Mt. st. helens lava dome dating

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Contents:
  1. Claim CD013.1:
  2. How Old Is the Mount St. Helens Lava Dome?
  3. How Old Is the Mount St. Helens Lava Dome?
  4. References & Further Reading

Orthopyroxene retains the most argon, followed by hornblende, and finally, plagioclase. It's certainly plausible that some excess argon could accumulate in small fractures or defects within the crystalline structures of pyroxenes, amphiboles, feldspars and other minerals Dickin, , p. While Austin claims that orthopyroxenes should retain the most argon followed by hornblende an amphibole and finally plagioclase, he provides no references to support this claim.

In reality, the crystalline structures of amphiboles, unlike feldspars and pyroxenes, contain open channels, which can hold argon gas and other fluids Klein and Hurlbut, , p. I'm skeptical that the defects and fractures in the orthopyroxenes and feldspars of Austin's dacites could hold more excess argon per mineral volume than the relatively large open structures within the hornblendes Dickin, , p. Therefore, IF hypothesis 1 was the only factor influencing the dates of Austin's samples, I would expect the hornblende-rich 'fraction' to provide an older date than the pyroxene- and feldspar-rich 'fractions.

From the above discussions, we already know that hypothesis 2 is a likely explanation for Austin's old dates. To evaluate hypothesis 3, we should look at the crystallization order of the phenocrysts as suggested by Bowen's Reaction Series. The series states that certain minerals will crystallize in a melt at higher temperatures than other minerals.

That is, different minerals have different freezing points. Mafic magnesium and iron-rich volcanic rocks, such as basalts, form from relatively hot melts C and hotter, Hall, , p. Felsic silica-rich rocks, such as granites, form at cooler temperatures perhaps as cool as C , Hall, , p. The most common minerals in rocks of intermediate chemistry, such as dacites, are located towards the middle of the series. Bowen's Reaction Series is a very important concept that undergraduate students learn in their introductory physical geology courses.

To be exact, Bowen's Reaction Series was the one diagram that I was required to memorize when I took my first geology course in college. Although Bowen's Reaction Series was established long ago by field and laboratory studies, Swenson, Austin and other YECs repeatedly fail to comprehend its importance and how it can produce ancient phenocrysts, which may affect the radiometric dating of very young samples. In a young volcanic rock, such as the Mt. Helen's dacite, the calcium-rich plagioclases may have formed thousands or even a few million years ago. Again, as a rock ages and 40Ar accumulates in both the glass and any 40K-bearing minerals, the differences in the ages of the materials becomes less significant.

That is, if the glass quenched in an eruption , years after the formation of the calcium-rich plagioclases, after Bowen's Reaction Series also predicts that pyroxenes will crystallize at higher temperatures before amphiboles.

Assuming that any argon contamination from Geochron's equipment hypothesis 2 is negligible, we see that the dates in Austin's table are consistent with the crystallization order in Bowen's Reaction Series. As expected, the purest pyroxene fraction provides an older date 2. That is, IF the dates are real, the pyroxenes formed in the melt before the amphiboles as predicted by the series.

Because the pyroxenes solidify before most other minerals, it's also not surprising that the 'pyroxene, etc. Depending upon the amount of zoned feldspars which consist of older calcium-rich cores and younger sodium-rich rims and the quantity of glass, amphibole and pyroxene impurities, the 'feldspar etc. On the basis of the following statements by Swenson, his gross misinterpretations of Dalrymple , and his unwillingness to respond to my earlier statements on Bowen's Reaction Series and its possible relevance to Austin's results, it is clear that Swenson does not know what Bowen's Reaction Series is and how it can affect the age distributions of minerals in very young volcanic rocks: They said that Dr Austin should have known they were old because the crystals were large and zoned.

However, Dr Austin's results Table 1 show that the wrong ages were not confined to one particular mineral.

Claim CD013.1:

The idea that the age of a mineral can be anticipated by its size or colour is incorrect. Dalrymple [], for example, found that the wrong ages in his samples were unrelated to crystal size, or any other observable characteristic of the crystal. Contrary to Swenson's implications, mineral zoning is much more than a color property. As discussed earlier, zoning and crystal growth are extremely important in understanding phenocryst ages. Based on the statements in his essays, Swenson simply assumes that excess argon is present in all of the components of the dacite and that any statements on the lack of a relationship between excess argon and crystal size in Dalrymple automatically apply to Austin's dacite.

