How to lie about radiometric dating, evolution, and even nuclear physics | Primate's Progress
Fossils can range from miniscule bacteria to behemoth dinosaurs that would shake . The U-Pb series isotopes are used to date ancient igneous intrusive rocks Carbon dating, developed by Nobel laureate Willard Frank Libby . Australia also offers an animated look at the formation of the layers that make up. Have you heard the one about the live snail with a carbon age of years? Another mixed ancestry woman needs bone marrow donor → A skilled cartoonist, Jack Chick manages to squeeze the largest number of . and the anomaly might even be used to tell us something about the specimen's. Creationists bring up to determine a two-legged feathered dinosaur fossils: dating the situation and how old have feathers? Many children, Did not have any carbon dating controversy is used to date exactly. Jan 19, albeit probably a pure cartoon. Now for Did not have applied carbon dating million years old?.
I think you can teach the kids the names of the bones and the muscles and teach 'em the biology, ok kid, here's your liver, here's your spleen, here's how it works. And if a kid says, Well how did we get this? Biology without any organizing principles. Kind of like memorizing bible verses, I guess. Now, lemme ask you, Ok, well I would start off by saying, If you add up the dates given in the Bible, it comes to about And I've read the Bible many scores of times, and studied it for many years, and have never found anything wrong with it.
Certainly has changed my life, and I believe the Bible is literally true and scientifically accurate in all of all of its, uh, when it deals with a scientific subject, it is absolutely correct.
Then Hovind also believes that: Then when you look at the scientific evidence. For instance, the moon is going around the earth. But the moon is leaving us "per year. It's slowly cycling out.
Because of a lot of complex physical factors. Bottom line is, the moon is leaving. Well, that means it used to be closer. Now if you bring the moon back closer, the tides get higher. Falling off with the inverse square law, actually, if you half [sic] the distance, it would quadruple the attraction Well somewhere in there the tides are gonna be so high it's gonna erode the beach clear back to Chicago.
And, uh, at one point two billion years ago, the moon would be touching the earth. Now here they're trying to tell the kids in school the earth is 4. I look at this as a science teacher and say, I'm sorry, it can't be.
Now you might need 4. And I can go all day on the scientific evidence against the earth being billions of years old. The trouble is that Hovind's so-called scientific evidence amounts to nothing but another Fractured Fairy Tale. The only way you're gonna get is from the Bible. Almost a true statement From a particular interpretation of the bible, using a date that was inserted in the King James Version in Many Christians do not accept this interpretation.
Hey, great topic tonightjust what I'd like to talk about. The creationists - they teach - I wouldn't want their teaching, their theology in the school either, because it's just as wrong as the [sic] evolution I believe. Evolution is pretty ridiculous if I think about it, but starting in Genesis, though, it does not counterdict [sic] life before Adam and Eve.
It's pretty clear, if you understand just a little bit of ancient Aramaic the first word, "was", "the earth was without form and void", that's really an impossible translation, because there was no past tense of the "to be" verb. So the more accurate translation should be "the earth became without form and void". And the other word - excuse me, tryin' to slow down a little bit here so I can be clear - the second word "replenish", he instructs the animals and Adam and Eve to replenish the earth.
That insinuates there was something there before, and considering the error in the translation in the King James of that verb, that makes a lot of sense. Alright, thank you, Mark, for calling. We cover this in great detail on our videotape 2, but I'll give you a quick answer.
Inwhen the word "replenish" was commonly used to just simply mean "fill", the King James translators used the word "replenish" because the Hebrew word there just simply called for "fill". God said, "Adam, go fill the earth. When I was a kid, the word "cool" meant "not hot".
Who knows what it means now. But, uh, English words simply change meanings. So this is a case where it changed meanings fromand there could not be any life before Adam and Eve for all sorts of scriptural reasons.
In Exodus 20 in the ten commandments the bible says the lord made everything in six days: An' he don't stutter [sic]. Jesus said in Matthew There was nothing before that. The end of, well it gets into the gap theory and the day-age theory, and that's all, you know, we got a [sic] hour long answer to that on videotape 2 of our 15 hour seminar. So I would disagree that there's life before Adam. Adam was the first man. The Bible says in 1 Corinthians Apparently taking the bible literally has its limits, even for Hovind!
