Uranium lead dating meteorites august

Clair Patterson, Rocks from Space, and Metal in the Air | Magpie's Miscellany

uranium lead dating meteorites august

By Katyanna Quach 14 Aug at The oldest rock formations on Earth were born when meteorites pummelled into the These rocks are believed to be around billion years old, judging from uranium-lead dating of tiny zircon. Since meteorites are samples of the universe outside our atmosphere they are kind of by August 15, · pm He used uranium-lead, then lead-lead dating methods on meteorite samples, including the Canyon Diablo meteorite. Radiometric dating and the age of the Earth by Ralph W. Matthews, Ph.D. [Click here for a summary of this article.] Since the lead in meteorites can no longer be ascribed to uranium/thorium decay, it may also be .. GB August 9th,

The meteorites were always contaminated with large amounts of atmospheric lead whenever they were exposed to air. Uranium decays into Lead. The Pb used as its abbreviation has the same root as the word plumber.

So once he established the age of the Earth, he began to look at all this atmospheric lead. It should not come as a shock then that the findings were neither truthful nor accurate. Their urine and feces were tested.

uranium lead dating meteorites august

Unfortunately, as the doctor appears not to have known, lead is not excreted as a waste product. In consequence, lead was given a clean bill of health.

Uranium–lead dating

Industry said that the amount of lead in the environment had only doubled with its industrial usage. EPA chart on atmospheric lead. Patterson found that deep ocean water had times less lead than surface water while other metal ratios remained steady. Studying ice core samples from Greenland plugs of ice frozen over the centuries that give a tiny sample of atmospheric conditions from the time when that snow or rain first fell showed that lead levels started to rise steadily after it began to be used as an additive in gasoline.

He found the source of the lead that was contaminating his samples, but he was concerned about the public health implications of all that lead and spent much of the rest of his life fighting to make sure the public knew about them. He was battling large and wealthy corporations and individuals, so many research centers were closed to him. Plenty of them were supposed to be neutral, but then as now money and corporate interests trump good science, due process or public interest.

Especially when one director was a Supreme Court judge and another an influential member of the National Geographic Society. Diagram of one lead isotope. He became a liability to schools, as companies began to pressure the institutions he worked for to fire him or shut him up.

He was excluded from a national research panel studying the effects of lead inwhich was particularly egregious since by then he was the foremost expert on the topic. He was also worried about the amounts of lead in soldering and paint. He that lead levels were much higher in canned than fresh foods. Again, it was a few orders of magnitude higher than what the food companies claimed. Clair Patterson died in Nor, more puzzlingly, did he gain any fame or even much attention from a half century of consistent and increasingly selfless achievement.

Third, the radiometric ages agree, within analytical error, with the relative positions of the dated ash beds as determined by the geologic mapping and the fossil assemblages; that is, the ages get older from top to bottom as they should. Finally, the inferred age of the shocked quartz, as determined from the age of the melted feldspar in the Manson impact structure The Ages of Meteorites Meteorites, most of which are fragments of asteroids, are very interesting objects to study because they provide important evidence about the age, composition, and history of the early solar system.

There are many types of meteorites. Some are from primitive asteroids whose material is little modified since they formed from the early solar nebula. Others are from larger asteroids that got hot enough to melt and send lava flows to the surface. A few are even from the Moon and Mars.

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The most primitive type of meteorites are called chondrites, because they contain little spheres of olivine crystals known as chondrules. Because of their importance, meteorites have been extensively dated radiometrically; the vast majority appear to be 4.

Radiometric Dating Does Work! | NCSE

Some meteorites, because of their mineralogy, can be dated by more than one radiometric dating technique, which provides scientists with a powerful check of the validity of the results.

The results from three meteorites are shown in Table 1. Many more, plus a discussion of the different types of meteorites and their origins, can be found in Dalrymple There are 3 important things to know about the ages in Table 1. The first is that each meteorite was dated by more than one laboratory — Allende by 2 laboratories, Guarena by 2 laboratories, and St Severin by four laboratories. This pretty much eliminates any significant laboratory biases or any major analytical mistakes.

The second thing is that some of the results have been repeated using the same technique, which is another check against analytical errors. The third is that all three meteorites were dated by more than one method — two methods each for Allende and Guarena, and four methods for St Severin.

