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Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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Author | Topic: The Age of the Earth (version 3 no 1 part 1) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Lake and Marine Varve Basics First some definitions:
Rhythmites(1)
quote: Varves(2)
quote: The difference between a rhythmite and a varve is that the rhythmite can have any periodicity, even be variable, but the varve is strictly an annual layering process. Varves can vary from barely distinguishable to quite dramatic contrasting layers. One of the ways to ensure you have an annual varve system is to look for a cycle of life and death in organisms that are present in one half of the varve (growing season) but are absent in the other half of the varve (non-growing season). Seasonal markers like diatom shells and foraminifera shells have been used, forming a white layer in contrast to a dark sediment layer. This is particularly effective when the dark sediment layer is a slow settling clay that takes months to form an undisturbed sediment layer.
Synchroneity of Tropical and High-Latitude Atlantic Temperatures over the Last Glacial Termination(3)
quote: With a well marked layering system, such as is shown above, the layers can be counted, just like tree rings, to form a chronology. Not all deposits are varves or rhythmites, as there can be many deposits that occur in random sequences with no discernable pattern or regularity. For example you can get volcanic ash (tuff) deposits mixed in with varves and rhythmites, and these may be correlatable to tuffs in other places to cross-check dates. The geological principle of superposition applies to varves, rhythmites and other sedimentary deposits:
Principle of Superposition(4)
quote: Varves and rhythmites provide a means to identify different layers accurately and varves in particular can be used to provide dates for the layers. Rhythmites and other sedimentary layering do provide relative dating and other means are needed to provide actual ages. Similarly such other means for dating sediments can be used to validate and confirm a varve system. The sediments in Lake Lisan, for instance are not varves or rhythmites , and they used radiometric dating of aragonites matched with the sediment levels:
Calibration of the 14C time scale to 440 ka by 234U—230Th dating of Lake Lisan sediments (last glacial Dead Sea) (abstract)(5)
quote: As these are not annual layers we cannot use this information for determining a minimum age for the earth by annual counting (they are mentioned here because they show up in IntCal references for 14C calibration). Because varves are an annual time-sequence deposition process, a core taken in a lake with varves will have new layers on top and old layers on the bottom. As with tree rings, individual cores can be cross-checked with others taken from different locations to account for false layers or missing layers. Cores can only be taken in sections due to the physical limitations of the equipment, so cores need to be taken in a manner to overlap ends of sections to ensure continuity of the data. Like tree rings there can be floating chronologies and absolute chronologies. If an artifact in a floating chronology can be absolutely dated, then the chronology can be tethered by the artifact age. If markers in a floating chronology can be matched to markers in an absolute chronology, then the floating chronology can be tethered to the absolute chronology. Organic artifacts (leafs, twigs, insect bodies, etc) and inorganic artifacts (volcanic tuff, flood rubble, etc) can be deposited in the lake, and then be buried by later layers, so their location in the cores provides direct evidence of their age. Because the organic artifacts contain carbon that was taken up when living, they will have both 14C and 12C. As noted previously 14C decays over time, and thus the ratio of 14C/14C(1950CE) in a sample changes with age (while the 12C content remains constant) and these samples can be used as markers to tether a floating chronology to an absolute chronology (like the tree rings). Care needs to be taken in choosing core sites to avoid taking cores near inlets where false layers from storm runoff and the like would be common.
