results in a large continental overlap between Gondwana and
Laurussia in excess of 1000 km. To solve this discrepancy, a
large disconnecting dextral fault operated during the Permian and Triassic periods was proposed (Irving 1977),
resulting in a relative movement of Laurussia to the north
and of Gondwana to the south. Based on paleomagnetic
data, the total dislocation length of this detachment could
have been several thousand kilometers, but could be much
less if observations in the field of the cumulated dislocations
of the known disconnecting faults in operation at that time
are considered. Moreover, the non-dipolarity of the magnetic
field (strong influence from an octupolar field) during this
period but more likely the lack of fidelity in the magnetic
field recorded in the red sandstones caused by inclination
shoaling may be “distorting” the paleomagnetic data
(Domeier et al. 2012).
At the beginning of the Jurassic, around 200 Ma, the
Pangea supercontinent broke into two vast continents,
Laurasia (Laurussia + Siberia + other smaller plates) to the
north and Gondwana to the south. This separation marked
the beginning of the opening of the central Atlantic Ocean.
The opening directed the drift of North America northwestwards. This initiated the subduction of the Farallon and
Kula plates (northeast region of the Pacific Ocean) under the
western margin of North America, resulting in the accretion
of small heterogeneous blocks and island arcs to the
North-American continent during the Jurassic. As this margin deformed, this was the Sevier orogeny which lasted until
the Lower Cretaceous.
Further east, the Paleo-Tethys Ocean became totally
subducted around 200 Ma and the Cimmerian plates collided with the North China and Tarim plates. This continental mosaic was separated from the southern margin of
Siberia by the Mongol-Okhotsk Ocean. Triangular in shape,
this ocean closed like a scissors during the Jurassic and at the
end of this period (*150 Ma), the small continent formed
by the mosaic of small plates collided with the southern
margin of Siberia. The Eurasian continent was formed. The
multiple collisions between the small plates more than likely
caused deformation, but probably did not create any significant reliefs. The opening of the central Atlantic Ocean
continued. The Panthalassa, Neotethys and Central Atlantic
oceans all become connected in the subtropical zone of the
northern hemisphere.
The Middle Jurassic (*170 Ma) marked the beginning
of the break-up of Gondwana. Madagascar, India, Australia
and Antarctica separated from the Africa-South America
duo. During the Lower Cretaceous (*130 Ma), South
America and Africa started to split and the South Atlantic
Ocean opened between Patagonia and Southern Africa. This
event could mark the beginning of the deformation of the
western central Andes margin in South America (Torsvik
et al. 2009). The complete separation of the two continents
and the connection with the central Atlantic Ocean only
occurred at the end of the Lower Cretaceous period, about
30 million years later. At the beginning of the Lower Cretaceous (*110 Ma), India began its drift northwards. The
Neo-Tethys Ocean was subducted under the southern margin
of Eurasia, while in the south of India, the Indian ocean
opened (McKenzie and Sclater 1971). Jagoutz et al. (2015)
concluded that the exceptional rate of convergence exceeding 140 mm yr
−1 is due to the existence of a double northward dipping subduction zones between the Indian and
Eurasian plates during the Cretaceous. Around 90 Ma,
Madagascar and India separated, the Carlsberg ridge is
formed and marked the beginning of the opening of the
northwestern part of the Indian Ocean.
The Cretaceous is characterized by a high sea level which
led to the formation of vast shelf seas starting at the Albian
(*100 Ma) to the Maastrichtian (*65 Ma). The flooding of
the continents reached its maximum at the beginning of the
Upper Cretaceous, around 95 Ma, when a large part of
Europe was inundated. At the height of the marine incursion,
a shallow sea developed over North Africa across the current
Sahara Desert, temporarily linking the Neo-Tethyan Ocean
to the South Atlantic Ocean. In North America, during the
Upper Cretaceous, a sea passage, the Western Interior Seaway, was established between the Arctic Ocean and the Gulf
of Mexico, while a new orogenic phase affected the margin
of this continent (Laramide orogeny). A sea passage formed
in western Siberia linking the Arctic Ocean and the
Neo-Tethyan Ocean, and only disappeared during the
Eocene.
The beginning of the Cenozoic is marked in the northern
hemisphere by the opening of the third and last part of the
Atlantic Ocean, the northern part. North America and Eurasia separated. However the Arctic Ocean remains almost
isolated from the rest of the oceans during the Early Cenozoic favouring the deposits of black shales due to poorly
oxygenated water (Jakobsson et al. 2007) until the deepening of the Fram Strait during the Late Eocene, *36 Myr
(Poirier and Hillaire-Marcel 2011). In the southern hemisphere, Australia and Antarctica are definitively separated
during the Eocene. The Antarctic migrated to its polar
position. The circum-Antarctic basin was formed. In the
western part of North America, subduction geometry
evolved, deformation progressed eastward, the Rocky
Mountains lifted up, while some more coastal reliefs were
lowered due to a change in the pattern of constraints in this
region. In South America, the uplift of the Andean Cordillera
appears to have accelerated towards the end of the Cenozoic.
