ISLAND PROFILES
St. Kitts - Geology
There are four volcanic centres on St. Kitts: the Salt Pond Peninsula, South East
Range, the Middle Range, and Mt. Liamuiga (Martin-Kaye 1959).
The Salt Pond Peninsula is dominated by lava domes with minor volcaniclastic deposits
that are interpreted to be pyroclastic flow (block and ash flow) deposits and/or
lahar deposits. Ages of 2.3 ± 0.6 Ma, 2.3 ± 0.5 Ma and 2.77 ± 0.3 Ma (Baker 1969)
were obtained for lava domes of this centre. These are the oldest known ages for
volcanic deposits on the island of St. Kitts.
The South East Range is a youthful-looking volcano that has a partly preserved crater
at its summit (Baker 1969). Ottley's Level and Monkey Hill are lava domes that formed
on the flanks of the volcano. The South East Range mainly consists of lava flows
and volcaniclastic deposits (Baker, 1969) although it is poorly exposed and little
is known about its past eruptive history. An approximate age of 1 Ma was obtained
from a lava flow on the southern slopes of the South East Range (Baker 1985).
Geological map of St. Kitts (adapted from Baker, 1969).
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The age, lack of seismicity and lack of geothermal activity suggest that both the
Salt Pond Peninsula and the South East Range are unlikely to be the sites of future
volcanic activity. The Middle Range also has a youthful appearance and has a small
summit lake that has filled a former crater. The Middle Range is poorly exposed
and there are few descriptions of its geology, although Baker (1963) described it
as consisting of similar deposits to the South East Range. There are no age dates
available for the Middle Range. Previous workers have considered the Middle Range
to be extinct; however, its youthful appearance, and the lack of age dates makes
the current state of the volcano difficult to interpret. New information (i.e. age
dates) is necessary to clarify its eruptive history. There is no geothermal activity
and no seismicity associated with the Middle Range at present. Mt. Liamuiga is the
youngest of the volcanic centres and probably last erupted about 1620 years BP (Baker
1985). The age, geothermal activity and seismicity associated with Mt. Liamuiga
suggest that it is a potentially active volcano and likely to erupt again in the
future.
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