LARAMIDE%20OROGENY

1
LARAMIDE OROGENY

• Major tectonic event that formed the Rocky
  Mountains
• Occurred 70-40 Mya
• Occurred in the interior of a plate
• Occurred 1,000 miles from nearest subduction zone
• Can you explain the Laramide orogeny using the
  paradigm of plate tectonics?

2
The Laramide orogeny refers to a phase of
mountain building from approximately 80 million
years ago to 40 million years ago. Laramide
uplifts are topographically high areas that were
created during this period. Although the cause
of these uplifts is still debated, the uplifts
are almost certainly related to ongoing
convergence and subduction of the oceanic
Farallon plate and possibly other oceanic plate
off the then-western margin of North America.
3
(No Transcript)
4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
(No Transcript)
15
Deformation occurred inland from the plate margin
Crustal deformation resulting in uplift, arched
domes, basins, and large anticlines
Believed to be the result of subduction of the
Farallon Plate beneath North America
Subduction along entire west coast Subduction
at an angle of 50 degrees Volcanic activity
150-200 km from trench Angle of subduction
decreased, resulting in Farallon Plate
moving nearly horizontal beneath Plate cools
enough to subduct in Colorado, forming the
Rocky Mountains