Lake Suigetsu and the 60,000 Year Varve Chronology(6)
quote:Dust and algae making alternate layers in location virtually undisturbed by flood and wind. Like tree rings there can be variation from year to year in the thickness of the varves, but unlike tree rings the older layers can become compressed by the weight of the other layers and become thin and harder to distinguish. This also means that absolute thickness at one depth cannot be simply compared to absolute thickness at a different depth to indicate climate changes, but the compression must be taken into account. Because these layers are annual they can have high precision and accuracy in the measured lengths of their chronologies, and errors should be similar to tree ring chronologies, producing high confidence in their results. There are more varve systems than the ones discussed here, but finding ones that can be anchored and extend beyond the ones used here is difficult. One well known floating varve system is the Green River varves:
Green River Formation(7)
quote: The Green River varves are a floating chronology that has not been tethered to our other layer counting systems, and the total age of the layers has only been estimated from the thicknesses, and thus it can only be used as a relative age indication. Thus, regardless of how old the Green River varves are, we know the earth is a lot older than has been counted by annual layers thus far, but this is still only the start of annual counting methods. Enjoy. References
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RAZD Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
An Introduction to Sediment Deposition Rates One of the things that affects rhythmite and varve formation is the sedimentation rates of different particles, and varves can have different layers with different size particles, some that settle faster than others:
Settling Velocity and Suspension Velocity(1)
quote: 13.6 Colloids(2)
quote: Particle Size Analysis Lab(3)
quote: Soil Colloids(4)
quote: How big are clay particles? According to the standard ISO classification ofGrain Size(5)
quote: (Note just the clay size is extracted from the table in the above link, clays are the smallest category) If we use 0.002 mm (0.0002 cm) for clay in the above formula we get = 1.62 cm/hr = 38.8 cm/day = 15.3 in/day. This is the maximum settling velocity for clay (because the velocity is related to the square of the diameter, a clay particle half that diameter (0.001 mm) would settle at 1/4th that speed, or 3.8 in/day or slower due to colloidal interactions). As you can see the theoretical settling velocity of clay according to Stoke's Law would be very, very slow. In a 100 ft deep lake a new clay particle deposited at the surface and settling at maximum velocity would theoretically take ~80 days to reach the bottom. Actual times are significantly longer however, due to the interaction of charged clay particles with water, and because the clay particles are not spherical, but it would take days if not weeks or months for new clay from rainstorms to settle to the bottom. This is especially true in the center of the lake as the new inflow must take time to mix with the lake water and get dispersed sufficiently to reach the center area. This means that a lake can act as a buffer to average out all the clay sediment being introduced to the lake by the inflow: even large variations in inflow will have little effect on the amount of clay settling to the bottom at the center of the lake. This means that clay layers in varves are strong indicators of annual events, as they have to occur over many months with no other depositions, like diatom or foraminifera shells, or disturbances of the water. These shell deposits can even peak several times in the growing months and not affect the varve layering. Enjoy. References
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RAZD Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Cariaco Basin Varves Off the coast of Venezuela are a series of varved deposits that form annual layers of foraminifera shells and soil runoff (sediment) from a river tributary to the basin. The layers are similar to tree rings in being annual and having different thicknesses due to climate factors that influence the growth of the foraminifera algae and the runoff sediment from the river The Cariaco basin varves have been used to make a floating marine varve chronology, with foraminifera tests alternating with sediments in a strongly discernible annual deposition pattern. These sediments were used in developing calibration curves for IntCal98 and IntCal04:
IntCal04 Terrestrial Radiocarbon Age Calibration, 0-26 CAL KYR BP(1)
quote: Not much about the varves, but we can look at the 2000 paper referenced for more information:
Synchronous radiocarbon and climate shifts during the last deglaciation (full PDF) or view on-line (with free sign-in)(2)
quote: Again we see a remarkable consilience between the dendrochonology data and the varve data. The "reservoir age" correction mentioned above was discussed in Message 17, Wiggle-matching 14C levels to Anchored Dendrochronologies, If the reservoir effect is constant in time then this just results in a horizontal shift of the data to younger ages (average 400 years), and the actual amount is incorporated into the wiggle-matching of the varve data to the dendrochronological data. The high consilience between the two independent sets of data also show that the reservoir effect did not change significantly during the overlap period. This study was done in 2000 CE, and thus it did not incorporate the 41 year correction in the oak chronology and it uses the old wiggle matched location for the German pine chronology. The error in the wiggle matching of the pine to the oak chronologies is now reduce, so