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showing also left-lateral displacement. The entrance
of Cave Duhlata lies exactly on this fault. The fault is
expressed in the relief, it stops the galleries of
Pepeliankata Cave, but its impact on the karst systems
is not very well expressed.
Clearer control on the karst processes can be found
along fault No. 1 (Fig.
2.44
). Namely, a subsidence of
the NW block is noted in the area inside the cave of
Duhlata. In this block the density of the karst galleries
is lower and the mapped galleries are active. This
fault is also controlling the morphology of the
Akademik Cave (Fig.
2.44
). One possible reason for
the expressed impact of this fault on the karst system
could be paleo-earthquake activity. The sudden sub-
sidence of the NW block adjacent to the fault could
juxtapose its old galleries to the active ones of the SE
block. The younger galleries of the NW block have
been filled with clay or other sediments, or are inside
the phreatic zone. This assumption is supported by the
fresh striations on the fault surface in the cave of
Duhlata. There are a lot of broken or inclined sta-
lagmites, but the caves of the region are frequently
visited by a number of people and thorough studies
have to be made for filtering the naturally from the
artificially broken stalagmites.
layer of Eocene limestones (Formation Charko
Redondo). Due to the geographical location of the
plateau in the subtropical zone, a seasonal dynamics
of the rainfall exists, with 70-76 % of the rains during
the humid season (May-October). The water balance,
calculated by Cuban hydrogeologists has proved that
considerable part of the water is drained to the South,
toward the Caribbean Sea, using unknown under-
ground ways. This water is extremely needed for the
normal water supply and development of the town of
Guantanamo and its vicinities. The main problem of
the expedition was the detection of the underground
way of the water and to improve the possibility to
exploit sufficient quantity of potable water from the
karst system. The base for the studies were the
topographic maps in scale 1:50,000, the geological
map in scale 1:50,000 drown by Hungarian and
Cuban geologists, as well as the aerial photos of the
region.
The
results
were
only
partially
published
(Andreychuk
and
Benderev
1991
;
Chanov
and
Benderev,
1993
).
2.3.3.2 Geological and Hydrogeological
Background
The rock massif of Guaso Plateau is built mainly of
carbonate rocks. The geological sketch of the studied
area
is
shown
in
Fig.
2.47
.
The
following
strati-
2.3.3
Cuba: Structural and Geophysical
Study of the Karst System
of Guaso Plateau (Eastern Cuba)
graphic units are present:
• BUCUEY
al - t
—magmatic, metamor-
phic and volcanic rocks with total thickness more
than 500 m. The outcrops are located predominantly
in the northern part of the plateau. On some of these
sites, a thick weathered soil (terra rossa) was
formed, containing manganese-iron concretions. On
the upper part of the plateau, over the sedimentary
rocks,
(BUC)—K
1-2
2.3.3.1 Regional Characteristics
Guaso Plateau is situated 1,000 km southeast of the
City of Havana (Republic of Cuba), in the district of
Guantanamo, Province Sierra Oriente (Fig.
2.46
). The
studied region by the Bulgarian-Cuban expedition in
1988 covered a territory of 230 km
2
, occupied by
tropical forests.
The altitude is between 100 m and 800 m above
sea level and the plateau is cut by canyon-like, narrow
valleys. This difference in the altitudes creates a sit-
uation, where the average annual temperature changes
from 20 to 23 C in the upper part of the plateau to
24-27 C at its foot. The plateau is a barrier for the
humid air from the North, from the Atlantic Ocean.
The abundant rains, even during the dry season, form
significant surface and underground water flows
toward North and only a part of the water runs toward
South as underground current inside the 500 m thick
remnants
of
an
allochtonous
serpentinite
overthrust can be found.
• PICOTA (PIC)—K
cp - m
—conglomerates and brec-
cias with thickness varying between 100 and 150 m.
• CHARCO REDONDO (CHR)—P
2
—Eocene lime-
stones with thickness from 200 to 500 m. In these
rocks intensive processes of karstification formed
numerous caves, hollows, abysses, underground
rivers and lakes. This formation was the principal
target for exploration from the Bulgarian-Cuban
expedition during 2 months. The total length of the
mapped karst galleries was about 20 km, 8,382 m of
them being active galleries with underground river
in the longest cave El Campanario. Unfortunately, in
