Geology 12 - Historical Geology
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Paleozoic Rocks

Reading: Parts of Chapter 13, 14, 15

For this reading guide, we're just looking at the sections of the chapters about rocks. The topic guide on Paleozoic Life picks up the sections of the chapters on critters.

The topic guide organizes the information regionally rather than chronologically. So you can either skip from chapter to chapter to find the necessary information (you'll find references to the right sections in each question) or you can work your way through each chapter, answering just the part of the question for that time period, and cycling through the questions for each chapter.

Chapter 13:

• Paleogeography of the Cambrian World (p. 312-313)
• Ordovician Paleogeography (p. 315-318)
• Regional Events of Early Paleozoic Time (p. 318-323)

Chapter 14:

• Paleogeography of the Middle Paleozoic World (p. 343-313)
• Glaciation (p. 344)
• Regional Events of Middle Paleozoic Time (p. 344-352; skip p. 346-347)

Chapter 15:

• Paleogeography of the Late Paleozoic World (p. 369-372)
• Regional Events of Late Paleozoic Time (p. 372-384; skip p. 374-375)

Key Concepts and Questions:

1. Flooding of the North American Continent (Paleogeography sections)

Sea level in North America changes dramatically throughout the Paleozoic. Find the evidence that supports this general model:

• Cambrian transgression
• Late Ordovician regression
• Silurian transgression
• Devonian regression in the east, western carbonate basin
• Mississippian transgression
• Pennsylvanian short cycles of transgression/regression
• Permian massive regression

2. Development of the Appalachians: (mostly Regional Events sections, some in the Paleogeography) Do what you can with this - we will add more information in class.

Find the evidence for each stage of the history of the Appalachians:

Cambrian passive margin:

 

Ordovician subduction:

 

Ordovician mini-collision (Taconic Orogeny):

 

Devonian collision of continental fragments(Acadian Orogeny)

 

Carboniferous collision with Gondwana (Alleghenian orogeny)

 

3. Cordillera:

Find the evidence for each stage in the development of the Cordillera:

 

Early Paleozoic passive margin

 

Middle Paleozoic arc collisions (Antler orogeny)

 

Late Paleozoic arc collisions (Sonoma orogeny and emplacement of exotic terranes)

 

3. On the craton: Note that the transgressive-regressive cycles all impact the craton

For each of these, find some evidence and write a brief description:

Middle Paleozoic basins of Michigan and Ohio

 

Carboniferous deltaic systems and cyclothems

 

Permian dunes and desert

 

Late Paleozoic Ancestral Rockies

 

4. Climate

A. Find the evidence for and impact of these glaciations:

Ordovician

Devonian

Pennsylvanian-Permian

 

 

 

Assessment

1. Transgression-Regression

You should be able to:

• describe the changes in paleogrography over the Early Paleozoic

2. Appalachians

You should be able to:

• describe the sequence of events that built the Appalachians
• cite the evidence for that history

3. Cordillera

You should be able to:

• describe the evidence of plate setting in the West

4. Craton and Climate

You should be able to:

• explain the origin of evaporites in the Michigan Basin
• explain explain what cyclothems are and how they form
• describe the formation of the Ancestral Rockies and their impact on local climate
• describe the evidence for pulses of glaciation throughlout the Paleozoic, and the impact of that glaciation