Semi-detailed Soil Survey of the LIuidas Vale Area, St. Catherine-St ...

DESCRIPTION OF THE SURVEY AREA
The Hills and Foothills in hard limestone, occupying the major part of the
survey area, show a cockpit karst topography. The best examples of cockpit
karst are found in the western and north-western part of the survey area at
an elevation of 500-600 m above msl. Relief intensity in this steeply
dissected area is about 100 m. The limestone hills are connected by saddles.
Separated by the Lluidas Vale fault, the central part of the limestone hills
consists of cockpit karst in a more advanced stage of degradation, with wider
valley bottoms on a kind of plateau, dipping to the south-east. The elevation
in the northern part is about 900 m and in the south-east about 500 m; the
relief intensity is less than 200 m.
In the south-west (Top Hill), there is an area of gently sloping doline karst
on soft limestone. Another area of doline karst, on hard limestone, occurs in
the central-south (Murmuring Brook).
The Inland basins are found at two elevations; the Lluidas Vale basin at
around 370 m and the fringe of the St. Thomas in the Vale basin at about
260 m above msl. The Lluidas Vale basin is a flat to undulating in-filled
polje, with old alluvial/lacustrine deposits derived mainly from the Central
Inlier, overlying degraded white limestone and limestone debris. The
drainage is subterranean. Some colluvial admixture is found in the longstretched
plainbands (finger-like fringes of the Inland basin in between the
hills, Pfeffer 1986) at the western side. The transition to the limestone hills
is quite sharp. The boundaries are determined by faults and lateral corrosion
(Landmarm 1989). In places along the eastern border, the Lluidas Vale fault
is not fully developed; limestone outcrops overlain by layers of
alluvium/colluvium derived from conglomerates of the Central Inlier are
found. Some small limestone outcrops occur in the northern part, protruding
through the old alluvial deposits.
In the large fringes of the St. Thomas in the Vale basin, several large
limestone outcrops rise from the alluvial deposits. The major part of this
basin has been studied earlier (SSU 1987b).
The Plains (i.e. river plains) are found along the Rio Cobre, at 360-370 m
above msl and consist of young alluvium, incised in the old alluvium. The
landscape is flat to undulating with different terraces. A small plain is found
in the St. Thomas in the Vale basin, not bordering any present day river
system.
13