2. INTRODUCTION
Tethys Sea, former tropical body of salt water that
separated the supercontinent of Laurasia in the north from
Gondwana in the south during much of the Mesozoic Era
(251 to 65.5 million years ago). Laurasia consisted of what
are now North America and the portion of Eurasia north of
the Alpine-Himalayan mountain ranges, while Gondwana
consisted of present-day South America, Africa, peninsular
India, Australia, Antarctica, and those Eurasian regions
south of the Alpine-Himalayan chain. These mountains
were created by continental collisions that eventually
eliminated the sea.
Tethys was named in 1893, by the Austrian geologist
Eduard Suess, after the sister and consort of Oceanus, the
ancient Greek god of the ocean.
3. TYPES OF TETHYS SEA
At least two Tethyan seas successively
occupied the area between Laurasia and
Gondwana during the Mesozoic Era.
1. PALEO TETHYS SEA
2. NEO TETHYS SEA
4. PALEO TETHYS SEA
Paleo (Old) Tethys Sea, was created when all landmasses
converged to form the supercontinent of Pangea about 320
million years ago, late in the Paleozoic Era. During the Permian
and Triassic periods (approximately 300 to 200 million years
ago), Paleo Tethys formed an eastward-opening oceanic
embayment of Pangea in what is now the Mediterranean region.
This ocean was eliminated when a strip of continental material
(known as the Cimmerian continent) detached from northern
Gondwana and rotated northward, eventually colliding with the
southern margin of Laurasia during the Early Jurassic Epoch
(some 180 million years ago). Evidence of the Paleo Tethys Sea is
preserved in marine sediments now incorporated into mountain
ranges that stretch from northern Turkey through Transcaucasia
(the Caucasus and the Pamirs), northern Iran and
Afghanistan, northern Tibet (Kunlun Mountains), and China
and Indochina.
5. NEO TETHYS SEA
The Neo (New, or Younger) Tethys Sea, commonly referred to
simply as Tethys or the Tethys Sea, began forming in the wake of
the rotating Cimmerian continent during the earliest part of the
Mesozoic Era. During the Jurassic the breakup of Pangea into
Laurasia to the north and Gondwana to the south resulted in a
gradual opening of Tethys into a dominant marine seaway of the
Mesozoic. A large volume of warm water flowed westward
between the continents and connected the major oceans, most
likely playing a large role in the Earth’s heat transport and
climate control. During times of major increases in sea level, the
Tethyan seaway expanded and merged with seaways that flowed
to the north, as indicated by fossil evidence of mixed Tethyan
tropical faunas and more-temperate northern faunas.
7. Clousure Of Tethys Sea
Tethys closed during the Cenozoic Era about 50 million
years ago when continental fragments of Gondwana—
India, Arabia, and Apulia (consisting of parts of Italy, the
Balkan states, Greece, and Turkey)—finally collided with
the rest of Eurasia. The result was the creation of the
modern Alpine-Himalayan ranges, which extend from
Spain (the Pyrenees) and northwest Africa (the Atlas)
along the northern margin of the Mediterranean Sea (the
Alps and Carpathians) into southern Asia (the Himalayas)
and then to Indonesia. Remnants of the Tethys Sea remain
today as the Mediterranean, Black, Caspian, and Aral seas.
8. Effect Of The Evolution Of
Tethys Sea
An important effect of the evolution of the Tethys Sea
was the formation of the giant petroleum basins of
North Africa and the Middle East, first by providing
basins in which organic material could accumulate
and then by providing structural and thermal
conditions that allowed hydrocarbons to mature.