India collided with Asia at the beginning of the Cenozoic
(*50 Ma). India’s drift to the north continued after the
collision at a rate of 5–6 cm/year. Part of the crustal thickening is accommodated by the play of large right-lateral
deformations reactivating old sutures between the plaques
44
F. Fluteau and P. Sepulchre
Laurussia in excess of 1000 km. To solve this discrepancy, a
large disconnecting dextral fault operated during the Permian and Triassic periods was proposed (Irving 1977),
resulting in a relative movement of Laurussia to the north
and of Gondwana to the south. Based on paleomagnetic
data, the total dislocation length of this detachment could
have been several thousand kilometers, but could be much
less if observations in the field of the cumulated dislocations
of the known disconnecting faults in operation at that time
are considered. Moreover, the non-dipolarity of the magnetic
field (strong influence from an octupolar field) during this
period but more likely the lack of fidelity in the magnetic
field recorded in the red sandstones caused by inclination
shoaling may be “distorting” the paleomagnetic data
(Domeier et al. 2012).
At the beginning of the Jurassic, around 200 Ma, the
Pangea supercontinent broke into two vast continents,
Laurasia (Laurussia + Siberia + other smaller plates) to the
north and Gondwana to the south. This separation marked
the beginning of the opening of the central Atlantic Ocean.
The opening directed the drift of North America northwestwards. This initiated the subduction of the Farallon and
Kula plates (northeast region of the Pacific Ocean) under the
western margin of North America, resulting in the accretion
of small heterogeneous blocks and island arcs to the
North-American continent during the Jurassic. As this margin deformed, this was the Sevier orogeny which lasted until
the Lower Cretaceous.
Further east, the Paleo-Tethys Ocean became totally
subducted around 200 Ma and the Cimmerian plates collided with the North China and Tarim plates. This continental mosaic was separated from the southern margin of
Siberia by the Mongol-Okhotsk Ocean. Triangular in shape,
this ocean closed like a scissors during the Jurassic and at the
end of this period (*150 Ma), the small continent formed
by the mosaic of small plates collided with the southern
margin of Siberia. The Eurasian continent was formed. The
multiple collisions between the small plates more than likely
caused deformation, but probably did not create any significant reliefs. The opening of the central Atlantic Ocean
continued. The Panthalassa, Neotethys and Central Atlantic
oceans all become connected in the subtropical zone of the
northern hemisphere.
The Middle Jurassic (*170 Ma) marked the beginning
of the break-up of Gondwana. Madagascar, India, Australia
and Antarctica separated from the Africa-South America
duo. During the Lower Cretaceous (*130 Ma), South
America and Africa started to split and the South Atlantic
Ocean opened between Patagonia and Southern Africa. This
event could mark the beginning of the deformation of the
western central Andes margin in South America (Torsvik
et al. 2009). The complete separation of the two continents
and the connection with the central Atlantic Ocean only
occurred at the end of the Lower Cretaceous period, about
30 million years later. At the beginning of the Lower Cretaceous (*110 Ma), India began its drift northwards. The
Neo-Tethys Ocean was subducted under the southern margin
of Eurasia, while in the south of India, the Indian ocean
opened (McKenzie and Sclater 1971). Jagoutz et al. (2015)
concluded that the exceptional rate of convergence exceeding 140 mm yr
−1 is due to the existence of a double northward dipping subduction zones between the Indian and
Eurasian plates during the Cretaceous. Around 90 Ma,
Madagascar and India separated, the Carlsberg ridge is
formed and marked the beginning of the opening of the
northwestern part of the Indian Ocean.
The Cretaceous is characterized by a high sea level which
led to the formation of vast shelf seas starting at the Albian
(*100 Ma) to the Maastrichtian (*65 Ma). The flooding of
the continents reached its maximum at the beginning of the
Upper Cretaceous, around 95 Ma, when a large part of
Europe was inundated. At the height of the marine incursion,
a shallow sea developed over North Africa across the current
Sahara Desert, temporarily linking the Neo-Tethyan Ocean
to the South Atlantic Ocean. In North America, during the
Upper Cretaceous, a sea passage, the Western Interior Seaway, was established between the Arctic Ocean and the Gulf
of Mexico, while a new orogenic phase affected the margin
of this continent (Laramide orogeny). A sea passage formed
in western Siberia linking the Arctic Ocean and the
Neo-Tethyan Ocean, and only disappeared during the
Eocene.
The beginning of the Cenozoic is marked in the northern
hemisphere by the opening of the third and last part of the
Atlantic Ocean, the northern part. North America and Eurasia separated. However the Arctic Ocean remains almost
isolated from the rest of the oceans during the Early Cenozoic favouring the deposits of black shales due to poorly
oxygenated water (Jakobsson et al. 2007) until the deepening of the Fram Strait during the Late Eocene, *36 Myr
(Poirier and Hillaire-Marcel 2011). In the southern hemisphere, Australia and Antarctica are definitively separated
during the Eocene. The Antarctic migrated to its polar
position. The circum-Antarctic basin was formed. In the
western part of North America, subduction geometry
evolved, deformation progressed eastward, the Rocky
Mountains lifted up, while some more coastal reliefs were
lowered due to a change in the pattern of constraints in this
region. In South America, the uplift of the Andean Cordillera
appears to have accelerated towards the end of the Cenozoic.
India collided with Asia at the beginning of the Cenozoic
(*50 Ma). India’s drift to the north continued after the
collision at a rate of 5–6 cm/year. Part of the crustal thickening is accommodated by the play of large right-lateral
deformations reactivating old sutures between the plaques
44
F. Fluteau and P. Sepulchre