Across
- 1. / a body or particle recognizably distinct from the substance in which it is embedded.
- 7. age (dating) / the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age, (i.e. estimated age).
- 9. decay / The spontaneous transformation of an unstable atomic nucleus into a lighter one, in which radiation is released in the form of alpha particles, beta particles, gamma rays, and other particles.
- 11. plate boundary / (also known as a conservative plate boundary, since these faults neither create nor destroy lithosphere), is a type of fault whose relative motion is predominantly horizontal, in either a sinistral (left lateral) or dextral (right lateral) direction.
- 12. drift / the gradual movement of the continents across the earth's surface through geological time.
- 13. spreading / the formation of new areas of oceanic crust, which occurs through the upwelling of magma at mid-ocean ridges and its subsequent outward movement on either side.
- 15. plate boundary / also known as a destructive plate boundary (because of subduction), is an actively deforming region where two (or more) tectonic plates or fragments of the lithosphere move toward one another and collide.
- 17. / the theory that changes in the earth's crust during geological history have resulted from the action of continuous and uniform processes.
- 18. ridge / a long, seismically active submarine ridge system situated in the middle of an ocean basin and marking the site of the upwelling of magma associated with seafloor spreading. An example is the Mid-Atlantic Ridge.
- 19. / the rigid outer part of the earth, consisting of the crust and upper mantle.
- 21. / a hypothetical supercontinent that included all current land masses, believed to have been in existence before the continents broke apart during the Triassic and Jurassic Periods.
- 22. Fossil / a fossil that is useful for dating and correlating the strata in which it is found.
Down
- 2. Zone / the biggest crash scene on Earth. These boundaries mark the collision between two of the planet's tectonic plates. The plates are pieces of crust that slowly move across the planet's surface over millions of years.
- 3. / the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
- 4. / A method used by geologists to fill in the measuring gaps in an area’s rock record by matching rocks and fossils from separate locations.
- 5. / a principle of quantum theory that describes a challenging concept about the nature and behavior of matter and forces at the sub-atomic level.
- 6. / a surface of contact between two groups of unconformable strata.
- 8. age (dating) / the process of determining an age on a specified chronology in archaeology and geology. Some scientists prefer the terms chronometric or calendar dating, as use of the word "absolute" implies an unwarranted certainty of accuracy.
- 10. / the time taken for the radioactivity of a specified isotope to fall to half its original value.
- 12. / the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.
- 14. Fossil / a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself.
- 16. plate boundary / A tectonic boundary where two plates are moving away from each other and new crust is forming from magma that rises to the Earth's surface between the two plates.
- 20. tectonics / a theory explaining the structure of the earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates that move slowly over the underlying mantle.