Lava flow in the context of Tibesti

In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on Earth form lava domes. The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day). The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite.

Existence of lava domes has been suggested for some domed structures on the Moon, Venus, and Mars, e.g. the Martian surface in the western part of Arcadia Planitia and within Terra Sirenum.

Rhyolite (/ˈraɪ.əlaɪt/ RY-ə-lyte) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite.

Its high silica content makes rhyolitic magma extremely viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations.

Basalt (UK: /ˈbæsɒlt, -ɔːlt, -əlt/; US: /bəˈsɔːlt, ˈbeɪsɔːlt/) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt has the same chemical composition and mineralogy as slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of Venus, which cover ~80% of the surface, are basaltic; the lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars.

Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flows that can spread over great areas before cooling and solidifying. Flood basalts are thick sequences of many such flows that can cover hundreds of thousands of square kilometres and constitute the most voluminous of all volcanic formations.

The Deccan Plateau (/ˈdɛkən/ DEK-ən ) is a geographic formation that extends over an area of 422,000 km (163,000 sq mi) on the southern part of the Indian peninsula. It stretches from the Satpura and Vindhya Ranges in the north to the northern fringes of Tamil Nadu in the south. It is bound by the mountain ranges of the Western Ghats and the Eastern Ghats on the sides, which separate the region from the Western and Eastern Coastal Plains respectively. It covers most of the Indian States of Maharashtra, Karnataka, Telangana and Andhra Pradesh excluding the coastal regions, and minor portions of Tamil Nadu and Kerala.

The plateau is marked by rocky terrain with an average elevation of about 600 m (2,000 ft). It is subdivided into Maharashtra Plateau, Karnataka Plateau, and Rayalaseema and Telangana Plateau. The Deccan Traps in the northwest were formed by multiple layers of igneous rock deposited by basaltic lava flows following a massive volcanic eruption occurred at the end of the Cretaceous period (66 mya). The underlying bed consists of granite and sedimentary rocks formed during the Precambrian era and the formation of Gondwana.

In volcanology, a Strombolian eruption is a type of volcanic eruption with relatively mild blasts, typically having a Volcanic Explosivity Index of 1 or 2. Strombolian eruptions consist of ejection of incandescent cinders, lapilli, and volcanic bombs, to altitudes of tens to a few hundreds of metres. The eruptions are small to medium in volume, with sporadic violence. This type of eruption is named for the Italian volcano Stromboli.

The tephra typically glows red when leaving the vent, but its surface cools and assumes a dark to black colour and may significantly solidify before impact. The tephra accumulates in the vicinity of the vent, forming a cinder cone. Cinder is the most common product; the amount of volcanic ash is typically rather minor.

Arcadia Planitia is a smooth plain with fresh lava flows and Amazonian volcanic flows on Mars. It was named by Giovanni Schiaparelli in 1882 after the Arcadia region of ancient Greece. It dates from the Amazonian period's arcadia formation's lava flows and small cinder cones. It includes a more recently developed large region of aeolian materials derived from periglacial processes.

It is located northwest of the Tharsis region in the northern lowlands, spanning roughly the region 33.9–64.2° North and 165.9–210.4° East, straddling partly in the Cebrenia quadrangle (MC-07), and partly in the Diacria one (MC-02), and centered at 47°12′N 184°18′E / 47.2°N 184.3°E / 47.2; 184.3. Arcadia marks a transition from the thinly cratered terrain to its north and the very old cratered terrain to the south.On its east it runs into the Alba Mons volcanoes.Its elevation relative to the geodetic datum varies between 0 and -3 km.

The Antofagasta Region (Spanish: Región de Antofagasta, pronounced [antofaˈɣasta]) is one of Chile's sixteen first-order administrative divisions. Being the second-largest region of Chile in area, it comprises three provinces, Antofagasta, El Loa and Tocopilla. It is bordered to the north by Tarapacá, by Atacama to the south, and to the east by Bolivia and Argentina. The region's capital is the port city of Antofagasta; another one of its important cities is Calama. The region's main economic activity is copper mining in its giant inland porphyry copper systems.

Antofagasta's climate is extremely arid, albeit somewhat milder near the coast. Nearly all of the region is devoid of vegetation, except close to the Loa River and at oases such as San Pedro de Atacama. Much of the inland is covered by salt flats, tephra and lava flows, and the coast exhibits prominent cliffs.

A mesa is an isolated, flat-topped elevation, ridge, or hill, bounded from all sides by steep escarpments and standing distinctly above a surrounding plain. Mesas consist of flat-lying soft sedimentary rocks, such as shales, capped by a resistant layer of harder rock, like sandstone or limestone, forming a caprock that protects the flat summit. The caprock may also include dissected lava flows or eroded duricrust.

Unlike a plateau, which is a broader, elevated region that may not have horizontal bedrock (e.g., Tibetan Plateau), a mesa is defined by flat-lying strata and steep-sided isolation. Large, flat-topped plateaus with horizontal strata, less isolated and often part of extensive plateau systems, are called tablelands. A butte is a smaller, eroded mesa with a limited summit, while a cuesta has a gentle dip slope and one steep escarpment due to tilted strata.

