Objectives:

Upon completion of this unit students should be able to: Use the proper textural terms to describe a sediment (sand) sample:  sorting, roundness, composition, size Define roundness, sphericity and form using mathematical relationships between long, intermediate and short grain axis Distinguish between compositional and textural maturity, and give examples of each

Reading Assignments:

Lecture 1: Sedimentary fabric and texture- Boggs, 5th edition, pp. 3- 12, 45-63 The first reading log assignment will be for week 1, and will be due at the start of class next Monday.  Reading logs will be due every Wednesday for the rest of the semester. Reading log

 

Class notes:

Lecture 1 notes

 

Graphics from lectures:

Lecture 1 graphics

Lab:   I will pass out a copy of the lab exercise.  You do not need to print out the lab exercise.  If you need another copy you can download it here:   Lab 1: Sieve analysis and sand texture   You will need a copy of an Excel spreadsheet to calculate the grain size distribution.  This is a special spreadsheet that has imbedded formulas and graphs.  If you enter the raw data (gross weight and weighing paper weight), the spreadsheet will do the rest!   Download the spreadsheet here:   Excel spreadsheet- grain size analysis   Objectives  The purpose of this lab is to determine the grain size distribution and texture of an unconsolidated sediment sample.  We will use a standard sieve set, a Ro-tap automatic shaker and graphical methods of data analysis.  Activities We will complete these activities during lab: Listen to a brief lecture about grain size and sieves. Look at examples of roundness and sorting using a binocular microscope.  I will provide the samples, and they will be available for the next week if you want to look at them again. Look at your unknown sample using a binocular microscope.  Describe the roundness and the sorting of the sample using this visual method. Sieve an unknown sand sample with the rotap machine, and enter the weights for each fraction in the worksheet attached to this lab handout.  Each lab will sieve one sample, and we will share the results. What to turn in You will turn in a lab report at the beginning of next week’s lab.  The lab report should use complete sentences and technical writing style.  This means you should keep things brief and to the point.  Don’t guess, speculate or use emotional terms.  Avoid personal reference.  Your report should be word processed and double spaced, with 1” margins.  Use a “normal” 11 or 12 point font.  You will not need to use outside references for this report.  Use your own words to describe the activities and results- avoid quotations. Your report should have these headings: Introduction and purpose Use several concise sentences to describe the purpose of the lab. Methods Write a brief paragraph that describes the approach.  You do not need to provide detailed instructions- an overview of the methods will be sufficient. Results Give a brief overview of the results in paragraph form.  Refer to the data table, histogram and cumulative frequency curve.  Example:  “The sample has more fine material than coarse material (Figure 1).”  Every table or figure must have a reference in the text that is similar to this example. Include these table and figures in the results section of your report: ·       a data table of your sieving results ·       a histogram that shows grain size distribution ·       an annotated cumulative frequency curve ·       a line graph that shows the mode ·       a table that shows your values for phi 5, phi 16, phi 50, phi 84 and phi 96 ·       a table that shows results of these calculations: mean, median, mode, standard deviation, skewness Show your calculations.  Computer-generated calculations can be included in the report, or calculations may be done by hand.  Hand calculations should be on a separate sheet at the end of the report.  Refer to this as an appendix. (“See Appendix A”). Include a brief visual description of the sample (from the binocular microscope).  Describe the roundness and sorting of the sample. Discussion Include a brief discussion with your report. What can you say about the grain size and texture of the sample?  Highlight the important findings of your sieve analysis and visual analysis.  Mention the error.  Do these methods agree with each other?  Can you make any environmental interpretations?