Earth History GEOL 2110 The Cenozoic Era The Modern World Emerges Tectonics.
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Transcript of Earth History GEOL 2110 The Cenozoic Era The Modern World Emerges Tectonics.
Major Concepts• The volcanic null that corresponded with the Laramide
Orogeny starting in the late Cretaceous ended in the late Eocene epoch (~40Ma) with the resumption of arc magmatism along the western margin of NA
• Starting in the Miocene (~20Ma), the collision of the East Pacific Rise created a transform boundary between the Pacific and NA plates; this brought on the Basin and Range-style extension tectonics, the uplift of the Colorado Plateau, the creation of the Rio Grande Rift, and shift in the motion of the Pacific plate
• The collision of India and various microcontinents spalled from Gondwana’s break-up closed the Tethy’s Sea and created the Alpine-Himalayan orogenic belt
Early Cenozoic (66-40 Ma)Paleocene - Mid-Eocene
Laramide Orogeny
Block uplift of the Precambrian basement
Sedimentation in Laramide Intermontane Basins
Lacustrine Shales of the Green River Basin, UT
Coal Seams in the Powder River Basin, WY
Lacustrine Shales Marls Bryce Canyon NP, UT
PRBHWR
GR
U
Middle Cenozoic (40-20 Ma)Late Eocene – Oligocene – Mid-Miocene
Resumption of continental volcanic arc magmatism as subduction of the Farallon Plate steepens
Tectonics during the Oligocene (~30 Ma)
Middle Cenozoic (40-20 Ma)San Juan Volcanic Field
La Garita Caldera (28Ma)
San Luis Tuff, Wheeler Geologic Monument
Middle Cenozoic (40-20 Ma)Burial and Exhumation of the Laramide Mountains
66Ma
57 Ma
50 Ma
35 Ma
15 Ma
Lara
mid
e O
roge
ny
Post
- Lar
amid
e O
roge
ny
Laramide Mtns Buried
Laramide Mtns Exhumed
Laramide Mtns Re-Exhumed
Laramide Mtns Re-Buried
Laramide Sediments and Volcanic Ash Spreads across the Great Plains
Eocene – Oligocene fluvial sediments of the White River Group, Badlands, SD
Late Cenozoic (20-0 Ma)Mid-Miocene – Pliocene –Pleistocene - Holocene
Collision of East Pacific Rise with NA plate creates the San Andreas Transform Fault System, Basin and Range Province, Colorado Plateau and Rio Grand Rift
Mid-Miocene (~15 Ma) Pliocene (~5 Ma)
Basin and Range ProvinceExtensional Thinning of the Crust
Extension due to mantle upwelling in area of Slab Gap
Basin and Range Province Extensional Thinning of the Crust
As the SA transform boundary grows, Basin and Range Extension migrates to the North. Establishment of rift zone in the Gulf of California kills extension in the southern Basin and Range.
The Slicing and Dicing of CaliforniaNarrow fault –bound basins
rapidly fill with great thickness of sediment that are simultaneously
deformed (e.g., Ventura Basin)
Pliocene (~5 Ma)
Columbia River Basalts, Snake River Basalts, and the Yellowstone Hotspot
Newberry
YellowstoneNA Drift
Edge of Craton
Mantle Plume-Generated Volcanism
Newberry Rhyolite
Columbia River Basalts
Yellowstone Hydrothermal Field
Passive Margins East and South
Triassic-sourced Halite DepositsPangea Break-up – Shallow Marine Deposits
Erosion of North America – River and Deltaic Deposits
The Closing of the Tethys Sea
25 Ma
5-6 MaMediteranean Dries Up -Evaporites
4 MaStraits of Gibraltar
open up