Science, Tech, Math › Science A Look at South American Geology Share Flipboard Email Print Mount Roraima marks the border between Venezuela, Guyana and Brazil. Martin Harvey / Getty Images Science Geology Types Of Rocks Landforms and Geologic Features Geologic Processes Plate Tectonics Chemistry Biology Physics Astronomy Weather & Climate By Andrew Alden Geology Expert B.A., Earth Sciences, University of New Hampshire Andrew Alden is a geologist based in Oakland, California. He works as a research guide for the U.S. Geological Survey. our editorial process Andrew Alden Updated November 12, 2019 For much of its geologic history, South America was part of a supercontinent comprised of many southern hemispheric landmasses. South America began to split apart from Africa 130 million years ago and separated from Antarctica within the past 50 million years. At 6.88 million square miles, it is the fourth largest continent on Earth. South America is dominated by two major landforms. The Andes Mountains, located within the Pacific Ring of Fire, are formed from the subduction of the Nazca plate underneath the entire western edge of the South American plate. Like all other areas within the Ring of Fire, South America is prone to volcanic activity and strong earthquakes. The eastern half of the continent is underlain by several cratons, all over one billion years in age. In between the cratons and Andes are sediment-covered lowlands. The continent is barely connected to North America through the Isthmus of Panama and is almost completely surrounded by the Pacific, Atlantic and Carribean Oceans. Almost all of South America's great river systems, including the Amazon and Orinoco, begin in the highlands and drain east towards the Atlantic or Caribbean Oceans. 01 of 14 Geology of Argentina Glacier Perito Moreno, Patagonia, Argentina. DANIEL GARCIA / AFP via Getty Images Argentina's geology is dominated by the metamorphic and igneous rocks of the Andes to the west and a large sedimentary basin to the east. A small, northeastern section of the country extends into the Río de la Plata craton. To the south, the Patagonia region stretches between the Pacific and Atlantic Oceans and contains some of the largest non-polar glaciers in the world. It should be noted that Argentina contains some of the world's richest fossil sites that are home to both gigantic dinosaurs and famous paleontologists. 02 of 14 Geology of Bolivia Sergio Ballivian / Getty Images The geology of Bolivia is somewhat of a microcosm of South American geology as a whole: the Andes to the west, a stable Precambrian craton to the east and sedimentary deposits in between. Located in southwest Bolivia, Salar de Uyuni is the largest salt flat in the world. 03 of 14 Geology of Brazil Serra da Beleza mountains, Brazil. Igor Alecsander / Getty Images Archean-aged, crystalline bedrock makes up a large portion of Brazil. In fact, ancient continental shields are exposed in nearly half of the country. The remaining area is made up of sedimentary basins, drained by large rivers like the Amazon. Unlike the Andes, the mountains of Brazil are old, stable and have not been affected by a mountain-building event in hundreds of millions of years. Instead, they owe their prominence to millions of years of erosion, which sculpted away the softer rock. 04 of 14 Geology of Chile Torres del Paine National Park, Chile. Manuel Breva Colmeiro / Getty Images Chile is almost entirely within the Andes range and subranges — around 80% of its land is made up of mountains. Two of the strongest recorded earthquakes (9.5 and 8.8 magnitude) have occurred in Chile. 05 of 14 Geology of Colombia Jesse Kraft / EyeEm / Getty Images Much like Bolivia, Colombia's geology is made up of the Andes to the west and crystalline basement rock to the east, with sedimentary deposits in between. The isolated Sierra Nevada de Santa Marta of northeastern Colombia is the highest coastal mountain range in the world, topping out at nearly 19,000 feet. 06 of 14 Geology of Ecuador Snowcapped Chimborazo Volcano, Ecuador. Guy Edwardes / Getty Images Ecuador rises east from the Pacific to form two imposing Andean cordilleras before descending into the sedimentary deposits of the Amazon rainforest. The famed Galapagos Islands lie approximately 900 miles to the west. Because the Earth bulges at the equator due to its gravity and rotation, Mount Chimborazo — not Mount Everest — is the farthest point from the center of the Earth. 07 of 14 Geology of French Guiana Phoebe Secker / Getty Images This overseas region of France is almost completely underlain by the crystalline rocks of the Guiana Shield. A small coastal plain extends to the northeast toward the Atlantic. Most of the approximately 200,000 inhabitants of French Guiana live along the coast. Its interior rainforest is largely unexplored. 08 of 14 Geology of Guyana Marcelo Andre / Getty Images Guyana is split into three geologic regions. The coastal plain is made up of recent alluvial sediment, while older Tertiary sedimentary deposits lie south. The Guiana Highlands form the large interior section. The highest point in Guyana, Mt. Roraima, sits on its border with Brazil and Venezuela. 09 of 14 Geology of Paraguay Cerro Koi red rocks, Paraguay. Jan-Schneckenhaus / Getty Images Although Paraguay lies at the crossroads of several different cratons, it is mostly covered in younger sedimentary deposits. Precambrian and Paleozoic basement rock outcrops can be seen at the Caapucú and Apa Highs. 10 of 14 Geology of Peru The Winicunca a.k.a. Rainbow Mountain, Cusco, Peru. HEINTZ Jean / hemis.fr / Getty Images The Peruvian Andes rise sharply from the Pacific Ocean. The coastal capital city of Lima, for instance, goes from sea level to 5,080 feet within its city limits. The sedimentary rocks of the Amazon lie east of the Andes. 11 of 14 Geology of Suriname Youri Stolk / EyeEm / Getty Images Much of Suriname's land (63,000 square miles) consists of lush rainforests that sit upon the Guiana Shield. The northern coastal lowlands support most of the country's population. 12 of 14 Geology of Trinidad De Agostini / Getty Images Although slightly smaller than Delaware, Trinidad (the main island of Trinidad and Tobago) is home to three mountain chains. Metamorphic rocks make up the Northern Range, which reaches 3,000 feet. The Central and Southern Ranges are sedimentary and much shorter, topping out at 1,000 feet. 13 of 14 Geology of Uruguay Santa Teresa Fort, Uruguay. NollRodrigo / Getty Images Uruguay sits almost entirely upon the Río de la Plata Craton, with much of it covered by sedimentary deposits or volcanic basalts. Devonian Period sandstones (purple on the map) can be seen in central Uruguay. 14 of 14 Geology of Venezuela Kamata Valley seen through The Window, Venezuela. apomares / Getty Images Venezuela consists of four distinct geologic units. The Andes die out in Venezuela and are bordered by the Maracaibo Basin to the north and the Llanos grasslands to the south. The Guiana Highlands make up the eastern portion of the country.