Across
- 4. group of single-celled protists
- 7. element most easily detected
- 10. highest honor in aviation
- 14. theoretical reason for world-wide die off
- 15. the age of dinosaurs
- 17. village nearest the crater
- 18. meaning "scale" or "flake"
- 20. an unusual science project partner
- 21. asteroid would create a hole in atmosphere ___ km across
- 22. American geologist; ______ Alvarez
Down
- 1. Manhattan Project weapon type
- 2. ancient Italian town
- 3. what blocked the sun & stopped photosynthesis
- 5. new era; age of the mammals
- 6. glass spherules that form with heat and impact
- 8. Earth's ______ field
- 9. 10000x richer in platinum group elements
- 11. Walter's colleague, Bill ______
- 12. time for 50% decay
- 13. name of boundary
- 16. June 1980 paper published in _____
- 19. company that initially discovered crater