this total error of +/-30 years overestimates the error at the end of the chronolgy. Note that the data points generally rise from left to right with increasing age due to the decreasing amounts of 14C in the samples as it decays. Thus we still do not need to know the decay rate or whether it is constant or changing, we just observe the values that occur in the samples. All we need are the 14C levels to compare to add to the correlation of 14C levels with calendar age derived from the annual layers of trees and lake varves. This general rising of the data points means that a false correlation of the varves to the tree rings would be quite evident, and the only issue is how accurate and precise is the best fit of the Cariaco varves to the German pine tree rings: and any shift in the tree chronology only moves the Cariaco varves horizontally by a fixed offset. Likewise any error that occurred in placement of the wiggle patterns would be shift of the whole varve pattern by a year or so horizontally. The estimated fixed error of +/-30 years would apply to each point, and this error becomes less relevant the older we get in terms of percentage age error. The chronology was in fact updated in 2004 with improved matches to the dendrochronologies and some revisions and additions to the varve chronology, and the wiggle match was updated as well:
Cariaco Basin calibration update: revisions to calendar and 14C chronologies for core(3)
quote: This chronology runs from 10,490 BP to 14,673 BP (last data point in data table 1 - see link for table), and is tethered to the German pine chronology (see Message 16, Anchoring The Floating German Pine Chronology) from 10,490 BP to 12,410 BP, or an overlap of 1,920 years with 375 data points listed, and the overall maximum error from the modern end of the European oak chronology in 2002 to the ancient end of the Cariaco Basin in varve chronology is +/-30 years in 14,673years of combined annual records, an error of +/-0.2%. The fact that this chronology matches the combined oak and pine dendrochronology so exactly means that the reservoir effect (see Message 17, Wiggle-matching 14C levels to Anchored Dendrochronologies) stayed very constant during the period of overlap. This, and the fact that all these varves were not disturbed by any major ocean level changes or current patterns or deep water upwelling, means there was no world wide flood in this time. The length of the overlap and number of data points shows a very high degree of consilience that gives us very high confidence in the accuracy and precision of the combined chronology: these two measuring systems are entirely different, unlike previous comparisons between dendrochronologies, and there is no rational reason for such consilience unless they were measuring the same thing: age. Remember: The challenge for old age deniers (especially young earth proponents) is to explain why the same basic results occur from different measurement systems if they are not measuring actual age? This extends our knowledge of the age of the earth based on annual counting mechanisms from 12,410 BP (10,461 BCE) to 14,673 BP or 12,724 BCE, another 2,263 years with high accuracy and precision.
The earth is at least 14,740 years old (2017) The minimum age for the earth is now at least 14,740 years old (2017), based on the highly accurate and precise German oak dendrochronology extending back to 12,724 BCE. This also means that there was no major catastrophic event that would have disturbed the deposition of any of the varve layers, organic or sedimentary -- ie no catastrophic flood occurred in this time that would have buried these ocean varves, or swept them away (depending on which fantasy flood behavior you choose). This is significantly older than many YEC models (6,000 years for those using Archbishop Usher's assumption filled calculations of a starting date of 4004 BCE), as this chronology extends to 12,724 BCE. This also begins to be a problem for the type of "Gap Creationism" where the earth is old but life is young ... because trees are living things. Enjoy. References
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RAZD Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Lake Suigetsu Varves The varves in Lake Suigetsu are similar to the ones in Cariaco basin, with alternating layers of diatoms and clay in an annual deposition pattern instead of foraminifera and river sediment. Unlike Cariaco Basin, however, this is a fresh water system and the organic samples for 14C measurements (leaves and twigs) have terrestrial\atmospheric origin and do not require a correction for any marine reservoir effect. This is also a floating chronology that is tethered to the Combined European Oak and German Pine chronology in Message 16, Anchoring The Floating German Pine Chronology by wiggle matching. The data from the lake does not have accurate information on the present, due to changes in the lake that disrupted the chronological deposition process (now connected by canal to another lake). They were able to tether this chronology to the European oak and German pine chronology using 14C/14C(1950CE) levels from organic artifacts found with the cores. This resulted in high correlation for the overlap period between 8,830 BP and 11,550 BP, making this a floating chronology that is now tethered by matching 14C/14C(1950CE) levels. BP refers to 'Before Present' which is defined as 1950 CE, which is why the standard amount for the calculation is the 14C(1950CE) level. The fast settling diatom shells (which settle to the bottom in days) and the slow settling clay particles (that can take months to settle) ensure that these layers are annual. Only during fall and winter months, after the diatoms have died, is there sufficient time to form a discernible clay layer.
