======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Wed, 16 Aug 1995 16:01:05 GMT Organization: TCC Lines: 93 Message-ID: <40sqlt$14l@granite.sentex.net> In article <40qqko$p9b@lace.Colorado.EDU>, greig@columbia.Colorado.EDU (David Iain Greig) wrote: >I really don't see why Doug Cox can't picture a convection cell working >in a porous medium. >How I envision midocean vents arising might go thusly. >1. Assume the crust in question is in the middle of an ocean basin. > It will naturally be saturated with water, with increasing pressure > as a function of depth. >2. A 'hot-spot' arises underneath the plate. This will give rise to > convection cells in the crust, as water is heated in the lower > crust, and this will rise towards the bottom of the ocean where > it is cooler. Since the oceanic crust is basalt, it was likely hot to begin with, and the descending water would warm up as it went down, decreasing the density. > The cooler water will in turn sink back down > into the crust, to be reheated. The flow of cool water downwards implies pore pressure decreases with depth, by Darcy's Law. Any heating of water in the pores and cracks at deeper levels will increase volume of the water and thus increase fluid pressure. So, which is correct? [NB: fluid pressure tends to act in all directions.] >(I don't think Doug can deny convection, even in a porous medium. It >is rather well established.) There is a big difference between convection in a pot on the stove and the hypothetical convection which is used to model the mechanism driving the oceanic vents. Besides, convection in a pot of water on the stove, (or in rice or porridge) does not shoot a steady stream of water 6 inches up unto the air. >3. At some point, due to stresses, the crust above the hot-spot begins > to fault. This causes cracking in the crust, giving the heated water > at depth a much faster route to rise than convection through the > crust. At this point, we will see 'vents' spewing heated water > from the fault region. >4. Given that the water is being depleted from the crust (this is > driven by the temperature difference between seawater at the vent > and the crustal water heated by magma), water will be drawn down to > replace vented water. This system will quite happily continue, with > crustal heat heating up deep water which will then be expelled > via vents. Cooler seawater will then be drawn down through the rock > of the crust. Naturally, this process will be slow, given the > limited porosity of crustal rock. However, water can be drawn down > over a much larger area then the vents, thus at a much slower > rate. Think of it as a convection cell in both a solid and liquid > matrix. >This system will work. I would expect a simple physical model could be con >structed to demonstrate it, using a hot plate and some porous substance to >model crust. Simply drill a hole through the porous material, and look >to see it heated water from the bottom of the tank is 'vented'. >Please feel free to show me to be in error. I do have some understanding >of fluid dynamics, to the extent of a few graduate courses in transport >phenomena. My undergraduate background was Engineering Physics, with >a specialization in Chemical engineering. I think the problem is you have not adressed the problem of the source of the high pressure that is driving the flow. SIEM does: the water flows up from within the earth's interior, where the pressures are very high. There is heating of the water due to friction as it flows through the conduits in the rocks of the ocean crust. You also need to explain the decreasing pressure with depth that is implied by your assumption of downwards flow, or are you saying the water flows down towards the higher pressure? Scientists have struggled to devise mechanisms for decreasing pressure with depth to allow the downwards flow. The density difference between the cold water and the hot water is insufficient to overcome the frictional resistance involved in a hypothetical convection model, and does not account for the high velocity of the flow from "black smokers." With SIEM, hydrothermal vents can readily form where new cracks or faults are created, and need not be confined to ridges. In convection models, the circulation cannot develop readily and requires very special fracture structures to exist in the rocks near oceanic ridges, which suggests evidence for oceanic hydrothermal vents would be rare. -- Douglas Cox ======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Fri, 18 Aug 1995 05:42:28 GMT Organization: TCC Lines: 227 Message-ID: <410v3v$k7p@granite.sentex.net> In article <40thrg$5hh@lace.Colorado.EDU> greig@atlantis.Colorado.EDU (David Iain Greig) wrote: >In article <40sqlt$14l@granite.sentex.net> Doug Cox wrote: >: In article <40qqko$p9b@lace.Colorado.EDU>, greig@columbia.Colorado.EDU >: (David Iain Greig) wrote: >: >I really don't see why Doug Cox can't picture a convection cell working >: >in a porous medium. >: >How I envision midocean vents arising might go thusly. >: >1. Assume the crust in question is in the middle of an ocean basin. >: > It will naturally be saturated with water, with increasing pressure >: > as a function of depth. >: >2. A 'hot-spot' arises underneath the plate. This will give rise to >: > convection cells in the crust, as water is heated in the lower >: > crust, and this will rise towards the bottom of the ocean where >: > it is cooler. >: Since the oceanic crust is basalt, it was likely hot to begin with, and >: the descending water would warm up as it went down, decreasing the >: density. >Well, crust temperature is an increasing function of depth. Ok. >: > The cooler water will in turn sink back down >: > into the crust, to be reheated. >: The flow of cool water downwards implies pore pressure decreases with >: depth, by Darcy's Law. Any heating of water in the pores and cracks at >: deeper levels will increase volume of the water and thus increase fluid >: pressure. So, which is correct? [NB: fluid pressure tends to act in all >: directions.] >In a convection cell, flow is driven by density differences, right? >So the less dense heated water in the lower crust will rise. As it >rises, cooler water will be drawn downwards, in a convection cell. >You seem to be fixating on a static situation, not on the dynamic one >arising from convective flow. Anyone can see that the flow that emerges from the "black smoker" vents is a pressurized flow. That is why it has such high velocity; it has been described as "fire-hose" velocity. To get their