Unlocking Secrets of the Grand Canyon's Age

How old is the Grand Canyon? Scientists haves been working on the answer for decades. Some believe the canyon is fairly young, in geologic terms, having been carved out by the Colorado River in the past five millions years (give or take a few years). Other researchers believe the canyon is much older, maybe by ten times that much. According to the latest discoveries, the answer seems to depend on how you define “the Grand Canyon,”  because different parts show a different history.

To help estimate ancient erosion rates, the team turned to thermochronology—the study of how a rock's temperature has changed through its history. Because temperature rises as depth in the Earth's crust increases, a rock's thermal history provides insight into when, and how quickly, terrain above it eroded away.

In the new study, the researchers used a variety of techniques to analyze samples of phosphate-bearing rocks taken from four of the five major sections of the canyon, both from river level and from the canyon rim, which typically lies almost a mile (1.5 kilometers) above the river.

The techniques used to date the canyon are a bit complicated, but you can read about them at National Geographic News. The conclusions of this latest research reveal that the area had several canyons in the distant past, with now-extinct rivers. Then they were joined together by events that happened 25 million years ago and then again at about five or six million years ago, when the Colorado River was formed. After all, when you’re that big and that old, you are bound to have a complicated history. -via the Presurfer

(Image credit: Erik Harrison)

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You can measure the half-life of C14 in a lab on non-historic timescales. Using that and the assumption that C14 levels haven't changed, you can get a basic dating without any use of historic material. C14 levels have not been constant though, and a correct can be made by dating known objects. A common method uses tree rings to date pieces of wood, you can find that there is ~10% correction in the last several years and maybe at worst a 20% correction going further back, without using any human history. Other methods test other materials, many of which are geological or biological in nature, and not connected to past human calendars, and some of which can cross check things with other kinds of radiometric dating. Rather detailed work shows very small changes in chemistry between C14 and C12 that can cause slight differences depending on what organism or mineral absorbed the C14, but from what I've seen, a lot of those corrections are smaller than typical error bars on the measurement of items of interest.

Losing ~236 years about 1000 years ago is large enough you would probably notice without even the corrections. I think the bigger question would not be how to could carbon dating screw up that badly, but how could you get that many countries to agree to change at the same time and to make up history to fill in the gap, considering what a mess it was to get countries to change to the Gregorian calendar (took Russia ~400 years to switch) and the Arabic calendar already started by that point, etc..
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According to some historians, around the year AD 764( ish) all the european countries/Kingdoms/realms had different ideas about the year number so one or more of them said enough of this cack next year will be the year 1,000 AD deal with it.
Would an error that large so recent have a huge effect on everything historic and geologic? Where does that put Carbon Dating? Does it explain the " Dark Ages"
We do know that many manuscripts were altered or rewritten shortly after and not always accurately and sometimes to show peoples ancestry in a better light.
Come on the nerds what would that small variable do to carbon dating etc..
Study and reply.
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