A 40,000-year varve chronology from Lake Suigetsu, Japan: extension of the 14C calibration curve(1)
quote: The Lake Suigetsu varve chronology was included in the IntCal98 study, but was dropped for IntCal04 due to the problems that had been identified. With new and additional core data and corrections to the 1998 data (see below for details) they were reinstated in IntCal13:
IntCal13 and Marine13 Radiocarbon Age Calibration Curves, 0 - 50,000 Years Cal BP(2)
quote: This serves as high validation of the varves, as the criteria and review process that goes into the IntCal calibrations are very strict compared to standard scientific peer review processes. Lake Suigetsu was re-cored in the summer of 2006 to resolve the issues that had been raised since the first core study:
Integration of Old and New Lake Suigetsu 14C Data Sets PDF(3)
quote: A new wiggle-match to the updated oak and pine chronology was made, and the original samples were not used, so this is an independent tethering of the chronology to the dendrochronologies. The original earliest (most ancient) counted varve was 37,930 cal yr BP (before 1950), and this has been corrected to be 39,523 +/- 98 BP, a correction to 1,593 years older, the error (+/-98 years) is 0.25%, and the varve count has now been extended to 42,098 BP (before 1950). This new study correlates with and confirms that the old study was within 4% of the new study data. They were able to use the old data together with the new data to form a combined chronology. This is mostly due to higher precision and accuracy in the varve counting in the new study. They also were able to count some more recent layers than before, and with the extension of the German Oak and Pine chronology this has increased the length of the overlap making the tethering of the varve chronology even more accurate. The current counted annual varves run for a time period of 35,075 years (from 7,023 BP to 42,098 BP if dates are correctly aligned with the tree chronology), and this alone is several times older than any YEC model for the age of the earth. The varve layers continue down below the limits of C-14 dating to ~100,000 years, with some assumptions made below the 42,098 BP cal yr BP level (the data below this level does not use annual varve layers but an estimated rate of sedimentation). Those estimated dates cannot be used for our minimum annual layer counts other than to say that the earth is older than the annual varves show. Thus either of these two scenarios must apply:
Note that this extends annual chronological dating to the archaeological dates found by 14C dating for the cave paintings at Lasceaux and Chauvet that can now be correlated to the varve ages by matching their actual 14C levels. The archaeological record shows that an early nomadic cave using civilization that involved stone tools, burial ceremonies and undeniably impressive artwork at the Lasceaux Caves in southern France around 15,000 to 13,000 BCE, (what is known as the late Aurignacian period) or 17000 years ago, and at a cave near Chauvet (south-central France) around 30,340 and 32,410 years ago. We have now verified a chronological age for these artifacts, and we have hardly begun to get into the age of Homo sapiens, the hominid ancestors of man, the age of life on the earth or even the actual ancient age of the earth. Note further that the layers extend back to 100,000 years ago but that this research only concentrated on the last 45,000 years to calibrate C-14 dating. Using only the counted varves this chronology extends back to 42,098 years BP (before 1950). However, this is one single source of information, and the multiple cores increase our confidence that they represent the varve layers in the lake, but there still could be multiple diatom layers and there still could be missing diatom layers, errors that could exist across the whole lake. Thus we can say that the varves are highly precise counting of layers, and that the match between the independent cores indicates good accuracy. This will be discussed in more detail in Message 22, Varve Accuracy and Precision (next).
The earth is at least 42,165 years old (2017) The minimum age for the earth is now tentatively at least 42,165 years old (2017), based on the accurate and highly precise Lake Suigetsu varve floating chronology tethered to the European oak and German pine anchored chronology extending back to 40,149 BCE. This also means that there was no major catastrophic event that would have buried these layers -- ie no catastrophic flood occurred in this time. This is ~7 times older than many YEC models (~6,000 years for those using Archbishop Usher's assumption filled calculations of a starting date of 4004 BCE), as this chronology extends to 40,149 BCE. This also begins to be a problem for the type of "Gap Creationism" where the earth is old but life is young ... because leaves and twigs from trees are from things living at that time. Enjoy. References
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RAZD Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Varve Accuracy and Precision Similar in effect to tree-ring chronologies, errors in the varve chronologies can occur through uncounted thin or missing varves and counting of extra varves that are not annual depositions, each causing minor errors if they are infrequent occurrences. Like tree-ring chronologies there are ways to identify and correct most of these errors. Cross checking with other cores ensures that the count accurately reflects the number of varves, but cannot check for errors across the whole area. For that you need an independent check. Both the Message 20, Cariaco Basin Varves, and the Message 21, Lake Suigetsu Varves, have been updated, adjusted and corrected for such errors, improving the precision and accuracy of these systems. Thus far we have two floating varve systems, and each can be: (A) Compared to Other Varve Systems — Lake Steele Varves from Steel Lake, in Minnesota cover the last 4,000 years and thus overlap the most recent highly precise and accurate tree ring data, and this can be used to verify the varve counting methodology:
Christian Geologists on Noah's Flood: Biblical and Scientific Shortcomings of Flood Geology(1)
quote: Note that this is NOT a 14C age calibration curve, it is a plot of the natural log of actual measured modern day 14C/14C(1950CE) levels vs annual calendar values from tree rings and lake varves, and this plot does not depend in any way on the half-life of 14C -- it just uses the ln(14C measured) for levels measured today. Note further that there is a discussion of the original Lake Suigetsu varve research at Answers in Genesis: Lake Varves(2)
quote: This recognizes that the consilience in the data from different sources gives high confidence in the results. As seen in Message 21, Lake Suigetsu Varves also matched the tree ring chronology with high precision and accuracy. This shows that 14C measurement levels from lakes correlate with tree rings with no apparent effect of time, depth and water saturation on the 14C measurements (as one should expect if they both measure actual age and actual 14C content). Unfortunately it only extends ~4,000 years from the present, and thus does not add to our knowledge for the minimal age of the earth. (B) To a Second Independent Core Set of the Varves Taken from a Different Location Just as two independent dendrochronologies of the same species were compared to cross-check the dendrochronological data, two independent sets of varve cores from the same source can be compared to cross-check the varve data. As noted in Message 20, Cariaco Basin Varves, this was done in 2004, at higher resolution of the layers, and the result was a shifting of the more ancient layers to older ages. The Blling period grew by 25%, from 634 to 790 years long, and the transition to the Younger Dryas lengthened by 33%, from 150 to 200 years. The German pine chronology update resulted in shifting the whole chronology to ~85 years younger. And as noted in Message 21, Lake Suigetsu Varves, this was done in 2006, at higher resolution of the layers, and the result was an extension with some later varves being counted (to 7,023 BP or 5073 BCE) and some shifting to older ages (1,593 layers in all were added), as very thin varves were counted that had been missed (or ignored previously), and some alignment errors were corrected, and the chronology was exteded to 42,098 BP (40,148 BCE). Note that 1,593 years in the 37,930 years of the original chronology is still an error of only 4.2%, so the original chronology still had fairly good accuracy and precision. The new Suigetsu varve chronology was independently wiggle-matched to the updated oak and pine dendrochronology using only 14C level measurements from the new cores. This was discussed in:
The multiple chronological techniques applied to the Lake Suigetsu (SG06) sediment core (PDF)(3)
quote: Thus the accuracy and precision of this wiggle-match tethering point is (A) 11,242 BP +/- 33 years in the center 95.4% (+/-2σ) of the probability distribution (between 11 275 and 11 209 BP) and (B) 11,238.5 BP +/- 16.5 years in the center 68.2% (+/-1σ) of the probability distribution (between 11,255 and 11,222 BP) ... or ~11,240 BP +/-17 years. Also note that they were able to align the original core sections with the new ones to correct their placement. This is similar to the adding of zero width tree-rings in the second Bristlecone pine chronology, (see Message 8, Bristlecone Pines Chronologies), and that when these adjustments were made then they both agreed for the sections between the corrections, such as volcanic ash and pollen depositions. This demonstrates the active updating of scientific information as new information becomes available. Scientists are able to find errors or missed varves when they look at the original information in finer detail and readily adjust the results to account for new information and data. This feed-back process improves the precision and accuracy in the most current results. (C) Compared to Each Other by 14C Amounts As we saw in Message 15, Comparing European Oak and Bristlecone Pine Chronologies by 14C Levels, the levels of 14C in samples declines over time due to radioactive decay, but to match one chronology to another doesn't rely on the rate of decay -- it doesn't matter what the decay rate of 14C is, or whether the rate varies or even if the ratio in the atmosphere varied over time -- samples from the same age start with the same level of 14C/14C(1950CE), and the 14C in each will decay by the same amount year by year, and they will end up with the same level today. Thus comparing the actual measured levels is a legitimate comparison, and any consilience in the data increases our overall confidence that these correlations are accurate and precise. We can compare two 14C tethered varve chronologies to see if they reflect similar values beyond the tethering period or whether they diverge. This is similar to the way dendrochronologies are built from different tree samples (using ring widths, as was used to tether the German pine chronology to the German