high pressure jets in their fire hoses, for fighting big fires or to reach tall buildings, firefighters often have a "pumper truck" which increases the pressure of the water from the hydrant. What is the pump that causes the high pressure that exists in the black smoker vents? Convection is inadequate as a mechanism for driving the flow from the black smokers, because the pressure "head" available is quite limited; if we consider two columns of water 5 km high, one consisting of hot water and the other of cold sea water, the water in the cold column has a density of about 1 g/cc and the water in the column of hot water may have a density of about 0.6 g/cc. Densities in this range have been measured in the water emerging from black smokers in the Pacific. So the pressure head available to drive the flow is equal to about 40% of the height of the cold column, or 200 kg/sq cm. But this has to drive the flow through a distance of 10 km (ie, down from the ocean floor to the vicinity of the hypothetical magma chamber and back up to the ocean floor again) so the available force for driving the circulation works out, on average, to only 20 kg/sq cm over each km, or 0.02 kg/sq cm for each meter, which is hardly enough to overcome frictional resistance, even in straight, smooth conduits several cm wide, and we know that rock fractures are not smooth and straight. So this is the basic problem faced by those who need a convection model to work. I don't, because there is SIEM, which has an excellent explanation for the high pressure which drives the black smokers and other kinds of vents: the water flowing from the black smokers is from the earth's interior, where it is under very high pressure due to the weight of the crust above. The oceanic crust sinks as the subcrustal ice layer melts and meltwater flows up through the conduits feeding the vents, into the oceans. Evolutionists have to believe circulation is involved in the oceanic hydrothermal vents, even though no plausible mechanism for driving it exists, because present rates of flow are so high that half the water of the oceans would leak out of the interior in 700,000 years, implying an earth that is much too young for evolution to have occurred. >: >(I don't think Doug can deny convection, even in a porous medium. It >: >is rather well established.) >: There is a big difference between convection in a pot on the stove and >: the hypothetical convection which is used to model the mechanism driving >: the oceanic vents. >This is an assertion. Convection is convection. Hot water rises, cold >water sinks. The 'difference' is scale and medium. Since we see >convection in the mantle, the scale is not a problem. You just don't >seem to be comfortable with convection of water through the crust. >Unless you can demonstrate some reason why water cannot convect in >the crust, you're hand-waving. Maybe convection is possible, with a suitable system of cracks, but it will not provide the pressures you need for the black smokers. Either the water is from the earth's interior, or you need a "magic pump." BTW, I don't think any one has seen convection occurring in the mantle. It is a hypothesis, after all. And the idea of mantle convection dragging the oceanic crust along in opposite directions from the MOR, (implying tension at right angles to the ridge axis) seems to be discredited by the presence of a zone of thrust faults (evidence for compression) in the equatorial region of the Mid Atlantic Ridge (10-20 degrees N) extending for 1000 km or so. A significant number of earthquakes at the MOR are compressional. >:Besides, convection in a pot of water on the stove, >: (or in rice or porridge) does not shoot a steady stream of water 6 >: inches up unto the air. >But it does cause visible disturbances on the surface of the water. >So you seem to accept the concept of convection through a porous >medium, right? I believe I have read where someone managed to produce some sort of convection in a can of water filled with marbles. >: >3. At some point, due to stresses, the crust above the hot-spot begins >: > to fault. This causes cracking in the crust, giving the heated water >: > at depth a much faster route to rise than convection through the >: > crust. At this point, we will see 'vents' spewing heated water >: > from the fault region. >: >4. Given that the water is being depleted from the crust (this is >: > driven by the temperature difference between seawater at the vent >: > and the crustal water heated by magma), water will be drawn down to >: > replace vented water. This system will quite happily continue, with >: > crustal heat heating up deep water which will then be expelled >: > via vents. Cooler seawater will then be drawn down through the rock >: > of the crust. Naturally, this process will be slow, given the >: > limited porosity of crustal rock. However, water can be drawn down >: > over a much larger area then the vents, thus at a much slower >: > rate. Think of it as a convection cell in both a solid and liquid >: > matrix. >: >This system will work. I would expect a simple physical model could be con >: >structed to demonstrate it, using a hot plate and some porous substance to >: >model crust. Simply drill a hole through the porous material, and look >: >to see it heated water from the bottom of the tank is 'vented'. >: >Please feel free to show me to be in error. I do have some understanding >: >of fluid dynamics, to the extent of a few graduate courses in transport >: >phenomena. My undergraduate background was Engineering Physics, with >: >a specialization in Chemical engineering. >: I think the problem is you have not adressed the problem of the source >: of the high pressure that is driving the flow. >Easy: it's convective flow. I did mention that. The same sort of >mechanism that causes Old Faithful to erupt jets of water: magmatic >heating. The exact processes differ, but water is drawn into the >system, heated, then expelled. >: SIEM does: the water >: flows up from within the earth's interior, where the pressures are very >: high. There is heating of the water due to friction as it flows through >: the conduits in the rocks of the ocean crust. >One caveat: others have shown that there is no such subcrustal ice >layer, from seismological data. Your 'magic tubes' notwithstanding. You mean "secret tubes", I think. These are part of SIEM theory; (ie, Subcrustal Ice Earth Model). These are hypothetical rock conduits in the form of dykes and sills of rock which convey hot mantle material from deep in the