Page 168 - Global Tectonics

154 CHAPTER 7

(a) 20 E 30 E 40 E 50 E
30 N 30 N
A R A B I A N P L A T E
AFRICA ARABIAN PLATE
A F R I C A
25 N 25 N
16 mm a
16 mm a 1 1

30 mm a

NUBIAN PLATE
N U B I A N P L A T E 30 mm a 1 1
20 N Red Sea 20 N
23 mm a 1 1
23 mm a

Red Sea
10 mm a
10 mm a 1 1
15 N 15 N
Gulf of Aden
Gulf of Aden
Afar
EP
6–7 mm a

10 N 6–7 mm a 1 1 EP Afar 10 N
Turkana Depression
Turkana Depression MER
MER
5 N S O M A L I A N 5 N
SOMALIAN
CB
CB PLATE
P L A T E
A
Western
Western
0 0
Rift
Rift Eastern
Eastern
Rift
EAP Rift
EAP
Indian
M Indian
Ocean
5 S Ocean 5 S
K
20 E 30 E 40 E 50 E
(b) 3 Karonga Basin L 120 km (c) 3 Manyara Basin L 87 km
km 0 km 0
3 Livingstone fault 3
Omo Chew Bahir Basin L 65 km
(d) 3 Albert Basin (e) 3 Basin
km 0 km 0
3 Bunia fault Toro–Bunyoro fault 3
Cenozoic volcanic rock
Late Cenozoic sedimentary rock
Figure 7.2 (a) Shaded relief map and geodynamic setting of the East African Rift system constructed using digital
topography data and software cited in Fig. 7.1. White arrows indicate relative plate velocities. Black arrows indicate
absolute plate motion in a geodetic, no-net-rotation (NNR) framework (Section 5.4). (b–e) Cross-sections showing fault
and half-graben morphology (after compilation of Ebinger et al., 1999, with permission from the Royal Society of
London). M, Manyara basin (from Foster et al., 1997); K, Karonga basin (from van der Beek et al., 1998); A, Albert basin
(from Upcott et al., 1996); CB, Chew Bahir basin (from Ebinger & Ibrahim, 1994); EAP, East African Plateau; EP,
Ethiopian Plateau; MER, Main Ethiopian rift; L, the length of the border fault.