And it looks like some of what you're teaching is what Hugh Ross teaches, you know about Adam being the first spirit-being. That there was actually life before that. Uh, he's a real nice guy, but he's just dead-wrong on a couple things, and I'm gonna straighten him out.
By the show, both Ankerberg and Ross are clearly irritated by Hovind, his nasty comments about Ross, and his myopic views. On one of these shows, Hovind admits that he knows no Hebrew, so this makes his comments to Mark above an argument from ignorance. There are two things that bother me right off the bat. One this comment about years. There are a lot of people who operated on the basis of a lunar year, which would have made that about 76 calendar years. And the other thing: I think it's rather presumptuous to assume that this is a 48 [sic] hour day, especially since God is so much more than we are.
Ok, well a couple of things. If you want to go with the lunar year idea, if you read the scriptures, you'll find out two of the people - Enoch, and one other one, I forget - were 65 when their son was born.
So if you're gonna divide that by 12, that makes him 5. I don't think so. They really were living to be years old, and there's a lot of biological reasons why they could do that. In the original creation, there was no genetic load.
There [sic] were not deformed chromosomes, and they didn't suffer under the You know, your gene code now is a copy off a copy off a copy off a copy who knows how many times of Adam.
And the fact that it even works at all is pretty amazing. After all this copying process it's been through and plus the hostile environment, we, and the extra things we throw at it.
If we are all copies of Adam, why aren't we all males? Why don't we all have one X and one Y chromosome? There is no genetic evidence at all that all humans originated from a single person. A recent article in The London Times points out that "Women were the complete article long before men, a new study has shown. Geneticists have found that female genes acquired their modern formyears ago but the male version was not up and running for another 84, years.
The result overturns the Biblical description of women being created from a spare rib left over from a man, and suggests that if Eve ever did meet Adam she was slumming it, genetically speaking. And as far as [it's] presumptuous to say that God used twenty-four hour days, God, God coulda done it in six seconds. I think he did it in six days just to select, just to create a week for us.
There's certainly no scientific reason, there's no lunar reason or solar reason why we have a seven day week. But just about every culture in the world operates on a seven day week. It's just like it's kind of built-in.
And I think that's [sic] remnants, people remembering from the original creation when God established this seven day week. Nobody's ever been able to tell us why we have a seven day week. Napoleon tried to change it to a ten day week and it was disaster for the French in the revolution over there. So, I would disagree. I think they really were living to be years old, and um, could not be a lunar year for the reason I mentioned, you know, they'd be five and six years old when they're havin' kids.
That just doesn't happen. Hovind is certainly selective in his miracles! He considers pre-flood people to have built the pyramids, and asserts that their long lives conferred unusual intelligence ie, ark constructionsays their chromosomes are in better shape than ours, then balks at the idea of these superhumans fathering children at age five.
His assumption must be that people are too ignorant or disinterested to investigate whether his claims about a seven day week are accurate. Again, his information is just plain wrong: A time unit longer than a day but smaller than a month is essential to human affairs. It was originally intended to set aside special days for recurring activities such as worship and marketing. Weeks of early peoples were not of the same length, but varied from one area to another.
Many primitive cultures used a four-day week, possibly in honor of the four directions.
The fatal flaw with radioactive dating methods
Central American peoples used a five day interval; Assyrians had a six day period; pre Christian Romans had periods of eight days called nundinae. For many centuries, ancient Greeks like Babylonians and Egyptians of the same period divided their thirty day months into three "decades" of ten days. Egyptians called their ten-day period decans.
Observation of the sky, in addition to originally fixing the beginning of a day, also resulted in determining the length of our weeks. It stems from an ancient and interesting tradition. The Jewish calendar is a modified Babylonian calendar.
Finally, the Maya adopted a religious calendar - the Tzolkin - based upon twenty thirteen day periods, which one source attributes to the time period involved in slash-and-burn corn agriculture The Origin of the Maya Calendar. Australian aboriginal peoples functioned with no weeks at all, but a rich astronomical knowledge of seasonal changes. And I think scientists have them pinpointed, I think it's three inches per year, and I was just curious, basically what your view is on that.
Ok, continental drift, you can get a long answer to that on my website, or in my video 6. As far as Pangaea, the continents all fitting together, it's just baloney. I taught earth science for years, Maybe it's not too late to get a tuition refund.
