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Author | Topic: Creationists: Where Are The Pillows? | |||||||||||||||||||||||||||
Rei Member (Idle past 7041 days) Posts: 1546 From: Iowa City, IA Joined: |
Pillow lava is a distinct type of formation that forms when flowing lava is submerged in water. The water quickly cools hard an outer shell, but the pressure from the flow continues to build up on the inside, forcing it to break; a new flow forms out of the break, which develops its own shell; etc. The end result is long successive chains of overlapping "pillows". The quenching of the surface additionally leaves clear lineations on the side. Overall, they're a quite distinctive feature:
In a number of areas in the world, we can clearly see many successive layers of basalt, each with fossils (often quite delicate, such as eggshells and footprints) in between. Ignoring the problems with this in a catastrophic flood, it pretty much requires creationists to accept that most of the basaltic layers in the fossil record were layed down underwater (strangely, in very flat horizontal sheets.....). If this is the case, *all basalt should show pillowing*. That is not the case. Does any creationist have an explanation for this, or is to be another unanswered question? "Illuminant light, illuminate me." [This message has been edited by Rei, 01-06-2004]
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TrueCreation Inactive Member |
quote:--All basalt shouldn't show pillowing. As you explained pillowing is the result of differential internal and surface pressures, and therefore will only apply for extrusive volcanics which characterize only a portion of the oceanic crust and extrusive terrestrial lava flows. Plutons and batholiths really are not effected by this potential inconsistency, young earth or not. --I would tell you what the real potentially inconsistent issue is, but I'm just going to lay back for a second.. Cheers,-Chris Grose OYSI [This message has been edited by TrueCreation, 01-06-2004]
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Rei Member (Idle past 7041 days) Posts: 1546 From: Iowa City, IA Joined: |
quote: Basaltic batholiths? You're kidding, right? Or are you confusing basalt with granite? Now, basalt can form near the surface without being exposed, but how would you propose this happen in a flood with waterlogged sediments everywhere? [This message has been edited by Rei, 01-06-2004]
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TrueCreation Inactive Member |
quote:--No, I don't believe I associated the two (if it seemed I implied differently, my mistake). Basalt is extrusive, not intrusive. quote:--It happens in the oceanic crust all the time. Also, basalt has to be considerably inundated by water in order for it to pillow. Even if such a global flood implied by catastrophic plate tectonics never happened, the logic behind the assertion that all basalt should have pillowed is false. Cheers,-Chris Grose OYSI [This message has been edited by TrueCreation, 01-06-2004]
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Rei Member (Idle past 7041 days) Posts: 1546 From: Iowa City, IA Joined: |
quote: Then what was the meaning of:
quote: It was a discussion about basalt layers, and you brought up granite layers. Why? Granite is irrelevant to this discussion.
quote: I assume you're talking about basalt formation at places such as the mid-atlantic ridge. Which was *not* just deposited by a flood, even by creationist standards, and whose magma is not a hundred feet or less from the surface in most places. Furthermore, we're also not talking about a dome of intruding magma, but a thin layer, a few feet to a few dozen feet in thickness, spreading out for dozens or hundreds of kilometers in each direction. And you're saying that such a thing would be not a flow, but some sort of intrusion? Pray tell, how? And also, pray tell why, with the only sediment above being relatively thin and freshly laid, that the magma feels the need to cut through the sediments instead of simply go upwards and flow over the surface? "Illuminant light, illuminate me."
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
OK, my geo-bs detector is buzzing again. I think you are making some "authoritative" statements here, than have some significant departures from accuracy. My disclaimer is, that I'm no great authority myself, but I do believe I understand the situation better than you.
quote: What you are saying here, is the situation where a lava is flowing from a subarial (above water) surface, into a body of water. I suspect that this is not what you meant to say. Anyhow, in the literal interpretation of your scenario, I suspect that the steam produced at 1 atmosphere of pressure, when the lava hits the water, would tend to shatter the lava mass, perhaps into sand. What I think you actually intended to say, was "Pillowed volcanics is a distinct type of formation that forms when a magma (lava) is extruded under a covering of water.
quote: When a magma (and I'm assuming a Basaltic magma) is extruded underwater, it tends to form globules, with plastic rinds. These globules tumble down slope, to form piles on previous globules. What a pillowed Basalt is, is a pile of now solidified globules. They tend to have points on the bottom, where the newer globules came to rest over and between previous globules. That is why pillows can be used as top direction indicators.
quote: I think this is somewhere between misleading and flat-out wrong. Not that pillow don't sometimes break open, but I don't think it's from internal pressure. I believe what you are referring to as "lineations", are radiating joint patterns. This is the pillow Basalt counterpart to the columnar jointing that can be seen at Devils Tower, in Wyoming, USA.
quote: True, but I believe that it is occasionally possible for apparent pillow structure to form in non-subaqueous situations. Again, I make no great claim to being a volcanologist. Some of my details may also be a bit off. Moose
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roxrkool Member (Idle past 1017 days) Posts: 1497 From: Nevada Joined: |
Pillow lavas generally form under relatively high pressures (weight of overlying water) and they've been described as looking like toothpaste coming out of a tube. The quenched flexible rind that forms initially is glassy and is through which the lava breaks through due to a build up of pressure. This process continues, with newer 'pillows' often stacking upon the older ones, until the lava is exhausted or is cut off. Externally, they look like rounded globules (pillows). Internally, just like the pic Rei provided - though I myself have never seen them so huge.
Subaerial lava that enters cold water will "explode" upon contact mainly because of the lack of pressure (coupled with the large heat differential, of course).
