Ice Core Dating | le-reiki.info
Ice core clamour Anti-creationist 'Infinity' objected to the YouTube video clip What Why is there no evidence of a flood in tree ring dating?. Do they cause a problem for the recent-creation model of earth history? . " Dating of Greenland ice cores by flow models, isotopes, volcanic debris, and. How far into the past can ice-core records go? as far back as million years, almost twice as old as the oldest ice core drilled to date.
Please go to the link provided in the post above this for the charts.
Creation: Why the Earth Isn’t Young
Greenhouse Gases The snow near the surface of the ice sheet is like a sponge with channels of air between the snow grains. As more and more snow is accumulated on top, the underlying snow is compressed into ice and the air forms bubbles in the ice. Ice cores therefore can be analysed not just for the chemical and physical properties of the ice, but also for the properties of the air trapped in the ice.
These bubbles are actual samples of the atmosphere up to thousands of years ago. So, analysis of them can tell us much about the atmosphere in the past. Concentrations of carbon dioxide and methane measured in the air bubbles trapped in the ice are shown in Figure 2 along with temperature and dust graphs.
Carbon dioxide and methane are greenhouse gases and the similarity between the graphs for their concentrations and the temperature change graph indicates that the greenhouse effect is real and that it has been around for many thousands of years. That is only if you are presuming many thousands of years.
Creation: Why the Earth Isn’t Young – The Return of Benjamin
I studied that chart for some time. What I saw corresponds to the idea that a post flood ice age would have less dust due to winds because everything was wet. But then you have that period in between ice ages where you see a rise in carbon dioxide as the plant life on earth was re-established and thrived.
This corresponds with the rapid rise in temperature which melted the ice. Now, keep in mind that we are ONLY talking about the one pole here -- the south one. These measurements do NOT tell us what the rest of the world was like at the time. As we move to the left in graph two, or toward the present, there is a sudden rise in the dust factor.
This would easily result from volcanism and the changes in relative air temperatures, and even changes in relative areas of sea temperatures, around the world. The would cause the massive winds that seek to equalize the temperatures. More dust at a time of increasing cold and the rapid onset of a much worse ice age. Then, to the far left of the graph, a rapid rise in temperature again as the dust settles down and the temperatures and thus the pressures have also settled.
The earth warms again and the ices melt, leaving what is left on the poles. You see, if one does not presume long ages, many rapid storms in a time of fluctuating temperatures and world upheaval can account for what we see in that graph. Has there been a significant increase in the atmospheric concentration of greenhouse gases since the industrial revolution? The answer is yes, as can be seen from Figure 3 which shows the concentrations of carbon dioxide in the atmosphere, measured in the bubbles from an Antarctic ice core from Law Dome near Australia's Casey Station.
The concentration of carbon dioxide has increased from about parts per million to parts per million, which is a rise of 25 per cent since the middle of last century. Nitrous oxide and other greenhouse gases also show similar trends from analysis of the ice-core bubbles.
The Law Dome ice core is at a location where the snow accumulation is much higher than at Vostok. Thus, the time scale for the Law Dome core is expanded and it can provide us with more detailed information about recent climate changes, though it can not go back in time as far as the deeper Vostok ice core.
It has already been seen that the delta value is related to air temperature when the snow was deposited. Because it is warmer in summer and cooler in winter, and provided the snow layers are not too disturbed by wind, the delta value can show annual cycles.
Thus, these values can be used to date the ice core. Hydrogen peroxide is created in the atmosphere by a chemical reaction that requires ultraviolet light. There is a lot less ultraviolet light in the winter than in the summer in Antarctica. Thus, measurements of hydrogen peroxide dissolved in the ice also provide a good annual cycle indicator.
Therefore the pattern is upset from the outset. Secondly, it is presumed that the variations in temperatures are correlative to summer and winter variations. However this does not necessarily have to be the case. Uniformitarian gradualism is a presumption which rests on a shaky foundation here simply because of the presence of the varying amount of dust if nothing else!