You know, get an earth science textbook and look up Pangaea, and you will see Mexico and all of Central America, you know Belize, well, not Belize. Honduras, Nicaragua, Costa Rica, Panama - they're all gone. They took 'em out. They twisted two continents clockwise and twisted another one counterclockwise.
I challenge anyone who buys this hooey to visit any of a number of great plate tectonics sites, including Deconstructing Pangaea and The Breakup of Pangea which show the actual movement of the plates.
What Hovind sees as a change in size is either wishful thinking or a change in the type of map projection he is used to seeing. As for Central America, it is not a matter of taking it out to get the continents to fit; it is that much of Central America did not exist until the Tertiary, a fact that can be substantiated by fossil and geological evidence. Plus it's pretty obvious if you look at the world, if you take the water out of the ocean, you'll find out there is dirt underneath.
You know, these continents are not floating around like lily pads in a bathtub. It's just the low places happen to be filled with water.
And this person claims to have taught earth science. No knowledge whatsoever of the composition or structure of the earth's crust, nor any evidence that Hovind has ever looked at a map of the world showing things like trenches, rifts, and other plate boundaries.
Jes' some good ol' water an' dirt! Continental drift theory, there's no question the continents are drifting a little bit. I was just standing on top of the San Andreas Fault last week. I was speaking out in California, and I'm goin' there again, let's see, day after tomorrow. There's no question they're moving a little bit.
The question is, How long has this been happening? And can we come to any conclusions or assumptions because of this? What we know is they're moving a few cm per year, sometimes a few inches per year. As anyone with even a minimal background in the earth sciences knows, that's not "it" at all. One particularly congruent example confirming both plate tectonics and the accuracy of radiometric dating can be found in the Hawaiian Islands.
Ingeologist James Dana noted that the Hawaiian volcanoes were more heavily eroded as he travelled from the southeast toward the northwest ie, Hawaii much less eroded than Kauai.
He could conclude only that Kauai was older than Hawaii, but had no mechanism that explained why this was so. When the Hawaiian islands were radiometrically dated, this trend was confirmed, with Kauai being 5 million years older than Hawaii.
When one follows this chain of seamounts northwest from Hawaii, the increase in age and erosion continues: There was no explanation for this trend until the advent of plate tectonics. The ages are explained well if the volcanoes were formed as the Pacific Plate passed over a hot spot; the hot spot that is currently forming the Loihi Seamount off the southeast coast of Hawaii the only part of the chain with active volcanoes.
Assuming only that plate velocities are similar to the rates measured today and in Hawaii it's about ten cm per yearone would expect to see a volcano that formed 27 million years ago to have moved km from the hot spot. Midway is about km from the hot spot. Hovind can neither explain these data away nor explain why, if radiometric dating doesn't work, there is a trend in the Hawaiian Islands consistent with erosion patterns.
As far as how long it's been going on, I think it all started at the time of the flood, when the Bible says the fountains of the deep were broken up. I suspect there was a lot more water under the crust of the earth, which is now on the surface. The Bible says in Psalm and in Psalm 24 that the earth was, when God built the earth, he made it, he founded it upon the seas. So apparently there was an awful lot more water in the crust of the earth that is now upon the surface.
And it probably came shooting out when the fountains of the deep broke open along those fault lines. Here Hovind opens up a major can of worms that no young earth creationist has addressed so far. If one is proposing that the "fountains of the deep" supplied the water, then that water was originally under pressure. InSoroka and Nelson explored the physical consequences of such an event, concluding that "Using the geothermal gradient and assuming that water within pores would be as hot as the rocks themselves, we estimate that the average temperature of the water would be oC The consequences of liberating this much heat within the time limits stated in Genesis would be that once again the Earth's surface and atmosphere would be raised to such high levels that the passengers on the 'ark' could not possibly survive.
Hovind never does this. Again, Noah-et-al are "toast". What I was wantin' to know is, so the supposition made so far is that the universe as a whole is only years old. How do you know that? I believe you're right, and you are right, probably, but you can't measure the star distance beyond about twenty light years.
I'm tellin' ya, it just can't be done. And the trigonometry was taught with all the talent he brought to the teaching of earth science, I bet.
Even twenty light years might be a stretch because the farthest you can get away from an object on earth is miles.
