Mesozoic earth cratonic sequences Flashcards
What kind of events happened in the Appalachians as North America separated from Africa
Erosion, Block faulting, and igneous activity
What did the erosion of the fault block mountains cause
think and poorly sorted non-marine detrital sediments
What happened to the Gulf Coastal Region before North and South America separated
It was above sea level until North and South America separated
What happened to sea levels during the Cretaceous
Sea levels rose steadily, seen in global transgressive sequences
How did the Cretaceous Interior Seaway form
Early Cretaceous: Arctic waters spread onto the North American Craton, forming a large inland sea.
Middle Cretaceous: Transgressions occurred due to active oceanic spreading ridges, rifting, and high heat flow.
Late Cretaceous: the Cretaceous interior seaway formed, extended from the Arctic to the Gulf of Mexico
Define Terranes
Small, exogenous lithospheric blocks
- Accreted onto larger continental blocks
What do Terranes include
Inland arcs, oceanic crust, small fragments of continents
In what ways do Terranes differ from one another
- Fossil content
- Stratigraphy
- Structural Trends
- Paleomagnetic properties
What is Wrangellia
Flood basalts formed in ocean
What happened to Wrangellia
it accreted to North America
What percentage of western margins of North America are composed on accreted terranes
25%
what kind of resources to the terranes contain
-coal
-petroleum
- uranium
- gold
- iron
- copper
What kind of Similarities did the Cordilleran Orogenies have in common
Although they began in different places and times, but they often overlapped
What are the 4 different Cordilleran orogenies
- Sonoma Orogeny
- Nevadan Orogeny
- Sevier Orogeny
- Laramide Orogeny
what was the Sonoma Orogeny
ocean rock thrust on top of continental rock
- transitions from passive margin to active margin with active subduction under North American Plate
