would become the Sierra Nevada Province (Figure \(\PageIndex{1}\)) started forming during the Mesozoic Era, what we see today did not exist and is very different from the Sierra Nevada of that time.
The Sierra Nevada Mountains started to form when a series of volcanic eruptions formed much of the range's granitic rock, including iconic features like Half Dome and El Capitan in Yosemite National Park. Over time, erosion and crustal extension gradually revealed plutonic granite formations. Tectonic forces then continued to uplift the emerging Sierra Nevada range, shaping it into the distinctive landscape we observe today.
During the Cenozoic Era, tectonic forces continued to uplift the Sierra Nevada, and the mountains were sculpted by glaciers during the Pleistocene, giving rise to the dramatic landscapes seen today.
This chapter explores the history of this region, including the emplacement, exhumation, and erosion of batholiths that represent the magma chambers that fed a once extensive volcanic arc, the accumulation of gold deposits that would make the Sierra Nevada famous in recent times, and glacial evidence attesting to a changing climate in this region.
- Describe the Sierra Nevada Mountains in terms of rock types, age, and tectonic development.
- Assess the geologic hazards and risks associated with the Sierra Nevada region.
- Analyze the pieces of geologic evidence found in the Sierra Nevada Mountains to help describe how this province formed.
- Describe the major form of gold deposits in the Sierra Nevada Province and the geologic process involved in their formation and preservation. Define placer and lode deposits relate to geology and how such were put in place through geologic processes.
- 9.1: Physiographic Properties and Characteristics of the Sierra Nevada
- The primary geologic feature in this province is the magnificent Sierra Nevada Mountains. This range is underlain by felsic to intermediate granitic rocks and metamorphosed sediments. The range is gently sloped to the west, with a steep eastern face that is bounded by the Sierra Nevada fault. Elevations range from ~2,700 to ~4,300 meters (9,000 to 12,000 feet), with the highest peaks found in the southern part of the range. Here, Mount Whitney (elevation 14,496 ft; 4,418 m) rises more than 10,00
- 9.2: Geology of the Sierra Nevada
- The geology of the Sierra Nevada Province is dominated by the plutonic rocks of the extensive Sierra Nevada batholith, along with the metasedimentary and volcanic rocks into which they intrude. The overall geologic trends parallel the range and provide exposure of the roots of an ancient magmatic arc along with the accreted metamorphic belts that were thrust onto them.
- 9.3: Geologic History and Formation of the Sierra Nevada
- Three major episodes of tectonism in the Sierra Nevada Province have resulted in an extensive mountain range. The rocks of the Sierra Nevada are usually divided into two series of rocks The first series consists of the basement metasedimentary rocks that contain igneous intrusions. These intrusions took on the form of upward-moving magma that did not reach the earth’s surface. In this case, the igneous intrusions cooled within the crust. The resulting body of rock is known as a pluton. Where sev
- 9.4: National Parks of the Sierra Nevada
- As of 2023, there are several national parks in or near the Sierra Nevada range in California. These parks include Devils Postpile National Monument, Sequoia National Park, Kings Canyon National Park, and Yosemite National Park. The tectonic and hydrologic forces that formed each of spectacular national parks is truly a saga of fire and ice.
- 9.5: Natural Hazards in the Sierra Nevada Province
- In exploring the Sierra Nevada region, it becomes evident that its breathtaking beauty is accompanied by a complex array of geologic hazards. From the rumblings of seismic activity to the cascading threat of landslides, this majestic landscape harbors a myriad of natural dangers. Nestled within its rugged terrain, earthquakes, landslides, rock falls, flooding, and volcanic activity intertwine, each presenting its own unique challenge to those who call this region home.
- 9.6: Gold of the Sierra Nevada
- Nestled within the geological tapestry of California lies a treasure that has shaped both the landscape and human history: gold. Renowned as the state mineral, gold embodies the intricate interplay of geological processes that have sculpted the rugged terrain of the Sierra Nevada and fueled the aspirations of generations.
- 9.8: Chapter Summary and Key Terms
- Summary of key chapter points and items related to the Sierra Nevada Province.