earth to volcanoes, and hot spots in the crust; they cut through the subcrustal ice layer. "Magic pumps" are needed, IMO, for the conventional convection models of hydrothermal vent circulation at mid ocean ridges, because density differences are insufficient to drive the flow and produce the effects observed. >: You also need to explain the decreasing pressure with depth that is >: implied by your assumption of downwards flow, or are you saying the >: water flows down towards the higher pressure? Scientists have struggled >: to devise mechanisms for decreasing pressure with depth to allow the >: downwards flow. The density difference between the cold water and the >: hot water is insufficient to overcome the frictional resistance involved >: in a hypothetical convection model, and does not account for the high >: velocity of the flow from "black smokers." >Doug, since hydrostatic pressure increases in any column of water, what >you are claiming would make convection impossible. What *I* claim is >that in a block of crustal material of a given porosity, saturated with >water, if you heat the bottom, convection will take place in the crust. >Given a network of faults to work with, the hot water could easily rise. >A large area of fault surface is constricted to narrow vent outlets. >Slow flowrate through rock then translates to a high flowrate at the vent >outlets. As hot water is expelled from the vents, water must flow >downwards into the lower mantle to replace it. The pressure *will* >drop in the lower crust, near the fault networks. This will, combined >with gravity, cause a flow of water from the upper crust to the lower crust. >: With SIEM, hydrothermal vents can readily form where new cracks or >: faults are created, and need not be confined to ridges. In convection >: models, the circulation cannot develop readily and requires very special >: fracture structures to exist in the rocks near oceanic ridges, which >: suggests evidence for oceanic hydrothermal vents would be rare. >Does SIEM require a local 'hot-spot' or ridge system to form? Are >vents observed in the absence of such? Why don't vents appear on >land, if "hydrothermal vents can readily form where new cracks or >faults are created"? Why isn't there water spewing from the San Andreas >fault? The argument you advance would clearly claim there ought to >be equivalent structures on land, clearly. The absence of >terrestrial vents weighs heavily against your theory. Vents can occur far from ridges or hot spots in SIEM; I read somewhere that low temperature seeps may occur in deep ocean trenches, which could represent flow from a subcrustal source penetrating the crust along faults. Effusions of fluids after large earthquakes are not uncommon. Examples are a 1974 earthquake in Iran, and the Kern County, CA earthquake of 1952, which was followed by discharge of approximately 10^7 m^3 of water over 2 months. Fluid pressures in the San Andreas Fault can be very high, approaching lithostatic at depths of 2-3 km. Where fluid pressures are abnormally high, SIEM suggests a subcrustal source is a possibility. -- Douglas Cox ======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Thu, 24 Aug 1995 01:08:59 GMT Organization: TCC Lines: 116 Message-ID: <41g9ef$foh@granite.sentex.net> In article <41167p$jfg@news.ccit.arizona.edu>, jnhead@dante.lpl.arizona.edu (James N. Head) wrote: >In article <410v3v$k7p@granite.sentex.net> tcc@sentex.net (Douglas Cox) writes: >>So the pressure head available to drive the flow is equal to about 40% >>of the height of the cold column, or 200 kg/sq cm. >kg/sq cm is not a unit of pressure. Try *dynes.* I used kg/sq cm because it is a bit more meaningful and easier to comprehend. F. Press and R. Siever Earth, 2nd ed., 1978) give the following conversion factors and units for pressure: 1 kg/sq cm = 0.96784 atm 1 kg/sq cm = 0.98067 bar 1 kg/sq cm = 14.2233 psi 1 ft of water = 0.03048 kg/sq cm 1 km of granite = 265 kg/sq cm (approx) >>Maybe convection is possible, with a suitable system of cracks, but it >>will not provide the pressures you need for the black smokers. Either >>the water is from the earth's interior, or you need a "magic pump." >Check out Turcotte and Schubert, chapter 9, for a discussion of >convection in a porous medium. But the book is weak on the mechanism of oceanic vent circulation. >>BTW, I don't think any one has seen convection occurring in the >>mantle. It is a hypothesis, after all. And the idea of mantle >>convection dragging the oceanic crust along in opposite directions >I've had to correct you on this point before. The notion that mantle >convection "drags" the crust along is *not* a part of plate tectonics. >Several observations about plate motions contradict it. As I posted >before, plate driving mechanisms include things like ridge push and >slab pull. Again, I refer you to Turcotte and Schubert (1982) Geodynamics >for a clear exposition of this material. If you are going to attack >the "standard model," please do us the courtesy of first getting the >standard model right. I did not say anything about a "standard model," my comments referred to "the idea of mantle convection dragging the oceanic crust along in opposite directions.." The idea of "hot spots" that move more slowly than the plates is another objection to basal drag forces as a mechanism for plate movement; also, the idea of basal drag (which you indicate has been rejected in the standard model) would suggest the rate of plate movement is greater for larger plates, but some of the smaller plates are supposed to be moving faster than large ones. >Regarding mantle convection, there are multiple lines of reasoning leading >geophysicists to conclude that the mantle is convecting. I gave a brief >explanation and references earlier. You have not responded to them. >Retract the objection or provide a substansive criticism of the >Rayleigh Criteria for convection (for starters, heat flow comes next). One of the assumptions of the convection hypothesis involves the assignment of a viscosity to the mantle material. We know this material must have high rigidity from the increase in seismic velocity at depth. It is supposed that the isostatic "rebound" after melting of continental glaciers allows a calculation of the viscosity, but I do not accept the reality of these former great ice sheets, or that there was "rebound" upon their melting. The problem I see is the assumption that the subcrustal material that flowed laterally towards uplifted areas had the same viscosity as the present mantle