This is extremely powerful verification of the validity of both the theory and practice of radiometric dating. In the case of St Severin, for example, we have 4 different natural clocks actually 5, for the Pb-Pb method involves 2 different radioactive uranium isotopeseach running at a different rate and each using elements that respond to chemical and physical conditions in much different ways.

And yet, they all give the same result to within a few percent. Is this a remarkable coincidence? Scientists have concluded that it is not; it is instead a consequence of the fact that radiometric dating actually works and works quite well. Creationists who wants to dispute the conclusion that primitive meteorites, and therefore the solar system, are about 4.

The K-T Tektites One of the most exciting and important scientific findings in decades was the discovery that a large asteroid, about 10 kilometers diameter, struck the earth at the end of the Cretaceous Period.

The collision threw many tons of debris into the atmosphere and possibly led to the extinction of the dinosaurs and many other life forms. The fallout from this enormous impact, including shocked quartz and high concentrations of the element iridium, has been found in sedimentary rocks at more than locations worldwide at the precise stratigraphic location of the Cretaceous-Tertiary K-T boundary Alvarez and Asaro ; Alvarez We now know that the impact site is located on the Yucatan Peninsula.

Measuring the age of this impact event independently of the stratigraphic evidence is an obvious test for radiometric methods, and a number of scientists in laboratories around the world set to work.

In addition to shocked quartz grains and high concentrations of iridium, the K-T impact produced tektites, which are small glass spherules that form from rock that is instantaneously melted by a large impact. The K-T tektites were ejected into the atmosphere and deposited some distance away. Tektites are easily recognizable and form in no other way, so the discovery of a sedimentary bed the Beloc Formation in Haiti that contained tektites and that, from fossil evidence, coincided with the K-T boundary provided an obvious candidate for dating.

Scientists from the US Geological Survey were the first to obtain radiometric ages for the tektites and laboratories in Berkeley, Stanford, Canada, and France soon followed suit. The results from all of the laboratories were remarkably consistent with the measured ages ranging only from Similar tektites were also found in Mexico, and the Berkeley lab found that they were the same age as the Haiti tektites.

The K-T boundary is recorded in numerous sedimentary beds around the world. Numerous thin beds of volcanic ash occur within these coals just centimeters above the K-T boundary, and some of these ash beds contain minerals that can be dated radiometrically.

Since both the ash beds and the tektites occur either at or very near the K-T boundary, as determined by diagnostic fossils, the tektites and the ash beds should be very nearly the same age, and they are Table 2.

There are several important things to note about these results. First, the Cretaceous and Tertiary periods were defined by geologists in the early s.

The boundary between these periods the K-T boundary is marked by an abrupt change in fossils found in sedimentary rocks worldwide. Its exact location in the stratigraphic column at any locality has nothing to do with radiometric dating — it is located by careful study of the fossils and the rocks that contain them, and nothing more.

Furthermore, the dating was done in 6 different laboratories and the materials were collected from 5 different locations in the Western Hemisphere.

And yet the results are the same within analytical error. These flows buried and destroyed Pompeii and other nearby Roman cities. We know the exact day of this eruption because Pliny the Younger carefully recorded the event.

They separated sanidine crystals from a sample of one of the ash flows.

uranium lead dating meteorites august

Incremental heating experiments on 12 samples of sanidine yielded 46 data points that resulted in an isochron age of 94 years. The actual age of the flow in was years.

uranium lead dating meteorites august

Is this just a coincidence? No — it is the result of extremely careful analyses using a technique that works. This is not the only dating study to be done on an historic lava flow. Two extensive studies done more than 25 years ago involved analyzing the isotopic composition of argon in such flows to determine if the source of the argon was atmospheric, as must be assumed in K-Ar dating Dalrymple26 flows; Krummenacher19 flows. Note, however, that even an error of 0.

Summary In this short paper I have briefly described 4 examples of radiometric dating studies where there is both internal and independent evidence that the results have yielded valid ages for significant geologic events. It is these studies, and the many more like them documented in the scientific literature, that the creationists need to address before they can discredit radiometric dating. Their odds of success are near zero.

uranium lead dating meteorites august

Even if against all odds they should succeed, it still would not prove that the Earth is young. Only when young-earth creationists produce convincing quantitative, scientific evidence that the earth is young will they be worth listening to on this important scientific matter. Acknowledgments I thank Chris Stassen and 2 anonymous reviewers for their thoughtful comments, which led to important improvements in the manuscript. T Rex and the Crater of Doom.

uranium lead dating meteorites august

Alvarez W, Asaro, F.