warm-upweek 16day 2 1.sedimentary rocks record past geological events and ___. a. changing life...
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Warm-up Week 16 Day 21. Sedimentary rocks record past geological events and ___.
a. changing life forms of the past b. written historyc. Earth’s circumference and d. astronomical
diameter in the past milestones
2. The dating process that places geologic events in proper sequence is referred to as a ____.a. numerical dating c. relative datingb. temporary dating d. radiometric dating
3. Index fossils allow geologists to ____.a. match rocks of the same b. identify organisms that did
age in different regions not leave fossil evidencec. determine rocks’ exact age d. determine why some
organisms became extinct
Radioactive Decay
• Isotopes Stable atoms– Parent Daughter
– Release Energy
• “Half-Life”– Time for ½ of nucleus stable.
1. Radiometric Dating– Isotopes decay at constant rate– Calculate “birth” of Parent Isotope
2. Radiocarbon Dating– Carbon-14 isotope
– All living things, from AIR (CO2)
– Ratio of Carbon 12: Carbon 14 gives “death” date.
Review: How do we know…?
1. Relative Dating
2. Fossils
3. Radiometric Dating
4. Radiocarbon Dating
So, Now What?...