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Received: from DESIRE.WRIGHT.EDU by (4.1/iWarpR.4.18); Tue, 23 Jul 91 09:03:15 PDT Message-Id: <3F9245D0CFFF01816C@WSU.BITNET> From: SBISHOP@DESIRE.WRIGHT.EDU Subject: Re: Request For Some Information From Past Posts Date: Tue, 23 Jul 91 12:03 EST Back by popular demand this post comprises the bulk of knowledge I have obtained in the last day of study on methods of ice-core dating. Outline I. Methods of Dating Ice Cores A. Counting of Annual Layers 1. Temperature Dependent 2. Irradiation Dependent B. Using Pre-Determined Ages as Markers 1. Previously Measured Ice-Cores 2. Oceanic Cores 3. Volcanic Eruptions 4. Ph Balances 5. Paleoclimatic Comparison C. Radioactive Dating of Gaseous Inclusions D. Ice Flow Calculations II. The Vostok Ice-Core A. How It Was Collected B. Experimental Methodology C. Results III. Conclusions A. Minimum Age of the Earth B. Worlds in Collision? IV. References A. Method of Collecting B. References ------------------------------------------------------------------------------ I. 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. The accuracy of such age determinations is within 2-3 years back to 8,000 BP (before present), increasing to 2%-3% back to 20,000 BP, and increasing to ~10% back to ~150,000 BP. I.A. 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. A major disadvantage of these types of dating is that they are extremely time consuming. I.A.1. 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 poor becomes 18O rich and then ends up 18O poor again. This process also depends on the relative temperatures of different years, which allows comparison with paleoclimatic data (see I.B.5). For similar reasons the ratio of deuterium to hydrogen (in the H2 part of water) acts the same way. The major disadvantage of this dating method is that isotopes tend to diffuse as time proceeds. I.A.2 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.e. 9Be and 35Cl) one can determine the season of the year the precipitation occurred. Thus each annual layer starts 10Be and 36Cl poor, becomes 10Be and 36Cl rich, and then becomes poor again. The major disadvantage of this dating method is that these isotopes also tend to diffuse over time. I.B. 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. I.B.1. Peviously 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 (see I.B.3) and acidic layers. The major disadvantage of this method is that one must have a previously age-dated ice-core to start with. I.B.2. 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. 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 I.B.3. 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 from 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 (I.B.4) limits this measure to approximately 8000 BP (Before Present). I.B.4. Ph Balances One unique marker of periods of glaciation is that precipitation during the ice ages are markedly alkaline. This is due to the fact that the ice ages tied up a large quantity of the available water thus exposing a larger portion of the continental shelves. From these shelves huge clouds of alkaline dusts (primarily CaCO3) were blown across the landscape. The major disadvantage of this method is that it gives only very approximate age ranges (i.e. this ice was laid down during the ice age). Furthermore, the lag time between the onset of glaciation and increased alkalinity are uncertain. I.B.5 Paleoclimatic Comparisons In this method, one compares long range climatic changes (e.g. ice ages and interglacial warmings) with markers (such as the 18O/16O ratios) found within the ice-cores. The major disadvantage of this method is that one must understand major paleoclimatic changes to have something to compare to. I.C. Radioactive Dating of Gaseous Inclusions. In this method one melts a quantity of glacial material from a given depth, collects the gases that were trapped inside and use standard 14C and 36Cl dating. The major disadvantage of this method is that a huge amount of ice must be melted to gather the requisite quantity of gases. I.D. Ice Flow Calculations In this method, one measures the length of the ice core and calculates how many years it must have taken for a glacier of that thickness to form. This is the most inaccurate of the methods used for dating ice-cores. First one must calculate how the thickness of the annual layer changes with depth. After this one must make some assumptions of the original thickness of the annual layer to be dated (i.e. the amount of precipitation that fell on the area in a year). II. The Vostok Ice-Core To demonstrate the methods used in dating ice-cores I will use the Vostok ice-core as an example because I found plenty of literature on it and because it is an Antarctic ice-core which was what the original post was about. II.A How It Was Collected The Vostok Ice-Core was collected in East Antarctica by the Russian Antarctic expedition. The Vostok Ice-Core is 2,083 meters long and was collected in two portions: 1) 0 - 950 m in 1970-1974, 2) 950 - 2083 m in 1982-1983. The total depth of the ice sheet from which the core was collected is ~ 3,700 meters. II.B. Experimental Methodology The ice core was sliced into 1.5-2.0 meter segments. A discontinuous series sampled every 25 meters and a continuous series