Geology 103 (Sedimentology and Stratigraphy)


California State University, Sacramento


Week 7: Alluvial fans,

braided streams


Upon completion of this unit students should be able to:

  • Describe longitudinal and lateral profiles (shapes) of an alluvial fan.

  • Discuss the difference between a debris flow and a stream-dominated alluvial fan.

  • List common features and deposits of an alluvial fan, including grain size patterns (longitudinal and vertical).

  • Name the parts of an alluvial fan, and discuss the sedimentary structures in each.

  • Discuss braiding parameter and meander wavelength as a method of classifying stream types (Rust's classification).

  • Describe the flow, load, gradient, bar forms, bank material and general architecture of a typical braided stream.

  • Distinguish between longitudinal, linguoid/transverse and lateral bar forms.

Reading Assignments:

Lecture 10: Alluvial fans- Boggs, 5th edition, pp. 208-209, 211-215

Lecture 11: Braided streams- Boggs, 5th edition, pp. 215-220


Fill out a reading log for each reading assignment.  Reading logs are due at the start of class on Wednesday


Reading log


Class notes:

Lecture 10 notes

Lecture 11 notes


Graphics from lectures:

Lecture 10 graphics

Lecture 11 graphics

Lab this week-


Drafted stratgraphic columns using Powerpoint.   Bring your yellow field notebook to class.