Introduction

Abstract

The national parks, reserves and conservation areas of central/southern Kenya and northern Tanzania reveal a wide range of geological terranes with spectacular landforms. The regional plateaus that are so characteristic of East Africa, e.g. the Serengeti and Tsavo Plains, are underlain by some of the oldest rocks on Earth. The most significant landforms, however, are associated with the East African Rift System (EARS) , specifically the eastern branch or Gregory Rift, a relatively recent geological phenomenon that includes intensive volcanism. Rifting and volcanism have dissected the regional plateaus into possibly the most iconic scenery on Earth. The Gregory Rift Valley is a narrow, linear, down-faulted feature, bounded by huge escarpments. A chain of mostly ribbon-shaped, shallow, alkaline lakes occurs in arid, desolate areas of the valley. The rift platforms, however, have been uplifted to elevations sufficiently high as to create a temperate climate with extensive montane forests , despite the equatorial setting. A unique feature is the occurrence of giant volcanic edifices in both the rift valley and on the rift platforms. Some of the volcanoes constitute the largest free-standing mountains on Earth. They are girdled by successive botanical zones of montane forests , heath and moorlands, with icefields and glaciers capping the two highest peaks of Kilimanjaro and Mount Kenya . The Ngorongoro Caldera and the Serengeti Plains are gazetted as natural wonders of the world, the former for its self-contained ecosystem and the latter for the famous biannual migration of several million large grazers . The diverse geology of East Africa is associated with some of the greatest concentrations of wildlife on Earth. The great diversity of species and the rapid speciation that characterises the region are a reaction to the intensity of the rifting and volcanism. The interrelationship between wildlife and geology is a remarkable feature and many of the parks and reserves could be reclassified as geoparks. The region can support extensive geotourism, particularly as there are active volcanic cones, e.g. the Oldoinyo Lengai Volcano and near-lunar volcanic landscapes.

Photographs not otherwise referenced are by the author.