LANDFORMS: A landform is a feature on the surface of a terrain, natural landforms usually form and change very gradually; some can take millions of years: UNDERWATER: 1- mid-ocean ridge 2- abyssal plain 3- oceanic trench 4- continental slope 5- continental shelf RELATED TO HIGH ALTITUDE: 1-mountain 2-mountain range 3- mountain system 4- glacier 5- plateau 6- (hill) COASTAL: 1- cape 2- gulf 3- bay 4- peninsula 5- delta 6-river mouth 7- cli� 8- island 9- coast RELATED TO LOW ALTITUDE: 1- plain 2- flood plain 3- coastal plain 4- valley 5- fluvial valley 6- depression 7- (hill)

1- mid-ocean ridge: an underwater mountain in the middle of the ocean. 2- abyssal plain: an area of flat seafloor at a depth of 4.000 meters 3- oceanic trench: large depression on the seafloor near a continent. 4- continental slope: a steep slope which separates the end of the continental shelf from the oceanic floor. 5- continental shelf: a sloping plain which joins the continents to the seabed, it’s part of the continental crust but it is beneath the sea water. 6- cape: a large piece of land sticking out into the sea. 7- gulf: large area of sea between two capes. 8- bay: is smaller than gulf and the entrance is more closed o�. 9- peninsula: area of land almost completely surrounded by sea, it is only connected to the mainland by a narrow strip of land. 10- Delta: a body of sediment deposited at the mouth of a river. 11- cli�: a high, steep area of rock which suddenly meets the sea. 12- island: is a piece of land surrounded by sea. 13- coast: land close to the sea. 14- mountain: natural elevation of land very high. 15- mountain range: part of a mountain system. 16- mountain system: group of mountains that are related.

17- glacier: create U-shaped valleys 18- plateau: flat landform that is elevated above the sea level 19- hill: natural elevation not very high 20- plain: flat land near a river or near the coast. 21- valley: depression between upland areas, like mountains. Are always formed by the force of water, either as a liquid or solid 22- fluvial valley: has V-shape 23- depression: area of land that is lower than the area around it.

THE MOST IMPORTANT LANDFORMS IN EACH CONTINENTS: Mountains, plateaus and plains. GEOLOGICAL STAGES: The Earth’s surface is constantly changing. During these changes and evolution, we can identify di�erent geological stages. • Precambrian time (4500 to 542 mya). The first mountain ranges formed. Erosion destroyed them. • Palaeozoic Era (542 to 250 mya). New mountain ranges composed of hard materials formed. • Mesozoic Era (250 to 65 mya). The sea covered dry land and there was intense sedimentation. • Cenozoic Era (66 mya) is divided into three Periods: – Paleogene Period (66 to 23 mya). Tectonic plate movement and alpine orogeny occurred. This formed young mountain ranges, such as the Alps. – Neogene Period (23 to 2.58 mya). Continental movements occurred, most importantly between North and South America. – Quaternary Period (2.58 mya to present). There were periods of glaciation when ice covered a large part of the continents. This caused intense erosion in mountain areas.