Facts about geologic dating
Nicolaus Steno (1638-1686) introduced basic principles of becoming known as “the Father of English Geology.” Nineteenth-century scientists developed a relative time scale using Steno’s principles, with names derived from the characteristics of the rocks in those areas.
The figure of this geologic time scale shows the names of the units and subunits.
Many geological samples contain multiple parent/daughter pairs, so cross-checking the clocks confirms that radioisotopic dating is highly reliable.
Meteorite is used for the rock on Earth, meteoroid for the object in space, and meteor as the object travels in Earth's atmosphere.
An atom that has different number of neutrons but the same number of protons.
Relatively chemically inert with a hardness of 8.5.
via Wikimedia Commons' src=" alt="Chart showing the names of the unit of the Geooogic Time Scale" width="300" height="300" srcset=" sizes="(max-width: 300px) 85vw, 300px"/ is the process of determining if one rock or geologic event is older or younger than another, without knowing their specific ages—i.e., how many years ago the object was formed.
The principles of relative time are simple, even obvious now, but were not generally accepted by scholars until the scientific revolution of the 17th and 18th centuries via Wikimedia Commons' src=" Superposition-228x300.jpg" alt="Photo of superposed strata with the younger on top of the older" width="270" height="355" srcset=" Superposition-228x300228w, Superposition-768x1009768w, Superposition-780x1024780w, Superposition-1200x15761200w, 1392w" sizes="(max-width: 270px) 85vw, 270px"/CC BY 2.0], via Wikimedia Commons' src=" alt="Photo of rock outcrop with a dike cutting through an older rock and another dike cutting across that one." width="215" height="287" srcset=" sizes="(max-width: 215px) 85vw, 215px"/ Wikimedia Commons, via Wikimedia Commons' src=" alt="Photo of the Grand Canyon showing expanse of canyon and the various rock layers" width="392" height="261" srcset=" sizes="(max-width: 392px) 85vw, 392px"/CC BY-SA 3.0], via Wikimedia Commons' src=" alt="The red rocks are layered, the dark rocks are not." width="300" height="225" srcset=" sizes="(max-width: 300px) 85vw, 300px"/All three of these formations have a disconformity at the two contacts between them.