Joshua Tree National ParkPágina 17 de 45
NPS Geodiversity Atlas—Joshua Tree National Park, California
Geodiversity refers to the full variety of natural geologic (rocks, minerals, sediments, fossils, landforms, and physical processes) and soil resources and processes that occur in the park. A product of the Geologic Resources Inventory, the NPS Geodiversity Atlas delivers information in support of education, Geoconservation, and integrated management of living (biotic) and non-living (abiotic) components of the ecosystem.
Introduction
Joshua Tree National Park (JOTR) is located approximately 160 km (100 mi) east of San Diego and the Los Angeles metropolitan area in Riverside and San Bernardino Counties, southern California. The park unit was proclaimed a national monument on August 10, 1936 and redesignated a national park on October 31, 1994. JOTR preserves approximately 319,959 hectares (790,636 acres) of sand dunes, dry lakes, flat valleys, rugged mountains, granitic monoliths, and oases. Several mountain ranges are found within or along the boundaries of the park: the Pinto Mountains on the northern boundary; the Coxcomb Mountains in easternmost JOTR; the Eagle Mountains in southeastern JOTR; the Cottonwood Mountains on the southern boundary; the Little San Bernardino Mountains on the southwestern boundary; and the Hexie Mountains in the central part of the park (Tocci et al. 2018). The park is home to a fascinating, diverse biological community representative of both the Mojave and Colorado desert ecosystems, and was designated a Biosphere Reserve in 1984.
Geologic Setting
The geologic history of Joshua Tree National Park records the effects of plate tectonics, volcanism, mountain-building, and stark erosion. The bedrock geology of the park is represented primarily by crystalline igneous and metamorphic rocks of several time intervals, with significant sedimentary units limited to approximately the past 10 million years (Tocci et al. 2018). The oldest rocks in the park date back to the Proterozoic Eon at 1.7–1.4 billion years old and consist of metamorphic rocks that have been intruded and altered by subsequent igneous activity. Within JOTR there are at least five different bodies of igneous rock; the oldest of which rival the metamorphic rocks in age, and the youngest only tens of millions of years old. Overall, the geologic time periods best-preserved at JOTR include the Paleoproterozoic Era, Mesoproterozoic Era, Mesozoic Era, and Miocene Epoch to present (Tocci et al. 2018).
Regional Geology
Joshua Tree National Park lies at the eastern terminus of the Transverse Ranges wiithin the Pacific Border Physiographic Province. The Transverse Ranges are unusual in that they trend east-west rather than north-south as do most ranges. The Transverse Ranges province extends about 325 miles from Point Arguello and San Miguel Island on the west coast of California to the Coxcomb Mountains in Joshua Tree on the east (Norris and Web, 1976). Principal mountain ranges include the Little San Bernardino Mountains to the southwest, the Pinto, Cottonwood, and Hexie Mountains in the central part, and the Eagle and Coxcomb Mountains on the east end. Elevations are generally between 2,000 to 4,000 feet. The highest point is 4,562 feet at Twentynine Palms Mountain.
Maps and Reports
Geologic Resources Inventory
The Geologic Resources Inventory produces digital geologic maps and reports for more than 270 natural resource parks. The products listed below are currently available for this park, check back often for updates as many maps, reports, and posters are still in progress.
Scoping summaries are records of scoping meetings where NPS staff and local geologists determined the park’s geologic mapping plan and what content should be included in the report.
- Digital geologic maps include files for viewing in GIS software, a guide to using the data, and a document with ancillary map information. Newer products also include data viewable in Google Earth and online map services.
- Reports use the maps to discuss the park’s setting and significance, notable geologic features and processes, geologic resource management issues, and geologic history.
- Posters are a static view of the GIS data in PDF format. Newer posters include aerial imagery or shaded relief and other park information. They are also included with the reports.
- Projects list basic information about the program and all products available for a park.
Source: NPS DataStore Saved Search 2912
. To search for additional information, visit the
NPS DataStore.
