Geologic age: using radioactive decay to determine geologic age
General Information Product
By: U.S. Geological Survey
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Abstract
At the close of the 18th century, the haze of fantasy and mysticism that tended to obscure the true nature of the Earth was being swept away. Careful studies by scientists showed that rocks had diverse origins. Some rock layers, containing clearly identifiable fossil remains of fish and other forms of aquatic animal and plant life, originally formed in the ocean. Other layers, consisting of sand grains winnowed clean by the pounding surf, obviously formed as beach deposits that marked the shorelines of ancient seas. Certain layers are in the form of sand bars and gravel banks -- rock debris spread over the land by streams. Some rocks were once lava flows or beds of cinders and ash thrown out of ancient volcanoes; others are portions of large masses of once-molten rock that cooled very slowly far beneath the Earth's surface. Other rocks were so transformed by heat and pressure during the heaving and buckling of the Earth's crust in periods of mountain building that their original features were obliterated.
Suggested Citation
U.S. Geological Survey, 1997, Geologic age: using radioactive decay to determine geologic age: General Information Product, HTML Document, https://doi.org/10.3133/70043861.
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Unnumbered Series |
| Title | Geologic age: using radioactive decay to determine geologic age |
| Series title | General Information Product |
| DOI | 10.3133/70043861 |
| Year Published | 1997 |
| Language | English |
| Publisher | U.S. Geologic Survey |
| Publisher location | Reston, VA |
| Description | HTML Document |