Re: Creationism claim cd250

jschuc1@xxxxxxxxxxx wrote:
http://www.talkorigins.org/indexcc/CD/CD250.html
It says here under response 1 that the stalactites that form rapidly
are because they are of a different chemical composition and aren't
limestone.

This may be so but the explanation that I have been given does not require
this.

I recently visited Natural bridge caverns outside of
Austin Texas and in the Jacobs ladder cave they put a handrail under
one of the stalactites by accident and in the last 15 years there is a
3 CM long stalactite growing on the handrail. Anybody from Texas
knows that that area is famous for Limestone and the stalactite is not
forming on or touching cement. Would someone try to explain this or
is it safe to say that the cave is much much more recent than all the
scientific "Millions Years Ago" plaques state.

I have been through dozens of limestone caves (not Texas) and spoken at some
length with the guides there. The explanation of age that I have been given
is that there is a huge variation in both the rate of erosion and deposition
in limestone caves. Some formations are millions of years old and others
only thousands. I have seen "man made" formations where deposition has
taken place on fittings and wiring that is of a known age (40-100 years)
which is between a few mm and cm thick. I was told by the guide that these
are calcite, perhaps he didn't know what he was talking about but I doubt it
as it would be so easy to analyse. It doesn't matter much for the point of
the discussion because showing that some deposition is fast says nothing
about the upper limit to the age of old material.

The reason for the variation is the speed depends on the flow of water, the
acidity and the rate of evaporation. Where there is a constant supply of
water bringing in dissolved calcium carbonate and it evaporates quickly in a
stream of dry air deposition can be very quick. Where water flow is very
slow, eg a drop every hour or two, and runs into a passage where evaporation
is slow then deposition is very slow. Where flow ceases deposition ceases
so there are some passages where deposition only takes place during very wet
spells or may have ceased thousands of years ago due to some change in the
aquifer.

The argument that some cave formations can happen very quickly, however that
may occur, and therefore a young earth is possible, is of course a very weak
because it says nothing about other situations where deposition is very slow
and ignores the direct radiometric measurement which makes no assumptions
about deposition rates at all. For those who are prepared to overthrow any
science that gets in the way of faith radiometry is but a trifle.

Here is another ref to add to those in those in the TO archive

http://www.csiro.au/news/ps21d.html


David

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Relevant Pages

  • Re: inorganic limestone ???
    ... there are three primary forms of limestone: ... temperature, pressure, or water chemistry ... where the calcite is basically the cement ... primary deposition of tufa, travertine, cave speleothems etc. is largely ...
    (sci.geo.geology)
  • Re: inorganic limestone ???
    ... Actually, there are three primary forms of limestone: The fossiliferous stuff you refer to above, crystalline limestone, which contains no fossils, is nearly all calcite, and can be deposited by changes in temperature, pressure, or water chemistry and micrite-- which is a fine grained, non-crystalline limestone which basically forms from a mix of lime and silicate mud --the limy mud under pressure limestone, where the calcite is basically the cement holding the clay together. ... hard water, or had the plumber saw through a pipe to find it clogged with calcite, you believe in precipitation, through the mechanism of temperature change laying down calcite. ... Even though the primary deposition of tufa, travertine, cave speleothems etc. is largely an agitation/offgassing process, initial deposition, and deposition rate can be greatly enhanced by microbial sized plants or critters, which sometimes provide nucleation sites for the calcite/limestone to preferentially precipitate. ...
    (sci.geo.geology)
  • Creationism claim cd250
    ... It says here under response 1 that the stalactites that form rapidly ... Austin Texas and in the Jacobs ladder cave they put a handrail under ... CM long stalactite growing on the handrail. ... knows that that area is famous for Limestone and the stalactite is not ...
    (talk.origins)