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The lava flood
At the beginning of the Triassic
Period (a part of the Mesozoic era), the super continent Pangaea
began to tear apart. This happened around 200 million years ago and
was one of the most major land shifts that the earth has witnessed.
As a result, rifts
developed between what we now know as North America and the African
portion of Gondwana Land. This tearing apart was also accompanied by
a huge outpouring of lava. This is, in fact, the largest known
outpouring of lava.
The area covered by the
lava that flowed out is estimated to have covered seven million sq.
kilometers. It is believed that the amount of carbon dioxide
released at this time was instrumental in altering the earth’s
climate.
Where to find formations that resulted from the
lava flood
The lava spread out over a huge area, and cooled to form various
physical formations that we are now familiar with. The physical
formations, as a result of the tearing apart of the Pangaea were
mainly deposits of red sandstone, siltstone, shale and a final layer
of basalt. Red sandstone from the same period has been found in the
Blue Mountains in Australia. Sedimentary deposits of limestone and
dolomite have been found in the Alps, the great mountain system of
south central Europe.
The Palisades basalt cliffs on the bank of the Hudson River at New
York and New Jersey are deposits from the torn Pangaea.
Rock from the Triassic period can be found in the High Veld plateau
region of South Africa. The period also witnessed the largest mass
extinction on earth. However, there is no evidence to prove that
this mass extinction was a result of the lava flood.
Plant and animal life in the super-continent
The Triassic period also saw the first
dinosaurs. The early dinosaurs were not as large as their
descendants. They were slender animals, given to running on their
hind legs and using their fleshy tails for balance.
The first mammals are also believed to have appeared during this
period. The tearing of the Pangaea resulted in the distribution of
many species of plant life all over the earth.
Seeds that could not have been distributed through the usual modes
of seed dispersion were carried to different parts of the world,
when the Pangaea tore apart.
The fourth mass extinction on earth near the end of the Triassic
period is believed to have claimed 76 per cent of all the species
present on earth. |
