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(Largest Free-Standing Boulder)


LOCATION: Giant Rock is located in Landers, CA.  From Yucca Valley, travel North on Route 247 to Landers. Turn right on Reche Rd. Turn left onto Belfield ​Blvd till pavement ends. Turn right onto Linn Rd.(the Integratron will be on the right) and then immediately left onto dirt road. Continue of rough road to Giant Rock.

GEOLOGIC FEATURES: Boulder; Jointing; Granites.

DESCRIPTION: Giant Rock is purported to be the largest free-standing boulder in North America, if not the world. The rock itself is seven stories tall and covers an area of 5800 sq. ft. It is composed of Quartz Monzonite or Granodiorite which is basically a Granite with varying amounts of plagioclase, alkali feldspars and quartz.

The rock was formed in the Cretaceous Period from a magma that cooled deep within the Earth (plutonic).  Ir was subsequently uplifted and exposed by weathering and erosion.

Massive granitic rocks such as this will often split along a series of geometrically spaced joints caused by regional tectonic stresses as well as a process of unloading whereby rocks expand and crack due to removal of overlying burden by uplift and erosion.  Weathering of rock edges along these joints are responsible for the formation of rounded boulders.

For many years native Americans performed spiritual ceremonies at the site of the rock in order to channel mystical powers. The rock became better known in the 1930s when an eccentric miner named Frank Critzer built a subterranean home underneath the boulder's north face.  The room measured 24 ft x 36 ft. and maintained a yearlong temperature range of 55 - 80 degrees F.  Critzer was killed in 1942 by a suspicious dynamite blast within the home.

Subsequent to Critzer's passing, his friend George W. Van Tassel moved to Giant Rock.  Three miles south of Giant Rock Van Tassel built the now famous Integratron which would eventually be used as a "Time Machine for Basic Research on Rejuvination, Anti-Gravity, and Time Travel" the plans of which were supposedly given to him through psychic transmissions and later personal contact with aliens during the 1950s.

Funding for the Integratron's construction was supplemented by Interplanetary Spacecraft Conventions held at Giant Rock for nearly 25 years as well as support from Howard Hughes.  The basic structure of the building was completed in 1959.  Van Tassel continued to work on the Integratron until his death in 1978. 

Currently, the "acoustically perfect" structure is used as a Sound Bath to calm tourists using the harmonic frequencies produced from vibrating quartz bowls.

A large portion of Giant Rock mysteriously split off in February of 2000 either through natural stresses within the rock or, as one mystic would have it, "the Mother had opened her arms to us cracking open her heart for the whole world to see."


(1) Define: Boulder

(2) What is the basic composition of a true Granite?

(3) CHALLENGE: How does a Joint differ from a Fault?  How are Joints formed?  Why are Joints geologically important?


-Ancient Phrophecy Fulfilled: Giant Rock Splits (2000, Feb 23). Lightnet. Accessed on  April 27, 2021 from

-Giant Rock Landers, California, A regular looking rock with an unbelievable history. Atlas Obscura. Accessed on April 27, 2021 at

-Stringfellow, Kim. (2018, May 15). Giant Rock, Space People and the Integratron. KCET.  Accessed on April 27, 2021 from

SPONSOR: This Field Trip Stop is sponsored by Scott and Casey of the nearby Red Tail Ranch Airbnb in historic Pioneertown, CA.


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Figure 1 - The north face of Giant Rock.  The area in the lower center of the rock is the area above the opening to Frank Critzer's underground room which has since been filled in and covered with concrete (Photo by Scott Marintsch.)

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Figure 2 - The east face of the seven story tall boulder.  The boulder's south side split off in February of 2000.

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Figure 3 - The relatively fresh face of the newly split boulder is white in color compared to the darker rind caused by continued exposure to weathering. (Photo by Scott Marintsch.)

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Figure 4 - A view of both freshly exposed faces of the split in Giant Rock.

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Figure 5 - Close-up of the newly exposed split in Giant Rock.  Crystals are of quartz (gray; between 1-2 mm in diameter), Feldspar (white), and minor darker minerals (probably amphibole and/or biotite mica).

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Figure 6 - Looking westward, smaller boulders surround the Giant. 

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Figure 7 - The Integratron located just south of Giant Rock was George W. Van Tassel's attempt to incur Rejuvination, Anti-Gravity, and Time-Travel using instructions provided to him by aliens. It measures 55 ft. in diameter and 38 ft. in height.

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