Are the layers still horizontal or are they bent Why?
Answer. Answer: Figure 10.6: Rocks that were originally deposited in horizontal layers can subsequently deform by tectonic forces into folds and faults. Folds constitute the twists and bends in rocks.
How is horizontal unconformity formed?
An angular unconformity is an unconformity where horizontally parallel strata of sedimentary rock are deposited on tilted and eroded layers, producing an angular discordance with the overlying horizontal layers. The whole sequence may later be deformed and tilted by further orogenic activity.
How is a Disconformity formed?
As with an angular unconformity, disconformities form in steps. In step one, sediments collect on an ocean floor (or perhaps on the bed of a large lake). They compact and become rock layers. In the second phase, sea level falls or the sea floor rises to expose the layers to weathering and erosion.
What happened to create an unconformity?
What happened to create an unconformity? The older strata below were eroded before the younger layers were laid down.
Why are older rocks found on top of younger rocks?
Thrust faults form where rocks are being compressed, usually by plate tectonic mechanisms. Thrust faults rip up older strata and pile it on top of younger rocks.
Which is not a very long lived radioactive isotope?
Quiz 7 Geology
| Question | Answer |
|---|---|
| Which of the following is not a very long-lived, radioactive isotope? | C-14 |
| Catastrophism _____ | was a philosophy that was first expounded by the early Greeks |
| The subdivision of the geologic time scale that represents the longest time span is called a(n) ________ | eon |
What is the half life ratio of parent daughter for 2 half lives?
Half-Lives
| No. of half lives passed | Percent parent remaining | Percent daughter produced |
|---|---|---|
| 1 | 50 | 50 |
| 2 | 25 | 75 |
| 3 | 12.5 | 87.5 |
| 4 | 6.25 | 93.75 |
What is the maximum limit on carbon 14 dating?
about 50,000 years
What does the present is the key to the past mean?
“The present is the key to the past” is an idiom that means you can’t fully understand the events of yesterday or why something happened…