Re: [asa] Accuracy vs. Methodology in Science Education

From: Steven M Smith <smsmith@usgs.gov>
Date: Fri Jun 01 2007 - 12:50:07 EDT

Christine Smith quoted the following:
>>
>> "Brian Benson, an eighth-grade student who won first
>> place in the Life Science/Biology category for his
>> project "Creation Wins!!!," says he disproved part of
>> the theory of evolution. Using a rolled-up paper towel
>> suspended between two glasses of water with Epsom
>> Salts, the paper towel formed stalactites. He states
>> that the theory that they take millions of years to
>> develop is incorrect.
>>
>> "Scientists say it takes millions of years to form
>> stalactites," Benson said. "However, in only a couple
>> of hours, I have formed stalactites just by using
>> paper towel and Epsom Salts.""

Merv replied:
>
> This also is not an answer to Brian's question /
> (statement really) over the antiquity of stalactites,
> but more commentary on it. Geologists on this list
> are the ones who could enlighten us. E.g. is it really
> claimed that these things all took millions of years
> to develop?

Merv,

Your post deserves a reply. I kept hoping one of the other geologists on
the list would respond since I am busy dealing with 2 graduations and
getting ready to do fieldwork this summer in Alaska. Alas! I couldn't
resist your appeal.

You have picked up on one of the primary misstatements in this 8th
grader's project. Geologists do not claim that all stalactites "take
millions of years to develop." As a teaching exercise, Brian should be
asked to document this statement using primary sources from speleothem
(cave formation) researchers. In secondary sources, Young-Earth
Creationists (YEC) claim that scientists claim that stalactites take
millions of years and then point to stalactites forming on bridges, tunnel
ceilings, and mines as if they think that we have never noticed. In
reality, the rate of stalactite growth depends on several factors -- (1)
the rate at which water seeps through the overlying rock; (2) seasonal
variation in groundwater flow; (3) the solubility of the specific
stalactite-forming mineral; (4) the concentration or saturation of the
dissolved mineral in the dripping water; and (5) even the atmosphere and
humidity of the cave or void where the stalactite is formed. Every cave
will be different. Some might only take a few years and some could
conceivable take a million years to form a particular stalactite.
(Sidebar: Although I think that stalactite formation is an excellent
topic for a science fair, it shouldn't belong in the Life Science/Biology
category.)

Within temperate zones, the seasonal differences in water flow and mineral
saturation often create distinguishable bands in speleothems. A cross
section through one of these stalactites would look like tree rings.
Assuming that each band or couplet represents annual deposition, one could
simply count the rings to determine a *minimum* age for the stalactite.
Note that the age of the stalactite is not necessarily equal to the age of
the cave and is certainly not equal to the age of the enclosing rock and
especially not equal to the Age of the Earth.

> Close to where I live, flood waters in the summer
> of '93 eroded some significant gullies (some around
> 30 feet deep) through hard rock & soil. The resulting
> "cliffs" were not trivial things to behold. This was
> taken by some local YECs as a triumphant answer to
> the claim of the Colorado river needing millions of
> years to carve out the Grand Canyon. If these large
> rock formations could be shaped in a matter of weeks
> by a local flood, then the Grand Canyon feat should
> be (relatively) quick child's play for global flood
> waters. So does that represent a slam-dunk for flood
> geologists on age issues?

There are a whole bunch of YEC arguments that can be described as one
fallacy. We could call this The Fallacy of Assuming Constant Optimal
Rates & Conditions. In the science fair experiment described above, Brian
created the optimal conditions for stalactite growth (an extremely soluble
mineral, in a saturated or even supersaturated liquid, transported at a
high rate through a very permeable paper towel, in a reasonably dry
atmosphere). Assuming Constant Optimal Rates & Conditions, Brian then
concludes that stalactites always form quickly; perhaps even within hours.
 This fallacy is almost always accompanied by a second and somewhat
related one. We could call this The Fallacy of Assuming a Minimum Age
Equals the Maximum Age. In reality, Brian's experiment only demonstrates
that, at a minimum, the stalactite, cave, or Earth is a few hours old. It
tells us nothing about the maximum possible age.

