an engineering geological characterisation of tropical clays - GBV
an engineering geological characterisation of tropical clays - GBV
an engineering geological characterisation of tropical clays - GBV
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possible use as building stone <strong>an</strong>d in the m<strong>an</strong>ufacture <strong>of</strong> bricks <strong>an</strong>d tiles, limes <strong>an</strong>d cements.<br />
His findings were published in a report issued by the Imperial Institute (1926).<br />
Bailey Willis (1936) described the Kikuyu scarp to the west <strong>of</strong> Nairobi, the warped peneplain<br />
around Nairobi <strong>an</strong>d the grid – faulting that has affected the volc<strong>an</strong>ic rocks <strong>of</strong> the Rift valley<br />
region <strong>an</strong>d western parts <strong>of</strong> Nairobi area. Saggerson <strong>an</strong>d Baker (1965) also investigated <strong>an</strong>d<br />
described, among others, the Kikuyu scarp <strong>an</strong>d the warped peneplain in the neighbourhood <strong>of</strong><br />
Nairobi area.<br />
Campbell Smith (1931) described <strong>an</strong>d classified the trachytes <strong>an</strong>d phonolites <strong>of</strong> Nairobi <strong>an</strong>d<br />
its surroundings after examining <strong>an</strong>d <strong>an</strong>alysing a number <strong>of</strong> rock specimens collected from the<br />
areas. His findings were published <strong>an</strong>d incorporated in a report.<br />
Bowen visited Kenya in the 1930´s <strong>an</strong>d made <strong>an</strong> excursion into the Rift Valley. He also<br />
collected specimens <strong>of</strong> volc<strong>an</strong>ic rocks from other parts <strong>of</strong> the country, including Nairobi <strong>an</strong>d<br />
the present study area. In 1937, he published the results <strong>of</strong> his studies in a paper in which he<br />
illustrated his experimental work with personal observations on the lavas.<br />
The nature <strong>of</strong> alkali – feldspars in certain Keny<strong>an</strong> rocks, including the Kapiti phonolite was<br />
investigated by Häkli (1960). The specimens <strong>of</strong> Kapiti phonolite had been previously<br />
collected by a Finnish Expedition in 1952 from the Stony Athi River <strong>an</strong>d Nairobi, including<br />
some parts <strong>of</strong> the study area.<br />
Williams (1967) outlined the geology <strong>of</strong> Nairobi <strong>an</strong>d its surroundings, in its regional setting.<br />
Various lavas have also been collected from the Nairobi succession <strong>an</strong>d dated (Baker et al,<br />
1988). Curtiss, Evernden <strong>an</strong>d Miller <strong>of</strong> the University <strong>of</strong> California, USA, carried out K/Ar –<br />
age dating on rock specimens collected from the Nairobi region. The volc<strong>an</strong>ic rocks were<br />
found to be Upper Miocene to Pleistocene in age (Evernden et al, 1964).<br />
Other studies involving Nairobi <strong>an</strong>d covering the present study area include palaeomagnetic<br />
studies by staff <strong>of</strong> the Department <strong>of</strong> Physics, University <strong>of</strong> Nairobi (Mussett et al, 1964-<br />
1965); <strong>an</strong>d the monitoring <strong>an</strong>d detection <strong>of</strong> seismic activities <strong>an</strong>d possible associated earth<br />
movements, by the Seismology Section, Department <strong>of</strong> Geology, University <strong>of</strong> Nairobi<br />
(1990-2002).<br />
A number <strong>of</strong> other <strong>geological</strong> investigations have been carried out in Nairobi <strong>an</strong>d its environs,<br />
including the study area; but they are recorded as unpublished works by the Mines <strong>an</strong>d<br />
Geological Department, Nairobi. Some <strong>of</strong> the unpublished works include those <strong>of</strong> Binge,<br />
Joubert, Pulfrey <strong>an</strong>d Saggerson (Mines <strong>an</strong>d Geological Department, Nairobi, 2001).<br />
Early works regarding detailed survey <strong>an</strong>d study <strong>of</strong> soils <strong>of</strong> the Nairobi area <strong>an</strong>d its environs<br />
were undertaken by Jones in 1952 <strong>an</strong>d published in 1953. His works were later carried<br />
forward to completion by Scott, <strong>of</strong> the then East Afric<strong>an</strong> Agriculture <strong>an</strong>d Forestry Research<br />
Org<strong>an</strong>isation. In his works, he described a variety <strong>of</strong> soils found as having developed under a<br />
wide r<strong>an</strong>ge <strong>of</strong> climatic conditions (Scott, 1963).<br />
Other works in the study <strong>of</strong> soils were undertaken by Stephen, Bellis <strong>an</strong>d Muir (1956), who<br />
investigated the nature <strong>of</strong> the black cotton soils overlying Nairobi phonolite in the Athi<br />
plains, with the purpose <strong>of</strong> establishing the cause for uneven growth <strong>of</strong> crops. They also noted<br />
that soils from Embakasi area, Nairobi, contained some minerals typical <strong>of</strong> metamorphic<br />
rocks.