Trona Pinnacles

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Trona Pinnacles

Designation	National Natural Landmark
Location	California
Nearest City	Trona, California
Coordinates	35°36′43″N, 117°22′10″W
Area	3,800 acres 1,537.8 ha
Date of Establishment	1968
Governing Body	Bureau of Land Management

The Trona Pinnacles is one of the most unusual geological features in the California Desert National Conservation Area. The unusual landscape consists of more than 500 tufa spires (porous rock formed as a deposit from springs of streams), some as high as 140 feet (43 m), rising from the bed of the Searles Lake (dry) basin. The pinnacles vary in size and shape from short and squat to tall and thin, and are composed primarily of calcium carbonate (tufa). They now sit isolated and slowly crumbling away near the south end of the valley, surrounded by many square miles of flat, dried mud and with stark mountain ranges at either side.

The Pinnacles are recognizable in more than a dozen hit movies. Over thirty film projects a year are shot among the tufa pinnacles, including backdrops for car commercials and sci-fi movies and television series such as Battlestar Galactica, Star Trek V: The Final Frontier, The Gate II, Lost in Space, and Planet of the Apes.^[1]

1 Geography
2 Geology
3 Gallery
4 References
5 See also
6 External links

[edit] Geography

The Trona Pinnacles, at an elevation of 1,800 feet (550 m) above sea level, are located approximately 10.0 miles (16.1 km) south of Trona, California. Access to the site is from a BLM dirt road (RM143) that leaves State Highway 178, about 7.7 miles (12.4 km) east of the intersection of State Highway 178 and the Trona-Red Mountain Road. The 5.0-mile (8.0 km) long dirt road from State Highway 178 to the Pinnacles is usually accessible to 2-wheel drive vehicles, however, the road may be closed during the winter months after a heavy rain.

The Pinnacles are located within 3,800 acres (15 km²) of federal land managed by the Bureau of Land Management. The Trona Pinnacles are inside a BLM Area of Critical Environmental Concern (ACEC) designated to protect and preserve unique resources.

[edit] Geology

During the Pleistocene, massive runoff spilled from the Sierra Nevada into a chain of inland seas. The system of interconnected lakes stretched from Mono Lake to Death Valley and including Searles Lake.

Deep beneath Searles Lake, calcium-rich groundwater and alkaline lake water combined to grow tufa formations. Today you can see the rare aftermath of the perfect geological conditions.

Known as tufa pinnacles, these strange shapes formed underwater 10,000 to 100,000 years ago. The pinnacles did not all form at the same time. They are divided by age and elevation into three groups. The groups are dubbed the northern, middle, and southern groups because they formed during three ice ages.

The northern group is the youngest at 10,999 to 25,000 years old. These are the best examples of what are known as tufa towers. The northern youngsters also include shapes called tombstones, ridges and cones. Close cousins to the northern group, the small middle group claims only 100 spires, but boasts the tallest "tower", rising 140 feet (43 m). The granddaddy of them all, the southern group, includes 200 tufa formations aged 32,000 to 100,000 years old.

People have historically given names to the strange forms. These ancient spires were once dubbed "Cathedral City". Geologically, the pinnacles are classified into four general shapes. Towers are taller than they are wide and rise 30 to 40 feet (12 m). Tombstones are stubby and squat and rise 20 to 30 feet (9 m). Most tombstones are in the northern-most tufa formations. Ridges are massive toothy tufa ruins. Trona has three ridges, one in the northern tufa cluster and two in the middle group. One ridge is 800 feet (240 m) long and 500 feet (150 m) wide and 140 feet (43 m) tall. Cones are less than 10 feet (3 m) tall. Dumpy and mounded, cone shapes lay scattered throughout the Trona Pinnacles.

[edit] Gallery

Sweep of pinnacles. NOTE: white SUV on right side provides scale.	Start of 5-mile (8 km) road to the Pinnacles.	Some of the pinnacles with dry Searles Lake in background.	Close-up of the tufa rock, with large pinnacle towers in background