Across
- 3. • process where nuclei of atoms spontaneously break apart (decay) • parent material decays into daughter product • occurs at a specific rate
- 4. Archbishop, added up generations from the Old Testament, came up with the idea of a 6000 year old earth, determined that Earth formed on October 23, 4004 BCE (creation beginning at nightfall on Oct. 22) “Ussher chronology"
- 5. this person studied rock formations dug out of canals in SW England • noticed rock similarities and changes in different locations • discovered that fossils could be used to correlate rocks of the same age
- 7. *Discovers lead as final decay product of uranium (1907) *Discovers that older rocks have greater Lead-Uranium ratios
- 10. – younger material is roughly parallel to older material
- 11. greatest expanses of time • Phanerozoic, Precambrian (Hadean, Archean, Proterozoic)
- 12. – type of inclusion, piece of rock contained within another
- 14. • understanding the time component of geological processes and age of rocks and formations • Earth is really old and quite big! Lots of stuff happens to and on a planet in 4.6 billion years
- 20. • correlation with fossil assemblages • fossils are arranged in rock layers according to their age (time during which they lived) • younger fossils are above older fossils
- 21. this person studied rock formations in British Isles • theorized that Earth’s internal heat created igneous rocks like basalt and granite • recognized that slow processes like erosion and deposition will cause great change in Earth’s landscape over long periods of time, Uniformitarianism.
- 24. • erosional surface • represent a break in the stratigraphic record (“pause” in deposition) • 3 types (disconformity, angular unconformity, nonconformity)
- 26. • older layer at bottom, younger at top • applies to any rock that is deposited horizontally • primarily sedimentary, but also lava flows and ash falls • e.g., Grand Canyon
- 28. = thousand years ago (1,000)
- 32. (4.6 Ba), Uniformitarianism, used the same scientific laws that operate today, also happened in the past… Gradualism also prominent
- 33. Form of numerical age dating, uses Ice cores and the configuration of snow, granular ice, firm, and glacial to draw conclusions about the past.
- 36. – putting things in relative (comparative) age order • Joey is older than Robbie • judged from height, facial features, etc. • The brown sandstone is older than the white limestone • judged by stratigraphic position, fossils, etc.
- 39. • the way Earth’s history is organized • calendar of events for Earth’s history • time units are divided based on rock units and changes on Earth • each unit is given a meaningful name
- 40. _______ also called an Unstable Isotope decays to a stable product
- 42. # of nucleons (protons + neutrons) in nucleus
- 44. index fossil existed in Jurassic and Cretaceous (201-66 Ma)
- 47. same scientific laws that operate today, also happened in the past…therefore: • Earth’s features shaped by processes that we can still see today (e.g., erosion, wind, water) • “the present is the key to the past” – use the modern to interpret the ancient
- 49. – determining a numerical age of something • Joey is 10, Robbie is 4 • determine from dental records, birth certificates, etc. • The brown sandstone is 5 Ma, the white limestone is 1 Ma • determined by radioactive isotopes, paleomagnetism, dendrochronology, etc.
Down
- 1. smaller divisions based on major changes in life • Paleozoic, Mesozoic, Cenozoic
- 2. • determining “equivalence” of rock layers that may be spread over great distances • sedimentary layers of the same origin can be found spread across great distances • e.g., Navajo sandstone in both Bryce canyon and Zion National parks
- 6. Form of numerical age dating using trees to draw multiple conclusions about the past
- 8. • sedimentary layers are initially deposited in horizontal layers • may later be deformed (but layered deposition happened first)
- 9. # of protons in nucleus
- 13. most processes occur slowly over long periods of time • e.g., transport, deposition, and lithification of clay to form shale
- 15. • the time it takes for half of the parent isotope to decay to a daughter product • constant rate of decay, specific to each isotope • examples • 40 Potassium → 40 Argon (1.25 billion years) • 14 Carbon → 14 Nitrogen (5730 years)
- 16. • an inclusion is older than the rock containing it
- 17. or Ga = billion years ago (1,000,000,000)
- 18. type of Unconformity – underlying sedimentary strata are at an angle to overlying strata
- 19. Form of numerical age dating that uses the magnetic time scale mapped using the magnetic polarity of the crust usually on the seafloor to make conclusions about the past
- 22. Earth’s features shaped by great catastrophes (e.g., worldwide floods, enormous eruption periods, earthquakes) and processes that no longer occur
- 23. (6 Ka): • early Europeans retrofitted observations to fit religious beliefs • the past before humans is “unknowable” (Dark Ages) • everything on Earth was created just as we see it today • inaccurate
- 25. smallest divisions within periods
- 27. • a rock is older than anything that cuts through it • e.g., dike (igneous intrusion) or fault (break) • you can’t break or intrude a rock that hasn’t formed yet!
- 29. index fossil existed in Paleozoic (521-252 Ma)
- 30. • calculating the ages of rocks and minerals that contain specific unstable isotopes • parent/daughter ratio is measured to determine how many half lives passed
- 31. Discovers radioactivity (1896)
- 34. Marie and Pierre,Discover heat energy is released from radioactive decay (1903)
- 35. – fossil that is especially useful for determining age of rock • must be: easily recognizable, abundant, wide geographic distribution, short range of time
- 37. smaller divisions within eras based on smaller changes in life
- 38. – sedimentary rocks overlie crystalline rock (igneous or metamorphic)
- 41. index fossil existed Miocene-Pleistocene (23 Ma-11 Ka)
- 43. • varieties of an element with different number of neutrons
- 45. index fossil existed in Mesozoic (252-65 Ma)
- 46. = million years ago (1,000,000)
- 48. this type of Isotope lasts forever