1. Life Long Learning: Fall 2012 Vagabonds Tramp Eastern Africa Session Five “Vagabonds Tramp through Eastern Africa: where the unique geology of the East African Rifts produced the advent of the human species and the Nile flood plain shaped the beginning of human history” Let’s recall that I’m postulating that the great nations of human history were and are located, because of continental drift, in the Northern Temperate Zone, and that they had geologic resources of farmland, plus iron, coal and in the 20 th century, oil Last week Sandi took us to Tanzania and the East African Rift lakes where fossils indicated humans first appeared. You and I looked at rock types, the welding of geosynclines as mountains that renewed the continental crust periodically, and the farm land of Zimbabwe Now let’s focus on Tanzania

2. Central Africa: Natural Resources Focus on Tanzania Tanzania: one of four former German colonies in Africa

3. German Colonies in Africa

4. African Geologic Map German Colonies in Africa

5. Natural Resources: largely in Igneous & Metamorphic Rocks Copper Tin Iron Africa today Natural Resources Focus on former German African Colonies Note: No Iron or Coal Now the natural resources of Tanzania

6. Almost no farming, no iron, & no coal Gold These very old, Pre-Cambrian rocks weathered into thin soils suitable for grazing, not rich farm soils Now, remember what Sandi said caused the long, narrow lakes? Why little or no farmland ? Conclusions: Rock type determines the soils produced by weathering, not rock age. But before we go to the lakes, let’s remember the farmland in Zimbabwe’s very old, Pre-Cambrian. Why did weathering there produce farmland and not here? The Natural Resources of Tanzania

7. Focus on possible farming areas in Zimbabwe Focus on this province

8. Focus on possible farming areas in Zimbabwe Note: no farming in river flood plain but all the surrounding hills are cultivated Back to the regional view and another possible area of farming

9. Focus on this province The regional view and another possible area of farming

10. Again the river flood plain is not cultivated but the surrounding hills are completely farmed Conclusion: Zimbabwe, Southern Rhodesia, though in the Tropics has great potential for becoming a prosperous nation based on its natural resources Does the farmland stop when we leave the light gray areas on the NASA maps?

11. Eastern limit of the northern farmland Rock that weathers into thick, rich soils Rock that weathers into thin soils Now to the southern area

12. Rock weathering into thick, rick farmland Rock weathering into thin soil Conclusion: Rock composition makes all the difference! Was Zimbabwe a great African nation before it was Southern Rhodesia?

13. Now to the long narrow Rift Valley Lakes in Tanzania Pre-colonial nations of Africa

15. Long Narrow Rift Valley Lakes They are the southern extension of the East African Rift System Let’s look at the “big picture”

16. Earthquake Epicenters: 25 years Focus on Africa East African Triple Junction

17. Complex Shape of Mantle Convection Cells Can you find Africa in the top panel? East African Triple Junction

18. Rift Valleys formed & Volcanoes Plate Tectonics: Uplift and rift faulting over a sub-crustal (mantel) convection cell Why was this event important? This unique geological event coincides with the advent of the human race here! East Africa: Triple junction More detail on the East African triple junction Tanzania

19. East Africa Rift Valley Eastern Rift Valley Western East Africa: Triple junction East African Triple Junction The triple junction up close

20. The triple junction up close: rift valleys and volcanoes Another view focused on the East African Rifts

21. Another view focused on the East African Rifts Might there be oil and gas in the rifts?

22. Kenya oil discovery Tanzania Current oil and gas exploration in the East African Rifts Comments: The economic viability of this discovery will depend on what deeper drilling encounters. Its remote location will require a very expensive pipe line. Commercial production, if any, is years in the future.

23. http://bulletin.geoscienceworld.org/content/98/4/439.abstract Rift Valley Exploration History In the early 1980’s Duke University designed a “portable” seismic survey vessel, conducted extensive seismic subsurface imaging of the African rifts, which was financed by several major oil companies. Results indicated possible oil & gas accumulations but the remote location of the rifts, the excessive water depths of the rift lakes, and the complex nature of the prospects caused all major companies to decline investing the additional funds needed to define drill sites. Note: Currently oil & gas exploration is being done in the rift valleys of Kenya because they contain the world’s richest source rocks (25 % organic C) Back to Africa and Early Human History & Geology

24. Africa: Early Human History & Geology East African Rift Valleys & the Advent of Humans Rift extensions & crustal warping produces rivers that provide provides routes for humans out of the Tropics of Africa Nile River flood plain: Bronze Age empire built on large scale agriculture in the Nile River flood plain Now let’s look more closely at the geology Tanzania The Tropics Note: The upper Nile River is in the Northern Temperate Zone Proposition: The geology of Africa shaped the advent & early history of Humans

25. Regional View of Southern Africa Zimbabwe Tanzania Ruvuma River Remember the rivers of Africa

26. Zimbabwe Tropics

27. Zimbabwe Tropics What age rocks are at the surface in Tanzania?

28. Age of the rocks are at the surface in Tanzania Mostly purple, Pre-Cambrian metamorphic and Igneous rocks >500 million years old, very similar to Zimbabwe (in age) And how have these rocks been affected by erosion; the topographic map

29. Tanzania Ruvuma River Tanzania; Topographic Map Note: Ruvuma River delta Long, narrow lakes Up-land topography like Zimbabwe Questions: Is the Ruvuma building a geosyncline prospective for oil & gas? Are the lakes part of the East African rift system? Will the up-land have farming like Zimbabwe?

30. Google Earth view of Tanzania & Vicinity The Ruvuma delta up close: flood plains & farm land?

31. The Ruvuma delta up close: flood plains & farm land? No farm land, only jungle Maybe small geosyncline prospective for oil & gas Let’s look at current oil exploration in the Ruvuma geosyncline, here Tanzania Mozambique

32. Tanzania Mozambique Current Oil & Gas Exploration in the Ruvuma river geosyncline Numerous small prospects

33. Numerous small, complex prospects Prospects in cross section

34. Prospects in cross section Now more detail

35. Detached Folds Look at the blue layer it is a “detached” fold What is a detached fold?

36. Detached Folds Detached folds, a massive slump A modern example affecting the surface

38. Windjammer Palma FB Thrust Play

41. Lagosta Oligocene & Eocene Deepwater Fans Back to the topographic map of Tanzania. Any other rivers that might have farm land? Conclusions: Small geosynclines can be prospective for oil & gas but here they are very complex. They might also be prototypes for understanding the oldest part of large geosynclines

42. Tanzania Ruvuma River Tanzania; Topographic Map Here?

43. No farming, only jungle Here?

44. Here?

45. Looks like grazing land. What does the natural resources map show?

46. East Central Africa: Natural Resources Focus on Tanzania

47. No farming (little cotton) no iron, & no coal Gold Can we find the cotton south of Lake Victoria? Focus on Natural Resources in Tanzania

48. Cotton fields? Next week: Advents of humans, Kenya, & Egypt