An analogy illustrating the two fallacies: The current land speed record
for a wheeled vehicle is a little over 763 miles-per-hour. Therefore it
should not take me more than an hour and 20 minutes to drive the 1,000
miles from Denver to Chicago. However, it actually took me almost 2 days
in my underpowered 4-cylinder Nissan pickup truck pulling a 20-foot
trailer. The morals of the story: In the real world, you seldom achieve
or maintain the constant optimal rates and conditions. Constant optimal
rates and conditions will only give us the MINIMUM possible time and not
the maximum. If I had broken down or had an accident in Beaver Crossing,
Nebraska, it might have taken me weeks or even years before I got to
Chicago.

Your example of erosion rates during the flood of '93 falls under the same
category. Geologists recognize that more erosion takes place during one
'100-year' flood than during 99 years of normal flow. I cringe every time
I hear someone say like "The Grand Canyon eroded one sand grain at a
time." Baloney! Most rates are variable and episodic. You can't
assume constant optimal rates and conditions over any sustained period of
time.

So how about Noah's Flood? Surely a massive one-year-long cataclysmic
deluge would provide those optimal rates and conditions, wouldn't it?
Well, perhaps ... for some things but not for everything. Note that Flood
enthusiasts call for the deluge to erode solid rock, sort out the debris,
deposit the sediments in well sorted layers, create solid rock out of the
layers, and finally erode it again. They also need optimal conditions for
depositing carbonates and then dissolving carbonates to create caves,
followed by precipitating carbonates to create speleothems. Each process
has its own set of optimal conditions and often these conditions are
mutually exclusive; they are the opposite of what is needed for a
different process.

The absurdity becomes apparent when you realize the enormity of all of the
optimal conditions and rates that you would need during the Flood and
ensuing 4,500 years just to create all the different geologic features
that we currently see. The following is only a partial list of some
geological processes and products. Each one takes some period of time to
happen. Some are fast, some are slow, and some rates we don't know but
most are probably variable. Only a few of these have ever been used to
estimate ages of any sort (usually minimum ages for a specific feature).
The short time frame for the YEC/Flood geology paradigm would require
optimal conditions and rates for almost all of these (both simultaneously
and consecutively) in order to produce what we see today in the geologic
record.

----Processes and Products that require time----
 * Erosion of solid rock to make sediment;

 * Sorting of sediment clasts by size and mineralogy (e.g. nearly pure
well-sorted, frosted, rounded quartz sands; winnowing of clays ...);

 * Chemical weathering (formation of clay minerals from feldspars, micas,
and other minerals);

 * Rock disintegration and soil formation (paleosols, saprolites,
pisolites, laterites, bauxites ...);

 * Formation of distinct clastic sedimentary rock types (shales,
mudstones, sandstones, siltstones, conglomerates, some limestones ...);

 * Formation of different chemical sedimentary rock types (evaporites,
gypsum, anhydrite, halite (rock salt), phosphorites, carbonates, sinter,
tufa, travertine ...);

 * Diagenesis -- the conversion of sediment into sedimentary rocks
(dewatering, compaction, cementation, recrystalization, dolomitization,
formation of chert nodules ...);

 * Formation of sedimentary structures indicating different environments
of deposition (ripple marks, mud cracks, salt casts, crossbedded
sandstones, paleochannels, facies changes, black shales, red beds, oolites
...);

 * Formation of structures indicating erosional environments
(disconformities, angular unconformities, basal conglomerates ...);

 * Formation of regularly alternating sedimentary layers (varves,
turbidites, rhythmites, cyclothems ...);

 * Formation of different organically derived deposits (oil, coal, reefs
and bioherms, crinoidal limestones, algal limestones, fecal pelletal
limestones, coquina, chalk, diatomaceous earth, coprolite layers ...);