Again, because Swenson does not provide any page numbers when referring to Dalrymple , we can only guess which sections of Dalrymple's article he is citing. The results for the Mt. Lassen plagioclase and the Mt. Etna flow, which contains a HIGH percentage of large phenocrysts, appear to support their contention. Thus, for THESE experiments there does not appear to be any correlation of excess 40Ar with large phenocrysts or with any other petrological or petrographic parameter.

Clearly, whether amphibole, pyroxene, plagioclase or other phenocrysts are effectively degassed or not during eruptions is a complex and, perhaps, unpredictable issue. Nevertheless, as discussed in Dalrymple , p. Furthermore, if excess argon is relatively abundant in older samples, Ar-Ar dating and K-Ar isochron dating can detect and eliminate its effects as examples, McDougall and Harrison, , p.

They claim that these pieces of old rock xenoliths contaminated the sample and gave the very old age.

In his report, Austin refers to the presence of 'lithic inclusions' in his samples. Helens lava dome is 'lithic inclusions': Although the mineral concentrates are not pure, and all contain some glass, an argument can be made that both mafic and non-mafic minerals of the dacite contain significant 40 Ar. The lithic inclusions in the lava dome might be thought to be the contaminant, in which case they might add "old" mafic and non-mafic minerals to the young magma. It could be argued that gabbroic clumps in the magma disaggregated as the fluidity of the magma decreased with time, thereby adding an assortment of 'old' mineral grains.

These inclusions are, therefore, regarded as a unique association within the recent magmatic system. Even IF 1 Austin's summation of Heliker is absolutely accurate and no gabbro xenoliths or xenoliths of any other lithologies were present in the dacite, 2 Austin succeeded in removing all of the 'lithic inclusions' from his samples as Swenson claims, 3 no microscopic xenocrysts were hiding in this messy dacite, and 4 hypothesis 2 was not a factor, Austin would still need to specify the lifespan of the 'recent magmatic system.

Sarfati's Support of Flood Geology. Again, Figure 4 by itself illustrates that ancient phenocrysts were present in the dacite, which would invalidate Austin's dates. Although Austin failed to properly fractionate and date the minerals and glass in Mt. Helens dacite, many scientists have been able to isolate specific minerals from older volcanics and successfully date them. Although xenocrysts and xenoliths are very common in the Peach Springs Tuff, Nielson et al. Unlike Austin, Nielson et al. Because Nielson et al. When confronted by Nielson et al.


  1. differences between radiometric dating and relative dating.
  2. Radiometric Dating Does Work!;
  3. Drive on to prove creation with science - Technology & science - Science - Evolution | NBC News.

Even if excess argon is present in a sample, YECs must still explain the ultimate origin of 40Ar. The Earth's atmosphere currently contains relatively abundant concentrations of argon 0. Where did all of this argon come from if the Earth is only a few thousand years old?

In nature, 40Ar is only known to originate from the radioactive decay of 40K. Some YECs might argue that the 40Ar could have come from the decay of another, unidentified isotope s. However, this is easier to say than to prove. Any advocates of unidentified parent isotopes need to identify these isotopes, produce any evidence of their former existence, and derive the appropriate decay reactions for them. Other YECs might simply ignore the problem by saying that God created the 40Ar out of nothing 6, to 10, years ago.

Again, this is an unproven fantasy and not science. Rather than invoking unproven miracles and plastering over the issue with 'God did it', scientists seek more profound, meaningful and useful natural answers. Currently, the only reasonable explanation for the presence of abundant terrestrial 40Ar is that the Earth is ancient. Although the Sun is much larger than the Earth, silicates and 40K are more concentrated on Earth. The Sun mostly consists of hydrogen and helium, whereas the Earth has too little mass to retain large concentrations of these volatile elements.

Instead, the relatively low mass of the Earth and its relatively close proximity to the Sun has resulted in silicon, potassium, iron and other less volatile elements concentrating in it. Rather than dealing with this evidence, Austin simply states that the origin of the excess 40Ar requires 'more study'.

How Old Is the Mount St. Helens Lava Dome?

In other words, YECs need more time to invent excuses to explain how abundant 40Ar could ever form on an Earth that is supposedly only 6, to 10, year old. Woodmorappe , Swenson, and other YECs frequently accuse geochronologists of 'rationalizing away' any anomalous radiometric dates. But scientific young-Earth creationism is a special case. Geologists insist that it is just as wrongheaded as old-school blind-faith creationism, but they do so with a touch of grudging respect. It is bad because it ignores the scientific method in interpreting them.