material. What if the material which flowed was a liquid, which has since solidified? Then the value assumed for the viscosity of the mantle would be invalid. There has indeed been uplift in the Great Lakes area, and in Scandinavia, and elsewhere, and SIEM provides a mechanism; relative uplift of continents occurred at the end of the flood, and was accompanied by relative subsidence of the ocean basins. In SIEM it is assumed these movements occurred during a time of crustal mobility before the subcrustal waters and sediments solidified. In these conditions there was lateral flow of subcrustal waters and sediments, which uplifted the continental crust and mountain areas by hydraulic pressure. Many of the mountainous regions of the earth show a great deal of folding and deformation has occurred along with uplift and it is reasonable to assume that when uplift occurred in one area, subsidence was happening somewhere else; or, alternatively, phase changes in the subcrustal ice could produce relative vertical movements. >>from the MOR, (implying tension at right angles to the ridge axis) >>seems to be discredited by the presence of a zone of thrust faults >>(evidence for compression) in the equatorial region of the Mid >>Atlantic Ridge (10-20 degrees N) extending for 1000 km or so. A >>significant number of earthquakes at the MOR are compressional. >Ridges have morpholgy consistent with extensional forces dominating >the stress field at the ridge. See T&S for an explanation. Overall, >the stress-state of plates is one of compression. >>You mean "secret tubes", I think. These are part of SIEM theory; (ie, >which I raised numerous un-answered objections to. I assumed you had >not responded because you were looking things up and coming up with >responses to the objections and questions I raised. Now it looks >like you're starting afresh with new foils. SIEM is still incompatible >with measured heat flow. You have a real problem even melting the >"ice" I think. OTOH, some have objected that there is too much heat down there. But the evidence from electrical conductivity in the lower crust suggests water exists at these depths which is incompatible with a very hot, (ie, > 1,000 degrees C) viscous upper mantle, as assumed in the convection hypothesis. -- Douglas Cox ======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Thu, 24 Aug 1995 18:20:28 GMT Organization: TCC Lines: 62 Message-ID: <41i5qi$b37@granite.sentex.net> In article , d-turnb@students.uiuc.edu (Doug Turnbull) wrote: >In article <41g9ef$foh@granite.sentex.net>, tcc@sentex.net (Douglas Cox) >wrote: >> In article <41167p$jfg@news.ccit.arizona.edu>, >> jnhead@dante.lpl.arizona.edu (James N. Head) wrote: >> >In article <410v3v$k7p@granite.sentex.net> tcc@sentex.net (Douglas Cox) writes: >> >>So the pressure head available to drive the flow is equal to about 40% >> >>of the height of the cold column, or 200 kg/sq cm. >> >kg/sq cm is not a unit of pressure. Try *dynes.* >> I used kg/sq cm because it is a bit more meaningful and easier to >> comprehend. F. Press and R. Siever Earth, 2nd ed., 1978) give the >> following conversion factors and units for pressure: >> >> 1 kg/sq cm = 0.96784 atm >> 1 kg/sq cm = 0.98067 bar >> 1 kg/sq cm = 14.2233 psi >> 1 ft of water = 0.03048 kg/sq cm >> 1 km of granite = 265 kg/sq cm (approx) > Something's screwy with those units- a kg is a unit of mass, a pound is >a unit of force. The proper unit for pressure is force/area, so the >english units above are correct. The metric units presumably should convert >the kgs to 9.8 Newtons. This is due to the common, sloppy equivalence of >pounds with kilograms, which is only valid for the surface of the earth. > 1 Pascal = 1 Newton/sq m = 10 dyne/sq cm = 1.45e-4 psi > 1 atm = 1.01 e5 Pa = 14.7 lb/sq. in. = 76 cm-Hg > 1 Newton = 1 kg m/sq. sec. The weight of a mass of 1 kg (= kgf) is 1 kgf = 9.80665 Newton >FWIW, the English unit of mass is the slug, which equals 14.6 kg. There is also such a thing as pound-force. In physics the pound is a unit of force, in some systems it is a unit of mass. There are two kinds of pound, avoirdupois and troy: 1 lb (av) = 1.21527 lb troy The unit for pressure, kg/sq cm is often used in the geo-sciences. This is a different system of units. I suppose it is understood that kg-force per sq cm is meant (as in psi). Dynes are units of force, not pressure. No doubt when this is all cleared up, the mystery of the force (mechanism? engine? pump?) which drives ocean vent circulation will be solved! Will physics prevail? Of course, in SIEM it's the pressure of waters from a subcrustal reservoir, and there is no circulation involved (or magic pump). -- Douglas Cox ======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Fri, 25 Aug 1995 16:45:07 GMT Organization: TCC Lines: 65 Message-ID: <41kkjf$kvl@granite.sentex.net> In article <41icpv$f74@news.ccit.arizona.edu>, jnhead@anaxamander.lpl.arizona.edu (James N. Head) wrote: >In article <41g9ef$foh@granite.sentex.net> tcc@sentex.net (Douglas Cox) >wrote: >>I used kg/sq cm because it is a bit more meaningful and easier to >>comprehend. >and later in article <41i5qi$b37@granite.sentex.net> he wrote >>There is also such a thing as pound-force. In physics the pound is a >>unit of force, in some systems it is a unit of mass. There are two >>kinds of pound, avoirdupois and troy: >> >> 1 lb (av) = 1.21527 lb troy >> >>The unit for pressure, kg/sq cm is often used in the geo-sciences. >>This is a different system of units. I suppose it is understood that >>kg-force per sq cm is meant (as in psi). Dynes are units of force, not >>pressure. No doubt when this is all cleared up, the mystery of the >>force (mechanism? engine? pump?) which drives ocean vent circulation >>will be solved! >which ranges from the irrelevant to the truly bizarre. It is the argument about units that is irrelevant to the question about the plausibility of oceanic vent circulation, which is the central question in the present thread. I say the pressure differences between the cold and heated water in the convection model are inadequate to drive the flow, regardless of the units of pressure. You have not answered this. > Kg/sq cm >*is not* a unit of pressure and *is not* often used in the geosciences. >Pressure is dy/sq cm. Pounds is a unit of force, not mass. The >confusion comes in lay-usage; often times people interchange kg and >lbs., though they are not measures of the same thing. In the sciences >though we don't confuse these things (at least not for very long) if >we want to keep our