Note: This is an Earthcache. There is no physical cache to find. Logging this Earthcache requires that you undertake an educational task relating to the specific Earth Science at the site.
Prior to logging this cache, click on Message this owner, or send an email with answers to the following questions:
- What is the diameter at the base of the Plunge Pool Room?
- Looking at the wall under the skylight, what evidence is there that water made this room?
- Do you think Cave Canyon was a narrow cave or a wide cave? Why?
- Required to log this cache:Please provide a photo of yourself or a personal item in the picture to prove you visited the site. Upload the photo with your log.
Mud Caves
Mud caves are found along the walls of Arroyo Tapiado. Arroyo Tapiado, translated from Spanish is “walled wash”. This is one of the most extensive mud cave systems in the world, containing approximately 22 known caves and 9 slot canyons. The length of the caves varies, with some extending over 1,000 feet and featuring ceilings as high as 80 feet. Caves have been reported up to 35 feet wide, and others so narrow, you have to squeeze through openings. Multi-level caves with skylights have been found, where erosion has created an opening, or sinkhole, in the ceiling of the cave. Some of the caves are fairly easy to navigate while others may require you to crawl in sections.
The mud caves are formed by fluvial erosion caused during periods of heavy rainfall. The area is primarily composed of a gypsiferous claystone know as mudstone. This layered sediment was deposited at the bottom of prehistoric Lake Cahuilla and uplift began in the middle of the Pleistocene. Initially, flash floods carved deep, narrow, twisting slot canyons through the soft mudstone. Sharp stream meanders allowed the rushing waters to undermine the canyon walls. Eventually, the mudstone slumped over, into the streambed. The stream continued to burrow under and through the mudstone, which is very cohesive when moist. The desert heat then dried the mudstone to a hard adobe-like material.
East of GZ you will see a 20 foot high and 3 foot wide opening to the Plunge Pool Cave. The entrance to this cave can be identified by the white ash layer. This volcanic ash settled hot in shallow fresh water about 2.3 million years ago. This is a true cave without light. Flashlights are necessary to see the inside. About 100 feet in from the entrance is the "Plunge Pool Room" which has a 50 foot high dry waterfall that plunges down from a skylight entrance. Water eventually broke through the hard sandstone ceiling and carved through the softer layers below, creating this dry subterranean waterfall. Turn off your lights and let your eyes adjust to answer the questions for this cave.
NW of GZ you will see a 30 feet high opening to Big Mud Cave or Cave Canyon. It’s very popular because it’s easily visible from the road. Cave Canyon is an example of the final stage of mud cave evolution, a collapsed remnant of an ancient cave. It’s a quarter mile long canyon of mudstone arches and bridges.
Safety Tips:
- 4WD is recommended. 2WD might be used under ideal conditions.
- Start with a full tank of gas. Carry extra water, shovel, tools, flares and blankets.
- Track your route to GZ. It is easy to go up (or down) the wrong arroyo.
- The caves are fragile. Please take care to preserve them for others to enjoy.
- Always use caution when exploring caves.
- Do not climb up the walls of the caves.
- Do not walk on top of the caves, along the ridges or in areas where the ground may cave in. These hills are made of mud and can be very unstable.
- Never enter the caves if it is raining, has rained recently or if rain is expected.
- Take a partner with you when you explore the caves. Let someone know exactly where you are going to be and when you will return.
- Carry several light sources and plenty of water.
Anza-Borrego Desert State Park is the largest state park in California. Five hundred miles of dirt roads, 12 wilderness areas and many miles of hiking trails provide visitors with an unparalleled opportunity to experience the wonders of the California Desert. The park is named for Spanish explorer Juan Bautista de Anza and the Spanish word borrego, or bighorn sheep. The park features washes, wildflowers, palm groves, cacti and sweeping vistas. Visitors may also have the chance to see roadrunners, golden eagles, kit foxes, mule deer and bighorn sheep as well as iguanas, chuckwallas and the red diamond rattlesnake. There is no admission fee.
Sources:
California State Parks - Anza-Borrego Desert State Park
Scott A. Schmitz, California Caver