 * Formation and preservation of different trace fossils (tracks, trails,
burrowing, bioturbation ...);

 * Formation of different ore deposits (hydrothermal precious metal
deposits, volcanic massive sulfides, sedimentary exhalitives, skarns,
porphyry copper or molybdenum deposits, Mississippi-Valley-Type lead-zinc
deposits, roll-front uranium deposits, banded iron formations, Carlin-type
disseminated gold deposits, multiple brecciation and void crystallization
episodes, accompanying alteration of host rock -- silicification,
argillization, propylitization, sericitization ...);

 * Formation of igneous rocks and associated features (cooling of
batholiths, plutons, contact metamorphism, roof pendants, cross-cutting
dikes, coarse-grained igneous minerals, porphyries, pegmatites ...);

 * Fossilization (burial rates, petrifaction rates, Lagerstatten, fossil
succession -- including distinct zones for ammonites, pollens,
foraminifera, radiolaria ...);

 * Formation of volcanic features (ash falls, welded tuffs, flood basalts,
pillow basalts, columnar jointing, shield volcanoes, stratovolcanoes,
cinder cones, diatremes, diamond-bearing kimberlite pipes, Hawaiian
Island-Emperor Seamount chain, Yellowstone-Snake River Plain volcanic
track ...);

 * Formation of glacial features (multiple ice ages, continental
glaciations, glacial tills, tillites, moraines, cirques, U-shaped valleys,
glaciers & ice sheets with multiple annual layers ...);

 * Formation of geomorphic features (incised meanders, retreating
waterfalls, arches, natural bridges, buttes, mesas, valleys, canyons ...);

 * Formation of karst features (solution caves, sinkholes, karst towers,
cave sediment, stalactites and other speleothems ...);

 * Plate Tectonics (mountain building episodes, continental rifts, thrust
faulting, recumbent folding, subduction zones, trenches, mid-ocean ridges
...);

 * Miscellaneous features -- lumped because I am running out of steam,
time, and inspiration (meteor craters, stretched-pebble conglomerates,
fossil-bearing conglomerates, deep ocean sediments, ocean chemistry, salt
domes, metamorphism, Precambrian history, reversed paleomagnetic sequences
...);
 
----------

I apologize for all the jargon. It was necessary shorthand to keep from
making a book out of this post. Any good Geology 101 textbook will
describe most of these. I recognize that YECs will pick certain items out
this list and say that they can explain them (however, see The Fallacy of
Assuming Constant Optimal Rates & Conditions above). I also recognize
that the significance of many of these processes and products will not be
immediately apparent to everyone (Why should we care about
stretched-pebble conglomerates? etc.).

In summary and conclusion ...

(1) Pointing out optimal conditions or accelerated rates is usually
irrelevant; at best they only give a minimum age for the specific feature
and have little to do with the total 'Age of the Earth'. For me, the
cumulative evidence all points to an Earth age that has to be much greater
than 6,000-10,000 years.

(2) Just about any geologic exposure has evidence for multiple processes
and products that require time. The challenge for the YEC/Flood Geology
paradigm is to logically demonstrate how you can simultaneously and
consecutively accelerate a large number of these processes to compress
time and produce an actual geologic section. A layer-by-layer explanation
of the stratigraphic and geomorphic exposure at the Grand Canyon would be
a good place to start since this seems to be a favorite YEC locality.

Steve
[Disclaimer: The statements in this post are my own. Do not credit or
blame my employer.]
_____________
 Steven M. Smith, Geologist, U.S. Geological Survey
 Box 25046, M.S. 973, DFC, Denver, CO 80225
 Office: (303)236-1192, Fax: (303)236-3200
 Email: smsmith@usgs.gov
 -USGS Nat'l Geochem. Database NURE HSSR Web Site-
  http://pubs.usgs.gov/of/1997/ofr-97-0492/

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Received on Fri Jun 1 12:50:22 2007

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