Geology 103 (Sedimentology and Stratigraphy)

California State University, Sacramento

Week 3:

Flow regimes, bedform progression, bedding and primary sedimentary structures

 

Objectives:

Upon completion of this unit students should be able to:

  • List and discuss the main transporting agents and methods of particle transport in a moving fluid.

  • Describe bedforms that occur under different flow conditions.

  • Use the appropriate terms to describe bed thickness and different types of bedding

  • Describe ripple morphology or name ripples in plan view and in cross-section

  • Use cross-bedding to tell flow direction

 

Reading Assignments:

Lecture 4: Density and viscosity, particle transport, Hjulstrom curve- Boggs, 5th edition, pp. 19-31

 

Lecture 5: Bedform progression, beds and bedding- Boggs, 5th edition, pp. 65-74

 

Fill out a weekly reading log for these assignments.  The weekly reading log is due Wednesday February 12.

 

Reading log

 

 

Class notes:

Lecture 4 notes

Lecture 5 notes

 

Lecture graphics:

Lecture 4 graphics

Lecture 5 graphics

 

Lab: Sand texture and composition

Lab and homework:

 

In lab this week we will look at two new sand samples.  You will describe the composition of each unknown sand sample, and interpret the sources or environments.

 

Your writeup should be word-processed and double spaced.  Use a technical writing style, with complete sentences.  Refer to your table in the text.

 

Your writeup should have these parts:

 

Observations:

Include general information first: sorting, Wentworth size range and color.

 

Follow this general information with specifics about the grains.  Use a table to keep track of information.  Your table should have composition, % of each grain type, size range, roundness and color.

 

Interpretations:

What can you tell about the composition of the source area?  If there is more than one source area, discuss it here.  How far has the sediment been transported (how far away is the source?).   Can you use texture (size and roundness) to tell what agent deposited the sediment?  Use language that identifies interpretations you are certain about, and also identify interpretations where you are less certain or there are multiple options.

Answer key for unknown BRB

 

Answer key for unknown NZV