Across
- 3. The process by which crust sinks back into the mantle at a colliding plate boundary
- 4. The process by which molten material adds new crust below Earthś bodies of water
- 5. A device that reflects sound waves off underwater objects and records the echoes
- 6. A person who specializes in writing and serves as a record keeper.
- 7. A deep undersea valley where crust sinks toward the mantle
- 9. A type of writing made up of wedge-shaped markings
Down
- 1. An undersea chain of mountains that is a part of a land system of underwater mountains
- 2. A picture or drawing that represents a word or idea
- 6. A sharpened reed used to press markings into clay tablets
- 8. A mixture of copper and tin; used to make stronger tools