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Senior University January 25 to March1 2010 Vagabonds tramping through Geology Africa “It is the supreme art of the teacher to awaken joy in creative expression and knowledge” Albert Einstein Grab your mental climbing gear and let’s scale the heights of Africa Tramping through the Stone Senior University Field Trip and Iron Ages in Central Texas March 9, 2010 Objective of this course: to show how geology shaped human history, e.g. in Africa Geologic Map: Africa Suggested Geological References Physical Geology, Judson & Kauffman,1990 Evolution of the Earth, Prothero & Dott, 2002 The focus of our study the geology of Africa Geological maps show different rocks at the surface if soils and vegetation removed Management Disclosure: The impact ofwere geology on shaping human history is not discussed in any geology textbook or in any scientific literature YET Where we’ll be studying the geology of Africa Geologic Map: Africa Congo River & Major Undiscovered Oil and Gas East African Rift Valleys & the Advent of Humans What supports Rift Extension & the proposition River Modification that geology human history? Creatingshapes Awesome Scenic Wonders Support for the Proposition that Geology Shapes Human History Four Awesome Scientific Discoveries in the last 50 years defining the Earth’s Rocky Crust First: . Continental (crustal plate) Drift 1. Continental (crustal plate) Drift 2. Plate Tectonics 3. Paleo-magnetics 4. Absolute Age Dating Four Discoveries of the last 50 Years That Define the Earth’s Rocky Crust 1.Continental (crustal plate) Drift The slow movement of the crustal plates over the face of the earth Crustal Plates: Both Oceanic & Continental Crustal Plates: Both Oceanic & Continental Indian plate under Asian plate = mountain building Combination Oceanic Combination Combination Combination Continents are carried on their crustal plate Present Day Continental Drift: Last 250 million years How has continental drift shaped human history? 250 million years ago http://schools.techno.ru/sch518/koridor/geograf /detrab/Tektonika/litosfera2.htm How has continental drift shaped human history? Western Hemisphere Eastern Hemisphere And Created the Western and Eastern Hemispheres Critical to the migration of humans out of Africa How has continental drift shaped human history? And Why is elongation important? Shaped the It determines the continents number of climate Three elongated north-south zones that the continent covers One elongated east-west How has continental drift shaped human history? Why is that important? Tropical climate zones Note that Africa and South In addition to continental drift,America what was Because nolocated world power discovered about geology ofever the are not well for thehas creation Positioned thethe continents Tropics!!! earth’s rocky crust inthe the last 50zones years? of a world power withdeveloped respect toin the climate Four Discoveries of the last 50 Years that Define the Earth’s Rocky Crust The deforming of earth’s crust 1. Continental Drift when continents (plates)collide 2. Plate Tectonics Two important types of deformation: 1. mountain building 2. broad warping of the continental crust Plate Tectonics: aka mountain building Collision: oceanic with continental plate Collision Mountains North American continental plate over riding the Pacific oceanic plate Next: Two continental plates collide Collision Mountains Plate Tectonics: Collision of two continents Why are mountain important? Next: Plateranges Tectonics Natural resources arefaulting concentrated Uplift and rift in and aalong mountainhotspot ranges over sub-crustal Plate Tectonics: Uplift and rift faulting over a sub-crustal hotspot Central Africa: Up-lifted Faulted Rift Valleys formed & Volcanoes Why thisTectonics: event important? Next,was Plate Broad warping This geologicalcrust eventproduces of unique the continental coincided with the advent of major river drainage systems the human race! Eastern Hemisphere: Major Rivers Produced by the Broad Warping of the Continental Crust Eurasia Africa The Tropics Major rivers The Third Discoveryin ofmajor the last 50 flood Years All early civilizations river that Define the Earth’s Rocky Crust plains in the Northern Temperate Zone! Four Discoveries of the last 50 Years that Define the Earth’s Rocky Crust 1. Continental Drift Paleo-magnetics defines the lat-long Plate Tectonics of a rock 2.when it is formed 3. Paleo-magnetics All our continental drift reconstruction What fourth discovery? maps is arethe based on Paleo-magnetics Four Discoveries of the last 50 Years that Define the Earth’s Rocky Crust Again, all our continental drift maps are heavily dependent on Absolute Ages 4. Absolute Age Dating Absolute Age Dating uses the decay of Now, four geological processes radio active minerals to determine the that shaped age ofhuman a rock history Now four geological