Question

EARTH SCHENCE RESOURCE MANUAL 7. A Crystored ova ow conta con crys. Amos como os used to count the percentage of otoms of Uranium-235 ond Leod 207 bolopes in con omstrom the love how the analyse d that percent of the glome were Uranium 235 and 2 percent of the stoms were los 2017 About how many hoes of the monum.235 L 207 deco pohoveloped in the conce what the absolute age of the love tow boned on this contra c. What the age of the strato beneath the love towt d. What is the age of the strato above the love ow! .. Dow a sketch showing the love tow and the strate above and be 8. Ponetary geologists propose that Earth formed at the same time o f the other rocky materials in our solar system, including the oldest meteorites. The oldest meteorites over found on Earth contain nearly equal amounts of both Uranium-238 and lead-206. Based on this data, what is the age of the Earth Show your work Using the Carbon-14 10 roger14 isotope por colculate the ope of the carbon Om motos porno doughter ratio of 1:3 Show your wOR

Answer 1

1 (7) The analysis revealed that Uranium-235 = 7 1. The percentage of head- 207 = 29. Initially, at the time of formation of Rock there will be no Lead is present. 1. We know that the half life of 935 to 207 pb is : 710 my. = 710 x 106 years o As we know that, according to definition of half life, It is the time taken to fall to half of its original value ie At half life 100%. Uranium becomes 50% which is initially present in the rock. But here, Hy is remained. in 29 t. of initial amocent of uranium got decayed into Lead. → For the decay of Band 50% of Initial amount, it takes 710 my But for the decay of zat. of Initial amocent - it takes : 29 xH10 my = 411.8 m.y. Ho. of half lifes elapsed in the Zircon crystal for the present decay pair = 4.8 0.58 half-lifes Wonen = 0.58 got elapsed,

b. can Based be on the Z ircon calculated as Half life of crystal age of the lavar follows. U238 to P6207 is : 70 my 710 X 10 y. Dibintegration consta d = 0,622 - 0.693,-0.946xió?. ty Hox106. The amount the rock The amount of is of Time required to reduced to N ta uranium present Initially in = 100 %. = No uranium at present = 74. =N No amount of Uranium to be amocent of Uranium 1.303 logements 2.363 log () = 350 x 100 years obsolute Age of Lavaltro = 350 my 2) The age of the strata beneath lava flow > 350 m. years di Age of the strata flow above the Lava < 350 my.

- Fie) The of Lava How and strata above and sketch below. ) overlying strate I Lavafloo W x + x x x x x to x underlying sheata.

8) Given that the oldest meteohites had equal amounts of Uranium-238 and Lead 06,206, The half life of 238 U to 206p6 = 4.47 by Since its containing equal amounts of Uranium and thorium Age of Rock = Half life | ie Age of Earth = Half life of 23 to 2"pb = 4.47 b. years Age of earth = 4.47x10 years | Given parent to daughter rate = 1:7. 5730 17 = M = 7:1 Half life of the to 14 = 5730 years, Decay const to 0:193 = 1.209x174. Age of Carbon Sample t= ln (20 pt) In () +1) . 1.2098104 = In 8 xiot 2.0794 X106 1.209 - - - 1.209 = (-7199 x104 | Age = 17, 199.66 years