Glenn, I have enjoyed your many posts which illustrate the magnitude
of problems that would be generated by a global flood of the
proportions which could accomplish all that the YEC flood geology
scenario requires. Personally, I think that the geological record is
so clear that we are only left with a simple choice wrt the Deluge.
Bluntly put - The Noachian flood was either a local event or a
complete miracle which left behind no evidence for science to find.
Having made my philosophical position clear, as an economic
geologist/exploration geochemist somewhat familiar with the
geochemical cycle of mercury I will now argue that your mercury
poisoning scenario is seriously flawed. That flaw is in your basic
assumption that mercury "must have been released by the erosion of
pre-flood igneous type of rock which was then made into sedimentary
rock".
This is too simplistic a picture of how mercury occurs in igneous
rocks. Mercury occurs most often as a trace element within sulfide
minerals and less frequently within the common silicate minerals. In
rare cases, mercury combines with sulfur to form the mineral cinnabar.
Large concentrations of cinnabar, although rare, is considered
mercury ore and is mined when found. (BTW, An additional factor which
affects your mathematics is the use of an average crustal abundance
value of 0.5 parts per million (ppm) mercury. Most crustal abundance
estimates range from 0.07 to 0.5 ppm mercury with the higher values
found primarily in the oldest literature. A more conservative value
would be 0.1 ppm mercury for igneous rocks.) An excellent readable
summary of information about mercury and its abundances in various
materials and forms is USGS Professional Paper 713, "Mercury in the
Environment" (1970).
Physical erosion of mercury-bearing sulfide and silicate minerals will
not release all of the contained mercury to the environment. Since
cinnabar is a resistate mineral, even erosion of mercury deposits will
not release all of the mercury to the environment. As an exploration
geochemist, I frequently sample stream sediments and chemically
analyze them to find traces of mercury (as well as other elements)
that have eroded from potential ore deposits. Thus my research
depends partly upon the observation that all of the mercury does NOT
escape from the rock during erosion. I have no firm data on how much
mercury does escape during erosion but my gut feeling is that it is
much less than 10% and most likely less than 1%.
When free mercury does enter the environment, its density (13.5 times
heavier than water) ensures a quick trip to the bottom of any stream
or lake. I have personally found free mercury in a gold pan after
washing out the dirt and gravel collected from a stream bottom.
Mercury is also easily adsorbed by clay particles suspended in the
water and hence is commonly enriched in shale deposits. (The shales
of the Green River formation have yielded mercury values that are 50
to 100 times average crustal abundance values.) Another important
scavenger of mercury in water is organic material. Thus the common
route of entry of mercury into the environment is to be adsorbed by
fine sediment and organic matter that is deposited in a lake or stream
and then eaten by small invertebrates which then in turn are eaten by
fish and so on. Plants also play a role but this can be considered
negligible for the YEC flood scenario.
Some friends of mine recently did some studies of mercury
contamination in fish that spawned in streams which drained
actively-eroding, naturally-occurring mercury deposits in SW Alaska
(See Gray, J.E. and Sanzolone, R.F., eds., 1996, Environmental Studies
of Mineral Deposits in Alaska, USGS Bull. 2156). The maximum mercury
concentrations in edible parts of these fish were 0.6 ppm which is
still below the FDA 1.0 ppm limits.
With these data in mind, I doubt that the flood survivors were really
at much risk from mercury poisoning due to the release of mercury *by
erosion of igneous rocks*. OTOH, the large amount of mercury vapor
released by the abundant volcanos and hot springs (the primary natural
sources of mercury) that must have erupted during the flood might have
finished off anyone who had survived the acid atmosphere (See "Bill's
flood and acidic waters" thread beginning with
http://www.calvin.edu/archive/evolution/199807/0173.html) and the
inevitable steaming away of the oceans from the release of heat due to
the volcanic eruptions, erosion friction, and other exothermic
reactions that must accompany the YEC version of the flood.
Additionally, we shouldn't forget that in addition to sulfuric acid and
mercury, those same volcanic emissions can also contain large amounts of
hydrochloric acid, arsenic, antimony, and cadmium. Choose your poison!
Finally, lest anyone think that this post in any way suggests mercury
poisoning is not a real problem today, let me point out that a major
contributor of mercury to the environment today is man. And that the
mercury which we release is most commonly in organic forms which are
several times more toxic than free mercury or mercury vapor. This
fact was recently brought home by the tragic death of chemist Karen
Wetterhahn. (See "The Trembling Edge of Science", by K. Endicott,
Dartmouth Alumni Magazine, April 1998, p. 22-31.) Wetterhahn was
carefully transferring a small amount of dimethylmercury from one
container to another, following all proscribed precautions, when 1 or
2 drops of liquid dripped onto her left-hand latex glove. Unbeknownst
to anyone at the time, latex gloves are permeable to dimethylmercury
and so the liquid was immediately adsorbed by her skin. Six months
later she was diagnosed with severe mercury poisoning and 10 months
later she died. Mercury poisoning is real and it is serious.
Since I am currently subscribing only to the digest-version of this
list, I would appreciate it if a copy of any reply was also sent to me
directly.
Steve
[The opinions expressed here are my own
and are not to be attributed to my employer]
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