Geologic Time Essay Sample
1. As an illustration of how radioactive decay plants. the TA may take a little presentation. Each pupil will have one penny and stand up. At this point all of the pupils are parent isotopes. Every pupil should so toss their penny. Students whose penny lands heads-up should sit down. These pupils who are now seated are now daughter isotopes. The staying standing pupils should once more toss their penny. and pupils whose penny lands heads-up should sit down to go daughter isotopes.
a. How many pupils started out standing?
All of them
B. How many girl isotopes were produced after the first somersault of the pennies?
About Half
c. How many parent isotopes remained after the 2nd somersault of the pennies?
About a one-fourth
d. How good does each somersault ( or half life ) really eliminate half of the staying parent isotopes?
Decently good
e. Would d. ) be improved by doing the sample population smaller or larger? Why?
D would be improved by doing it larger because larger Numberss represent more general populations. Likelihood of extinguishing half would be greater.
2. ) Sometimes numerical day of the months are referred to as ‘absolute dates’ . Why do you say this is? Why might these numerical day of the months non really be absolute day of the months?
Because it gives us a figure but there is still a scope on the sum of mistake. Because absolute day of the months through radioactive dating are truly merely for igneous/metamorphic stones and because heat and force per unit area affect the day of the months. hence non doing them absolute.
3. ) In order to acquire an accurate numerical day of the month. geologists require on mean 0. 5-1 gms of stuff. Why might this be hard to obtain from some recent ( & lt ; 5. 000 old ages old ) volcanic ashes or other thinly bedded sedimentations?
It’s difficult to roll up that sum because the ash is so thin that it is easy distributed by air current and H2O can administer the ash. doing it difficult to garner. 5-1 gms of the same ash.
4. ) In metamorphous stones. minerals form at different temperatures and force per unit areas. What could this potentially do to radiometric day of the months from a metamorphous stone?
Because it causes some of the girl and parent isotopes to leak from minerals. hence doing inaccurate day of the months for igneous/metamorphic stone when being radioactively dated.
5. On the side tabular array are three fossil samples. Using figures 7-7 and 7-8. identify the invertebrate group to which each belongs. and indicate the scope of geologic period ( s ) in which each lived.
Specimen # | Invertebrate Group| Range of Geologic Period ( s ) |
Fossil A| Trilobite| Cambrian – Permian|
Fossil B| Brachiopod| Cambrian – Cenozoic|
Fossil C| Nautiloid| Cambrian – cenozoic|
6. Analyze the diagram below to reply the inquiries a through g. ( a ) List the comparative ages of units A through I in order from oldest to youngest.
Oldest Tocopherol H C I G A F D B Youngest
( B ) Which stratigraphic rule did you utilize to find the relationship between unit I and units ( C. E. H ) ?
Law of Cross-Cutting dealingss
( degree Celsius ) The contact between unit C and unit G is called an angular unconformity. Speculate as to the events that occurred between the deposition of these two units.
Events such as hits in a convergent border. or any such event that causes uplift. would take to the angular uniformity of units degree Celsiuss and g.
( vitamin D ) How has the energy of the depositional environment changed between the deposition of unit G and unit A?
Unit G was in a higher energy depositional environment. because conglomerate’s grains are coarser. Unit A was in a lower energy depositional environment because shale’s grains are more all right.
( vitamin E ) Unit F has been numerically dated at 60 Myr ( million old ages ) and Unit I has been numerically dated at 220 Myr. Give this information what can be said about the ages of units G and A relation to F and I?
Unit F is the youngest of the 4 at 60 million old ages old. Unit A is somewhat older. Unit G is older than A. but less than 220 million old ages. Unit of measurement I is the oldest at 220 million old ages.
( degree Fahrenheit ) Would you anticipate to happen Fossil C. from inquiry 18. in units G and A?
Unit of measurement A.
( g ) If unit C contained belemnoids and trilobites. how old might these sedimentations be?
The sedimentations could be 543 million old ages old. Belemnoids can be 323 million old ages old. trilobites can be 543 million old ages old.
8. Although it may look strange. the storage of radioactive stuffs can be related to geologic clip. It is believed that after about 10. 000 old ages many of the awful radioactive stuffs contained in this waste will hold experienced one or more ( the more the better! ) half life. This means that this waste needs to be stored in a ‘facility’ that will be safe from perturbations for at least 10. 000 old ages.
a. How many coevalss of worlds will come and travel during this clip? ( Assume that the really optimistic life span of any one coevals is 100 years. )
10. 000 old ages / 100 = 100 coevalss
B. Knowing human nature. what are some jobs with the waste sitting un-molested for 10. 000 old ages?
As populations expand. people move outwards. This can upset the waste. Therefore. the likeliness of waste sitting untasted for 10. 000 old ages is less.
c. If we are optimistic about human nature. what are some geologic jobs to see? For illustration. what are some locations ( plate tectonic graduated table ) that would be good topographic points to hive away this waste?
Problems could be temblors or related natural catastrophe. The best topographic point to hive away the waste would be in the center of a home base. Less geologic perturbations.
d. What might be some jobs that future geologists may hold if they tried to day of the month stones that were storage installations for radioactive waste?
Different isotopes from environing stones may acquire on the stones they try to day of the month. which would upset the computations.