They start with their conclusion — that God created the Earth in six days — and then look for the proof. To Mike Clynne, a stratigrapher for the U. Geological Survey — he maps volcanoes — the young-Earth creationists make another fatal error, in how they think of time and scale. The geologic record proves that Mount St.

Helens has been erupting for about , years, Clynne said in an interview. And no matter how violent the eruption may seem to us, it pales in significance compared to the awesome processes that created the geologic wonders of the world. They misunderstand radiocarbon dating. When scientists talk about a theory, they mean something far different from the everyday understanding of a guess or a supposition. The National Center for Science Education works to defeat attempts to teach creationism in the schools as internally illogical, among many other reasons.

Wryly suffering the slings and arrows Lloyd and Doris Anderson do not blink at such criticism. They know what the scientific community thinks of them: Lloyd Anderson says he honors scientists for their determination to ask questions and follow wherever the evidence leads.

St. Helens used in drive to prove biblical creation with science

For her part, Ingrid Carnine takes a rare break from corralling her sons to say the presentation reinforced her belief that children should be taught biblical creationism. For the latest from the frontiers of science, check http: The stirring on the mount St. In a young volcanic rock, such as the Mt. Helen's dacite, the calcium-rich plagioclases may have formed thousands or even a few million years ago.

Again, as a rock ages and 40Ar accumulates in both the glass and any 40K-bearing minerals, the differences in the ages of the materials becomes less significant. That is, if the glass quenched in an eruption , years after the formation of the calcium-rich plagioclases, after Bowen's Reaction Series also predicts that pyroxenes will crystallize at higher temperatures before amphiboles. Assuming that any argon contamination from Geochron's equipment hypothesis 2 is negligible, we see that the dates in Austin's table are consistent with the crystallization order in Bowen's Reaction Series.

As expected, the purest pyroxene fraction provides an older date 2. That is, IF the dates are real, the pyroxenes formed in the melt before the amphiboles as predicted by the series. Because the pyroxenes solidify before most other minerals, it's also not surprising that the 'pyroxene, etc. Depending upon the amount of zoned feldspars which consist of older calcium-rich cores and younger sodium-rich rims and the quantity of glass, amphibole and pyroxene impurities, the 'feldspar etc. On the basis of the following statements by Swenson, his gross misinterpretations of Dalrymple , and his unwillingness to respond to my earlier statements on Bowen's Reaction Series and its possible relevance to Austin's results, it is clear that Swenson does not know what Bowen's Reaction Series is and how it can affect the age distributions of minerals in very young volcanic rocks: They said that Dr Austin should have known they were old because the crystals were large and zoned.

How Old Is the Mount St. Helens Lava Dome?

However, Dr Austin's results Table 1 show that the wrong ages were not confined to one particular mineral. The idea that the age of a mineral can be anticipated by its size or colour is incorrect. Dalrymple [], for example, found that the wrong ages in his samples were unrelated to crystal size, or any other observable characteristic of the crystal. Contrary to Swenson's implications, mineral zoning is much more than a color property.

As discussed earlier, zoning and crystal growth are extremely important in understanding phenocryst ages. Based on the statements in his essays, Swenson simply assumes that excess argon is present in all of the components of the dacite and that any statements on the lack of a relationship between excess argon and crystal size in Dalrymple automatically apply to Austin's dacite.

Again, because Swenson does not provide any page numbers when referring to Dalrymple , we can only guess which sections of Dalrymple's article he is citing. The results for the Mt. Lassen plagioclase and the Mt. Etna flow, which contains a HIGH percentage of large phenocrysts, appear to support their contention.

Thus, for THESE experiments there does not appear to be any correlation of excess 40Ar with large phenocrysts or with any other petrological or petrographic parameter. Clearly, whether amphibole, pyroxene, plagioclase or other phenocrysts are effectively degassed or not during eruptions is a complex and, perhaps, unpredictable issue. Nevertheless, as discussed in Dalrymple , p. Furthermore, if excess argon is relatively abundant in older samples, Ar-Ar dating and K-Ar isochron dating can detect and eliminate its effects as examples, McDougall and Harrison, , p.

They claim that these pieces of old rock xenoliths contaminated the sample and gave the very old age. In his report, Austin refers to the presence of 'lithic inclusions' in his samples. Helens lava dome is 'lithic inclusions': Although the mineral concentrates are not pure, and all contain some glass, an argument can be made that both mafic and non-mafic minerals of the dacite contain significant 40 Ar.