The only thing indicating "annual" cycles in the ice core is the presumption of the person interpreting the data. In order to date the ice cores accurately, the annual layers need to be thick enough to obtain about ten measurement samples from each year. The thickness of the annual layers depends on how much snow falls each year. Thus, to obtain an ice core from which accurate, detailed dating can be derived, we need to find an Antarctic site where the snow accumulation is relatively high.
Which could also mean it got blown there in snowdrifts during windstorms. This would usually mean we need to find a low elevation site, but it must also be a site where there is no melt. If the snow was to melt at any time during the year, some measurements such as those involving trapped gases would be spoiled.
In addition, the annual layers would be destroyed by the melt water which would, effectively, wash the evidence away. And the only way they have of estimating melt rate is to take what we have today and presume it has been that way for a very long time.
This kind of gradualism presumes no catastrophes, no bolide hits, nothing to disturb the quiet ebb an flow of the seasons. I do not think this is a reasonable presumption when the rest of the world is looked at and the evidence for catastrophes of various kinds is so clear. Such locations high snow accumulation, yet low summer temperatures are not easy to find.
One such location, however, is near the summit of Law Dome, approximately kilometres from Casey Station, where an ice core has been drilled 1, metres through the ice sheet to the underlying bedrock. Accurate dating for this core has been obtained back to 8, years ago using annual cycles obtained by analysis of delta value and hydrogen peroxide. A section of the graph of delta value and hydrogen peroxide is shown in Figure 4, along with the year.
Ice Core Dating
The ice core depth for this section is to metres, corresponding to the dates to AD. Detailed analysis of section of the DSS ice core summit of Law Dome, Antarctica showing del value, Peroxide concentration, Sulphate concentration and Conductivity values.
Section of ice core is from to metres depth, covering the time period toand including evidence of two volcanic eruptions. I am curious to know the sulfate measurements for core depths that are dated thousands of years ago Volcanic Horizons Measurements of electrical conductivity are also made on the ice cores - these are closely linked to the acidity of the ice.
Conductivity shows an annual cycle and is higher in the summer snow than the winter snow. This is probably because of chemical reactions in the atmosphere involving dimethyl sulphide a chemical produced in greater quantities during the summer months by marine algae and phytoplanktonwhich result in production of low concentrations of sulphuric acid which is then distributed over the ice sheet.
Sulphuric acid is often blasted into the atmosphere by volcanic eruptions. Therefore, the conductivity in the ice cores sometimes shows a peak at the depth corresponding to the time shortly after a volcanic eruption. I am not criticizing the hesitancy in attributing the effect to a particular cause in the first sentences of this paragraph. But I do think it should be noted. A more reliable method of detecting volcanic eruptions from the ice cores however, is to measure sulphate directly.
Sulphate also exists in sea salt which is deposited on the ice sheet in small quantities from wind-blown sea spray. Thus, to examine the sulphate derived from volcanoes, the sea-salt sulphate needs first to be accounted for. This can be easily done by measuring the quantities of other chemicals of marine origin.
On Figure 4, along with the accurate dating of the ice core from delta value and hydrogen peroxide, plots of conductivity and non-sea-salt Sulphate are also included. The conductivity graph does indicate annual cycles, but more interesting are the large peaks in this and in the sulphate graphs, which occur at about and between about and AD.
The peak is due to the eruption in of Tambora, a volcano in Indonesia. The peak in about certainly seems to be due to another volcanic eruption, but none is known to have occurred around then.
Volcanic eruptions are useful to glaciologists as a check on the other ice core dating techniques. On the other hand, there are previously unknown volcanic eruptions have been discovered from the evidence from the ice cores. For me, this article ended much too soon. If you know of more data and other articles online, please let me know. I'll do some checking myself.
The Vostok Ice-Core A. How It Was Collected B. Minimum Age of the Earth B. Methods of Dating Ice Cores Of the four distinct methods for determining the ages of ice cores, the first three are direct experimental tests and the fourth rests on somewhat uncertain theories. Counting of Annual Layers The basis of this method lies with looking for items that vary with the seasons in a consistent manner.
