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Geologie Antiguy

15.11.2009
Geologie Antiguy

Antigua and Barbuda is located between latitude 17 0' and 17 45' N and
longitude 62040' and 62 54' W (Map 1), and has a total land area of 440 km 2
(Antigua 280 km2, Barbuda 160 km2) and population of 65,200 (Antigua 64,000,
Barbuda 1,200).

8. The climate is tropical-maritime, with a mean annual temperature of 26 C,
varying from 16.7 to 28.3 C. Average annual precipitation is 1100 mm, but
variable throughout the year; the islands are susceptible to severe droughts
(as well as earthquakes and hurricanes). The main rainy season is from
October to November.

9. The geology of Antigua consists of a hilly limestone zone to the east, a
central plain of marl and clay overlying volcanic material, and volcanic
mountains in the southwest rising to 410 m above sea level at Boggy Peak
(Map 2). The topography is mainly gently undulating with slopes of 11 - 20
degrees. Shallow soils overly volcanic material and the limestone, over most
of the island. Barbuda, which lies 32 miles north west of Antigua, is a low-
lying coral limestone island, no higher than 60 m in the east, but with a
large coastal lagoon enclosed by a long sand spit in the west.

10. Like most of the Caribbean Islands, Antigua was completely wooded when
"discovered", but following European settlement it was almost totally
cleared to make way for cultivation of sugar cane and cotton. With sugar as
the dominant crop for over 300 years, Antigua & Barbuda's natural landscape
was undergoing irreversible changes which created negative pressures on
wildlife habitat and watershed areas. The demise of the sugar industry in
the 1970's led to the abandonment of sugar cane plantations. Presently,
Barbuda is affected by the overgrazing of animals which have continually
removed valuable vegetation protecting watersheds.

11. As described by the Wildlife/National Parks consultant, the ecosystems
of Antigua and Barbuda range from evergreen woodlands, xerophytic woodlands,
scrublands, grasslands to mangrove forests, herbaceous swamps, saltponds,
sandy beaches, rocky shores, coastal lagoons, sea grass beds, coral reefs,
coral reef outcrops and oceanic islands and rocks. Ecosystem variety is
enhanced by the presence of caves in the north-eastern limestone area and by
natural seasonal drainage channels, streams, potholes and ponds. Barbuda's
giant coastal lagoon is unique to the Region and together with its extensive
tidal flats, sand bars, underwater sand dunes, salt ponds, cliffs, caves and
"highlands", all providing special habitats for wildlife. Wildlife species
associated with these natural ecosystems have developed physical,
behavioural and physiological adaptations.

FOTO:http://www.geologyrocks.co.uk/images/category/limestone

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