from 1,406 to 2,803 meters were then sent in solid form to Grenoble, France for further analysis. At Grenoble the ice was put into clean stainless steel containers. The samples were crushed and then melted with the gases given off collected and saved for further analysis. The melt water was tested for chemical composition and a quantity of this water was then electrolysised. The methods used in the determination of the ages include 18O/16O isotopic analysis [1], independent ice-flow calculations [1], comparison with other ice cores [1], paleoclimatic comparison [1], comparison with deep sea cores [1], 10Be/9Be isotopic analysis [2], deuterium/hydrogen isotopic analysis [3], comparison with marine climatic record [3], CO2 correspondances between dated ice-cores [4] and CO2 correspondances with dated oceanic cores [4]. The results determined from these various samples were consistent between the continuous and discontinuous slices within the sections that overlapped. They were also consistent with Greenland ice-cores, other Antarctic ice-cores, dated volcanic records, deep sea cores, and paleoclimatic evidence. II.C. Results While unable to provide specific dates (within a millenia), the analysis show definate evidence of the the last two ice ages. Using the methods listed above the bottom of the ice-core was laid down 160,000 +- 15,000 years ago. It should be noted that all of the methods listed above were consistent with the above results. III. Conclusions In this section I will provide a brief review of how the ice-core data effects both the age of the earth question and the Velikovskian catastrophism. III.A. Minimum Age of the Earth From the data gathered from the Vostok ice-core indicates that the MINIMUM age of the earth is at least 145,000 years. Furthermore there exists ~ 33% of additional ice below the core sample which would hold a disproportionate number of years due to thinning of the ice layers under the tremendous pressure of the ice above it. To maintain an age for the earth of 50,000 years, one would need to describe a mechanism that allows more than 2 false ice layers to form per year. It should be noted that one also needs to describe why this mechanism has ceased to function in historic times since the Vostok ice-core demonstrates a number of the historically recorded volcanism at the correct periods of time. III.B. Worlds in Collision The Vostok ice-core shows no effects of catastrophic geological changes. By this I mean no petroleum, no vermin, no weird Venus gasses, no red snow, no manna in amongst the layers. Also no evidence for rapid rotational changes in the earth, no floods, no major asteroid bombardments. Finally, there is absolutely positively fur-darn-tootin no evidence of the earth ever having occupied any position in the solar system other than that which it holds now. IV. References A brief note on the references I used. IV.A. Methods of Collecting When I went to look for references on the dating of ice-cores, I decided to follow a simple simple as scientifically possible. I chose to do this to demonstrate that there is no excuse for someone to make the blatantly ignorant attack that Ted made when answering Sue Bishop's original post on ice-core data. The above sections on the Vostok ice-core was taken from references 1-4. The general information on dating methods comes from references 5-8. The last two references are about Greenland ice-cores. IV.B. References [1] C. Lorius et al., NATURE 316 (1985) 591-596. [2] F. Yiou et al., NATURE 316 (1985) 616-617. [3] J. Jouzel et al., NATURE 329 (1987) 403-408. [4] J.M. Barnola et al., NATURE 329 (1987) 408-414. [5] van Nostrands' SCIENTIFIC DICTIONARY [6] THE ENCYCLOPEDIA OF SCIENCE AND TECHNOLOGY [7] E. Wolff, GEOGRAPHICAL MAGAZINE 59 (1987) 73-77. [8] Julie M. Palais OCEANUS 29 (Winter 86/87) 55-60. [9] W. Dansgaard et al., SCIENCE 218 (1982) 1273-1277. [10] C.U. Hammer et al., NATURE 288 (1980) 230-235. From SBISHOP@DESIRE.WRIGHT.EDU Tue Jul 23 09:03:24 1991 Received: from by (4.0/iWarpX.4.18); Tue, 23 Jul 91 09:03:23 PDT Received: from DESIRE.WRIGHT.EDU by (4.1/iWarpR.4.18); Tue, 23 Jul 91 09:03:21 PDT Message-Id: <3F9241FBAC1F01816C@WSU.BITNET> X-Envelope-To: X-Vms-To: IN%"" X-Vms-Cc: SBISHOP From: SBISHOP@DESIRE.WRIGHT.EDU To: sbradley Subject: Re: Request For Some Information From Past Posts Date: Tue, 23 Jul 91 12:03 EST Matt Brinkman writes: \Been doing a little more reading on the ice-core dating techniques. I found \something that should have been included in my original post... \The accuracy of ice-core dating techniques is within 1-2 years back 8,000 BP \(before present), within 2%-3% back to 20,000 BP and increasing to ~10% for \dates ranging back to ~150,000 BP. \If I lead anyone to believe that the methods were 100% precise, I apologize. I want to complement Matt on his extremely well written and concise explanation of ice core dating. Once again there is no response from either Bob or Ted..... -------------------------------------------------------------------------------- Matt Brinkman Sue From SBISHOP@DESIRE.WRIGHT.EDU Tue Jul 23 09:04:44 1991 Received: from by (4.0/iWarpX.4.18); Tue, 23 Jul 91 09:04:42 PDT Received: from DESIRE.WRIGHT.EDU by (4.1/iWarpR.4.18); Tue, 23 Jul 91 09:04:39 PDT Message-Id: <3F921502EA7F01816C@WSU.BITNET> X-Envelope-To: