Time, Fossils, Tectonic Plates Crossword Puzzle

QUESTIONS LIST:

• lithosphere : tectonic plates are pieces of this layer
• apart : sea floor spreading is when plates drift _
• halflife : the amount of time it takes for half of a radioactive sample to decay into a stable form
• asthenosphere : tectonic plates float on this layer.
• hadean : the first eon of the earth when there was no life of any kind
• paleozoic : the era when plants and animals first appeared on land
• radiometric dating : a method of determining the age of an object by comparing the amount of a radioactive parent isotope to the stable daughter isotope
• fossils : wegener thought that the continents had once been joined together because he found matching _ on the coasts of certain continents.
• eons : the longest periods of geologic time
• isotope : an atom that has the same number of protons as other atoms of its kind, but a different number of neutrons, possibly making it unstable
• mesozoic : the era that's called the age of the reptiles
• crust : the entire geological column is found in this layer of the earth.
• seismic : earthquakes produce these waves
• wegener : who first proposed the idea of pangaia?
• paleontologist : a scientist who studies fossils
• magma : the molten rock that comes up from the mantle
• geologist : a scientist who studies rocks
• core : the dense center of the earth
• compare : relative dating is when paleontologists _ the age of one thing with the age of something else.
• pangaia : the name of the super continent that existed 245 million years ago
• index fossil : the fossil of an organism which is known to have lived during a particular time in geologic history. these fossils are useful in determining the age of a rock sample.
• cenozoic : the era in which we live
• period : a piece of an era
• together : a convergent boundary is where plates come _