HERE are a couple of movies that show how pillow lavas are formed. Really cool stuff.
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TrueCreation Inactive Member |
quote:--I was thinking a bit far ahead of the discussion. Since pillows are not the problem I was thinking of other properties of igneous rocks, such as crystal size, which are problematic. quote:--What else would you expect from an episode of runaway subduction if not the formation of large ocean basins?? Runaway subduction as a means for CPT is the only even slightly viable YECist explanation for the earths geology and so I don't find a problem in assuming that if a YEC wants to try and explain the data that they need the formation of oceanic lithosphere by means of seafloor spreading to progress rapidly as is given in CPT. quote:--You don't think this has ever happened on the ocean floor? Extrusive lavas are expelled from dikes interconnected with major magma chambers terrestrially and at active spreading ridges anyways. quote:--Well intrusive volcanics will spread laterally to significant distances relative to the vertical, but I was refering to extrusive volcanics flowing above the surface. I may have misinterpreted your assertion. quote:--The time involved since original deposition isn't really significant, but the degree of induration is. Nevertheless, I was refering to extrusive volcanics above the surface. Cheers,-Chris Grose
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roxrkool Member (Idle past 1017 days) Posts: 1497 From: Nevada Joined: |
TC, I think Rei was referring to terrestrial lava flows, such as the Columbia River Basalts, the Deccan Traps, etc. That those, if the flood theory is correct, would have to have been deposited under water; and therefore should exhibit pillow structures. Which they don't. At least not at the scale required.
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Rei Member (Idle past 7041 days) Posts: 1546 From: Iowa City, IA Joined: |
quote: It is largely irrelevant whether it started by flowing across land or not. For example, you can get pillow lava from a flow running into a freshwater lake.
quote: Nope. For example, the Watchung basalt pillows. Bill Berkeland has also discussed this issue on the site; he provided this reference (I haven't checked it myself, but you can if you'd like): Cas, R., and Wright, J., 1987, VolcanicSucessions: Modern and Ancient, Kluwer Academic Publishers Group, 544 pp. According to Bill (who knows far more about this subject than me), pillow lava can even form when basaltic lava sinks into water-saturated sediment, such as wet sand or mud, with no body of water being present.
quote: No, that is not what I meant to say.
quote: And how is that different from what I stated (apart from the fact that your statement doesn't point out the fact that it's generally not a continuous flow while mine does? Pillow lava flows intermittently)?
quote: Wrong yet again. Here, pick your source: pillow lava pressure - Google Search The University of North Dakota's site on volcanos? Pacific Northwest National Laboratory? The University of Alaska's Geophysical institute? The US Geological Survey? Any of the other >10,000 examples?
quote: No. Lineations. Use a dictionary: "An arrangement of lines". Pillow lavas have a distinctive patterns that give the surface either a rippled or bumpy texture.
quote: Right. That's not the issue here - the issue is just the opposite: Why isn't there pillowing *everywhere*? Even if the argument is that the extrusion is too rapid, surely enough it won't be at the periphery. I'm sorry if my reply seems a bit harsh. But perhaps you should think before you open a post with "OK, my geo-bs detector is buzzing again." I don't claim to be an expert either, but for God's sake, that's a pretty basic definition of pillow lava that I used. Did you want me to be more concise or verbose? I mean, if you want concise, I could simply have stated "the underwater equivalent of pahoehoe" and had mostly described in 5 words, but I thought I'd be nice and elaborate. I guess I made a poor choice. "Illuminant light, illuminate me."
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Rei Member (Idle past 7041 days) Posts: 1546 From: Iowa City, IA Joined: |
quote: Actually, from runaway subduction, we *would* expect pillowing, because it would be pretty hard for runaway subduction to occur without exposure of the basaltic magma to water.
quote:quote: And lava erupting from undersea dikes forms... pillows! The question is why, if the entire earth was flooded when the basalts were formed, are there not pillows?
quote:quote: If it's flowing above the surface, it's exposed to water, and thus going to form pillow lava at the periphery. "Illuminant light, illuminate me."
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roxrkool Member (Idle past 1017 days) Posts: 1497 From: Nevada Joined: |
Oh yes, I forgot that I read pillows can form in lakes and water-saturated seds (I think from Bill), but I don't know how or why. I was always told you needed pressure to keep them from 'exploding' (like what happens in Hawaii when the lava reaches the ocean).
The seds would qualify, but not sure about the lakes. How deep did the pillows form in the lakes, I wonder? I would think the textures and perhaps sizes would be different. [This message has been edited by roxrkool, 01-06-2004]
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TrueCreation Inactive Member |
quote:--Probably, but he was very general in his statements. I don't have significant data yet on the structure of the lavas at such traps, though I think that in order for a CPT view of earth history to be correct, there should be extensive evidence for either pillowing and/or glassy flows for the latest extrusive events. Much more detail could be worked out for would be expected if I knew the geology well. Cheers,-Chris Grose OYSI
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TrueCreation Inactive Member |
quote:--It wouldn't be expected for the same reason dessication cracks are found all throughout the geologic record. Cheers,-Chris Grose OYSI
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Rei Member (Idle past 7041 days) Posts: 1546 From: Iowa City, IA Joined: |
quote: Heh, now you're going beyond the realm of my knowledge on the subject. I was just giving a basic definition. Certainly you'll get different effects between the part that is above the surface and the part that is below, but the role that water pressure plays when it's fully submerged, I can't really say. (it's, what, 1 atmosphere pressure for every 33 feet?). Where's Bill when you need him? "Illuminant light, illuminate me."
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