oak chronology before it was anchored dendrochronologically), but there is less likelihood to place the sample in the wrong location due to the declining 14C as it decays over time. Both the Message 20, Cariaco Basin Varves, and the Message 21, Lake Suigetsu Varves were wiggle-matched to the same Combined Oak and Pine chronology (see Message 16, Anchoring The Floating German Pine Chronology), and that means we can compare them beyond the tethering overlap to see whether they diverge, or match, over their length of overlap. The matches are not always identical from one to the other, due in part to small natural variation and in part to (small) measurement errors, but they should be relatively close, and with a long enough overlap we can make a best fit compare results with a high degree of confidence. Unless there is a significant difference, any match-up error from wiggle-matching their starting points would result in a possible shift of a few years older or younger for the absolute counting rather than a whole-sale change. This error would be the same Δ for any date on the tethered chronology, and become less critical with age (the % error declines as age increases). We also saw in Message 20, Cariaco Basin Varves, and in Message 21, Lake Suigetsu Varves, that these matches were pretty strong:
quote: The one for Cariaco Basin on the left shows very fine detail of the match-up, a level of detail that would be astounding if it were due to random variation in either chronology's correlation to 14C levels. The one for Lake Suigetsu on the right is at a larger scale and has fewer data points for the overlap, so it is not as strong a correlation as the Cariaco Basin varves. Unfortunately it is from the 1998 data and not the updated, corrected and extended 2006 data. There does not seem to be a good one-on-one comparison graph of the updated Cariaco Basin varves to the updated Lake Suigetsu varves. This one also uses the original Lake Suigetsu data:
Radiocarbon calibration curve spanning 0 to 50,000 years BP based on paired 230Th/ 234U/ 238U and 14C dates on pristine corals,PDF(4)
quote: It is a little difficult to pick out the Lake Suigestsu varves ( Δ ) and the Cariaco varves ( • ) in this graph, especially when they combine Cariaco non-varve dates with the varve dates (the other data is from other non-annual counting systems, so we can't include them here other than to show that these other systems do derive similar data to the annual varves, a consilience that should only occur if true age is being measured by all these different systems). The Cariaco Basin varves only extend to 14,673 BP or 12,724 BCE (Message 20, Cariaco Basin Varves), so we can only compare them that far for out annual counting systems. There appears to be about 400 to 500 years difference between these data sets (with the uncorrected data for Suigetsu varves) an error of 3% in the last 14,740 years (2017). This shows good accuracy and precision for the updated Cariaco Basin varves and the updated Lake Suigetsu varves, but it doesn't get us to the earliest Lake Suigetsu varves. (D) To Volcanic Eruptions Similar to the way tree-ring chronologies could be linked to historical events through frost-rings caused by known volcanic eruptions (Message 14, Accuracy and Precision in Dendrochronologies Compared to Historical Events), varves can be linked to volcanic eruptions through the deposition of ash layers in the varves. Unfortunately, history does not record events this far back in time, and so these ash layers will have to be dated by other means. This introduces a measure of error in these cross-checks. in Message 21, Lake Suigetsu Varves, it was noted that the ages determined for some of the ash layers were concordant with the ages from testing at another site. While not a precise check this certainly shows that they are in the right ball-park. Another volcano tephra layer in Lake Suigetsu has now been linked to a Korean volcano:
The multiple chronological techniques applied to the Lake Suigetsu (SG06) sediment core (PDF)(3)(again) quote: Thus this tephra is dated to 10,000 BP +/-300 years by 40Ar/39Ar and to 10,216 BP +/-17 years (between 10 231 and 10 202 BP at the center +/-1σ of the probability distribution). Again, in the right ball-park and confirming the accuracy and precision of not only the Lake Suigetsu varve tethering, but also the dendrochronology it is tethered to.
Conclusion Varve counting is well developed as a discipline that has developed the methodology necessary to match different varves in the same and different locations with a high accuracy and precision for a continuous chronology. Two such chronologies agree with over 97% accuracy back to 14,673 BP or 12,723 BCE. The longest chronology extends back to 42,098 years BP - before 1950 - or 40,148 BCE. Remember: The challenge for old age deniers (especially young earth proponents) is to explain the consilience in all this data: why the same basic results occur from different measurement systems if they are not measuring actual age? Enjoy. References
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RAZD Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Radiocarbon Dating and Corrections Radiocarbon dating (14C dating) uses the decay of the radioactive isotope 14C:
Carbon-14(1)
quote: Note that water is not affected by 14C in any way different from 12C and 13C, nor does the environment affect them in any way other than normal chemical reactions involving carbon. There is no physical system to "sort" 14C that is any different than other carbon atoms.
