General Geology 1162303 Dr WORRAWAT 9 Historical Geology

General Geology 1162303 Dr. WORRAWAT คาบท 9 ธรณประวต Historical Geology หวขอ Radiometric dating 2

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p+ en 23 Na 11 31 P 15 85 137 2+ Rb Ba 37 56 + 35 Cl- 17 79 Se 34 2 - b 4+ X a General Geology 1162303 Dr. WORRAWAT อน ภาค มล ฐาน 6

Some isotopes are radioactive; they are unstable because their nuclei are too large. To achieve stability, the atom must make adjustments, particularly in its nucleus. General Geology 1162303 Dr. WORRAWAT Stable and Unstable atom 8

การสลายตวใหอนภาคอลฟา Alpha decay 234 4 Th 90 + He 2 An alpha particle is the nucleus of a helium atom travelling at around 1/10 the speed of light. An alpha particle carries two electronic units of positive charge and General Geology 1162303 Dr. WORRAWAT 238 92 U 11

General Geology 1162303 Dr. WORRAWAT การสลายตวใหอนภาคเบตา Beta decay Beta particles are electrons travelling at around 0. 9 the speed of light. Each beta particle carries one electronic unit of negative charge and can be stopped by a few millimeters of aluminium. 12

General Geology 1162303 Dr. WORRAWAT Wrong assumptions, Wrong dates http: //www. answersingenesis. org/articles/am/v 4/n 3/radi ometric-dating 13

General Geology 1162303 Dr. WORRAWAT 14 http: //www. answersingenesis. org/articles/am/v 4/n 3/radi

General Geology 1162303 Dr. WORRAWAT 15 http: //www. answersingenesis. org/articles/am/v 6/ n 2/creationist-puzzle

uranium-lead (238 U - 206 Pb) 4. 5 billion years potassium-argon (K -Ar) 1. 3 billion years rubidium 4. 7 billion strontium years (Rb -Sr) Note: These radioactive dating methods can only be used on: – Igneous Rocks Or Metamorphic Rocks – Not Sedimentary Rocks. General Geology 1162303 Dr. WORRAWAT Some examples of radioactive elements used in dating rocks are : Parent-Daughter Half Life 16

General Geology 1162303 Dr. WORRAWAT Uranium-Lead dating 17 http: //www. purifiedbyfaith. com/Creation. Evolution/Genesis 5 and 11/Gen 5%20 -

• Uranium-Lead dating only works on igneous and metamorphic rocks because sedimentary layers contain small pieces of a other rock layers • Uranium-lead dating has a range that it works best. For uranium-lead has a range of 10 million to 4. 6 billion years. General Geology 1162303 Dr. WORRAWAT Limitations of Uranium-Lead dating method 18

General Geology 1162303 Dr. WORRAWAT Potassium–Argon dating (K– Ar dating) 19

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General Geology 1162303 Dr. WORRAWAT Carbon Dating 21 http: //hyperphysics. phy-

Carbon-14 Dating—Understanding the Basics n+ 14 N→ 14 1 C+ p General Geology 1162303 Dr. WORRAWAT 1 http: //www. answersingenesis. org/articles/am/v 6/ n 2/creationist-puzzle CARBON-14 IS CREATED : When cosmic rays bombard the earth’s atmosphere, they produce neutrons. These excited neutrons then collide with nitrogen atoms in the atmosphere, changing them 22

General Geology 1162303 Dr. WORRAWAT http: //www. answersingenesis. org/articles/am/v 6/ n 2/creationist-puzzle CARBON-14 IS ABSORBED : Plants absorb this carbon-14 during photosynthesis. When animals eat the plants, the carbon-14 enters their bodies. The carbon-14 in their bodies breaks down to nitrogen-14 and escapes at the same rate as new 23

14 6 C 14 N +7 e - General Geology 1162303 Dr. WORRAWAT http: //www. answersingenesis. org/articles/am/v 6/ n 2/creationist-puzzle CARBON-14 IS DEPLETED : When an animal dies the carbon-14 continues to break down to nitrogen 14 and escapes, while no new carbon-14 is added. By comparing the surviving amount of carbon-14 to 24

• Because the half-life of carbon-14 is 5, 730 years carbon dating is only reliable about up to 40, 000 years. General Geology 1162303 Dr. WORRAWAT Limitations of Carbon dating method 25

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