credibility. According to Encyclopedia Britannica, [1960. Vol 15, p. 135] the U.S. pound is defined in terms of the kilogram: 1 U.S. pound = 0.4535924277 kg The U.S. pound is therefore a unit of mass: The international prototype kilogram is defined as a standard of mass, and the U.S. pound is therefore regarded in weights and measures work as a unit of mass. The word =weight= has often been used in the sense of =mass= and critical reading is often necessary to determine in what sense this word has been used. This remark also applies to the French word =poid=. The British Imperial (avoirdupois) pound is defined as the mass of a certain cylinder of platinum about 1.35 in. high and 1.15 in diameter. However, by convention, in physics the pound is regarded as a weight or force. -- Douglas Cox ======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Fri, 25 Aug 1995 17:35:38 GMT Organization: TCC Lines: 32 Message-ID: <41kni5$ou7@granite.sentex.net> In article <41ifpl$ov@lace.Colorado.EDU>, greig@atlantis.Colorado.EDU (David Iain Greig) wrote: >Douglas Cox (tcc@sentex.net) wrote: >: The unit for pressure, kg/sq cm is often used in the geo-sciences. >: This is a different system of units. I suppose it is understood that >: kg-force per sq cm is meant (as in psi). Dynes are units of force, not >: pressure. No doubt when this is all cleared up, the mystery of the >: force (mechanism? engine? pump?) which drives ocean vent circulation >: will be solved! Will physics prevail? Of course, in SIEM it's the >: pressure of waters from a subcrustal reservoir, and there is no >: circulation involved (or magic pump). >Why aren't there vents at the San Andreas (or any other) fault? If >a subcrustal ice layer is down there, why don't we see 'black smokers' >anywhere but the bottom of the sea? The ascent of waters from subcrustal regions to the land surface would involve losses of pressure head and thus much less vigourous flow rates. During the ascent there would be mineral deposition due to cooling and lower pressure which would tend to seal conduits. IMO, volatiles released in volcanic eruptions probably can have a subcrusal source like that I have proposed for the black smokers. Of course the equivalent of a black smoker on land would be a fumarole as the waters at black smoker temperatures would vaporize in surface conditions; they remain liquid on the ocean floor only because of the pressure. A likely place for such phenomena is Iceland as it lies on the oceanic ridge system. -- Douglas Cox ======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Fri, 25 Aug 1995 18:25:10 GMT Organization: TCC Lines: 97 Message-ID: <41kqf1$s01@granite.sentex.net> In article <41ig8o$10a@dv.ics.uci.edu>, hadley@dv.ics.uci.edu (Tedd Hadley) wrote: > In <41g9ef$foh@granite.sentex.net> tcc@sentex.net (Douglas Cox) writes: > [...] > >OTOH, some have objected that there is too much heat down there. But > >the evidence from electrical conductivity in the lower crust suggests > >water exists at these depths which is incompatible with a very hot, > >(ie, > 1,000 degrees C) viscous upper mantle, as assumed in the > >convection hypothesis. > What was your response the last time someone addressed your problem? > Subject: Re: Subcrustal ice > Date: 7 Sep 1994 10:55:47 +0300 > Message-ID: <34jrm3$c0f@kruuna.Helsinki.FI> > From Chris Nedin via Tero Sand in response to Douglas Cox: > |>In my theory, heat is conveyed from the oceanic basins to the ridges by > |>this subcrustal flow. There is evidence for this; the high electrical > |>conductivity of the lower crust, which is "orders of magnitude" higher > |>than that predicted for hot, dry rock. IMHO, if temperatures were as > |>high as you suggest at all regions below the crust, all water would be > |>driven off from rocks and conductivity would be low. > |True to a certain extent. There is little water in the lower crust, most of > |it tied up in minerals. However. it should be pointed out the the rocks of > |the lower crust are not "dry" i.e. devoid of water. very small quanities do > |exist, either trapped in mineral lattices or in minute interstitial spaces. > |Totally dry rocks are far stronger and show different characteristics from > |those exhibited by rocks of the lower crust. However, you have not kept up > |with the literature on this. > |The high conductivity of the lower crust was indeed an intreging problem, > |since it was commonly though that there was insufficient free water to > |allow conductivity. A 1% saline solution would account for the > |conductivity, but this has been rejected as the sole cause because, and > |this is where your explanation of the conductivity fall down, if such a > |fluid is present there is no known mechanism to stop such a fluid flowing ^^^^^ ^^ ^^ ^^^^^ ^^^^^^^^^ > |upward away from the lower crust. Tedd, thanks for reposting this. Chris has clearly stated one of my own main objections to the idea of circulation at the oceanic vents. Thermodynamics would indicate that waters flowing up from the ocean floor represent degassing of the earth and the idea that water goes back in is untenable. It must be a one-way process. > | The upper margin of the high conductivity > |zone is sharp and coincides with approx. the 450 degree centigrade > |temerature thermocline *in all areas irrespective of composition*. Even in > |continental crust, where water is almost certainly inadequate to explain > |the phenomenon, the high conductivity zone occurs. In your scenario, if the > |zone is caused by the upward migration of water into the lower crust, you > |have no mechanism for blocking the continued rise of water through the > |crust. Here again, Chris has put his finger on an important problem, but it this not a problem for SIEM, it is a problem for those who postulate circulation as the mechanism for flow from oceanic vents. Water would tend to rise from deeper levels in the earth, where pressures are higher, not go back down. But, to prop up evolutionary theory, and the assumed great ages needed for it, geophysicists and oceanographers have to say the opposite to what Chris has said here. They need circulation to work or the oceans would be too young for evolution to have occurred. In SIEM, there is a continual replenishment of the waters which cause the high conductivity in the lower crust due to melting of the ice layer. Indeed the water does continue to flow upwards to higher levels, along faults during earthquakes, and through permeable layers or aquifers, but it is replenished from below. > |This would mean that the zone