Basalt

Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock chemically equivalent to volcanic basalt or plutonic gabbro.

In February 2026, following weeks of strong waves and easterly winds, part of the iconic basalt columns collapsed along with significant erosion of the beach.

The monument protects Devils Postpile, an unusual rock formation of columnar basalt, "all closely and perfectly fitted together like a vast mosaic", and Rainbow Falls a waterfall on the Middle Fork of the San Joaquin River, which are also the two main attractions.

The Traps consist of many layers of solidified flood basalt that together are more than about 2 kilometres (1.2 mi) thick, cover an area of about 500,000 square kilometres (200,000 sq mi), and have a volume of about 1 million km3 (200,000 cu mi).

It is composed of basalt, and it is the most active of the volcanoes in Ethiopia.

It poured out an estimated 42 billion tonnes or 14 km3 (18×10^9 cu yd) of basalt lava, as well as clouds of poisonous hydrofluoric acid and sulfur dioxide compounds that contaminated the soil, leading to the death of over 50% of Iceland's livestock population and the destruction of the vast majority of all crops.

The main feature of the zone is basalt rock formations in capricious forms, created by erosion over millions of years.

Along the sides of the gorge are cliff walls of well-preserved basalt columns, carved out by the Goght River.

It is a 2m long depression in basalt.

It is also renowned for its unique natural feature of columnar basalt landscape.

Dubh Artach (; Scottish Gaelic: Dubh Hirteach [t̪u ˈhirˠʃtʃəx]) is a remote skerry of basalt rock off the west coast of Scotland lying 18 miles (29 km) west of Colonsay and 15 miles (24 km) south-west of the Ross of Mull.

From south to north, these are: Soldier’s Cap Sugarloaf South Island Noddy Roach Island Tenth of June North Rock Flat Rock Roach Island is the largest, being about 15 ha in area, 800 m long and 86 m in maximum height, with a much-photographed 15-metre-tall tunnel at its northern end. Basalt lava flows are crossed by many dikes.

A flood basalt (or plateau basalt) is the result of a giant volcanic eruption or series of eruptions that covers large stretches of land or the ocean floor with basalt lava.

Small explosions of gas and ash occur every 15 to 20 minutes, but larger eruptions are less frequent. Andesite and basalt lava types dominate.

The Giant's Causeway (Irish: Clochán an Aifir or Clochán na bhFomhórach) is an area of approximately 40,000 interlocking basalt columns, the result of an ancient volcanic fissure eruption, part of the North Atlantic Igneous Province active in the region during the Paleogene period.

slopes: the Golan Heights to the east and the Upper Galilee's Naftali Mountains to the west rise to 400 to 900 meters above sea level. Basalt hills of about 200 meters above sea level along the southern side of the valley intercept the Jordan River, and are commonly referred to as the basalt "plug", the Korazim block, or

At one time this fault was very geologically active and gave rise to the Brokenback range that feature prominently in the Hunter valley. Strips of basalt found throughout the region also bear witness to the volcanic activity that has occurred in the history of this fault.

The archipelago consists predominantly of pre-Tertiary continental islands primarily of quartzites and shales covered by basaltic lava.

Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression.

Plateaus formed by large igneous provinces were formed by the equivalent of continental flood basalts such as the Deccan Traps in India and the Snake River Plain in the United States.

Two edifices, less than 2.5 kilometres (1.6 mi) wide, flank the 1.3-by-0.5-kilometre-wide (0.81 mi × 0.31 mi) summit crater on its eastern and western side. Basalt, gravel, pumice and scoria crop out in its rim, which is lower on the northern side.

These rocks are largely igneous in origin, mixed with metamorphosed marble, quartzite and mica schist and intruded by later basaltic dykes and granite magma.

The islands themselves are crossed by many calcareous faults, some marbleised, and made of basaltic rock, ash, and other volcanic materials.

The volcano is believed to have spread over more than 5000 m2 and resulted in a thick sequence of basaltic lava some 3,000-3,500 m thick that was deposited on Precambrian crystalline basement.

Both the ancient river valley and the Silurian sedimentary rock lies buried beneath the basaltic volcanic rocks of the New Volcanic Group.

Mountains sides have tertiary volcanic rock, mostly basalt and andesite along with pyroclastic matter and breaches.

The Tunkin volcanic field has filled the Tunkin Depression with about 500 metres (1,600 ft) of volcanic products, which range from Miocene to Quaternary and include basaltic lava flows and tuffs.

Lava tube, Basalt

Basalt, Quartzite

Andesite, Basalt, Basaltic Andesite, Picro-Basalt, Dacite

Such features are generally composed of highly fluid basalt lava, and can extend for tens or hundreds of kilometers across the underlying terrain.