Overview of Antler Orogeny
- The Antler Orogeny was a mountain building episode that occurred from the Late Devonian period and lasted until the Early Mississippian period.
- Involved oceanic rock from the West Coast being pushed on top of the continental rock to the East.
What
A: This is before the collisions started
B: The island arc is formed
C: The west coast is pulled towards the island arc
D: The ocean curst reaches the continental crust
E: The ocean crust subducts pushing some land up (Rocky Mountains)
F: North American plate overrides Farollan Plate. Subduction continued moving east.
G: The Farollan plate moves further inland than usual
Where
- The Antler Orogeny occured on the West Coast of the Laurentia continent.
- The Laurentia continent contained much of the landmass of present day North America.
End of Antler Orogeny
Beginning of Antler
Orogeny
Where
- Off the West Coast of the Laurentia Continent.
Periodic View of Events
Late Jurassic Period
Present Day
When
How We Know:
- The Antler Orogeny is believed to have began in the Late Devonian Period and lasted until the Early Mississippian period.
- 350-380 Million years ago.
- Rock type
- Dispersion of rocks
- Ocean crust
Beginning
Present Day
- Approximately 380 Million years ago.
- In terms of relation to a marathon, the Antler Orogeny began 24 miles in.
End
- Approximately 350 Million years ago.
- In terms of relation to a marathon, the Antler Orogeny ended 24.2 miles into the marathon.
In this image we see the sheared and folded deep water sediments of the distal Antler marine basin thrust over and emplaced on top of the shallow water deposits of the continental margin.
An Alternative Hypothesis
Counter points
Accretionary Prism
Evidence
Accretionary Prism Theory
-Wedge shaped group of sediments
-Collision happened after mountains formed
-very lacking
-timing of actual collision
-no volcanic material
Antler Orogeny
By: Nick DeCouto & Emmitt Mikkelson