Earth Science Today
Russ Colson
Minnesota State University Moorhead

Historical Geology:

Topic 1: Geological time and life of the past, reading stories in rocks and fossils.

Often classification of rocks substitutes for geology.  One student told me once "I always thought geology was just about rocks."  But, in fact, geology is about telling stories, not knowing names of rocks.  However, understanding the different types of rocks and how they form is crucial in knowing how to read their stories.

                   Grain size              large                        small
             More SiO2              granite                   rhyolite

             Less SiO2               gabbro                   basalt

  Type of rock that is metamorphosed                     shale           sandstone           limestone
                                 degree of metamorphism
                                              low                             slate            quartzite           marble
                                              medium                     schist           quartzite           marble
                                              high                           gneiss          quartzite           marble

Thought Puzzle:  You find a gneiss at the top of a large mountain.  What story does it tell us of the past? (answer, est2a3.html)

 Thought puzzle:  You find two rocks.  One is a limestone containing fossil crinoids (a filter feeder) in great abundance, along with many other types of fossils.  The other is a very fine-grained gray shale with black imprints of willow leaves in great abundance.  What can you say about the ancient environment in which these rocks formed?  (answer, est2a5.html)

Rock Cycle puzzle:  knowing the processes by which each type of rock forms, and knowing that one rock is changed into another rock through geologic time, you can complete the following schematic diagram of the Rock Cycle.  In each circle, I have written the name of a type of rock.  On each arrow write a process by which one rock can be changed into another rock.  (answer, est2a6.html)

Lab Activity:  Rocks and stories they tell (in MSWORD)
Lab Activity: Invertebrate fossils. (in MSWORD)

A dinosaur identification activity is available in MSword.

Also, a 12-15 hour unit sediment stories activity for kids age 9-14 is available in MSword. This unit teaches kids about how to read the stories written in simple sediments and sedimentary rocks.

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