Geology of Pacific South America and the Andean Region By: Becky Baker, Marissa Bond, Collin Whelley, Jackie Nagel November 17, 2004

Introduction Four Themes Formation of the Andes Atacama Desert Geology Galapagos Islands Amazon River Basin CW

What is the “Andean Region” The Andes Mountain Range Second highest range in the world The areas of geography on either side The indigenous peoples “ of Andean decent” CW

Formation Nazca and South American Plate Boundaries South American plate is moving westward while the Nazca plate is moving eastward. Subduction Zone The Rise: late Tertiary period (40 million years ago) Volcanic Process Magma cools in magma chambers creating extreme pressure and violent eruptions CW

Nazca Plate vs. South American Plate CW

The Subduction Zone CW

Mountain Effects Ecology People Industry and agriculture Earth quakes and active volcanoes Climate effects continued CW

The Atacama Desert Location and Description Northern region of Chile Known as the “most arid desert in the world” High altitude and cold temperatures Series of dry salt flanks Absence of rain and precipitation Wealth of desert based on mining Saltpeter and other fundamental natural resources MB

The Desert’s Aridity is explained by: Global and local climate aspects Geography and oceanography factors The high mountains in the Andes The flowing of the Humboldt current The result of these factors is:  Large barren landscapes  Variations of earthly colors MB

The Geology of the Atacama Desert: Volcanic and erosive forces Volcanoes dominate the terrain Altiplano (high plane) Salt flats, multicolored lakes and hot springs Wind eroded hills and rock formations Valle de la Luna (Moon Valley)  Fantastic lunar landscapes  Most inhospitable place on the planet MB

Geological Landscapes: El Tatio Geysers Highest geysers in the world Strange mineral formations 86 degree Fahrenheit hot springs Fumaroles and mountains MB

Geological Landscapes (cont.) Salar de Atacama (Salt Lake) Chile’s largest salt flat Extraordinarily dry air World’s largest lithium deposits MB

Geological Formations: Cordillera de la Sal (Salt Hills) Horizontal rock and sediment layers Tertiary periods (ca. 23 millions years ago) Wind and rain erosion sculpt formations  Gypsum creates salt-sprinkled look Left: red salt water due to algae Right: thick layer of salt encrusts soil MB

Chilean Volcanoes: Lascar: (Right) Active stratovolcano Erupted in 1993 and 2000 Most active volcano in the central Andes  Licancabur: (Left)  Stratovolcano  Summit lake is one of highest in the world:  low oxygen, low atmostpheric-pressure and high UV radiation MB

The Galapagos Islands Overview Off the West coast of Ecuador in South America Hot spot volcanoes Belong to Ecuador (1832) BB

The Galapagos Islands “Islas de Galapagos” Charles Darwin (1835) Five year expedition National Park BB

The Galapagos Islands Geology Hot spot volcanoes like Hawaii Shield Volcanoes Composed of Basalt Non-explosive eruptions 16 Islands formed in Cenozoic Era: Pliocene Epoch (5.1 to 2 million years ago) BB

The Galapagos Islands Geology (continued) One of most active oceanic volcano areas on Earth Igneous Islands Very young and still forming BB

The Galapagos Islands Volcanoes 6 shield volcanoes come together to form the largest island, Isabela Steeper than Hawaiian Islands with barren hardened lava areas Cliffs form jagged points along the coast BB

The Galapagos Islands Volcanoes (continued) Calderas/Cones (several thousand) Unusual landforms produce a lunar-like landscape BB

The Galapagos Islands Islands (Major of 16) Isabela Dry climate Largest Island 70 miles long, covering half the land area of all the islands put together Fernandina West of Isabela Home of rare tortoises BB

The Galapagos Islands Islands (continued) Santiago Northeast of Isabela Santa Cruz Charles Darwin Research Station (1964) San Cristobol Farthest east Seat of government BB

The Amazon River Basin Introduction: Second longest in length in the world It is estimated that the Amazon discharges between 9 million and 32 million gallons of water per second Accounts for one- fifth of the world's liquid fresh water The largest and wettest tropical plain in the world. JN

Geology of the Amazon River Giant river valley bordered to the north and south by the Guiana and Brazilian shields Comprised of hard Precambrian rock Pacific marine like animals Water levels within the Amazon basin changed with the sea level huge lakes formed in the valley JN

Location of the Amazon River Starts in Brazil and flows to Ecuador over 200 tributaries in Brazil alone Mouth of the river is in Brazil Bordered by Guiana and Brazilian shields Previously opened into the Pacific ocean JN

Features of the Amazon River Headstreams are found in the heights of the Andes Average depth of the river 150 miles wide at Atlantic estuary Rate of the flow Bed of the river World’s largest tropical rain forest (40% of South America’s landmass) JN

Effects on the Amazonian Rainforest Watershed and a wet tropical plain Flooding of thousands of square miles of forest Determinants of fish distribution, behavior and diversity within the floodplain Habitats for animals JN

Animal Life of the Amazon over 2,000 types of fish are in the Amazon River Piranhas, 200 lb. Catfish Arapaima- largest freshwater fish Freshwater stingrays Anaconda Cuban Crocodile JN

Supporting Life in the Amazon River Basin The forest shelters the largest biodiversity of the planet It helps to regulate regional hydrology and climate, protects the soil, ameliorate floods, and supports indigenous communities Great diversity of indigenous languages and cultures With nearly 400 different ethnic groups, million indigenous people JN

Questions Regarding the Geology of Pacific South America and the Andean Region: What are the two major plates that were and are involved in the formation of the Andes Mountain range? -CW What does the Andean region include? -CW What fundamental mineral was at one time the leading export of Chile? -MB What mineral creates the salt-sprinkled look of the salt flats in the Atacama Desert? -MB What type of volcanoes make up the Galapagos Islands? Describe them. -BB How were the islands formed? Were they on tectonic plate lines? geographic location? hot spot? -BB How much of the worlds fresh water is found in the Amazon River Basin? -JN The mouth/inlet of the river is located in what country, while its outlet is located in the Pacific country of Ecuador? -JN MB

Bibliography “A Brief History of the Galapagos Island,” (10 Nov 2004). “Amazon Rising: Season of the River,” (13 Nov 2004). “Amazon (river),” Microsoft Encarta Online Encyclopedia (2004) encarta.msn.com/encyclopedia _ /Amazon_(river).html. (13 Nov 2004). "Andes," Wikipedia, the free encyclopedia. (13 Nov 2004) (14 Nov 2004). “Atacama,” Latin Discover (12 Nov 2004). Corte, Arturo., Llibouty, Louis. USGS, satellite Image Atlas of glaciers of the world. (March of 1999) (14 Nov 2004). “El Tatio Geyser, Chile,” (2003) (12 Nov 2004). Encyclopedia search, tiscali., (14 Nov 2004). “Galapagos Overview,” (10 Nov 2004). “Humboldt Current,” _History/Oceanography/Humboldt_Current.htm (12 Nov 2004). “Lanscar, Chile,” (12 Nov 2004). “Licancabur Volcano,” (12 Nov 2004). MBarron.net Production (13 Nov 2004). Roach, John, National Geographic News (October 22, 2003) news.nationalgeographic.com/news/2003/ andesrise.html. (14 Nov 2004). “Salar de Atacama,” LanChile (2003) (12 Nov 2004). The Columbia Electronic Encyclopedia, 6th ed. Copyright 2004, Columbia University Press. (13 Nov 2004). “Valle de la Luna,” (12 Nov 2004). (13 Nov 2004). MB