The 14C Method(2)
quote: There is a lightly fluctuating equilibrium of 14C concentrations in the atmosphere around a long term average.
How Carbon-14 is Made(3)
quote: This takes energy to accomplish, and the decay releases this energy: Carbon-14 decays back to Nitrogen-14 by beta- decay:
Beta Decay(4)
quote: Thus cosmic ray activity produces a "Carbon-14 environment" in the atmosphere, where Carbon-14 is being constantly produced or replenished by cosmic rays, while also being removed by radioactive decay due to a short half-life. This results is a variable but fairly stable proportion of atmospheric Carbon-14 for absorption from the atmosphere by plants during photosynthesis in the proportions of C-12 and C-14 existing in the atmosphere at the time, and then by herbivores and then carnivores and then biological decay bacteria, etc. The level of Carbon-14 has not been constant in the past, as it is known to vary with the amount of cosmic ray bombardment and climate changes. Carbon-14 has a half-life of 5730 years and this can be used to calculate an apparent "C-14 age" from the proportion of C-14 to C-14(1950CE) in an organic sample (that derives its carbon from the atmosphere) and this "date" can be checked against samples of known dates to determine the amount of C-14 that was in the atmosphere. This has been done for all the annual counting methods covered so far, and this has resulted in a calibration curve:
Radiocarbon Dating(5)
quote: Note that the "C-14 age" is really a measurement of the actual ratio of C-14 to the 1950 reference amount in the sample using the "Libby half-life" of 5568 years (rather than the actual half-life of 5730 years), and a comparison of that to modern day proportions.
Dating a Fossil(6)
quote: and where (-0.693) = ln (1/2). This means we can look at the "C-14 age" as a measurement of the Carbon-14 actually remaining in the samples from what was absorbed from the atmosphere at the time that the tree-rings, varve biological samples, etc were formed and note the following:
Using the calibration curve to correct the calculated age takes care of both the atmospheric variations and the difference caused by using the "Libby half-life" as this represents a physical proportion of 14C/14C(1950CE) existing in the samples at the time of testing them. This calibration makes the resulting ages as accurate and precise as the annual age counts and the accuracy and precision of the 14C measurements.
Age Calculation(7)
quote: Note that 5568 is the "Libby half-life" for 14C that was used in the first calculations of "14C-age," and this has been adopted as the standard to avoid correcting this twice when making calibrations and obtaining calibrated dates. The value of Aon is constant, established so that the measured 14C calculation will start at 1950: Aon = Asn(1950 14C). Thus the above formula could be reduced to 14C'age' = Kln(14C level measured) by combining all the constant values into K, or we can simply calculate Asn as a percentage of Aon:
Asn/Aon % = 100e^(-t/8033) where -8033 = 5568/ln(1/2) to convert to natural logs. This is the mathematical basis for radiocarbon dating calculations. It is a purely mathematical conversion of the measured 14C/14C(1950CE) levels to the theoretical age based on the decay half-life of 5568 years.
Marine varves and the reservoir effect One known source of error for marine varves is the marine reservoir effect. Up until now we have dealt with terrestrial organic samples for 14C/14C< levels obtaining carbon from the atmosphere reservoir, where 14C is created from 14N by cosmic rays (inflow) and is removed by decay, by consumption into organic life and by absorption into the oceans (outflow). Similarly the marine reservoir has inflow from the atmosphere, and outflow via decay, consumption and deposition (sediments).
