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Title: The geology of the area around lake Hannington and the Perkerra river, Rift Valley Province, Kenya.
Author: Griffiths, P. S.
Awarding Body: Royal Holloway, University of London
Current Institution: Royal Holloway, University of London
Date of Award: 1977
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A ;'1ew r~eologtcal map of an area of the Kenya '=1ift betwep.n thp. equator and 00 30' 1;, is presented, and the geolosy of this area described. The area consists of three structurally and stratigraphically distinct regions. Conseq uently, corr8la tion across the area lar/!ely cley..ends on K/Ar a~es, which have been determined for some of the lavan. The e3.sternmost region - part of the rift shoulder - consists of volcanics of middle Miocene to middle Pliocene age: The oldest sequences of aH:ali. tasaltic and rocks are succcc:2e:!, first r.y plateau phonolttes, then by trachytes. j·jost of the faulting and til tine>; succeeded each volcanic episode. The wcsternnost reg-ion is a strip alonr: the castel"I1 foot of the Kamasia Hills. Alkali basalts-hawaiites of middle Pliocene age are ubiqui tous. These are overlain by localised S€)q UC!'1ces of upy:er Pliocene, and Pleistocene, age that contain, variously, Gedim8n~1.ry and pyroclastic forma tions, trachytes, phonoli tes and mu!,earitic assemblaR'es. There are no major faults, but local structures appear to be the result of displacement of the edge of the Kamasia range. The intervening region consists of a wide 'depression', within which only Pleistocene and Recent strata .. outcrop. Two phaGes of eruption of I m. alkali and 'transitional' basalts were separated by an episode of ~idespread eruption of lavas of trachyte-to-phonolite composition. Small-scale faulting accompanied and succeeded this activity. Most of the fluvial erosion, and deposition in various environments has been controlled by the volcanic and tectonic events.The structures are described, and com:oared with those of adjacent areas. Suggestions for their fonnation are made. The petrography of the lavas is described, and ma,ior element analyses of fifty-five. rocks are presented. The petro~enetic implications of the major and trace element chemistry of some Pleistocene lavas are also discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available