of conductivity would not have a sharp > |upper boundary. There is *no* evidence for a permeability trap at the 450 > |degree thermocline, and even if there were, you would have to explain how > |such a barrier occurred at the same level *throughout the Earth* and in > |totally different rock types. [...] The idea of water as the cause of anomalous high conductivity seems better supported than the concept of carbon or sulphide layers, although such deposits may indeed exist. See for example: Vanyan, L. and A. Shilovski, 1989. Fluids in the lower crust inferred from electrmagnetic data. R. F. Mereu et al, editors, Properties and processes of Earth's lower crust, AGU Geophysical Monograph 51, p. 243-246. One way in which the SIEM concept of water from subcrustal ice aids our understanding of the earth is that flow of conducting fluids upwards from deeper levels along faults prior to earthquakes might explain the anomalous changes in the magnetic field that precede these events. -- Douglas Cox ======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Sat, 26 Aug 1995 02:06:35 GMT Organization: TCC Lines: 166 Message-ID: <41llfv$q52@granite.sentex.net> In article , Stuart Weinstein wrote: >tcc@sentex.net (Douglas Cox) wrote: >>In article <41167p$jfg@news.ccit.arizona.edu>, >>jnhead@dante.lpl.arizona.edu (James N. Head) wrote: >>>Regarding mantle convection, there are multiple lines of reasoning leading >>>geophysicists to conclude that the mantle is convecting. I gave a brief >>>explanation and references earlier. You have not responded to them. >>>Retract the objection or provide a substansive criticism of the >>>Rayleigh Criteria for convection (for starters, heat flow comes next). >>One of the assumptions of the convection hypothesis involves the >>assignment of a viscosity to the mantle material. We know this >>material must have high rigidity from the increase in seismic velocity >>at depth. It is supposed that the isostatic "rebound" after melting of >>continental glaciers allows a calculation of the viscosity, but I do >>not accept the reality of these former great ice sheets, or that there >>was "rebound" upon their melting. >Well now, that is sound scientific reasoning. Ignore data which refutes your >theory. Give a reason for not accepting the reality great ice sheets. If you >don't know the reasons for accepting them, ask. The Niagara Escarpment represents a wall of rock that would be an immense obstacle to the flow of an ice sheet over it. Directional indicators such as drumlins show the flow, whether of ice or water, was from the low to the high side for its entire length. Along the eastern side of the Bruce Peninsula and in Georgian Bay the total height of the cliff the ice would have to overcome is 800 feet in places. The escarpment would form a barrier to any movement of the base of the hypothetical ice sheet. There are numerous fragile pillars or stacks along the escarpment that discredit the idea of former ice movement across it. Several occur on the eastern shore of the Bruce Peninsula, others at Flowerpot Island, Mount Nemo, and other locations. There are also many deep fissures in the rock close to the exposed rocky cliffs that could not have resisted the wear and tear of a great ice sheet. All along the Escarpment in Southern Ontario, the features are those typical of an unglaciated area. Glacialist A.P. Coleman, referring to the deeply fissured rocks exposed in the Bruce Peninsula, suggested the ice sheet was thin and must have somehow missed these apparently unglaciated areas. Features found in exposed bedrock areas along the escarpment are identified as "karst" phenomena, and it is claimed many of them formed by solution processes since the ice melted, but deep, wide fissures and large cave openings could not have formed by solution processes acting today in only a few thousand years. There are many examples of silicate and dolomite boulders wedged tightly in the fissures. The boulders are thought to have been transported to their present positions by ice; how could the boulders become wedged in fissures which had not yet formed? There are areas where the rock is shattered and yet hangs together, particularly under large overhanging ledges. Big overhangs and rock ledges would be unlikely to have survived ice movement over them. The rock basins of the Great Lakes in the vicinity of the escarpment, Lakes Huron and Ontario could not have been excavated by ice erosion as is sometimes suggested; much of the debris from these lakes has disappeared! Ice could have transported this material only a limited distance. It must have been moved much further than the southernmost extent of the ice. There is not enough debris remaining, in the gravels and till deposits south of the lakes, for the excavation of the lakes to be attributed to ice. And ice could not effectively erode such deep rock basins anyway. The orientation of drumlins in the vicinity of the escarpment shows that there was flow in a direction normal to the trend of the escarpment. Generally the flow corresponds to the regional dip of the sedimentary rocks. This suggests differential uplift of the basement, or the Canadian Shield at different centres caused rapid flow of the overlying flood waters which excavated the lake basins and streamlined the sediments, while they were still unconsolidated. Outliers of sedimentary rock in the Shield reveal a formerly extensive cover has also been removed; it was likely due to the same events. The more inticate streamlining of drumlins at elevated regions in northwestern New York, compared with the larger and wider drumlins on the plains around Lake Ontario, clearly shows that fluids were the agents of streamlining, rather than a rigid glacier being pushed from the north, because a glacier being pushed uphill can only move as fast as the ice causing the push, whereas a current of water will speed up at higher elevations where the depth is less, causing more intricate streamlining and erosion, due to the principle of continuity. Drumlins in northwestern New York show a pattern of flow to the south in the central region, but north of Lake Ontario, for example in the Guelph area, the drumlin orientations show flow was towards the north or northwest. Others around Caledon in the Niagara Peninsula west of Lake Ontario show flow direction to the west. At the eastern end of Lake Ontario there are drumlins that have their tails deflected by flow to the south, down towards the Hudson Valley. How could a great ice sheet have caused all these various patterns