Uniformitarianism
fossils
radioactive decay
48 million
after
The youngest age of the shale is 910 ka. According to the principle of inclusions, the shale formed before the tephra, so the tephra must be younger than 910 ka.
Urban
I don’t know what else to but but that’s the answer lol
They can occur anywhere between the Earth's surface; about 700 kilometers<span> below the surface.</span>
<span>An eon is a geologically around tens of millions of years. A period is a million year included in an eon which is also made up of several eras. Therefore my answer is a period due to it being a subset of an era which is a subset of an eon.</span>
