NPS Archeology Program: Coso Rock Art

setting the scene The landscape

The Coso Rock Art District occupies a landscape of stark beauty. Formed by titanic forces of colliding continental plates and upwelling molten rock, and carved by rushing waters of glacial melt and eons of endless rain, today's desert conditions seem almost preternaturally silent.

This is California's high desert where the northernmost stretches of the Mojave meet the Great Basin. It is surrounded by the Coso Mountains to the north, the Panamint Mountains to the east and the Sierra Nevada to the west. The District itself sits at the southern edge of the Coso range, among the foothills and tableland that step down a series of basalt terraces southwest towards the dry bed of China Lake.

Canyons cut through the basalt formations give evidence of the wet conditions that once prevailed here. As glaciers from the last ice age retreated into the high Sierras, meltwater and constant rain blasted through the volcanic rock to form streams, canyons, and river valleys. Cut off from the ocean, inland lakes formed between the mountain ranges and created a lush environment perfect for large mammals.

Broad savannas with willow and cottonwood-lined streams stretched away from the marshy lakeshores. Oak and pine woodlands rose from the China Lake basin up into the Sierras. This habitat supported horses, camels, bison, sloth, and the carnivores that hunted them—saber-toothed tigers and jackal-like dogs. more >>

In this mild climate, food was plentiful. The earliest people lived in small villages along the lakes, taking game and collecting plant foods with relative ease.

But the climate became progressively hotter and drier, forcing life to adapt. Between 9,000 to 7,000 years ago, rapid drying led to the extinction of most large mammals. Others, like pronghorn antelope and desert longhorn sheep, endured until recent times.

Inyo mule deer still roam here, along with smaller mammals like rabbits, coyote, and fox. Desert rodents, lizards, insects, and snakes survive in abundance.

As the climate became more arid, desert plants or barren soils replaced temperate vegetation. The landscape finally became among the driest in the nation with an annual rainfall of only 4.5 inches. No permanent water sources now exist in the District.

Today, the Coso District supports only desert and Great Basin plant communities. No trees grow here, leaving only topographic diversity to create the vast and dramatic vistas for which this area is known.

COSO VOLCANISM

Coso's volcanic nature is evident in such features as this cinder cone, formed when ash and small bits of rock were blasted from a vent in a fountain-like jet. Tephra, as the material is known, piles up around the vent as it falls to the ground, leaving a steep-sloped cone. Some cones at Coso are thought to be less than 500 years old.

The most active sign of the area's volcanism is the Coso hot springs. Underground water is heated by molten rock near the surface, producing wells of bubbling mud. Today, the Navy uses this geothermal energy to produce electricity; however, it also respects the traditions of local peoples and allows them to use the springs for healing purposes.

(photo) Old lava flow between hills. Far Western Anthropological Research Group, Inc.

FIRE MOUNTAINS

The Coso (Fire) Range was formed of volcanic rock spewed from the earth as shifting continental plates pulled apart the intermountain landscape. This basaltic lava flow is typical of the process that created the stepped terraces of Coso as it flowed across the landscape, producing a more or less flat surface eroding to a sheer front. The resulting rimrock walls give the Coso Mountains their distinct appearance.

Other volcanic activity produced large deposits and scattered outcroppings of high-quality volcanic glass. Coso's obsidian was traded throughout California, and is found at archeological sites as far away as the Pacific coast.

NICHE ECOSYSTEMS

Despite the generally dry conditions in the Coso Mountains, the terraces, canyons, and other landforms create a variety of niche ecosystems, some of which collect water and become rich with life. These niches help support a larger variety of seed-producing plants than on the featureless desert floor. As the seasons progress, different plants come to seed one after another, according to local conditions and altitude.