동아프리카 열곡 (East Africa's Great Rift Valley)

East Africa's Great Rift Valley: A Complex Rift System

 

 

 

 

출처 : Forbes

 

이게 도대체 어찌 된일 일까요?

궁금하시면 아래부터 쭈욱~ 읽어보시길^^

 

 

 

 

 

geology홈페이지에 동아프리카 열곡에 관한 좋은 기사가 있길래 가져왔습니다.

From : http://geology.com/articles/east-africa-rift.shtml

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 1: Colored Digital Elevation Model showing tectonic plate boundaries,
outlines of the elevation highs demonstrating the thermal bulges and large lakes of East Africa

 

 

Figure 2: Rift segment names for the East African Rift System.
Smaller segments are sometimes given their own names,
and the names given to the main rift segments change depending on the source.
Click Image to Enlarge. The basemap is a Space Shuttle radar topography image 

 

 

Figure 3: "Textbook" horst and graben formation (left) compared with
actual rift terrain (upper right) and topography (lower right).
Notice how the width taken up by the trapezoidal areas undergoing normal faulting
and horst and graben formation increases from top to bottom in the left panel.
Rifts are considered extensional features (continental plates are pulling apart)
and so often display this type of structure.

 

Figure 4: Triple Junction in the Afar region of Ethiopia.
Image shows areas of stretched and oceanic crust as well as areas of exposed flood basalts that preceded rifting.
Areas unshaded or covered by flood basalts represent normal continental crust.
As the crust is pulled apart you end up with thinned crust with a complex mixture of continental and volcanic rock.
Eventually the crust thins to the point where oceanic-type basalts are erupted
which is the signal that new ocean crust is being formed.
This can be seen in the Gulf of Aden as well as a small sliver within the Red Sea.
The original extent of the flood basalts would have been greater,
but large areas have been buried within the rift valley by other volcanic eruptions and sediments.

This image shows several fault scarps that are progressively farther away.
Essentially we are looking at the edges of several horst blocks from within a graben that contains Lake Baringo.

This was taken at the Njorowa Gorge in Hell's Gate National Park. The gorge was carved by water, and is quite spectacular in many regards, but here we have an igneous dike cutting through the wall of the canyon, with Dr. Wood and one of our guides for scale.

 

 

Volcanic, tectonic, erosional and sedimentary landforms are all evident in this comparison of two elevation models of a region
along the East African Rift at Lake Kivu.
The area shown covers parts of Congo, Rwanda and Uganda. <From : NASA>

 

 

 

 

 아래 지도의 붉은색 점있는 방향에서 북쪽을 바라보고 찍은 위성사진입니다.

 

 

 

 

 

 

 

 아래 지도의 붉은색 점있는 방향에서 북쪽을 바라보고 찍은 위성사진입니다.
사진의 오른쪽이 에티오피아의 고원입니다.

 

 

 

 

 

 

 

에티오피아의 고원 사진 (딱 봐도 Basalt Trap)

출처 : 조선일보

 

 

 

 

 

 

 

Earth Structure - An Introduction to Structural Geology and Tectonics by Ben A. van der Pluijm, Stephen Marshak (2nd) (2003) - 383page

 

 

 

 

 

 AFAR 지역은 지판이 3곳이나 벌어지고 있는 지역입니다.

 

게다가 해수면 보다도 매우 낮은 지역으로 지열로 증발이 많아 내륙지역 소금공급을 담당하고 있습니다.

 

 

 

 

 

2012년 1월 National Geographic 에서..

 

 

 

 

 

 

rift valley 밑바닥 분지에는 이런 호수가 존재하고 있습니다.
화산폭발로 형성된 creator lake 입니다.

 

 

 

 

출처 : Global Tectonics (3rd) by Frederick J. Vine, Keith A. Klepeis, Philip Kearey (2001) - 204page

 

 

 

 

 

 

 

그리고,
완전 신기한 지도 한개 더~~

Geographic distribution of early hominins. Hominins are limited to the continent of Africa until about 1.8 million years ago.
Some of the important sites for Australopithecus and other early hominin fossils are located on the map.
Although most known sites are in eastern and southern Africa, Australopithecus likely inhabited most of the African continent.

출처 : Exploring Biological Anthropology - The Essentials (4th) (2017) - 251page

 

 

 

Essentials of Geology by Stephen Marshak (4th) (2012) W . W . NORTON & COMPANY - 280page

 

 

 

 

출처 : Maps of Time - An Introduction to Big History, With a New Preface (2011)