Aberdare and Mount Kenya National Parks

Abstract

The Aberdare and Mount Kenya National Parks are upland areas located on the Eastern Rift Platform to the north of Nairobi, central Kenya. The dominant physiographic features of the two parks is the Aberdare Range, a 160 km belt of rolling hills and high plateaus, and Mount Kenya, a massive free-standing mountain with a diameter of more than 100 km. The Aberdare Range is comprised of Late Miocene age basaltic volcanics that flooded and smoothed out the topography of this section of the rift platform. Two volcanic groups are identified, the older Satima Volcanics, which dominate the southern part, and the younger Simbara Volcanics, located in the central and northern parts. The dome-shape of Mount Kenya is characteristic of a giant shield volcano. The gentle outer slopes rise some 4,000 m above the regional plateau to an iconic group of central peaks. The volcanism is dominated by the Mount Kenya Volcanic Suite, a thick succession of Pliocene age basalt and phonolite lavas erupted from a central conduit. Blocking of the conduit at approximately 2.6 Ma by an intrusive plug of syenite marked the end of the main phase of activity. The syenite plug is associated with most of the central peaks, including the two highest of Batian (5,199 m) and Nelion (5,188 m). These are formidable obstacles that can only be climbed with a degree of technical difficulty; most trekkers settle for the gentle slopes of Point Lenana (4,985 m). Mount Kenya was severely glaciated during the Late Pleistocene Ice Ages, but the small flank glaciers that surround the central peaks are relicts of a Holocene age icecap that was far larger when first observed by Europeans in the latter part of the nineteenth century. Large parts of the Aberdare Range, as well as the lower slopes of Mount Kenya are covered by montane forests that are unusually luxuriant due to the nutrient-rich volcanic soils and proximity to the Equator. These forests are famous for the occurrence of unusual melanistic variants of large mammals, including leopards.