So if you looked at a star in January and you waited six months, and now you're on the opposite side of earth's orbit, which is a huge circle, and then you look at the star again, you can get a little bigger base to calculate the distance using parallax trigonometry.
But even then, earth's orbit around the sun, as huge as that is, is only sixteen light minutes in diameter. One year hasminutes in it. Over half a million minutes in a year. And so to look at a star one light year away, using opposite sides of our orbit as a base, which is as big a circle as we can get, that's like having two surveyors 16" apart looking at a dot 8. That's just for one light year, and that is assuming you can tell where you were six months ago with any amount of precision, which I doubt.
Most astronomers will tell you light-years is the max you can measure using parallax, "Most astronomers" would never say anything this incredibly ignorant. Hovind went on this jag against Hugh Ross on the Ankerberg Show as well. Hovind doesn't understand much about modern science; he certainly knows nothing about the degree of sophistication in instrumentation. Proud of his ignorance, Hovind told Dr. Hugh Ross that Ross was "crippled by your education". Not similarly crippled, Hovind is free to dismiss all of modern astronomy using the "argument from personal incredulity", another logical fallacy.
Physicist Tim Thompson comments: Ross referred to parallaxes of 0. The stars are probably billions of light-years away; I don't know. Nobody knows; they probably are. After parallax, the cepheid distance scale is the next rung in the cosmic distance ladder, and so is crucial to the measure of long galactic and extragalactic distances. The bottom line for cepheids is that there exists a period-luminosity relationship.
If you measure the period, you can deduce the true luminosity. By comparing the true luminosity to the apparent luminosity what your eyes or telescope actually seesthen you can derive the distance because we know that the light intensity falls off as the inverse square of the distance over non-hugely cosmic distances.
All of this was discovered back in by Henrietta Swan Leavitt at the Harvard College Observatory when she moved from volunteer to staff in she earned a salary of 30 cents per hour.
Leavitt's discovery may be the single, most important discovery in all of astronomy, but she and other early women astronomers remain essentially unknown outside of the professional community. Before Hipparcos there was no link between the cepheid and parallax distance scales, as no cepheid variable star was close enough to Earth for a parallax distance measure.
Hipparcos changed all that by measuring the parallax for a number of cepheids. Hovind thinks that the cepheid distance scale would not hold up in court, but I suspect that his legal opinion is about as valuable as his scientific opinion. Now calibrated by Hipparcos data, the cepheid scale would hold up in any court. Cepheids are the primary extragalactic distance measurers too. Only a few galaxies are close enough for cepheids to be seen from Earth, and that's how Hubble proved that the Andromeda galaxy was a galaxy, and not a "nearby" nebula back in the 20s thanks to Henrietta.
Now the Hubble Space Telescope can see cepheids in galaxies as far away as 50, light years or more, and that same cepheid distance scale is directly tied by Hipparcos to the parallax distance scale". But we certainly do not know that the speed of light has always been constant. Last month there was an article in the newspaper. I can find it here for you quickly on my computer, where they speeded light up to X the speed of light.
This was in [the] New York Times, May 30, the year You can get it on newyorktimes. Three hundred times the normal velocity ofmiles per sec. Both of those neat tricks were accomplished by establishing very weird conditions in a laboratory that are as close to impossible as it gets in nature. The slowing of light was done in a superdense, supercold Bose Einstein condensate; cosmological light will never encounter such a thing.
The speeding up of light which does not violate any law of physics by the way was done in an artificially "supercooled" gas with two Raman pump lasers, which are very unusual in the intergalactic environment. But indeed, it is true that we don't know that the speed of light has always been a constant, and there are a number of legitimate "variable speed of light" cosmologies on the drawing board.
But we have pretty good reasons to believe that the speed of light has been constant throughout that part of spacetime that we can see the strongest evidence regards the constancy of the Fine Structure Constant.
Hugh Ross also pointed out the support for a constant speed of light via the hyperfine splitting. Ken - is it Bovine? Ok, I want to make a point. I notice you were happy to include history and other cultures to substantiate that there was a golden age where people lived for thousands of years cuz you mentioned the Greeks and the Sumerians.
But when it comes down to; things that agree with your paradigm [sic]. But when you refer to the Sumerians that they say things that don't agree with your paradigm, you reject them. So you just, you know, if it substantiates your position, history or mythology, you accept it. If it doesn't meet your paradigm, you reject it. Because if you look into the golden ages of those other cultures, they'll say that that yes there is a golden age, but that golden age lasted, for instance in the Hindu calendar, foryears.
