Earth's History Crossword Puzzle

QUESTIONS LIST:

• extrusion : igneous rock that has formed from lava
• meteorite : passes through the earth's atmosphere and strikes the ground
• mass extinction : widespread and rapid decrease in biodiversity
• eon : a very long period of time
• superposition : this law states that the oldest layer is at the base of the rock and the layers get younger as you ascend
• catastrophic event : very harmful or disastrous that results in substantial damage
• geologic time : used by scientists to describe the timing and relationships of events in geologic history
• strata : sedimentary rock's layers
• ice age : a long period in the reduction of temperature indicated by the expansion of ice sheets and glaciers
• intrusion : igneous rock that has crystallized from molten magma
• younger : cross-cutting principle states that the geologic feature which cuts another is the _ of the two features.
• absolute : the type of age that can be plotted on a calendar.
• periods : a subdivision of geological time to show when a rock originated
• relative : the type of age where the age of a rock is determined by comparing whether it is younger than other material around it.
• index fissile : useful for dating the strata where it is found
• coal beds : a layer (stratum) of mineral coal
• unconformity : surface contact between two groups of strata
• stromatolites : a calcium mound where lime-secreting bacteria are trapped and contain some of the earliest known fossils
• photosynthesis : the process how some organisms make food from sunlight to create oxygen as a byproduct
• outcrop : a rock formation that is visible on the surface