GEOL 462: Principles of Sedimentology and Stratigraphy

Lecture 08: Thursday, February 05, 2009

Topics
1. Depositional Environments: overview
2. Field Examples: processes
3. Glacial Environments: Processes
4. Glacial Environments: Facies and Facies Model
5. Alluvial Fan System: Geomorphology and Processes
6. Alluvial Fan System: Facies and Facies Model

Depositional Environments: overview
• Look at the diagram in the slide, think carefully on:
a) what are the major processes in each depositional environments?
b) what typical sedimentary rocks and sedimentary structures may you find in each depositional environments ?
Most of our lectures have been dealing with these processes and their products left in the sedimentary record.

Field Examples: processes
• Learn how to interpret the possible depositional processes from a rock record;
• Start with the possible background depositional environments, and then think about what other processes you need to
   bring the blocks/particles into the backgrouhd environments;
• Learn the method not the single example.

Glacial Environments: Processes
• Understand the micro-environments in a glacial environment;
• Think about the major processes in each micro-environments;
• What may be different comparing the Mountain ice caps and ice sheets covering the continental shelves?
• What is the characteristic process in a glacial environment ?

Glacial Environments: Facies and Facies Model
• What characteristic depositional features would you expect to find in glacial deposits ?
• If you measure sections in the field, what features would help you to interpret the facies as glacial rather than alluvial origin?
• Can you think about the differences between a glacio-marine diamictite and glacial tillite (formed by glacials directly)?

Alluvial Fan System: Geomorphology and Processes
• Understand the micro-environments in an alluvial fan system;
• What processes (physical, chemical, biological) are available in an alluvial fan system ?
• Under what climate condition an alluvial fan system would be best developed?
• What are the most characteristic features of the alluvial deposits ?

Alluvial Fan System: Facies and Facies Model
• What are the two most common flows in allvual fan deposits ?
• Think about the different sequences you may get in the three different types of alluvial fan systems;
• Understand the climate and tectonic control of the alluvial fan system;
• Do the excerise marked in the slides (although we have done it once in class, it's better to do another time by yourself)