of the Luangwa Rift, and running east–west: the Zambezi Rift Valley and the Chicoa Trough. A tributary of the Shire River at the south end of the Great Rift Valley then cut back eastwards through the Chicao Trough and Zambezi Valley, capturing the southerly overspill of the Madumabisa Lake. This tributary became the Zambezi, which over millions of years captured the Kafue, Cuando and the upper Zambezi. Faulting lowered the land between the Luangwa Rift and the Zambezi Rift allowing Madumabisa Lake to drain out into the Zambezi in a channel which became the lower Luangwa River. The Luangwa as a barrier The Luangwa Rift Valley and rivers within it form a natural barrier, with a very low population density. This, the steepness of the terrain, and the existence of the wildlife reserves have resulted in no highways crossing the valley between the Lusaka-Kabwe roads in the west and the Isoka-Chisenga road in the north, a distance of about 800 km. The lower Luangwa Valley is crossed by just one road, the Great East Road at the Luangwa Bridge, about 10 km south of the Luangwa-Lunsemfwa confluence. Further reading Camerapix: Spectrum Guide to Zambia, Camerapix International Publishing, Nairobi, 1996. Terracarta: Zambia, 2nd edition, International Travel Maps, Vancouver, Canada, 2000. Jean-Jacques Tiercelin et al., "Source Rocks and Reservoirs in Rift Lake Basins over the Past 300 Ma in Central and Eastern Africa", AAPG Annual Meeting, Houston, 2002. Accessed 18 February 2007. A.E. Moore: '"Drainage evolution in south-central Africa since the breakup of Gondwana". South African Journal of Geology, March 2001, v. 104; no. 1; p. 47-68. J.H. Dumisani: "Seismotectonics of Zimbabwe." African Journal of Science and Technology (AJST), Science and Engineering Series Vol. 1, No.4, pp. 22–28 “Hot springs in the Luangwa Valley”. The Northern Rhodesia Journal, Vol 2 No 3 (1954) pp. 65–66. Accessed 26 February 2007. References Rivers of Zambia Tributaries of the Zambezi River Geography of Central Province, Zambia Geography of Eastern Province, Zambia