processes that shaped human history 1. Continental Drift 2. Plate Tectonics 3. Weathering 4. Erosion Four Geologic Processes that shaped Human History Continental Drift Weathering: Natural destruction of the rockyPlate continental crust Tectonics Weathering Weathering produces soils of different Erosion Finally, Erosion fertilities depending on the rock type Four Geologic Processes that shaped Human History Erosion: Continental Drift Natural process of moving Tectonicsthe oceans rock debrisPlate toward Weathering What Natural Resources Erosion define Human History? Erosion Produces: Topography River flood plains Rock outcrops with natural resources Rock outcrops Proposition: & natural resources: Resources Shaping these Human History Lands controlling natural resources become major nations Iron, Coal, Petroleum, & Uranium Iron, Coal, & Oil Iron and Coal Here’s how natural resources Iron shaped historic Copper, Tin, Arsenic,time Zinc Copper Flint and Obsidian What Natural Resources define Human History? Geologic Division of Historic Time Iron,Iron, Coal, Oil & Uranium Coal, Petroleum, & Uranium Age Oil Iron, Coal, & Oil Age Iron & Coal Age 2 Iron & Coal: Industrial Age Iron & Coal: Renaissance 1950 to Present 1900 to 1950 AD 1830 to 1900 AD 1700 to 1830 AD Next: Five Geologic Events Shaped 1450that to 1700 AD Iron Iron & Coal: Middle Ages Human History470 to 1450 AD & Coal Copper, tin, arsenic, & zinc Flint & Obsidian Iron Age 2 Rome Iron Age 1 Greece Bronze Age to 470 AD 750 BCE 1400 to 750 BCE 3300 to 1400 BCE Copper Age 3300 to 3000 BCE Stone Age (end of Ice Age) 70,000 to 3300 BCE Five Geologic Events that Shaped Human History 1. Continental Drift shapes & positions the continents Migration path of humans created How has continental drift shaped human history? Eastern Western Hemisphere Hemisphere The second history shaping event Created the Western and Eastern Hemispheres Critical to the migration of humans out of Africa Five Geologic Events that Shaped Human History 1. Continental Drift shapes & positions the continents Migration path of humans created 2. Continental Drift & Plate Tectonics: Africa drifts into Europe = Alps India collides with Asia = Himalayas Optimum farming environment created in six major river flood plains. Geological Event # 2: 6000 mile mountain range created by Africa & India colliding with Eurasia Yellow Yangtze Nile Tigris Euphrates Indus Ganges Event #3. Plate Tectonics: East Africa uplifted, rift faulted with advent of human beings Ideal trend for the early development of large scale farming civilizations Five Geologic Events that Shaped Human History 1. 2. Continental Drift shapes & positions the continents Migration path of humans created Continental Drift & Plate Tectonics: Africa drifts into Europe = Alps India collides with Asia = Himalayas Optimum farming environment created 3. Plate Tectonics: East Africa uplifted, rift faulted with advent of human beings 3. Plate Tectonics: East Africa uplifted, rift faulted with advent of human beings Eastern Africa: Up-lifted Faulted Location of oldest human fossils Rift Valleys formed & Volcanoes Event # 4. Weathering exposes critical ores andPlate oil atTectonics: or near the earth’s surface: Uplift and rift faulting over a sub-crustal hotspot Five Geologic Events that Shaped Human History 1. Continental Drift shapes & positions the continents Migration path of humans created 2. Continental Drift & Plate Tectonics: Africa drifts into Europe = Alps India collides with Asia = Himalayas Optimum farming environment created 3. Plate Tectonics: East Africa uplifted, rift faulted with advent of human beings 4. Weathering exposes critical ores and oil at or near the earth’s surface: Example: Natural Resources of Africa Natural Resources that shaped World History Iron Age Africa Iron Coal Natural Resources that shaped World History Africa today Natural Resources Copper Tin Iron Coal Oil Very large deep water oil reserves Natural Resources that shaped World History Major Rivers Nile Niger Congo Copper Tin Iron Coal Oil Event # Very large deep water oil reserves \ 5. Continental Glaciation prevents early farming civilizations in the northern half of the Northern Temperate Zone Five Geologic Events that Shaped Human History 1. Continental Drift shapes & positions the continents Migration path of humans created 2. Continental Drift & Plate Tectonics: Africa drifts into Europe = Alps India collides with Asia = Himalayas Optimum farming environment created 3. Plate Tectonics: East Africa uplifted, rift faulted with advent of human beings 4. Weathering exposes critical ores and oil at or near the earth’s surface: Example: Natural Resources of Africa Event # 5. Continental Glaciation prevents early farming civilizations in the northern half of the Northern Temperate Zone Yellow Yangtze Nile Tigris Euphrates Indus Ganges Next Week: Africa and the Major Nations of the World World