1. Part 4b: Stratigraphy and Tectonics of Silurian and Devonian Periods
Earth History GEOL 2110
The Paleozoic Era
Part 4b: Stratigraphy and Tectonics of Silurian and Devonian Periods

2. Major Concepts
The proliferation of coral reefs caused restricted basins wherein great thickness of limestone and evaporites were deposited.
Along the eastern margin of North America the collision with the European craton and Avalonian micro- continents and volcanic arcs created a new orogenic belt in the Devonian
This orogenic event caused intense warping of the craton that accentuated the arches and basins that had begun to form in the Ordovician.
It also generated a new clastic wedge of redbed molasse sediments in eastern NA and northern Europe
Devonian tectonism also affected arctic regions and the western margin of North America

3. Silurian – Devonian Major Events

4. Carbonate Reefs and Evaporites

5. Carbonate Reefs

6. Evaporites Sabhkas Density of Brines Salts in Normal Seawater
NaCl – 2.72% Halite(Salt)
MgCl2 – 0.38%
MgSO4 – 0.16%
CaSO4 – 0.12% Anhydrite
K2SO4 – 0.08%
CaCO2 – 0.01% Calcite
Calcite  Dolomite
2CaCO3 + Mg+2 
CaMg(CO3)2 + Ca+2
Density of Brines

7. Evaporite Basins of the Silurian

8. Early Devonian Regression Break between Tippecanoe and Kaskasia Sequences

9. Early Devonian Regression Much of the Silurian Removed on Arches
Silurian Missing from MN

10. Kaskasia Sequence of the Devonian Mountain-building and Craton-warping affects Sedimentation

11. Craton Warping Creates Multiple Unconformities
Mississippian LS
thin Silurian LS
Ordovician LS
Devonian Missing
Unconformities draping the Ozark Dome, Missouri

12. Acadian Orogeny A New Clastic Wedge Forms
Coarse Immature Sandstone (Molasse)
Black Slate
(Flysch)
Redeformation of
Late Ordovician Taconian Deformation

13. Acadian Orogeny Overprints Precusor Orogens
Late Ordovician Middle Silurian Late Devonian
K-Ar ages

14. Remember the Grenville
Collision of Laurentia with Amazonia (SA) at 1 Ga

15. Caledonian Orogeny Europe Docks to the North in Early Devonian

16. Caledonian Orogeny A Continent-Continent Collision

17. Devonian Old Red Sandstone Clastic Wedge on European Side of the Caledonian Orogen

18. Minor Devonian Orogenies Ellesmerian (Arctic) Antler (Western NA)

19. More to Come Making Pangea

20. Feedback of the Organic and Physical World

21. Part 5a: The Carboniferous and the Making of Pangea
Next Lecture
The Paleozoic Era
Part 5a: The Carboniferous and the Making of Pangea
Quiz on Chapter 12 and
13 (p )