Unlike catastrophism, states that mountains formed slowly over time.

william smith was working as a surveyor in the late eighteenth century. he noticed that certain fossils were found in certain layers of sedimentary or igneous rock, that the same order of strata could be found in areas that were far apart, and these strata contained similar

isotopic dating relies on a process called where heavier radioisotopes transform into lighter elements.

the permian period lasted from 299 ma to 251 ma. this means that the permian period lasted years.

a rock inclusion in a basalt lava flow is dated at 56 ma. this means the lava flow must have occurred 56 ma.

respond to the following based on your reading.

you are trying to assign a date to a layer of tephra. while examining the tephra, you notice that it contains several shale inclusions. if you determine that the dates of the shale inclusions range from 910 ka to 1.3 ma. what can you say about the age of the tephra layer?