So you'll reject that part, but you'll, you know what I mean? You talked about Adam and Eve as the first created beings. Sure, but they said that the Anunnakis, that was the first genetically-engineered humans by the Anunnaki. And "Anunnaki" means "from those who came from heaven". So you'll reject, you know, I mean, like, we could go on and on about this, but basically you're being very prejudicial to your own point of view.
Oh, I think probably everybody is. I'm sure you would be too. I believe the Bible is literally true and scientifically accurate, and I know of no mistakes in it. And I would defend that against anybody. If you know of some, I'd like to see it [sic]. I think you'd find these other cultures, these other writings, you find all sorts of obvious scientific errors.
You know, like the earth is on top of a giant turtle. You know, which is standing on top of a big elephant. I'm comin' up to speak in Ontario here pretty soon. I've spoke [sic] at the University of Guelph, and I've seen all your texts. Not all, but a lot of the textbooks up there. You teach the same things they teach down here in the United States: They just state it dogmatically like, I was there. And, you know, that's just not fair.
I think the main problem is, there, Ken, that people have their own points of view, and they believe them wholeheartedly. OK, Do you believe the earth is billions of years old? I believe this universe is really old. I mean billions, yes. Were you listening when I said the moon is moving away a couple inches a year?
Ok, well, the moon moving out 2" a year. You say we don't know if that is a constant. But, you know, there is a theory that the moon came out of the earth.
So, obviously it would have been touching the earth. It woulda came [sic] from the earth. We're just talkin' theory now, I realize. But I don't think you've looked at all the theories. Dawson is the one who dated the moon rocks.
When he was working for NASA, he was in charge of their science division. Dawson, how old is the moon? We got these rocks. We got samples from. This prompted me to visit JP Dawson's website, which had an extensive biography. Obviously there is a substantial misrepresentation here, but by whom - Hovind, Dawson, or both? I decided to get more information by emailing both Hovind and Dawson. Here are the emails: Hey Karen -- The moon rocks were studied by many different people -- all agree that we can not determine the actual date they were formed -- most of the rocks were composites of various minerals that were not formed at the same time.
Many will not accept it regardless of the data. NASA stopped promoting the idea of 4 billion years because of the dating measurements on the Genesis rock see webpage -- the answers were inconsistent. Methods of Age Dating Back to Top Time sets geology and in many ways biology apart from other sciences. While particle physicists discuss the decay of subatomic particles in miniscule fractions of a second, paleobiologists are discussing spans of time longer than recorded human history.
Two types of geologic timeare relative time and absolute time. Relative time ioncvolves the placing of events into a sequence based on their relative positions in the geologic or rock record.
Absolute time is the placing of a specific number of years plus or minus a certain amount based on the accuracy od the equipment used in this analysis on an event or rock sample. This ability was not developed until the early part of the 20th century. Most of the building of ourt framework of geologic time sprang from the application of relative dating techniques.
Archbishop James Ussher of Ireland, in the late 's, calculated the age of the earth based on the geneologies from Adam and Eve listed in the biblical book of Genesis. According to Ussher's calculations, the Earth formed on October 22, B.
These calculations were part of Ussher's book, History of the World. The chronology he developed was taken as factual, and was even printed in the front pages of bibles.
Ussher's ideas were readily accepted, in part because they posed no threat to the social order of the times; comfortable ideas that would not upset the linked applecarts of church and state.
The fatal flaw with radioactive dating methods – Biblical Geology
Image from the Internet. Often new ideas must "come out of left field", appearing as wild notions, but in many cases prompting investigation which may later reveal the "truth". Ussher's ideas were comfortable, the Bible was viewed as correct, therefore the Earth must be only years old. Geologists had for some time doubted the "truth" of a 5, year old earth.
Leonardo da Vinci ; painter of the Last Supper, and the Mona Lisa, architect and engineer calculated the sedimentation rates in the Po River of Italy. Da Vinci concluded it tookyears to form some nearby rock deposits. Niels Stensenmore widely known by his Latinized name of Nicholas Steno, made a series of observations about the nature of fossils and the rocks that contained them.
