The answer to your question is somewhat related to
the answer to the first question. It is believed
that the shale beds that are good sources of oil
in Iran were deposited in a shallow marine
environment offshore along a passive margin. A
passive plate margin is one like our Atlantic
coast ,where there is no plate collision
occurring and there are few earthquakes and
The shale beds are Cambrian to
Carboniferous in age and were deposited off
the coast of Gondwana, a Paleozoic
supercontinent composed of land we now know as
Australia, India, South America, Africa, and
Antarctica. Iran was located at the northern
edge of Gondwana along the margin of the
Panthalassic Ocean. The Panthalassic Ocean is
basically the ancient Pacific Ocean.
Plankton populations depend on
ocean circulation patterns because upwelling of
deep ocean water supplies the nutrients the
plankton need to live. Blooms of plankton are
often associated with areas of upwelling. Perhaps
during the Cambrian to Carboniferous, the coast
along Iran was the site of significant upwelling.
I found a website that shows the position of Iran
relative to other countries and the oceans
throughout geologic time.
And Iran is labeled "IR".
Click Here to return to the search form.