Soil Resources inventory
A NPS Soil Resources Inventory project has been completed for Joshua Tree National Park and can be found on the NPS Data Store.
Source: NPS DataStore Saved Search 2984
. To search for additional information, visit the
NPS DataStore.
Related Links
Joshua Tree—Geologic Formations
NPS—Arid and Semi-arid Region Landforms
NPS—Volcanic Landforms: Intrusive Igneous
Related Articles
Joshua Tree National Park
- Desert Varnish — Ever wondered what those dark lines were on the rock walls of canyon country? These black, brown, and red streaks are called desert varnish.
- Closing Abandoned Mines — The legacy of mining is readily visible today. Within the boundaries of what is now a national park are about 300 abandoned mining sites with more than 720 mine openings. Visitors are often intrigued by the idea of exploring old mines, but abandoned mine workings pose a serious resource management challenge for the park.
- Fossils in Joshua Tree — National parks are special lands that are designated to permanently protect things that are part of our collective heritage like stunning views, unique wildlife, endangered species, areas of recreation, and wilderness. Seventeen national parks in the United States were created partly to protect the fossils found in them. Joshua Tree National Park is one of these!
- Studying the Past and Predicting the Future Using Rat Nests — In the western United States, packrat middens are one of the best tools for reconstructing recent environments and climates. These accumulations of plant fragments, small vertebrate remains, rodent droppings, and other fossils can be preserved for more than 50,000 years. Packrat middens have been found in at least 41 National Park Service units.
- Series: Park Paleontology News - Vol. 14, No. 2, Fall 2022 — All across the park system, scientists, rangers, and interpreters are engaged in the important work of studying, protecting, and sharing our rich fossil heritage. Park Paleontology news provides a close up look at the important work of caring for these irreplaceable resources. Contribute to Park Paleontology News by contacting the newsletter editorLearn more about Fossils & Paleontology Celebrate National Fossil Day with events across the nation
- From Sea to Shining Sea: "Fossils from Your Public Lands" at the Western Science Center — The Western Science Center in Hemet, California serves as a repository for fossils from several land management agencies. It is currently running an exhibit, “Fossils from Your Public Lands”, to showcase examples of these fossils with the cooperation of additional parks and repositories.
- Series: Geologic Time—Major Divisions and NPS Fossils — The National Park System contains a magnificent record of geologic time because rocks from each period of the geologic time scale are preserved in park landscapes. The geologic time scale is divided into four large periods of time—the Cenozoic Era, Mesozoic Era, Paleozoic Era, and The Precambrian.
- Quaternary Period—2.58 MYA to Today — Massive ice sheets advanced and retreated across North America during much of the Quaternary, carving landscapes in many parks. Bering Land Bridge National Preserve contains geologic evidence of lower sea level during glacial periods, facilitating the prehistoric peopling of the Americas. The youngest rocks in the NPS include the lava of Hawaii Volcanoes National Park and the travertine at Yellowstone National Park, which can be just a few hours old.
- Neogene Period—23.0 to 2.58 MYA — Some of the finest Neogene fossils on the planet are found in the rocks of Agate Fossil Beds and Hagerman Fossil Beds national monuments.
- The Precambrian — The Precambrian was the "Age of Early Life." During the Precambrian, continents formed and our modern atmosphere developed, while early life evolved and flourished. Soft-bodied creatures like worms and jellyfish lived in the world's oceans, but the land remained barren. Common Precambrian fossils include stromatolites and similar structures, which are traces of mats of algae-like microorganisms, and microfossils of other microorganisms.
National Park Service Geodiversity Atlas
The servicewide Geodiversity Atlas provides information on geoheritage and geodiversity resources and values within the National Park System. This information supports science-based geoconservation and interpretation in the NPS, as well as STEM education in schools, museums, and field camps. The NPS Geologic Resources Division and many parks work with National and International geoconservation communities to ensure that NPS abiotic resources are managed using the highest standards and best practices available.
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