pinnacles

Pinnacles are tall, slender rock formations that rise abruptly from the surrounding landscape. They are often called spires or towers and occur in a range of geologic settings around the world, from desert plateaus and canyon walls to coastal cliffs and alpine ledges. Pinnacles can vary greatly in height, width, and degree of isolation.

Formation: Pinnacles form mainly through differential erosion and weathering. A harder, more resistant caprock or layer protects the upper portion of the pillar, while softer rock beneath erodes away. Over time, wind, rain, and frost widen joints and fractures, producing slender columns. In volcanic regions, cooling of lava and subsequent tectonic uplift can produce columnar forms that are later isolated by erosion.

Composition and distribution: Pinnacles occur in sandstone, limestone, volcanic rocks, and other lithologies. They are common in arid and semi-arid regions, as well as in coastal and alpine landscapes. Notable examples include Pinnacles National Park in California, which preserves a landscape of tall stone spires formed from ancient volcanic and sedimentary rocks.

Ecology and use: Pinnacles provide habitats for lichens, mosses, and specialized plants, and can host nesting birds. The narrow crevices offer shelter and breeding sites. They attract hikers and rock climbers, though rockfalls and weathering pose hazards, and many pinnacles are protected within parks or reserves.

Etymology: The term pinnacle comes from the Old French pinnacle, ultimately from Latin pinnaculum, meaning a little wing or peak.