Metamorphic rocks form when igneous or sedimentary rocks are subjected to extreme heat, pressure or chemical reactions. These forces alter the composition of the rocks, leading to changes in the rocks' density, appearance and structure.
A:Nearly 3.8 billion years ago, temperatures on Earth cooled below 100 degrees Celsius for the first time, allowing water, which existed on the planet in gaseous form, to condense into rain and collect on the planet's surface, according to the American Museum of Natural History. This water collected in low-lying areas, eventually becoming a primitive ocean.
A:Mountains affect climate by blocking wind and receiving more rainfall than low-lying areas. As air is forced over higher ground, it cools, causing moisture to condense and fall as rain. The higher a location is above sea level, the colder it is. This occurs because as altitude increases, the surround airing becomes thinner and less effective at absorbing and retaining heat.
A:A gorge is a much smaller, narrower version of a canyon. A gorge is similar to a ravine, while a canyon is similar to a valley. Gorges are located between mountains or hills and often have small streams at their bottoms.
A:Volcanoes form landforms when the lava that flows out of the peak solidifies into rock. Magma is molten rock from the Earth's mantle pushed up by the action of plate tectonics. When the magma flows or explodes out of the top of the volcano, it is called lava. Over geological timescales, this lava keeps piling on top of successive strata of cooled rock, making several different kinds of landforms.
A:A billabong is essentially a large pond or creek that at one time extended from a river. A billabong is the cut off extension of a river that changed its course over time. During a wet season, the billabong often connects back with the river, receiving fresh water, at least until the area dries back up.
A:A plateau refers either to a piece of land that is level and located above nearby land, or the term can refer to a situation that is relatively unchanged for a period of time. In the case of an unchanged situation, the word has either a negative or a positive connotation, depending on whether change is advantageous.
A:A continent is a large land mass on Earth that is distinguished by a separation from other land by water or by a distinct cultural difference. Earth has a total of seven continents: North America, South America, Europe, Africa, Asia, Australia and Antarctica.
A:Most caves form in karst, which is a type of landscape composed of dolomite, gypsum and limestone rocks that gradually dissolves in the presence of slightly acidic water, according to National Geographic. Some caves are found in cliffs at the edge of a coastline. Others form in areas where the outer surface of a lava tube cools and hardens, and the molten rock’s inner content drains away.
A:A geyser is essentially an underground hot spring that, owing to pressure exerted against its constricted plumbing toward the surface of the ground, issues a stream of steam and boiling water from time to time. The term "geyser" is derived from the Icelandic word "geysir," which means to rush forth. A geyser stops erupting once its reservoir is empty, or the water below the surface cools.
A:The Highveld, the Pampas, steppes and prairies are all grasslands, which are biomes dominated by grasses, flowers and herbs. Savannas and the Llanos region of northern South America are also grasslands.
A:According to Geology professor Atle Nesje of Bergen University, fjords occur where there was glacial activity below where the sea level is as of modern times. Fjords.com notes that Norway and Canada are home to fjords and fjord lakes.
A:The arctic lowlands consist of several barren low-lying islands with coastlines dominated by sheer, towering cliffs and frigid surrounding waters of the Atlantic that contain pieces of massive ice sheets. Together, the lowlands comprise the southwestern Arctic Archipelago. They vary in size and shape: some are small and unpopulated, while others, including Victoria Island, are much larger.
A:The three types of plateaus are dissected, volcanic and oceanic plateaus. A plateau is described as a raised landform that extends above the surrounding area on at least one of the plateau's sides. Plateaus are found on every continent and make up 30 percent of the land on Earth.
A:Metamorphic rocks form when igneous or sedimentary rocks are subjected to extreme heat, pressure or chemical reactions. These forces alter the composition of the rocks, leading to changes in the rocks' density, appearance and structure.