Empires: last 7000 years Stone Age Hunters & Gatherers Families, clans, & tribes Sticks and stones 3500 3000 Copper Age 4500 2500 Bronze Age: World 1500 Iron Age Iron & coal Age Farming Flood plain empires Hill country empires Iron & steel tools & Bronze tools weapons weapons Iron, coal, oil Age Archeological Ages Geologic Division of Historic Time Iron, Coal, Oil & Uranium Iron, Coal, Petroleum, & Uranium Age 1950 to Present Iron, Coal, & Oil Age 1900 to 1950 AD Iron & Coal Age 2 1830 to 1900 AD Iron & Coal: Industrial Age 1700 to 1830 AD Iron & Coal: Renaissance 1450 to 1700 AD Iron & Coal: Middle Ages 470 to 1450 AD Iron Age 2 Rome to 470 AD 750 BCE Iron Age 1 Greece 1400 to 750 BCE Bronze Age 3300 to 1400 BCE Copper, tin, Iron How does the history of Africa & fit in with world history? Coal arsenic, & zinc Flint & Obsidian Copper Age 3300 to 3000 BCE Stone Age (end of Ice Age) 70,000 to 3300 BCE Nations of World History Left half of chart: 5000 BC to 1400 BC: pre-Iron Age Right half of chart: 1400 BC to present time Let’s look at nations in the pre-Iron Age Stone Age 4500 4000 3500 3000 2500 1500 Bronze Age: Copper Age 5000 Africa Ancient Times: 5000 BC to 1000 BC Sumeria Mature Indus Xia Yellow River Iron age Egypt: Nile Where were these nations located? World’s Earliest Civilizations: pre-Iron Age Egypt Nile River Sumeria Tigris & Euphrates Xia Dynasty Yellow River Now, nations in the early Iron Age Ganges Yangzi River Mature Indus River From: Hammond Atlas, 1972 All are in major river flood plains! Rome Greece Iron & Coal age Let’s look at Africa Islamic States Iron, Coal & Oil age Iron age Iron Age Nations & Empires Worldwide Nations of (in) Africa Mediterranean Africa Egyptian Kingdoms Greece Rome Islamic States Central & Southern Africa Where is Kush? Ancient Egypt Nile River Kush Kush aka Nubia Why is Kush where it is? http://geology.com/world/africa-physical-map.shtml The basis of Kush economy Egypt: Natural Resources Nations of Africa (excluding Egypt) Where is Axum? Kingdom of Axum aka Aksum Nile River Kush Axum Ethiopia Kingdom of Axum aka Aksum White Nile River Now, the last of the African nations White Nile River A trading nation between Ethiopia, Egypt, & Arabia Nations of Africa (excluding Egypt) Niger River http://exploringafrica.matrix.msu.edu/students/curriculum/m7a/activity3.php Ghana Traded in gold, iron, and salt Summary: There have been no major African nations since ancient Egypt! Why? How Geology shaped human history Four geologic processes Five geologic events Four Geologic Processes that shaped Human History Continental Drift Plate Tectonics Weathering Erosion Four Geologic Processes that shaped Human History Continental Drift Plate Tectonics The slow movement of the continents over the face of the earth Weathering Erosion Present Day Continental Drift: Last 250 million years 250 million years ago http://schools.techno.ru/sch518/koridor/geograf /detrab/Tektonika/litosfera2.htm Continental Drift Created two Hemispheres Western Hemisphere Eastern Hemisphere Continental Drift Shaped the Continents Significance of Position & Shape Northern Temperate Climate Zone: Historically ideal for major civilizations Tropical Climate Zones: Historically unfavorable for major civilizations Eastern Hemisphere: Major Rivers & Mountains Eurasia Africa The Tropics Major mountains Major rivers All early civilizations in major flood plains in the Northern Temperate Zone! Four Geologic Processes that shaped Human History The deforming of earth’s crust Continental Drift when continents collide Plate Tectonics Weathering Two important types of deformation: 1. mountain building 2. broad warpingErosion of the continental crust The Earth’s Rocky Crust (aka skin) Continental Crust Oceanic Crust The earth’s skin, aka crust, is broken into many plates, both large and small http://pubs.usgs.gov/gip/dynamic/inside.html Crustal Plates: Both Oceanic & Continental Indian plate under Asian plate = mountain building Combination Oceanic Combination Combination Plate boundaries are sites for earthquakes and volcanoes Combination Crustal Plate Boundaries & Earthquakes Earliest Major Civilizations in flood plains of major rivers draining Two types of crust: (under zones the deep(mountains) oceans) highoceanic earthquake continental (the continents) Two types of Crust: 1. Continental crust 2. Oceanic crust Cross Section: Two types of Crust Oceanic Crust Continental Crust 5 miles thick 20 to 50 miles thick Plate tectonics: deformation when two or more plates collide Plate Tectonics: aka mountain building. Collision: oceanic with continental crust New Mountains Oceanic Crust 5 miles thick Continental Crust 20 to 50 miles thick Plate Tectonics: aka mountain building Collision of two continents Africa Europe New Mountains Mountain Building: collision of an oceanic & a continental plate Plate Tectonics: aka mountain building Collision: oceanic with continental plate Collision Mountains North American continental plate over riding the Pacific oceanic plate Next: Two continental plates collide Collision Mountains Plate Tectonics: Collision of two continents Plate Tectonics: Uplift and rift faulting over a sub-crustal hotspot Central Africa: Up-lifted Faulted Rift Valleys formed & Volcanoes Plate Tectonics: Uplift and rift faulting over a sub-crustal hotspot Block Diagram of a Rift Valley Rift Valley Central Africa: Equatorial How thick is High elevation a continent? Rift environments Volcanic Uplift http://www.tiscali.co.uk/reference/encyclopae dia/hutchinson/image_preview.html?image How thick is A continent? 