1								2
											3
									4
																							5
								6
	7
						8												9
	10		11
								12	13
						14
															15
					16
												17
18
		19
															20

Across 3. A type of crust, mainly basaltic and 6-10km thick. (2 words) 4. The person who suggested that the continents were once all joined together. (2 words) 6. The most common type of volcano on land, created by layers of rock and ash from previous eruptions. (2 words) 10. A very large tectonic plate that Britain is on. (2 words) 12. The study of the record of the Earth's magnetic field. 14. A linear shaped lowland between highlands or mountain ranges. (2 words) 16. Studying volcanoes by looking at the ground around them (2 words) 17. The study of earthquakes and other tectonic activity. 18. May be caused by plumes of magma beneath the earth's surface. (2 words) 19. Where 2 plates pull apart there is a weaker zone in the crust and an increase in heat near the surface. (2 words) 20. Semi molten with temperatures of 5000°C.

Down 1. The densest part of planet earth, about the size of Mars. 2. Where two plates meet and the direction of plate movement is parallel or almost parallel. (2 words) 5. The idea that continents could be joined together. (2 words) 7. A gently sloping volcano that erupts gently. (2 words) 8. Occurs when an elongated crackin the crust allows lava to spill out over a large area. (2 words) 9. A type of crust, composed of igneous, metamorphic and sedimentary rock. Can be 70km thick. (2 words) 11. A type of volcanic rock that is acidic. 13. The ductily-deforming region of the upper mantle of the Earth which lies below the lithosphere. 15. The thinnest layer of the earth, which has the coolest, least dense rock.