Anyuyskiy (Russian: Анюйский Вулкан; Annuyskiy Vulkan) is an extinct volcano in the Anyuy Mountains, Chukotka Autonomous Okrug, Far Eastern Russia. It is formed by two systems: one is formed by long lava flows which disrupted the valley of the Monni River. Later, a volcanic cone formed, experiencing explosive activity and eventually extruding a long lava flow.

The volcano erupted more than one cubic kilometre of lava. It was considered to have been active during the 14th and 18th centuries, but radiometric dating has shown ages of almost 250,000 years ago.

The law of included fragments is a method of relative dating in geology. Essentially, this law states that clasts in a rock are older than the rock itself. One example of this is a xenolith, which is a fragment of country rock that fell into passing magma as a result of stoping. Another example is a derived fossil, which is a fossil that has been eroded from an older bed and redeposited into a younger one.

This is a restatement of Charles Lyell's original principle of inclusions and components from his 1830 to 1833 multi-volume Principles of Geology, which states that, with sedimentary rocks, if inclusions (or clasts) are found in a formation, then the inclusions must be older than the formation that contains them. For example, in sedimentary rocks, it is common for gravel from an older formation to be ripped up and included in a newer layer. A similar situation with igneous rocks occurs when xenoliths are found. These foreign bodies are picked up as magma or lava flows, and are incorporated, later to cool in the matrix. As a result, xenoliths are older than the rock which contains them.

The Tibesti Mountains are a mountain range in the central Sahara, primarily located in the extreme north of Chad, with a small portion located in southern Libya. The highest peak in the range, Emi Koussi, lies to the south at a height of 3,415 meters (11,204 ft) and is the highest point in both Chad and the Sahara. Bikku Bitti, the highest peak in Libya, is located in the north of the range. The central third of the Tibesti is of volcanic origin and consists of five volcanoes topped by large depressions: Emi Koussi, Tarso Toon, Tarso Voon, Tarso Yega and Toussidé. Major lava flows have formed vast plateaus that overlie Paleozoic sandstone. The volcanic activity was the result of a continental hotspot that arose during the Oligocene and continued in some places until the Holocene, creating fumaroles, hot springs, mud pools and deposits of natron and sulfur. Erosion has shaped volcanic spires and carved an extensive network of canyons through which run rivers subject to highly irregular flows that are rapidly lost to the desert sands.

Tibesti, which means "place where the mountain people live", is the domain of the Toubou people. The Toubou live mainly along the wadis, on rare oases where palm trees and limited grains grow. They harness the water that collects in gueltas, the supply of which is highly variable from year-to-year and decade-to-decade. The plateaus are used to graze livestock in the winter and harvest grain in the summer. Temperatures are high, although the altitude ensures that the range is cooler than the surrounding desert. The Toubou, who were settled in the range by the 5th century BC, adapted to these conditions and turned the range into a large natural fortress. They arrived in several waves, taking refuge in times of conflict and dispersing in times of prosperity, although not without intense internal hostility at times.

Madeira is a Portuguese island, and is the largest and most populous of the Madeira Archipelago. It has an area of 740.7 km (286 sq mi), including Ilhéu de Agostinho, Ilhéu de São Lourenço, Ilhéu Mole (northwest). As of 2021, Madeira had a total population of 245,595.

The island is the top of a massive submerged shield volcano that rises about six kilometres (20,000 ft) from the floor of the Atlantic Ocean. The volcano formed atop an east–west rift in the oceanic crust along the African Plate, beginning during the Miocene epoch over five million years ago, continuing into the Pleistocene until about 700,000 years ago. This was followed by extensive erosion, producing two large amphitheatres open to south in the central part of the island. Volcanic activity later resumed, producing scoria cones and lava flows atop the older eroded shield. The most recent volcanic eruptions were on the west-central part of the island only 6,500 years ago, creating more cinder cones and lava flows.

Pioneer species are resilient species that are the first to colonize barren environments, or to repopulate disrupted biodiverse steady-state ecosystems as part of ecological succession. Various kinds of events can create good conditions for pioneers, including disruption by natural disasters, such as wildfire, flood, mudslide, lava flow or a climate-related extinction event, or by anthropogenic habitat destruction, such as through land clearance for agriculture or construction or industrial damage. Pioneer species play an important role in creating soil in primary succession, and stabilizing soil and nutrients in secondary succession.

Because pioneer species quickly occupy disrupted spaces, they are sometimes treated as weeds or nuisance wildlife by humans, such as the common dandelion or stinging nettle. Even though humans have mixed relationships with these plants, these species tend to help improve the ecosystem because they can break up compacted soils and accumulate nutrients that help with a transition back to a more mature ecosystem. In human-managed ecological restoration or agroforestry, trees and herbaceous pioneers can be used to restore soil qualities and provide shelter for slower growing or more demanding plants. Some systems use introduced species to restore the ecosystem, or for environmental remediation. The durability of pioneer species can also make them potential invasive species.