Geology 103 (Sedimentology and Stratigraphy)

 

California State University, Sacramento

 

Week 8:

Meandering and anastomosing streams;

Evaporite minerals and deposits

Objectives:

Upon completion of this unit students should be able to:

  • Describe the general characteristics that are associated with a meandering stream.  Include gradient, common bar forms, load, bank material, channel form and sinuosity.

  • Show how helical flow contributes to erosion of the cut bank and deposition on the point bar.

  • Describe the vertical and longitudinal grain size patterns that you would expect to see in a point bar.

  • Discuss the features that form on the floodplain of a meandering river, including crevasse splays, the natural levee, floodplain deposits, and ox-bow lakes.

  • Describe how a meandering stream migrates across the floodplain, producing a fining-upward sequence.

  • Differentiate between braided, meandering and anastomosing streams.

  • Identify common evaporite minerals and their sequence of precipitation
  • Discuss the geochemistry of evaporite deposits
  • Relate hypersaline lake environments to evaporite deposits

  

Reading Assignments:

Lecture 12: Meandering streams- Boggs, 5th edition, pp. 215-220

and:

GSA Today article- Katrina crevasse splay deposits

 

or get a high resolution version here:

 

https://www.geosociety.org/gsatoday/archive/16/9/pdf/i1052-5173-16-9-4.pdf

 

Lecture 13: Evaporite minerals and deposits- Boggs, 5th edition, pp. 168-174 and 189-194.

 

Please fill out a reading log for the GSA article, meandering streams reading and evaporite deposition sections.  Reading logs are due Wednesday at the start of class.

 

Reading log

   

Class notes:

Lecture 12 notes

Lecture 13 notes

   

Graphics from lectures:

Lecture 12 graphics

Lecture 13 graphics

  

Lab this week-

 

Sedimentary petrography week 2.  This week we will meet in Placer Hall rm. 1002, and will continue to look at clastic sediments in thin section.  

 

Your lab writeup will be due one week from today.  In today's lab period we will finish drawing and describing common clastic grains.  You will turn in a "grain catalog" one week from today.

 

Bring drawing pencils and colored pencils to lab!

 

You should already have a copy of the lab from last week.  If you need to print out more pages you can get a new copy here:

 

Grain catalog