15: Peninsular Ranges
- Page ID
- 20349
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Introduction to the Peninsular Ranges
The Peninsular Ranges province of California, which includes the coasts of Orange and San Diego counties, is known throughout the world as the home of beautiful beaches, surfing, usually fantastic weather, and many theme parks. It’s also just south of the Transverse Ranges, which makes for an easy drive north to the winter ski resorts of the San Gabriel and San Bernardino Mountains. This is how the challenge known as “California Double” began, to both surf and ski between sunup and sundown of the same day. Life here can be downright delightful, but geologically, things are complicated.
The province is named after a series of northwest-southeast trending mountain ranges starting south of the Transverse Ranges and extending into Mexico, where the mountains form the spine of the Baja California Peninsula. These mountains are underlain by a batholith. The California portion of this batholith has historically been referred to as the Southern California batholith, ignoring the reality that most of the batholith and the mountains are actually in Mexico and only the small, northernmost tip is in California. In an effort to help correct this misconception, more recent publications have started to refer to the batholith as the Peninsular Ranges batholith instead.
These ranges formed as part of the Mesozoic volcanic arc that dominated what is now the western coast of California (see Geologic History Mesozoic Era (250 – 66 Ma)) and are therefore similar, but not identical, in rock type and timing to the Sierra Nevada. While there are small exposures of pre-Mesozoic rock in the mountains, most of the rock exposed in the Peninsula Ranges and on the coastal plain is Mesozoic and younger.
The coastal plain to the west of the mountains, along with its beaches, is dominated by marine terraces, headlands, sea cliffs, wave-cut platforms, pocket beaches, and other landforms common on erosional coasts where earthquakes are common (see California Coastline Anatomy). While the province is named after the mountains, most of the population, and the resources in use today are concentrated on the coastal plain. Generally, when people think of this part of California, they think beaches, not mountains. For most people, the mountains form a picturesque background that enhances living near or vacationing on the beach (Figure \(\PageIndex{1}\)).
By the end of this chapter, you should be able to:
- Describe the Peninsular Ranges province in terms of its key geographic and geologic features.
- Explain how the Peninsular Ranges fit into the broader context of the tectonics and geologic history of California.
- Describe the timing of the formation and characteristics of the rocks of the Peninsular Ranges, including their similarities and differences with the Sierra Nevada.
- Assess the geologic hazards and risks associated with the Peninsular Ranges province.
- Describe the natural resources within the Peninsular Ranges province.
- 15.1: Geomorphology of the Peninsular Ranges
- This page covers the Peninsular Ranges in Southern California, noting their extensive length, diverse geological features, and significant peaks like San Jacinto. It describes the influence of climate and glaciation on coastal geology, highlighting marine terraces and erosional phenomena.
- 15.2: Tectonics and Geologic History of the Peninsular Ranges Province
- This page covers the geological history of California's Peninsular Ranges, highlighting three phases: a passive margin, subduction, and transform boundaries. It discusses the evolution from the Paleozoic to the late Cenozoic era, noting significant volcanic activity and sediment deposition influenced by tectonic changes, particularly the Farallon plate.
- 15.3: Rocks of the Peninsular Ranges
- This page summarizes the geological features and history of the Peninsular Ranges province, focusing on the composition of plutonic igneous rocks, notably granitic formations, and the rarity of volcanic rocks. It outlines the formation of batholiths and significant geological events from the Mesozoic to Cenozoic eras, including shifts between marine and non-marine environments.
- 15.4: Geologic Hazards of the Peninsular Ranges
- This page addresses various geologic hazards in California, highlighting earthquake risks from local fault zones and significant historical flooding events. A focus on the Palos Verdes, Rose Canyon, and Elsinore faults reveals potential for serious damage in future scenarios. Issues like saltwater intrusion in coastal areas, particularly in Huntington Beach, are discussed alongside geological monitoring techniques and the impacts of climate change.
- 15.5: Natural Resources of the Peninsular Ranges
- This page details the Peninsular Ranges' resource management, highlighting the mining history and urban development challenges due to water scarcity. Key resources include sand, gravel, limestone, and significant oil production, particularly in Huntington Beach. While agriculture's importance diminishes, innovative water conservation methods like recycling and desalination are explored.
- 15.6: Chapter Summary
- A summary of the Peninsular Ranges chapter.
- 15.7: Detailed Figure and Video Descriptions
- Descriptions of complex images and video animations within this chapter, intended for users who have difficulty seeing and interpreting images.
Thumbnail: "Peninsular Ranges Province" is licensed under CC BY-NC 4.0 by Allison Jones.