3/2/24 EARTH SCIENCE UNIT 5 EXAM

Question 1

deep time

Answer 1

it refers to the time scale of geologic events

Question 2

what is the difference between relative and absolute time?

Answer 2

relative time is the age of events in a sequence (oldest to youngest, no numbers), absolute time is the identification of events by a number

Question 3

geological cross-section

Answer 3

is a side view of exposed rock layers which is drawn with symbols to indicate different rocks

Question 4

law of superposition

Answer 4

the oldest rock layers are found at the bottom and the youngest layers are found at the top

Question 5

law of cross-cutting relationships

Answer 5

the rocks had to have formed first before geological processes have affected the rocks, ex: a fault is younger than the rocks that broke in the faulting

Question 6

law of original horizontality

Answer 6

the rocks had to have formed first, in order for geologic processes to have affected them after

Question 7

law of included fragments

Answer 7

the rocks had to have formed first, in order for geologic processes to have affected them after

Question 8

law of folding/tilting

Answer 8

the rocks had to have formed first in order for geologic processes to have affected them after

Question 9

uncomformity

Answer 9

an old buried surface that was eroded, overtime new rock layers were deposited on top of it, the erosion erases some of the rock layers, creating a “gap” of missing geologic time, like millions of years

Question 10

what are the three types of unconformities?

Answer 10

disconformity, angular unconformity, and nonconformity

Question 11

what is the siccar point?

Answer 11

an angular unconformity in Scotland that consists of sedimentary rocks, gray sandstone, red sandstone and proves the unconformity theory

Question 12

disconformity

Answer 12

an erosion surface between two packages of sediments, but the lower package of sediments was not tilted prior to deposition of the upper sediment package

Question 13

noncomfortmity

Answer 13

are unconformities that separate igneous or metamorphic rocks from overlying sedimentary rocks

Question 14

angular unconformity

Answer 14

are those where an older package of sediments has been tiled, transacted by erosion and than a younger package of sediments was deposited on this erosion surface

Question 15

law of uniformitarism

Answer 15

is a law stating that geologic processes that are acting presently are the same processes that have changed Earth in the past

Question 16

erosion

Answer 16

geological processes in which materials are worn away by natural causes such as wind

Question 17

tilting

Answer 17

a change in attitude of any portion of the Earth’s surface

Question 18

faulting

Answer 18

fracture or zone fractures between two blocks of rock

Question 19

contact metamorphism

Answer 19

a type of metamorphism where rock minerals and texture are changed, mainly by heat, due to contact with magma

Question 20

half life

Answer 20

the time required for one half of the radioactive (parent) isotopes in a sample to decay to radiogenic (daughter) isotopes

Question 21

isotope

Answer 21

atoms of the same elements contain different numbers of neutrons

Question 22

parent product

Answer 22

results from the decay of a parent

Question 23

radiometric dating

Answer 23

the abundances of parent and daughter isotopes in a sample can be measured and used to determine their age

Question 24

radioactive decay

Answer 24

is useful because each half life takes the same time approximately as the next one therefore it is reliable to obtaining absolute ages for rocks

Question 25

element

Answer 25

the simplest form of matter that has a unique set of properties

Question 26

parent isotope

Answer 26

an unstable isotope that will undergo radioactive decay

Question 27

what do atoms of a given element always contain?

Answer 27

the same number of protons

Question 28

isotope

Answer 28

atoms of an element with different numbers of neutrons are called protons

Question 29

how does carbon-14 get in our bodies?

Answer 29

carbon-14 forms when cosmic rays form neutrons in the atmosphere, these neutrons collide with nitrogen-14 which is one of the most common gasses in the atmosphere

Question 30

what is carbon 12?

Answer 30

carbon 12 is the form of carbon that are almost all atoms on Earth

Question 31

radiometric dating

Answer 31

the rate of decay of unstable isotopes can be used to estimate the absolute ages of fossils and rocks

Question 32

radio carbon dating

Answer 32

the best known method of radiometric dating is carbon 14 dating

Question 33

when is carbon 14 super useful?

Answer 33

carbon 14 is super useful when trying to date organic remaining

Question 34

how does radio carbon dating works?

Answer 34

a living thing takes in carbon-14, along with stable carbon-12, through photosynthesis is and the food web. As the carbon-14 decays it is replaced with more carbon-14. After the organism dies it stops taking in new carbon. The carbon-14 that is in its body contains to decay into nitrogen-14, which is lost to the atmosphere. So the organism decreases less and less carbon014 as time goes on, while the stable carbon-12 remains in place