Walking with the Dinosaurs Lab - Part 2

Note: Remember you are responsible for graphs, charts and other items that form part of the overall summary of this topic.

Upon completion, the Walking with the Dinosaurs Lab activity will introduce you to the life of a paleontologist from the planning of an expedition, to the actual “dig” of a dinosaur skeleton and finally to the building of a dinosaur showcase.  Be sure to familiarize yourself with the Paleontological Studies notes; geologic timeline and extinction theory notes as you complete this lab.  You may also wish to visit the Walking With Dinosaurs website.  Be sure when completing the lab report, that you follow the given format.

Vocabulary

• active margin – where colliding continental and oceanic plates trigger volcanic eruptions, earthquakes and mountain building

• Cenozoic Era – 65 million years ago to present; this Era is associated with the development of and domination by mammals

• Cretaceous Period – last period of the Mesozoic Era; time period during which dinosaurs became extinct

• excavate – to dig-up or unearth

• formation – a group of rock layers that are recognizable from one place to another

• geologic column – shows rock units as they were laid down in sequence

• geologic map – depicts the age of rocks (ancient, dinosaur age, or mammal age) and under what conditions the rock formed (on land, in the sea, on a volcano)

• Gondwana – southern portion of Pangaea; consisted of the present day continents of Africa, Australia, South America and Antarctica

• igneous rocks – formed when melted rock in volcanoes or under the earth’s surface cools and hardens (also known as volcanic, intrusive or extrusive)

• Jurassic Period – second period of the Mesozoic Era; time period during which Pangaea began to rift apart

• Laurasia – northern portion of Pangaea; consisted of the present day continents of North America, Europe and Asia

• magma – hot molten rock formed beneath the earth’s surface.

• marine rock – rock that formed in the ocean (limestone)

• metamorphic rock – formed when igneous or sedimentary rocks are subjected to extreme heat and pressure

• Mesozoic Era – 248-65 million years ago; geologic time period during which dinosaurs lived; composed of the Triassic, Jurassic and Cretaceous Periods

• Paleozoic Era – 540-248 million years ago

• Pangaea – an ancient super-continent composed of all the major continents we recognize today

• petrified – “turned to stone”; petrification is the long process by which organic material is replaced by rock materials

• plate tectonics – study of the movement of the plates under the earth’s crust; most plates are composed of two parts: ocean floor and continental crust

• sedimentary rocks – most form from particles eroded from rocks on land; some form from dissolved chemicals or organic particles from shells or other living organisms

• Triassic Period – first period of the Mesozoic Era; time period when dinosaurs first evolved

Background

Luck plays a part in finding fossils, but research and hard work play a larger role.  Your expedition team will need to use geographic maps, geologic maps and scientific reports to decide where to look for dinosaur fossils.

Remember that a geographic map shows cities; villages; roads; trails and surface features (dry river beds; sandy areas; cliffs; mountains), as well as areas of exposed rock not covered by dirt, sand or grass, which might yield fossils.  Your team will use this kind of map to plan campsites and vehicle routes.

On the other hand, a geologic map shows the ages and kinds of rock that form on the surface of the land.  Your team will use a geologic map to find rocks that formed during the dinosaur era.  Geologists have mapped each distinct rock layer and have given each layer a different color and letter symbol.  For example, Cretaceous rocks (145 to 65 million years old) are shown on geologic maps as different shades of green and labeled with the letter “K.”  The key on geologic maps gives more information about the type of rock that composes each area.  Some rock types include marine (ocean floor), terrestrial (land) and volcanic (volcanoes).  Your team is interested in terrestrial rocks because that is where the fossil bones of the animals that lived on land will be found.  To look for Cretaceous dinosaurs, your team will locate Cretaceous (green) areas in the maps and then check the key to make sure the rocks in these areas are terrestrial.

Finally, scientific reports describe scientific discoveries.  Before your team departed, they went to a library and found all the reports that described the area under investigation: its geology and its fossils.  Your team then decided where to look by combing information from geographic maps, geologic maps, and scientific reports.

Laboratory Activity – Hunting for Dinosaurs

Remember that paleontologists use three sources of information to decide where to search:

• geographic maps
• geologic maps
• scientific reports

The geologic map tells the age of the rocks (mammal era, dinosaur era, or older.)  These rocks are divided into five (5) time periods:

• Paleozoic Period - 543-245 million years ago (pre-dinosaur)
• Triassic Period - 245-208 million years ago
• Jurassic Period - 208-145 million years ago
• Cretaceous Period - 145-65 million years ago
• Tertiary Period - 65-1.8 million years ago (mammal era)

Dinosaurs are found only in the rocks of Mesozoic age (dinosaur era.)  A geologic map also indicates where the rocks were formed (on land, in the sea, or in a volcano).  Dinosaurs are usually found in terrestrial rocks.  Dinosaurs or other land animals are never found in volcanic rocks and rarely found in marine rocks.

Directions

Your team of paleontologists wants to discover new Cretaceous dinosaurs in the Sahara Desert in Africa.  First, you go to the library to look for previous scientific reports on the area.  You find one report with pictures of large pieces of fossil bones that look like they might belong to a dinosaur.  The report also mentions that there is a large area of exposed rock where the fossil fragments were found.  This sounds interesting, but there is no map that shows exactly where the fossil fragments were found.  All you know is that the fossils were found somewhere near an oasis called In Gall.

Your team returns to the library to study maps of the area.  You find a geographic map and a geologic map of the area.  Now you have the information you need to lead an expedition to the area and decide the best place to look for fossils.

Questions

1. Can the town of In Gall be reached by truck?  Do you need to pass through any other towns?  If so, what are they?

2. What is the area around In Gall like?  Where is the rock covered by sand or trees?  Describe your answer using compass directions by stating "North of In Gall there are....".

3. Determine the ages and types of rocks by locating the rock age symbols and the rock type symbols in the map key.  Create a table of your finding.

4. Do you think it is possible to find dinosaurs of Triassic age in this area?  Why or why not?

5. You need to know where to search for Cretaceous dinosaurs.  Are there rocks of Cretaceous age?  If so, are any of these Cretaceous rocks terrestrial?

6. If terrestrial Cretaceous rocks exist in the map area, are any exposed at the surface?

7. If you were camping in In Gall, where would you take your team to search for new Cretaceous dinosaurs?  Use compass directions and distances.

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