

The main event during the Mesozoic was the
breakup of Pangaea.
The Rocky Mountains and the Atlantic ocean were formed.
Fig.14.1 Note the large bay of the Tethys
ocean- future source of Middle Eastern oil fields.
North America was the first continent to break away from Pangea (190 mya-Triassic).
South America broke away later (130 mya).
Original split was on the western side of Greenland; Mid-Atlantic ridge later
shifted to the eastern side.
Cretaceous was marked by a large rise in sea level that flood much of the
continents.
Flood # 5 Zuni
See Fig. 14.6...Cretaceous Interior Seaway
Movements of the continents as Pangea broke up changed ocean currents and the
climate.
Temperatures moved downwards as continents moved northwards.
A chain of volcanic islands existed in the western portion of North
America. Fig 14.4 8 14.5
Appalachians were eroded flat.
When N. America broke away, there was basin and range faulting along East coast
with
block faulting and volcanism. (Fig, 14.7)
Gulf coastal area---Gulf of Mexico started to form; a lot of salt was formed due
to evaporatiion.
Most of the exciting geology was taking place along the western coast due to the
Pacific plate
sliding under N. America; mountains were pushed up.
SONOMA OROGENY (Permian-Triassic), Nev/Calif. border area Fig.14.10
and Fig.14.13
Famous formations-Chinle Formation of Northern Arizona (Petrified Forest
p.287)
Morrison Formation (dinosaur fossils-Dinosaur National Monument Vernal,
Utah)
NEVADAN OROGENY (Jurassic-Cretaceous)--first part of Cordilleran Orogeny
huge granite intrusions...Sierra Nevada Mountains of eastern California
followed by SEVIER OROGENY and later by LARAMIDE OROGENY (copper)
Accreted Terranes-added to N. America during the Mesozoic Fig 14.21