of flow? In the flood theory, there were various differential uplifts centered at different places so that the flow was first to the south, due to uplift of the rocks in the Algonquin area; this generated the currents which eroded the basins of the Finger Lakes and formed the north-south oriented drumlins of northwestern New York. As the land rose above the surface in the Allegheny highjlands, cutting off the southward flow, the waters became channelled to the southwest. The uplift of the Adirondack region generated rapid current flow towards the west, that excavated the deep basin of Lake Ontario. Some large north-south drumlins along the shores of Lake Ontario were cut in half by this westward flow. Subsequent channelled flow towards the south and east eroded the Hudson and the St Lawrence valleys. I suggest that during this period, when the flood waters were retreating as the continents emerged from the waters, deep submarine canyons were carved in the continental shelves by sediment-laden currents. >>The problem I see is the assumption that the subcrustal material that >>flowed laterally towards uplifted areas had the same viscosity as the >>present mantle material. What if the material which flowed was a >>liquid, which has since solidified? Then the value assumed for the >>viscosity of the mantle would be invalid. >IFology is not a science Doug. The fact of the matter is that analysis of the >great ice sheets give similar values within the uncertatinties of the data. >Who says the mantle wasn't solid in the first place? The mantle flows via solid >state creep. Can you explain how the upper 1000km of the mantle (which is >sampled by glaical rebound data) can cool significantly in 10,000 years? In SIEM, there could be chemical processes involved as the sediments and subcrustal waters resolidified. Perhaps the "ice" of SIEM is not a pure water ice but contains some bonding material, or a kind of cement. >>as indeed been uplift in the Great Lakes area, and in >>Scandinavia, and elsewhere, and SIEM provides a mechanism; relative >>uplift of continents occurred at the end of the flood, and was >>accompanied by relative subsidence of the ocean basins. In SIEM it is >>assumed these movements occurred during a time of crustal mobility > >Why did the crust become mobile? The presence of liquid water and sedimentary material below the crust, in which the crust foundered during the flood as some of it overflowed the continents, was the reason for this mobility. The evidence for this is best seen in the rocks of mountainous areas, which are sometimes called, appropriately enough, "mobile belts." >>before the subcrustal waters and sediments solidified. >> In these >>conditions there was lateral flow of subcrustal waters and sediments, >>which uplifted the continental crust and mountain areas by hydraulic >>pressure. Many of the mountainous regions of the earth show a great >>deal of folding and deformation has occurred along with uplift and it >This indicates horizontal shortening, not epeirogeny. Uplift occurs as a result >due to the accumulation of material and isostacy. Your thinking like a 19th >century geologist. -- Douglas Cox ======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Sat, 26 Aug 1995 13:18:00 GMT Organization: TCC Lines: 52 Message-ID: <41msqf$1os@granite.sentex.net> In article <41l251$i73@nbc.ksu.ksu.edu>, lver@ksu.ksu.edu (Lloyd Paul Verhage) wrote: >Good and Bad stuff deleted >>>before the subcrustal waters and sediments solidified. In these >>>conditions there was lateral flow of subcrustal waters and sediments, >>>which uplifted the continental crust and mountain areas by hydraulic >>>pressure. Many of the mountainous regions of the earth show a great >>>deal of folding and deformation has occurred along with uplift and it >If mountains were raised by hydralic pressure, shouldn't they show >signs of stretching rather than folding? >The folding occurs because they are compressed from the sides, not >pushed up from below. Even your above statement proves your >"water" hypothesis is wrong >Back to the drawing board. SIEM offers some promising concepts for explaining the structure of mountain areas. Suppose the crust subsides, so that there is a basin, geosyncline, grabben, trench or some similar depression. As the subsidence occurs, there is sediment deposited from above, and some added to the pile from below. The material from below consists of hot fluids, which cause metamorphism, along with sediments. This material added to the pile tends to promote subsidence. This happens in many areas around the world the same time. Then these depressed sediments and broken crustal blocks are uplifted relative to the surrounding crust, by hydraulic pressure, because of subsiding ocean basins. As this uplift occurs, the topmost sediment is eroded off, for the depth of water above them decreases, and current velocity increases. But when the rocks break the surface, they are no longer subject to erosion; the erosion becomes concentrated into valleys, which are widened and deepened. In this case, uplifted sediments will tend to spread laterally onto nearby areas. These are overthrusts. In a long, trough-shaped basin, the pattern across the long axis will tend to be fan-shaped. This structural pattern is commonly seen in mountains. The erosion of uppermost sediment by currents tends to leave more resistant rocks and crustal blocks intact. The debris is removed far away by the currents and redeposited. The removal of material promotes uplift, so these regions become the highest parts of the land, as the levels of continents and ocean basins are restabilized. -- Douglas Cox ======== From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins Subject: Re: Hydrothermal vents Date: Sun, 27 Aug 1995 16:39:45 GMT Organization: TCC Lines: 146 Message-ID: <41pt0a$2eq@granite.sentex.net> In article <41l6fp$lba@lace.Colorado.EDU>, greig@atlantis.Colorado.EDU (David Iain Greig) wrote: >Douglas Cox (tcc@sentex.net) wrote: >: In article <41ig8o$10a@dv.ics.uci.edu>, hadley@dv.ics.uci.edu (Tedd >: Hadley) wrote: >: Tedd, thanks for reposting this. Chris has clearly stated one of my >: own main objections to the idea of circulation at the oceanic vents. >: Thermodynamics would indicate that waters flowing up from the ocean >: floor represent degassing of the earth and the idea that water goes >: back in is untenable. It must be a one-way process. >This is garble to me. How does thermodynamics have anything to say >about 'degassing'? Thermodynamic potential is a measure