Traprock (or basalt) mountains, ridges, (or just traps) are elevated landscape features made of trap rock, most often basalt. Basalt, due to its high quantity of iron, is a characteristically dark-colored rock that weathers to shades of red and purplish-red when exposed to the air. Basalt is the substance of many elevated topographic features worldwide (hills, mountains, ridges, rock formations, etc.). Landscape features composed of basalt may include:
Elevated sections of prehistoric ocean floor that have been raised above sea level via plate tectonics
Prehistoric terrestrial lava floods that have become upended and/or exposed via faulting and erosion
Various surface volcanic landforms both recent and ancient.
Because basalt has a tendency to fracture at abrupt angles, topographic features made of basalt often have a "postpile" appearance. Basalt ridges make up hundreds of square miles of topographic features in the northwestern United States, from Wyoming to Oregon.
Prominent basalt ridges, mountains, buttes, canyons, and other landscape features include:
The ridges and cliffs of the Columbia River Gorge in Oregon and Washington (state)
Basalt Mountain in Colorado, for which the town of Basalt, Colorado is named.
The Metacomet Ridge of Connecticut and Massachusetts.
The New Jersey Palisades and Watchung Mountains
Parts of California's inner coastal range.
Most of the Hawaiian Islands and their mountains are composed of basalt or similar volcanic rock.
The Paraná Traps of Brazil
The Deccan Traps of India
The Siberian Traps of Russia
The Green Gardens region of Gros Morne National Park in Newfoundland
The island of Surtsey in Iceland, a new (1963) volcanic island.