Of these are items that depend on the temperature colder in the winter and warmer in the summer and solar irradience less irradience in winter and more in summer.
Once such markers of seasonal variations are found, they can be used to find the number of years that the ice-core accumulated over. This process is analagous to the counting of tree rings.
Ice Core Dating
A major disadvantage of these types of dating is that they are extremely time consuming. Temperature Dependent Of the temperature dependent markers the most important is the ratio of 18O to 16O. The water molecules composed of H2 18O evaporate less rapidly and condense more readily then water molecules composed of H2 16O.
Thus, water evaporating from the ocean it starts off H2 18O poor. As the water vapor travels towards the poles it becomes increasingly poorer in H2 18O since the heavier molecules tend to precipitate out first.
This depletion is a temperature dependent process so in winter the precipitation is more enriched in H2 16O than is the case in the summer. Thus, each annual layer starts 18O rich, becomes 18O poor, and ends up 18O rich.
This process also depends on the relative temperatures of different years, which allows comparison with paleoclimatic data. For similar reasons the ratio of deuterium to hydrogen acts the same way.
The major disadvantage of this dating method is that isotopes tend to diffuse as time proceeds.
Irradiation Dependent Markers Of the irradiation dependent markers the two most important are 10Be and 36Cl. Both of these isotopes are produced by cosmic rays and solar irradiation impinging on the upper atmosphere, and both are quickly washed from the atmosphere by precipitation. By comparing the ratios of these isotopes to their nonradioactive counterparts i.
Thus each annual layer starts 10Be and 36Cl poor, becomes 10Be and 36Cl rich, and then becomes poor again. I really mucked this one up. Although what is said above is true, this is an exceedingly minor effect. Both 10Be and 36Cl are formed as charged ions in the ionosphere. The Earth's magnetic field then traps them, with only a slight "leakage" of the isotopes to the lower atmosphere.
The amount of "leakage" depends on the height of the ionosophere, which changes primarily in response to the Solar cycle, with periods of maximum solar activity corresponding to the highest extent of the ionosphere.
The major disadvantage of this dating method is that these isotopes also tend to diffuse over time. Using Predetermined Ages as Markers In these methods, one uses the age of previously determined markers to determine the age of various points in the ice-core. The major advantage of these methods is that they can be completed relatively quickly. The major disadvantage is that if the predetermined age markers are incorrect than the age assigned to the ice-core will also be incorrect.
Previously Measured Ice-Cores In this method one compares certain inclusions in a ice-core whose age has been determined with a seperate method to similar inclusions in an ice-core of a still undetermined age. These inclusions are typically ash from volcanic eruptions and acidic layers. The major disadvantage of this method is that one must have a previously age-dated ice core to start with.
Oceanic Cores In this method one compares certain inclusions in dated ocean cores with related inclusions found in the ice-core of a still undetermined age.
Examples of such inclusions are a decrease or increase in temperature over a period of years that can be determined from flora and fauna found in the oceanic core and a decrease increase in the 18O enrichment over this same period of years. Another example is volcanic ash. Hyde has posted separately some of the relationships between ocean core data and their astronomical causes.
These are the primary "inclusions" that are compared. I apologize for my use of nondescript terminology here. The major disadvantages of this method are that one must compare different signatures of climatic change that correspond to the same event and that one is not certain of the lag times if any between oceanic reactions and glacial reactions to the same climatic changes.
Volcanic Eruptions After the eruption of volcanoes, the volcanic ash and chemicals are washed out of the atmosphere by precipitation. These eruptions leave a distinct marker within the snow which washed the atmosphere. We can then use recorded volcanic eruptions to calibrate the age of the ice-core. Since volcanic ash is a common atmospheric constituent after an eruption, this is a nice signature to use in comparing calibrated time data and an ice-core of undetermined age.
Another signature of volcanism is acidity. The major diasadvantage of this method is that one must previously know the date of the eruption which is usually not the case. Furthermore the alkaline precipitants of the ice ages limits this measure to approximately BC. Ph Balances One unique marker of periods of glaciation is that precipitation during the ice ages are markedly alkaline.