Steno, along with his contemporaries John Ray and Robert Hooke, recognized "tongue stones" as the teeth from ancient sharks. Steno's Principle of Superposition states that in undisturbed strata the layer on the bottom is oldest. This is one of the founding principles of modern geology. Another of Steno's observations was that sedimentary particles tended to settle out of water as thin sheets or horizontal layers. Steno noted that sediment layers extended laterally in all direction until they thinned, pinched out or met the edge of the depositional basin.
James Huttona Scottish physician, intellectual, and farmer, is regarded as the father of modern geology. His investigations led to his development of the Theory of Uniformitarianismthe basis of modern geology and paleontology. According to Hutton's work, certain geological processes operated in the past in much the same fashion as they do today, with minor exceptions of rates, etc. Thus many geological structures and processes cannot be explained if the earth is only years old.
British geologist William Smith recognized different strata layers had their own unique collections of fossils. He concluded that fossil assemblages succeed one another through time. This led to the process of correlation of rock strata, as well as evolution change in life over time.
The 18th century French scientist Georges Louis de Buffon cooled iron balls he thought simulated the Earth, arriving at an age of at least 75, years.
This date was well beyond Ussher's calculations! Georges Louis Leclerc Comte de Buffon. Inthe prominent British physicist Lord Kelvin given name William Thompsonattempted to experimentally determine the age of the Earth. Kelvin assumed that the Earth was originally molten and calculated a date of its formation based on cooling through conduction and radiation. He calculated the age of Earth as about million years. This was wrong since his cooling experiment did not account for the internal heat generated by radioactive decay, unknown iwhen he did his calculations.
French physicist Antoine Henri Becquerel discovered radioactivity in Later recognition of isotopic decay sequences is now used as a way to place numerical dates on rock samples. New Zealand physicist Ernest Rutherfordinsuggested the use of radioactivity to determine the age of a rock. Rutherford also worked out the concept of half-life. Radioactive decay is the process where unstable nuclei are spontaneously transformed into another element.
A half-life is the amount of time needed for one-half of a radioisotope to decay into its stable end or daughter product. By measuring the various isotopes in a sample, geologists can calculate the age of the specimen. Long-lived radioactive isotope pairs have half-lives in millions or billions of years. The U-Pb series isotopes are used to date ancient igneous intrusive rocks such as granite.
Likewise, Rb-Sr isotope ratios can be applied to ancient rocks and meteorites. Fine-grained volcanic rocks, such as bentonite and basalt, are dated by the ratios of K-Ar. Many readers will be familiar with the principle of carbon dating.
Carbon decays with a half-life of years. Nonetheless, the fraction of carbon in the atmosphere stays roughly constant or did before we started adding to it by nuclear weapons testing, and diluting it with carbon dioxide from fossil fuels.
That is because the upper atmosphere is bombarded with cosmic rays, which cause nuclear reactions that convert nitrogen stable to carbon Mixing distributes this radiocarbon through the atmosphere, where it is taken up by plants and, in due course, animals.
As long as you are alive, you are part of the circulating pool of carbon, but as soon as you die, the carbon in your body starts decaying. Of course, cosmic ray intensity is not really constant over a long period, but we can calibrate carbon dates by comparison with carbon in tree rings dendrochronology.
The tree ring correction is small for most purposes, but matters for things like precise dating of Egyptian dynasties. The point, of course, is that the carbon in the lettuce being fed to the snails is part of the general pool, but the carbon in calcium carbonate minerals is radiochemically dead, having been out of circulation for a long time.
What the paper really showed was that the snail exchanges carbonate in its shell with carbonate from dissolved minerals, giving a spurious depletion of radiocarbon in the snail. You will find the story in Science,p. What about these rocks in Hawaii? Here again the paper is behind a pay wall, but if you follow this link it will take you to the title and abstract, which is all you need. In fact, the title alone is all you need: Xeno- foreign, as in xenophobia; lith rock, as in monolith.
Anomalies happen all the time in geology. They are, in the original sense of the expression, exceptions that prove the rule; if there were no rule, we would not consider them exceptional. Uranium-lead and potassium-argon dates of rocks usually agree, but not if the rock has been so strongly heated that argon gas can escape.
Whole rock dates can be misleading, as in the example of the Hawaiian volcano, if the rock has been contaminated from some source, in this case fluid from the mantle.