Corrections to radiocarbon dates(8)
quote: The database is fun to play around with, looking at the variation around the globe. It is also pertinent to note that Creationists have tried to use the (and other known) reservoir effects to discredit 14C dating by intentionally not correcting samples they have had tested that are subject to this effect:
A freshly killed seal was carbon-14 dated at 1300 years old(9):
quote: You can check the reservoir effect for McMurdo Sound with the on-line database. The Lake Suigetsu organic samples, leaves, twigs, etc., have atmospheric carbon origin and thus are not affected by the reservoir effect. The amount of variation in this correction makes it important to have reservoir correction data for the area being studied, and to have an idea of how those reservoir effects have changed over time. This was discussed in relation to the Cariaco Basin varves:
Cariaco Basin calibration update: revisions to calendar and 14C chronologies for core PL07-58PC(10)
quote: So two things to note here: (1) there is a floating dendrochronology that could become tethered to the German pine chronology and extend the dendrochronologies age measurements further into the past, and (2) that the older Cariaco varve 14C/14C(1950CE) correlations need to be corrected by a larger marine reservoir. This uncertainty in the marine reservoir effect means that differences between the Lake Suigetsu varves and the Cariaco Basin varves are partly due to adjustments in the reservoir effect. Note, however, that the effect of a 200 year shift in the 14C 'age' at 14,000 BP is an error of 1.4%, so the consilience between the two varve systems is still robust even without additional corrections. One needs to explain the precise and accurate correlations of these data sets from several independent sources of data (German pine, two sets of Lake Suigetsu varves, two sets of Cariaco varves and 14C levels) with an actual mechanism that would cause these precise and accurate matches if one continues to contend that they are not due to measuring the actual age of the samples. Enjoy. References
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RAZD Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Summary of Part 1 - Biological Counting Systems In this first part we saw how dendrochronologies were assembled (Message 7), compared (Message 13 and Message 15), and then integrated into a single Combined Dendrochronology, using Bristlecone Pines (Message 8), Irish Oaks (Message 10), German Oaks (Message 11), and German Pines (Message 16), that extended back to 10,461 BCE, showing that the earth is at least 12,477 years old (in 2017), based on the highly precise and accurate data (error < 1%). Then we saw how the naturally occurring wiggle pattern of atmposheric 14C levels in organic samples (tree rings and organic debris embedded in annual varves) was used to tether and connect floating chronologies to the anchored Combined Dendrochronology, how possible errors in this tethering only shift the data horizontally so the accumulated error by the end of the tether chronologies is again in the 1% range. Not only did this tethering of the Cariaco Basin Varves (Message 20) and the Lake Suigetsu Varves (Message 21) extend the overall chronology back to 40,149 BCE, showing that the earth is at least 42,021 years old (in 2017) based on accurate and precise data (±3% possible error), but it also showed there was no world wide flood during this time, as these counting systems would have been disrupted by it -- wood would have floated off and varves would have shown an entirely different pattern. The data also shows changes in climate patterns (tree ring and varve thicknesses etc), and this will be discussed more in Part 2. In addition, this data validates that 14C was indeed decaying exponentially during this time, that the difference between measured age 14C and 14C calculated age was explained by the wiggle pattern observed in 14C production by cosmic rays that we see today. Thus there was no massive alteration in physics that would have caused any significant change to radioactive decay rates. This too will be discussed more in Part 2. This ends Part 1 -- the biological counting systems, using annual tree rings, and foraminifera layers and diatom layers in annual varves. Part 2 will involve physical\chemical counting systems, where the layers are identified by physical\chemical changes from summer to winter. Enjoy Note that I have restructured the whole thread to ensure links are correct and to break some posts into two posts for clarity and focus. Edited by RAZD, : . Edited by RAZD, : ..by our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
You will note a long list of edits on these posts, most of it is due to correcting misformating and to restructuring the thread, but the significant one is due to moving the site of pictures to a dedicated folder.
IF you see this
The age measurement pictures can be fixed by changinghttp://i862.photobucket.com/albums/ab184/RAZD/AM... to http://i862.photobucket.com/...RAZD/Age_of_the_Earth/V3-1/AM... This is across the board for a lot of my thread picture sources, so if you find a broken link let me know and I will see about fixing it (unless in a closed thread). Such as skeleton and skull pictures in The story of Bones and Dogs and Humans, changinghttp://i862.photobucket.com/albums/ab184/RAZD/... to http://i862.photobucket.com/...184/RAZD/Skeletons_and_Skulls... and Evolution pictures and diagrams in Introduction to Evolution, changinghttp://i862.photobucket.com/albums/ab184/RAZD/... to http://i862.photobucket.com/albums/ab184/RAZD/Evolution/... I have fixed the thread, but many of those pictures have been used in other posts on other threads, so they will crop up. Update: I have now put the pictures on Imgur instead of Photobucket. Enjoy Edited by RAZD, : . Edited by RAZD, : . Edited by RAZD, : ... Edited by RAZD, : No reason given.by our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1794 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Age of the Earth |
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Message 28 of 29 (827374)
01-23-2018 11:19 AM |
Reply to: Message 27 by RAZD 07-14-2017 6:53 AM |
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