8000 miles 4000 miles = radius How thick is A continent? 2000 miles How thick is A continent? 1000 miles How thick is A continent? 500 miles How thick is A continent? 100 miles thick 500 1000 2000 4000 8000 How thick is A continent? 100 miles thick A continent is 25 to 50 miles thick! How far does Africa extend? North Pole North Africa Center of the earth Equator West African Continent Now the third geological process: weathering South Africa South Pole Four Geologic Processes that shaped Human History Continental Drift Weathering: Natural destruction of the rockyPlate continental crust Tectonics Weathering Erosion Weathering: Natural destruction of the rocky continental crust Causes: sun rain plants wind Products: rock debris soils WEATHERING: Destroys Rocks Creates: 1. soils (+ decaying plants) 2. rock debris Produces: unique environments Rock “Debris” 1. quartz sand 2. muds (clays) 3. calcium carbonate solutions All three carried away by erosion, the fourth process that shaped history Four Geologic Processes that shaped Human History Continental Drift Erosion: Plate Tectonicsof moving Natural process rock debris toward the oceans Weathering Erosion Erosion: Natural process of moving rock debris to the oceans at the continental margins Products: topographies rock outcrops river flood plains geosynclines Erosion: Moving the weathered rock debris to the sea by: 1. gravity!!! It all goes down hill 2. water: brooks streams rivers Erosion: 1. produces topography 2. creates river flood plains 3. created geosynclines 4. exposes different rocks at the earth’s surface The erosional topography of Africa The Erosional Topography of Africa Nile River Basin Mountains Niger River Basin Congo River Basin Highlands http://geology.com/world/africa-physical-map.shtml Mountains & Volcanoes Erosion: Natural process of moving rock debris to the oceans at the continental margins Products: topographies river flood plains creates geosynclines Cross section: Typical Geosyncline land ocean river debris Geosynclines are sites for the generation of oil and gas Nile, Congo, or Niger river geosyncline Erosion: Moving the weathered rock debris to the sea by: 1. gravity!!! It all goes down hill 2. water: brooks streams rivers Erosion: 1. produces topography 2. creates river flood plains 3. Creates geosynclines 4. exposes different rocks at the earth’s surface The surface rock outcrops of Africa Rocks of the earth’s crust exposed at the surface in Africa by erosion Each color represents a different rock at the surface Weathering & erosion of each rock produces unique: 1. soils 2. topographies 3. outcrops A. flint, obsidian, B. copper & tin, C. iron & coal Proposition: These “outcrop” materials helped to shape human history! USGS Geological Map: Africa Natural Resources that Shaped World History Bronze Age Africa Copper Tin Iron Coal Oil World’s greatest concentration of Cu and Sn! Tropics World’s greatest concentration of Cu and Sn! No Bronze Age nations here; why? Obviously we need more than Cu & Sn! Remember Significance of Position & Shape Northern Temperate Climate Zone: Historically ideal for major civilizations Tropical Climate Zones: Historically unfavorable for major civilizations Natural Resources that shaped World History Iron Age Africa Iron Coal Natural Resources that shaped World History Iron Age Africa Egypt Africa’s only major nation Iron Coal Apparently Tropicseven in the Temperate Zone we need more than Fe & Coal Why no major nations here and here Natural Resources that shaped World History Africa today Natural Resources How did four geologic processes account for the history of Africa? Copper Tin Iron Coal Oil Very large deep water oil reserves Natural Resources that shaped World History Major Rivers Nile Niger Congo How did five geologic events account for the history of Africa? Copper Tin Iron Coal Oil Very large deep water oil reserves \ How Geology shaped human history Next week, Five geologic events that shaped human history \ http://commons.wikimedia.org/wiki/File:Africa_topography_map_with_borders.png http://en.wikipedia.org/wiki/File:CongoLualab a_watershed_plain_political.png http://pubs.usgs.gov/of/1997/ofr-97-470/OF97-470A/AFRICA.pdf http://pubs.usgs.gov/of/1997/ofr-97470/OF97-470A/AFRICA.pdf