of energy available to do useful work. A gas under pressure can do work when it expands as it moves to lower pressure, which is a change to a state of increased entropy, one which has lower potential. Degassing of the earth involves gasses escaping from regions of high pressure to lower pressure, and heat is transferred to the surface in the process. Heat flows from hot to cold. Degassing is one of several different ways for heat transfer, along with conduction, radiation, etc. Hot objects tend to degass, fluids flow away from high pressure to regions of lower pressure. In the process the PE of the gas is decreased and entropy of the system increased. The earth's atmosphere and oceans are thought to be due to degassing; F. Press and R. Siever say [Earth, 2nd ed., 1978, p. 12]: Differentiation is perhaps the most significant event in the history of the earth. It led to the formation of a crust and eventually the continents. Differentiation probably initiated the escape of gasses from the interior, which eventually led to the formation of the formation of the atmosphere and oceans. It is as if our planet gave a "big burp" during this violent upheaval. The escape of gasses from the earth's interior is a process of heat transfer, and the waters of "black smokers" are hot enough to be considered a gas, being above critical temperature. SIEM predicts that subcrustal waters would tend to flow upwards towards the upper layers of the earth's crust on continents and in the oceanic crust. >: > | The upper margin of the high conductivity >: > |zone is sharp and coincides with approx. the 450 degree centigrade >: > |temerature thermocline *in all areas irrespective of composition*. Even in >: > |continental crust, where water is almost certainly inadequate to explain >: > |the phenomenon, the high conductivity zone occurs. In your scenario, if the >: > |zone is caused by the upward migration of water into the lower crust, you >: > |have no mechanism for blocking the continued rise of water through the >: > |crust. >: Here again, Chris has put his finger on an important problem, but it >: this not a problem for SIEM, it is a problem for those who postulate >: circulation as the mechanism for flow from oceanic vents. Water would >: tend to rise from deeper levels in the earth, where pressures are >: higher, not go back down. >Doug continnues to claim that water cannot move downwards through rock >here. Doug: assuming there's NO subcrustal ice layer for a minute... >Water will saturate the crust at the ocean floor. Pressure will >increase with depth. Temperature will also increase with depth, >as we approach the lower crust and mantle. >So what we have is waterlogged rock, with cool water at the >top, and hot water down below. This system is clearly going to >transfer heat from the hotter to the cooler. It will do this >slowly, via conduction. It will also convect, albeit slowly, >by hot water rising, and cool water falling. >By adding a fault system into this model, we now >have a more ready means for hot water to rise to the water- >crust interface. Now convective heat transfer can pick up >by hot water rising towards the vents, expanding as it rises, >increasing in velocity. The pressure below the vents must >be considerable, given the heat and velocity of the water as >it emerges. So, why doesn't the high pressure force the ocean water back up along the route by which it came down? What sort of valves are present that would prevent this? >Douglas claims that the reason we don't see fountains on land is >due to frictional losses required to pu mp the water up to the >surface. But I was under the impression that Doug's mythical >ice layer was under quite a bit of crust... considerably more crust than >the additional distance to the surface of the continental plates. > How deep is your ice layer, Doug? How far down do we have to >drill to hit it? A deep bore hole, 12 km deep, drilles on the Kola Peninsula in NW Russia encountered high temperature gradients, hot water, and fractured rocks. Bottom temperature was about 200 degrees C and pressure 3 kbar. Interpretations of seismic reflection profiles were not confirmed by drilling; an expected basalt layer was not found. It would be hazardous to say how deep one would have to drill to find subcrustal ice but SIEM predicts evidence of ice at deeper levels should increase as information about the lower crust is obtained. IMO, it is possible some seismic reflections merely represent pore fluids that are present in rock layers deep in the crust and upper mantle rather than structural features. >: But, to prop up evolutionary theory, and the >: assumed great ages needed for it, geophysicists and oceanographers >: have to say the opposite to what Chris has said here. They need >: circulation to work or the oceans would be too young for evolution to >: have occurred. In SIEM, there is a continual replenishment of the >: waters which cause the high conductivity in the lower crust due to >: melting of the ice layer. Indeed the water does continue to flow >: upwards to higher levels, along faults during earthquakes, and through >: permeable layers or aquifers, but it is replenished from below. >Why is water from aquifers not laden with chemicals from the trip >thru the crust as is deep ocean vent-water? Again, aquifer water is >much more consistent with an origin from the surface, Doug. The rise of hot waters from subcrustal regions would involve losses of pressure head; during the ascent to the upper crust there would be mineral deposition due to cooling and lower pressure. Mineralized sedimentary rocks where vein fillings and fissures contain, for example, lead and zinc sulphides are found in many areas. The heat of ascending fluids is lost to the host rocks. As they cool, solutions moving through rocks lose their mineral content by deposition in openings such as joints and cavities. Various replacement processes can occur in wall rocks. The waters are thus cleaned up as they rise through the crust, which is good for everyone. >It look like the only one using special pleading to save a theory >is you. There is no problem with hot water rising through faults, >Doug. Somehow you invoke the pressure fairy to drive your model, >but then use it to deny upwelling of hot water through the faults. >The further examples you cite don't support you, they refute you. I don't deny "upwelling of hot water through the faults" but I do have doubts about cold ocean water being the true source of this rising, pressurized hot water. -- Douglas Cox