Plate Tectonics and Geologic Time

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849
Across
  1. 4. Earth is approximately 4.6 _____________ years old
  2. 5. This type of stress occurs at divergent boundaries
  3. 7. The idea of continental drift began when people noticed South America and Africa looked like they fit together like pieces of a _________
  4. 9. Subdivisions of eras
  5. 10. A zipper-like chain of undersea mountains
  6. 14. the shaking that results from the movement of Earth's plates
  7. 17. The geologic time scale is constantly being _________, or made more accurate
  8. 18. This class of volcano is currently erupting or shows signs of erupting soon
  9. 19. The name given to a "sleeping" volcano
  10. 21. The ring of volcanoes that surround the pacific ocean
  11. 22. This type of stress occurs at transform boundaries
  12. 24. This mountain range was created as a result of India colliding with Asia
  13. 25. A place where lava frequently erupts onto Earth's surface independent of a plate boundary
  14. 26. This is a gap in the geologic record where rock layers have been lost due to erosion
  15. 27. The geologic time scale is divided into the Precambrian time and the three major _____
  16. 29. This chain of islands in the Pacific Ocean formed as a result of a hot spot
  17. 34. Magma that has reached Earth's surface
  18. 37. This method of aging compares rocks by looking at the layers above or below it
  19. 41. Mass _______________ mark when one era ends and another begins
  20. 42. This type of crust is larger and less dense than oceanic crust
  21. 44. A fern like plant found on five different continents used as evidence for continental drift
  22. 46. The record of geologic events and the evolution of life on Earth
  23. 47. Waves produced by an earthquake
  24. 48. This boundary sees two plates moving towards each other
  25. 49. Tectonic plates are said to move at the same rate as your ___________ grow
Down
  1. 1. This type of volcano is made of alternating layers of hardened lava and ash
  2. 2. The method of determining the absolute age of rocks
  3. 3. This law states that in undisturbed, horizontal sedimentary rock layers, the oldest rocks are on the bottom and the youngest rocks are at the top.
  4. 6. Alfred __________ claimed the continents "drift" around the glove very slowly
  5. 8. Molten mixture of rock forming substances, gases and water from the mantle
  6. 11. This occurs when dense oceanic crust sinks under less dense crust
  7. 12. The farther you are from the mid ocean ridge, the ________ the rocks get
  8. 13. This type of boundary sees two plates moving away from each other
  9. 15. When atoms of an unstable element break down to form atoms of a more stable element
  10. 16. Undersea valleys that are the deepest parts of the ocean floor
  11. 20. The San Andreas Fault in California is an example of this type of boundary
  12. 23. The remains or traces of things that used to be alive
  13. 28. This type of volcano is made of only hardened lava
  14. 30. This type of volcano is made of ash, cinders and bombs
  15. 31. This volcanic mountain range formed as the Juan de Fuca plate subducts under the north american plate
  16. 32. The age of rock given as a number of years since that rock formed
  17. 33. The force that acts on rock to change its shape or volume
  18. 35. This type of crust converges with oceanic crust to create a volcanic island arc
  19. 36. A break in the rock that creates an earthquake
  20. 38. The structure that forms when magma reaches Earth's surface
  21. 39. This is where the magma collects under a volcano before an eruption
  22. 40. The name of the supercontinent that broke apart about 200 million years ago
  23. 42. This type of stress occurs at convergent boundaries
  24. 43. This is what drives plate tectonics
  25. 45. The name given to a volcano that is "dead" and will likely never erupt again