Trinidad`s geology is closely related to the
geology of the South American continent and more specifically
Venezuela. In addition to this it is also part of the southern margin
of the Caribbean Plate. It is these two factors that are responsible
for the complex gelogical structure of Trinidad.
ORIGIN
Trinidad was once connected/part of the
South American continent, however, it became isolated from the South
American mainland after a series of glogal cilmatic events. From the
Pleistocene a series of temperature changes took place which resulted
in the advancement and retreat of the world`s glaciers and increases
and decreases in sea level. During this period of continuous change in
global temperatures Trinidad became separated from Venezuela. Rising
sea levels filled the wide basin between Trinidad and Venezuela to
formed the Gulf of Paria leaving Trinidad separated from South America.
Geological Structure
The northern part of Trinidad consists of
metamorphic and limestone rocks. This block of land was pushed
upwards by faulting to form the Northern Range. This mountain sustem
stretches in a straight line due the the El Pillar and Arima faults
which run parallen to each other and the north coast of the island from
east to west. It is these two faults that are responsible for the
formation of the mountains. The Northern Range is in fact an extension
of the Serran`a del Interior. The El Pillar Fault stretches straight
across the northern tip of the Venezuelan mainland as well.
The central and southern areas of Trinidad
is much more complex than the bands of metamorphic rocks of the
northern parts. Central Trinidad forms a wide plain with small folded
hills that run towards the south. The underlying geology is mainly of
sedimentary origin that trend diagonally from a high gradient in the
east to a low gradient in the west. The Caroni area consists of recent
alluvial material due to the Caroni River.
Southern Trinidad is populated with a
complex network of faults which has allowed oil to seep to the surface.
The Los Bajos wench fault which has a sharply defined right-lateral
displacemrnt of about eight miles is one example. These faults were
produced bt the Cretaceous -Miocene geosynclinial orogeny of Venezuela
and Trinidad and possible by the plate movement associated with
the Antillian Arc .The Trilobites fossils were compressed by the
sedimentary layers to form oil.
A typical feature of Southern and Central
Trinidad is the mud volcano. They are usually found along faults where
gases that lie above layers of sedimentaru rocks emerge to the surface.
Underground water mixes with the soil and gases to produce an eruption.
Another striking feature is the Pitch Lake {the largest of its kind in
the world}. This asphalt lake occupies a very deep basin that overlies
sedimentary rocks.
