PALEOGEOGRAPHIC MAPPING
(O.K. fossils are neat but what good are they?)

Linda E. Okland
2702 McKenzie Drive
Anchorage, AK 99517

Level: Lower elementary to junior high

 

Anticipated Learning Outcomes

Background

Previous knowledge of fossils is not essential. It is preferable, however, to preface this exercise with some discussion/activities on fossils, including what they are, how they form, and what they tell us. [Relatively inexpensive fossil reproductions are available through many scientific supply catalogs. To cite just one example, kits developed by the Earth Science Curriculum Project are available for $3.60 each from Science Kit & Boreal Laboratories, 777 East Park Drive, Tonawanda, NY 14150.]

Materials

Procedures

  1. Pass out the maps. Explain that this is a map of an imaginary continent. Locations A through I are places where fossils have been found in rocks of Mesozoic age (the "Age of Dinosaurs", roughly 70 million-250 million years ago). The object of the activity is to make a map of what the continent looked like during Mesozoic time, i.e. where the land and ocean areas were at that time.
  2. Have students select colors for land and water and make a key for the map.
  3. The table at the bottom of the handout shows what fossils were found at each location. (The locations and fossil types are arbitrary and can be adjusted to suit your needs or preferences.) Have students color each locality as either land or ocean. With elementary students it generally works better to provide this information orally rather than to give them the written table. (For example, "At location A we found shark teeth. Was this land or ocean? O.K. color that area with your color for ocean.")
  4. Ask the students to color all the areas around and between the localities as either land or ocean (interpolate between data points). Emphasize that the outline of the modern continent may have no relationship to the Mesozoic boundary.
  5. Ask students whether location X was land or ocean in the Mesozoic, according to their maps.
  6. Have students use the same data to make a different possible map (interpretation). For extra credit or homework, have them see how many possible interpretations they can make from the same data.

Results and Discussion

  1. No two maps should be identical. The class should be fairly well split on the interpretation of location X. This provides an opportunity for discussion of questions such as: Who is right? Is there a right answer? (yes) Do we know what the right answer is? (no) How could we find out what interpretation is correct? (get samples from location X) Older students can explore ways to get more information from the data already in hand. For example: Are the corals reef-builders, indicating proximity to a shoreline? Do the sediments in which the fossils were found give any clues to the depositional environment? Is there any evidence of transport of the fossils after the death of the animals?
  2. This activity is a simplified version of the process used in activities such as oil and gas exploration. In oil exploration, a geologist maps a variety of data, interpolates between the data points, and develops an interpretation which is usually in the form of a map. This interpretation is then tested by drilling an exploratory well (at a cost of anywhere from several hundred thousand to tens of millions of dollars). The vast majority of such wells do not produce any oil. The data from failed wells is incorporated into a revised interpretation and the process starts over.
  3. This activity provides an opportunity to make the point that it is O.K. to be wrong in science. A great deal of scientific progress is made by testing and eliminating incorrect interpretations or hypotheses. Formulating hypotheses which are later disproved is an essential part of this process. An axiom of the oil industry is that someone who never drills any dry holes (failures) never finds any oil. A possible follow-up activity would be to have students interview scientists (by mail if suitable individuals are not available locally) and ask about the scientists' "failures".
  4. Language arts can be incorporated into this activity by talking about some of the terminology. The prefix geo- is drawn from the Greek and refers to the earth as in geology, the study of the earth. Paleo- means old as in paleontology, the study of fossils (old life). Graphic also comes from a Greek root and refers to a drawing or painting. Paleogeographic could therefore be "translated" as "Old Earth Picture". A written description of the results can be assigned, even if it is only "We learned that some of the land areas used to be under water and some of the water areas used to be dry land". This helps to reinforce the learning process and to make the point that scientists must be able to communicate the results of their research to others.
  5. Comparisons can be made between maps, such as the one in this activity, and graphs. Graphs are a way of displaying information (data). Maps are a means of displaying data in relation to its location. Connections to math and social studies lessons can be made at this point. Additional math activities can be incorporated by adding a scale to the map.

Fossils found in Mesozoic Rocks

A. shark teeth   E. Assorted seashell fragments
B. Petrified wood   F. Teeth and bones of small mammals
C. Starfish   G. Dinosaur bones
D. Leaf imprints   H. corals
    I. Dinosaur footprints

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