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