X-Vms-To: IN%"" X-Vms-Cc: SBISHOP From: SBISHOP@DESIRE.WRIGHT.EDU To: sbradley Subject: Re: Request For Some Information From Past Posts Date: Tue, 23 Jul 91 12:04 EST I have asked this question of Bob Bales with no answer. I am asking it of Ted Holden. Why am I fairly sure he won't answer either? Ted, you keep talking about a world wide flood. Where did all that water come from? Even if the polar icecaps melt there would only be a rise of sea level of about a hundred or so feet. I'm going to be generous and give you some latitude. Say the flood only flooded to the depths of the Rockies, i.e. 14,000 feet. I could be tough and say the depth of Mount Everest which would satisfy the Bibical account but I AM being generous. Calculate the volume of the earth as it is now. Then add a total extra depth of 14,000 feet. This would increase the diameter of the earth a total of 28,000 feet. Calculate how much is the volume of the encreased globe. Then subtract the original volume. Compare it to the actual volume of the oceans. I'm sure that some source book in the library can give you this number. Any good reference librarian should be able to find it for you. Then come back and explain to me where all that extra water came from. I'm sick of creationists and catastrophists coming up with crazy theories and not even trying to work out the numbers to see if it is feasible. I am asking you to put up or shut up. From SBISHOP@DESIRE.WRIGHT.EDU Tue Jul 23 09:04:49 1991 Received: from by (4.0/iWarpX.4.18); Tue, 23 Jul 91 09:04:48 PDT Received: from DESIRE.WRIGHT.EDU by (4.1/iWarpR.4.18); Tue, 23 Jul 91 09:04:45 PDT Message-Id: <3F921150DEFF01816C@WSU.BITNET> X-Envelope-To: X-Vms-To: IN%"" X-Vms-Cc: SBISHOP From: SBISHOP@DESIRE.WRIGHT.EDU To: sbradley Subject: Re: Request For Some Information From Past Posts Date: Tue, 23 Jul 91 12:04 EST I am reposting this information since it is germaine to the discussion regarding the Bibical Flood. Please note the ENORMOUS volume difference between actual water on earth and the amount needed for even enough to cover Mount Ararat. My thanks to Steven Timm who wrote this. Sue Bishop Date: Mon, 2 Jul 90 23:53:54 EDT From: TIMM@FNAL.Bitnet It was suggested a while ago that someone calculate the amount of water required for a global flood which would cover the highest mountains. Most probably the poster knew (as I do) that this calculation is already done in Strahler. But since I don't have Strahler with me, I'm doing the calculation for myself. After I answer the question, I'll go on to calculate the first-order objections to the calculations that creationists including myself would otherwise raise. X-Envelope-to: ST0O@ANDREW.CMU.EDU AMOUNT OF WATER ON THE EARTH TODAY: (EB is Encyclopedia Britannica) Ocean volume: (EB 25:125) 1.37 E09 km^3. Ice cap volume: EB 1:440 3 E08 km^3 of Antarctic ice. Antarctic ice is 90% of all ice, and ice is ..9 the density of water (can be denser under high pressure, but I believe it's a second order effect.) Thus 1.67E09 km^3 of water is available to make a flood. Why no more? Water is massive enough so that it won't make escape velocity, unless pushed to high temperatures. (RMS vel 100 C is 700 m/s, esc. vel is 7000 and some. Thus whatever water was here still is here. AMOUNT OF WATER TO COVER EARTH UNIFORMLY TO A DEPTH r. With earth of radius R=1.2 E 7 m, the volume of water to cover a perfect sphere to depth r above its surface is 4/3 pi *( 3 r * R^2 + 3R* r^2 + r^3). For the cases I will consider, R>>r and only the first term is important. Cover Mt. Everest: (8900 m) 1.6 E10 km^3 of water needed. If oceans were present depth, add an additional 1.37E09. A first-order correction is that we must consider the volume of land mass above sea level. But it's clear there's not enough water to go around. The first Creationist objection would be: How do you know Everest was that high during the flood? All right. Let's take Mt. Ararat (3900 m) which the Bible says the ark landed *on the top of*. For waters that high, 2.78E09 km^3 of extra water is needed. If all this came from forty days and forty nights of rain, this would mean a flow of 821 km^3 per second. Whether from "fountains of the deep or from above, the average precipitation would be 1.1 mm /sec or ~6 cm/minute (assuming uniform depth build-up to 3900 m over the 40 days, not quite correct) >From here on creationists must play with the initial conditions. In particular, if someone suggests that all continental drift and most mountain formation happened during the flood, and perhaps the ocean wasn't as deep then as it was now, let's calculate how shallow the ocean would have to be. Take ocean surface area 3.6E8 km^2, mean depth 3.8 km. (now). Reduce ocean depth to 1 km, say. Now only 3.6E8 km^3 of water is needed to fill ocean, rest (1.2E9), is available for flood, enough to flood earth uniformly to a depth of 2.7 km. I won't claim that the above scenario happened. Some will, or variations on a theme of that. Point is, where they are free to use the Bible to pick their initial conditions, they can come up with volumes of water that are at least on the right order of magnitude. So there's the science and speculation. Take it for what it's worth. Share and enjoy, Steve


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