The lithic inclusions in the lava dome might be thought to be the contaminant, in which case they might add "old" mafic and non-mafic minerals to the young magma. It could be argued that gabbroic clumps in the magma disaggregated as the fluidity of the magma decreased with time, thereby adding an assortment of 'old' mineral grains. These inclusions are, therefore, regarded as a unique association within the recent magmatic system. Even IF 1 Austin's summation of Heliker is absolutely accurate and no gabbro xenoliths or xenoliths of any other lithologies were present in the dacite, 2 Austin succeeded in removing all of the 'lithic inclusions' from his samples as Swenson claims, 3 no microscopic xenocrysts were hiding in this messy dacite, and 4 hypothesis 2 was not a factor, Austin would still need to specify the lifespan of the 'recent magmatic system.

Sarfati's Support of Flood Geology. Again, Figure 4 by itself illustrates that ancient phenocrysts were present in the dacite, which would invalidate Austin's dates. Although Austin failed to properly fractionate and date the minerals and glass in Mt. Helens dacite, many scientists have been able to isolate specific minerals from older volcanics and successfully date them.

Although xenocrysts and xenoliths are very common in the Peach Springs Tuff, Nielson et al. Unlike Austin, Nielson et al. Because Nielson et al. When confronted by Nielson et al. Even if excess argon is present in a sample, YECs must still explain the ultimate origin of 40Ar. The Earth's atmosphere currently contains relatively abundant concentrations of argon 0. Where did all of this argon come from if the Earth is only a few thousand years old?

In nature, 40Ar is only known to originate from the radioactive decay of 40K. Some YECs might argue that the 40Ar could have come from the decay of another, unidentified isotope s. However, this is easier to say than to prove. Any advocates of unidentified parent isotopes need to identify these isotopes, produce any evidence of their former existence, and derive the appropriate decay reactions for them.

Other YECs might simply ignore the problem by saying that God created the 40Ar out of nothing 6, to 10, years ago. Again, this is an unproven fantasy and not science. Rather than invoking unproven miracles and plastering over the issue with 'God did it', scientists seek more profound, meaningful and useful natural answers. Currently, the only reasonable explanation for the presence of abundant terrestrial 40Ar is that the Earth is ancient.

Although the Sun is much larger than the Earth, silicates and 40K are more concentrated on Earth. The Sun mostly consists of hydrogen and helium, whereas the Earth has too little mass to retain large concentrations of these volatile elements. Instead, the relatively low mass of the Earth and its relatively close proximity to the Sun has resulted in silicon, potassium, iron and other less volatile elements concentrating in it.

Rather than dealing with this evidence, Austin simply states that the origin of the excess 40Ar requires 'more study'. In other words, YECs need more time to invent excuses to explain how abundant 40Ar could ever form on an Earth that is supposedly only 6, to 10, year old. Woodmorappe , Swenson, and other YECs frequently accuse geochronologists of 'rationalizing away' any anomalous radiometric dates.

However, how is the obvious mess in Austin's Figure 4 a 'rationalization'? Why would we expect a young dacite that is full of zoned phenocrysts to give one uniform date?

References & Further Reading

How is the reality of Bowen's Reaction Series a 'rationalization'? How are the limitations of Geochron's equipment a 'rationalization'? Certainly, there are times when scientists obtain anomalous results and they can only say 'we don't know why we got these results'. These mysteries then provide new avenues for further research. Nevertheless, the bogus K-Ar results from Austin's dacite are obvious and Austin et al. Figure 4 in Austin's report, by itself, indicates that ancient zoned grains phenocrysts and perhaps some xenocrysts were common in Austin's dacite from Mt.

It's also obvious from Austin's text that he was unsuccessful in adequately separating the volcanic glass from the much older minerals. Austin should have known that if he wanted to date the AD eruption the phenocrysts needed to be entirely removed from his 'fractions' and that another method besides K-Ar dating would have been required. Furthermore, when Austin submitted his samples to Geochron Laboratories, he failed to heed warnings from the laboratory about the limitations of their equipment.

Both Austin and Swenson ignored the implications of zoned minerals and Bowen's Reaction Series on the age of the dacite. Obviously, it's Austin's improper use of the K-Ar method and not the method itself that is flawed. Rather than recognizing the flaws in Austin's essay, Swenson simply parrots Austin's erroneous claims without really understanding the chemistry and mineralogy of dacites. Swisher III; and M. Cohen, , Introduction to Logic , 9th ed.