Laboratory 12
Microfossil Lab Exercises

 

Pamela J. W. Gore

Department of Geology, Georgia Perimeter College

Clarkston, GA 30021

Copyright © 1998-2005 Pamela J. W. Gore

 

 

1. Examine the microfossil slides set up on the microscopes and fill in the chart below. You are to use the taxonomy indicated by your instructor. See, for example, the classification in the back of your textbook by Levin, or the latest classification system by Lynn Margulis and Karlene V. Schwartz (1998) as well as the modified classification system used by Dr. Anderson.

#

Microfossil
Group

Kingdom

Phylum

Sub-
phylum

Class    

Order    

Compo-
sition

Unicellular
or
Multicellular

1

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

3

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

 

5

 

 

 

 

 

 

 

 

6

 

 

 

 

 

 

 

 

7

 

 

 

 

 

 

 

 

8

 

 

 

 

 

 

 

 

9

 

 

 

 

 

 

 

 

10

 

 

 

 

 

 

 

 

 

 

 
 
 
 
 
 
2. Examine the vials of unsorted microfossils. Which microfossil groups (or pieces of invertebrate macrofossils) are present? What range of geologic periods could each be from?

Vial

Fossil groups present

Possible range of geologic periods?

1

 

 

2

 

 

3

 

 

4

 

 

5

 

 
 
 
 
 

  

3. Examine the samples of large foraminifera (nummulitids and fusulinids). Draw a sketch of each in the boxes below.

 

 

 

Nummulitid foraminifera

Fusulinid foraminifera

 
 
 
 

 

4. Microfossils are useful for biostratigraphy or correlating sedimentary rocks. Put an X in the chart for the periods in which the microfossil groups are found.

Microfossil Group

Paleozoic

Mesozoic

Cenozoic

C

O

S

D

M

P

Pm

Tr

J

Cret

P

N

Foraminifera

 

            

 

    

 

  

Radiolaria

 

            

 

    

 

  

Diatom

 

            

 

    

 

  

Coccolithophores

 

            

 

    

 

  

Dinoflagellates

 

            

 

    

 

  

Ostracodes

 

            

 

    

 

  

Conodonts

 

            

 

    

 

  

Sponge spicules

 

            

 

    

 

  

Spores

 

            

 

    

 

  

Pollen (gymnosperm)

 

            

 

    

 

  

Pollen (angiosperm)

 

            

 

    

 

  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

5. Microfossils are useful for paleoenvironmental interpretation. Put an X in the chart for the environments in which the microfossil groups are found.

Microfossil Group

Continental (Non-marine)

Marine

Foraminifera

 

 

Radiolaria

 

 

Diatom

 

 

Coccolithophores

 

 

Dinoflagellates

 

 

Ostracodes

 

 

Conodonts

 

 

Spores

 

 

Pollen (gymnosperm)

 

 

Pollen (angiosperm)

 

 

 

 

6. In some areas of the sea floor, foraminifera shells are accumulating at a rate of 1 cm per 1000 years. How thick a deposit could have accumulated during the 65 million years (65,000,000 years) of the Cenozoic era?

_____________________________________________________

 

 
 
 
 
 
 
 
 
 
 
 
 
7. A particular sequence of sedimentary rocks is found to contain the following sequence of microfossils:

Position in vertical sequence

Microfossil groups

Depositional Environment (Marine or Non-marine or mixed)

List the geologic periods represented by the groups in the layer

Layer A (Top)

Pollen

    

Layer B

Pollen and ostracodes

    

Layer C

Ostracodes, pollen, and diatoms

    

Layer D

Foraminifera and ostracodes

    

Layer E (Bottom)

Coccoliths, foraminifera, and radiolaria

    

 

    Using the microfossil groups in this sedimentary sequence, answer the following questions:

  1. Fill in the depositional environment (marine or non-marine or mixed) of the groups in each layer.

  2. Fill in the geologic periods in the ranges of the groups in each layer.

  3. From what you know about the environments which these groups inhabit, is this a transgressive or a regressive sequence?

    4. _____________________________________________________

  4. Which layers (give letter) contain microfossil groups characteristic of marine only environments?

    5. _____________________________________________________

  5. What ages (geologic period names) might this sequence be (considering the assemblage of all of the fossil groups listed)? In other words, find the periods in which the ranges of all of these groups overlap. For the rock sequence (A - E) to be a certain age, ALL of the microfossil groups must have been living during that geological period. The answer will be more than one geological period name. Please review your geological time chart if you do not remember the period names.

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This page created by Pamela J. W. Gore, pgore@gpc.edu
Georgia Perimeter College

July 20, 1998
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