Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Chapter 12
Discovering Earth's History
| Question | Answer |
|---|---|
| what is the significance of rocks on recording earth's history? | Rocks record geological events and changing life forms of the past. |
| How did the geological time scale revolutionize the way people think about time? | We have learned that earth is much older than anyone had previously imagined and that its surface and interior have been changed by the same geological processes that continue today. |
| What is the primary goal of geologists? | To interpret earth's history by studying rocks, especially sedimentary rocks to understand and explain the past. |
| What is uniformitarianism? | States that the physical, chemical, and biological laws that operate today also operated in the geological past. It means that the forces and processes that we observe today have been at work for a very long time. |
| What is relative dating? | Identifying which rock units formed first, second, third, and so on. It tells us the sequence in which events occurred, not how long ago they occurred. |
| Laws of superposition | A geological observation that states that in an uninformed sequence of sedimentary rocks, each bed is older than the one above it and younger than the one below it. |
| Can the law of superposition apply to other surface-deposited materials? | yes. it applies to lava flows, an beds of ash from volcano eruptions, and the grand canyon. |
| What are Nicolas Steno's observations? | A set of geological observations that are the basis of relative dating. They are: The law of superposition Principal of Original Horizontality Principal of Cross-cutting Relationships |
| Whar is the principal of original horizontality? | Means that layers of sediment are generally deposited in a horizontal position. |
| What demonstrates the principal of original horizontality? | Rock layers that are flat. Layers in the grand canyon. |
| To what rock type can the law of superposition and the principle of original horizontality be best applied? | sedimentary rocks |
| What is the principle of cross cutting relationships? | States that when a fault cuts through rock layers, or when magma intrudes other rocks and crystallizes, we can assume that the fault or intrusion is younger than the rocks affected. Because they cut through the layers of sedimentary rock, the faults and |
| What are inclusions? | The pieces of one rock unit that are contained within another.The rock unit next to the one containing the inclusions must have been there first in order to provide the rock fragments. The rock containing the inclusions is the younger of the two. |
| What do inclusions indicate? | That the sedimentary layer was deposited on top of the weathered igneous rock. |
| What are unconformities? | Represents a long period during which deposition stopped, erosion removed previously formed rocks, and then deposition resumed. |
| Why are unconformities important features? | They represent significant geological events in earth history. Their recognition helps to identify what intervals of time are not represented in the rock record. |
| What are the three basic types of unconformities? | Angular unconformities disconformities nonconformities |
| What is angular unconformity? | Indicates that during the pause in deposition, a period of deformation and erosion occurred. |
| What is a disconformity? | Two sedimentary rock layers that are separated by an erosional surface. |
| Which are more common - angular unconformities or disconformities? | Disconformities |
| What are nonconformities? | Means the erosional surface separates older metamorphic or intrusive igneous rocks from younger sedimentary rocks. |
| What is correlation? | Matching up rocks of similar age in different regions in order to develop a geologic time scale. |
| What are fossils? | The remains or traces of prehistoric life. They are important components of sediment and sedimentary rock. |
| How are types of fossils formed? | They are determined by the conditions under which an organisim died and how it was buried. |
| What are unaltered remains? | Some remains of organisms such as teeth, bones and shells may not have been altered. It is very uncommon to find remains of an entire animal. |
| What are altered remains? | Fossils often become petrified, or turned into stone. When a fossils is petrified, mineral-rich water soaks into the small cavities and pores of the original organism. The minerals precipitate from the water and fill the spaces. |
| What are types of fossils? | unaltered remains altered remains molds casts |
| How is a fossil mold created? | When a shell or other structure is buried in sediment and then discovered by underground water. The mold accurately reflects only the shape and surface markings of the organism. It does not revel any information about its internal structure. |
| How are cast fossils created? | Created if the hollow spaces of mold are later filled with mineral matter. |
| What is carbonization? | occurs when an organism is buried under fine sediment. As time passes, pressure squeezes out the liquid and gaseous components of an organism and leaves behind a thin residue of carbon. |
| What type of fossilization is effective in preserving leaves and delicate animal forms? | Carbonization |
| What is indirect evidence? | Trace fossils such as footprints made of soft sediment that was compacted and cemented. Burrows - holes made by animal in sediment, wood, or rock that were later filled with mineral matter and preserved. |
| What are the oldest know fossils? | worn burrows |
| What are coprolites? | fossils of dung and stomach contents. |
| What two conditions are important for preservation? | rapid burial and the possession of hard parts. |
| What is the principal of fossil succession? | states that fossil organisms succeed one another in a definite and determinable order. Therefore, any time period can be recognized by its fossil content. |
| What is the order of fossils? | Age of Trilobites Age of Fishes Age of Coal Swamps Age of Reptiles Age of Mammals |
| What are the "ages" of fossils? | They correspond to particular time periods and are characterized by distinct and abundant fossils. |
| How were fossils important in correlating rocks? | Once fossils were recognized as time indicators, they became the most useful means of correlating rocks of similar age in different regions. |
| What are index fossils? Their presence provides an important method of matching rocks of the same age. | Widespread geographically, are limited to short span of geologic time, and occur in large numbers. |
| How can fossils be used to study ancient environments? | Geologists can conclude that a region was covered by a shallow sea when the remains of certain clam shells are found in the limestone of that regio. And fossils with thick shells capable of withstanding pounding waves must have lived near shorelines. Fo |
| Electrons | Have a negative electrical charge |
| Protons | Have a positive electrical charge |
| Neutrons | Has no charge |
| Atomic number | the number of protons in a nucleus |
| Atom's mass number | the number of protons and neutrons in an atom's nucleus |
| radioactivity |
Created by:
jclicurse
Popular Earth Science sets