Geology 103 (Sedimentology and Stratigraphy)
California State University, Sacramento
Week 7:
Evaporite minerals and deposits; Chert, ironstone, glauconite, phosphate |
Objectives:
Upon completion of this unit students should be able to:
Identify common evaporite minerals and their sequence of precipitation
Discuss the geochemistry of evaporite deposits
Relate hypersaline lake environments to evaporite deposits
Distinguish between microquartz (chert) and megaquartz
Describe the common appearance of jasper, opal, flint and porcelanite
Discuss the origins of bedded and nodular chert
List the marine organisms that produce bedded chert
Discuss the origin and age of iron-rich rocks
Describe the geochemical environment (Eh and pH) that leads to the formation of iron-rich rocks
Reading Assignments:
Lecture 10: Evaporite minerals and deposits- Boggs, 5th edition, pp. 168-174 and 189-194.
Lecture 11: Chert and ironstone- Boggs, 5th ed., pp. 175-194
Please fill out a reading log for evaporite deposition, chert, ironstone. Reading logs are due Wednesday at the start of class.
Class notes:
Graphics from lectures:
Field trip stratigraphic column assignment:
Your stratigraphic column is due the Friday before spring break (March 16).
Choices:
You can draw a weathering profile or a grain size profile.
You can use computer graphics or hand-draw the stratigraphic column
Guidelines for drawing a stratigraphic column:
Examples of stratigraphic columns:
Powerpoint template for stratigraphic columns:
Reference:
Compton, R.R., 1985, Geology in the field, NY, Wiley and Sons, 398 p.
Lab this week-
Sedimentary petrography week 1. This week we will meet in Placer Hall rm. 1002, and will start to look at clastic sediments in thin section.
Your lab write up will be due after spring break. In today's lab period you will start drawing some common clastic grains. Next week you will finish drawing the grains, and your lab will be due the following week.
Grains this week
Where to find them
quartz
slides S-150, S-1500, Navajo
orthoclase fs
slide Dove Springs
plagioclase fs slide Dove Springs hematite cement
slides DD, 5, 205
plutonic rock fragment
slides DD, 5, 205
quartz overgrowth slides S-150, S-1500, Navajo
Bring drawing pencils and colored pencils to lab!
I will pass out a copy of the lab. If you need to print more pages you can get a new copy here: