1. Divergent Plate Boundaries
Lithologic Associations

2. Global Patterns of Divergence

3. Doming continental lithosphere
What Processes are Illustrated?
What Geologic Features would be Preserved?

4. Processes Accompanying Doming
Normal Faulting
Earthquakes
Volcanism
What is the source of the magma?
Based on this source, what type of volcanism would you expect?

5. The Dome Collapses – Rift Valleys, Horsts, Grabens and Half Grabens
In Addition to the Faulting and Volcanism,
What Other Processes would Operate Here?
What types of rocks would you expect?

6. Additional Processes Accompanying Collapse of the Dome
Weathering
Erosion
Deposition

7. Additional Processes Accompanying Collapse of the Dome
How much weathering would you expect in this setting?
What would be the composition of the sediment?
How much modification of sediment would take place during transport?
What textures would you expect?
What patterns of deposition would you expect?

8. As Lithosphere Stretches
Lithosphere thins
Mafic magma is added intrusively and extrusively
What happens to the density of the lithosphere?
Why?
What happens to the buoyancy of the lithosphere?
What is the result of this?

9. Lithosphere Subsides Below Sea Level
Modern Linear Seas: Red Sea, Dead Sea, Persian Gulf
What would be the geologic record of this?
What happens to the tectonic activity on the edges of the continents?

10. From Rifting to Drifting
Passive Margins of Continents drift away from axis of tectonic activity - Mid-Ocean Ridge (MOR)
As distance from MOR increases, continental margins cool, become more dense and subside – continental shelves
What kinds of sediments would you expect?

11. From Doming to Rifting to Drifting

12. Example of Rift Lithologic Association
Mesozoic rift basins up and down the Eastern Seaboard
Igneous and Sedimentary record in rift basins

13. Evidence of Rifting – Palisades Sill

14. Palisades Sill – lower contact

15. Evidence of Relief – “Fanglomerates”

16. Evidence of Relief - Arkose

17. Rift Basins – Closed Drainage - Lakes