Climate and Plate Tectonics
the Ordovician, tectonic activity occurred in New England and the
British Isles as North America moved toward the equator and began
to collide with Europe. This led to mountain-building along these
major plate margins. As plates continued to shift in position, diverse
faunas were brought into contact with one another. Plate movement
may also have contributed to the formation of the first Paleozoic
ice age, as the southern continent of
moved over the South Pole. Glaciers began to form in what is now the
Sahara region of Africa. This climate change was possibly associated
with the mass extinction at the end of the Ordovician.
These tectonic clues allow scientists to make sense out of geologic
patterns in the Earth, and to map present-day continents and islands
onto these old deposits.
The Ordovician world was dominated by diverse marine environments,
mostly populated by a wide variety of invertebrate animals. Nearly
all the major animal groups were evolving rapidly in the Ordovician,
developing into many new species. Terrestrial plants were still rare
so the land was probably a relatively barren desert. In fact, there
is evidence for continental glaciation on Gondwana
(North Africa and elsewhere). As a result, the globe was divided between
mostly warm, shallow, tropical and subtropical marine zones and cold,
barren terrestrial regions.