Thank you. Unfortunately the college system often inhibits good,
honest questions because the student is afraid of being seen as a
I bought my college geology text in high school for different
reasons. My hs friends were from a family whose dad was one of
Ontario’s most eminent geologists and his wife was my hs chem teacher
(later my TA in college chemistry). Also I had discovered two species
of shell fish replacement fossils in the sand stones about 30 miles
SW of Ottawa. The replacing mineral was quartz and the crystals were
small but visible.
The text is written by a team of ivy league geologists and there is
a section titled “The Radioactive Clock” and “The Scale of Time”. I
will quote it directly and ask the questions I should have asked 40
years ago. The worst that can happen now is that somebody may take
away my rocking chair at the eventide home and declare me “off my
rocker” for a while.
I have sampled, stratum by stratum from 47 strata of a rockface at
about 1,000 foot elevation on a mountain side. I will submit these
samples to the local historic society when I know more. Map 92GE of
the GSC says the rocks of this mountain are Jurassic-Cretaceous so I
guess that means about 100 mya to 160 mya. I have some questionable
fossils/pseudofossils but the fossilized wood is a for sure. I have a
palm-sized piece here and a dozen others in my sampling right here.
Here is what Longwell (Yale) et al say in their text, using uranium
to illustrate the general principle:
Radioactive “decay” proceeds as the U clock runs down.from Time 0
and atoms are lost as they convert to Pb which “changes the atom of
uranium to something different”.
Thus “the ratio of lead to uranium should give the age of the
They caution about the MIGRATION of minerals which invalidates the
clock, and they give the most obvious example of surface weathering.
Here then are the problems I have with being sure this U clock or
similar radioactive clocks are valid:
(1) The Transformation Problem:
When was the quartz in those Ottawa replacement fossils created? It
migrated into the sandstone and the shells of those shell fish we
assume via rock-borne water. Other than cracks in rocks as conduits
for water, rocks are like sponges I have learned. What the gemologist
needs to know in selling the fossils is when they arrived in the
______ was transformed into U to start the clock. What is _______?
My rock samples typically contain the whole Periodic Table or close
to it. Were all those elements created at the same time? Did they all
turn to the constituent minerals at the same time? Do we assume that
ALL of the rock clocks in that rock formation with radioactive decay
had the same Time 0? Did the Si and O in the quartz have the same
Time 0? What was Time 0 when they bonded?
(2 The Migration Problem
Parallel this with U. When was the U created? U and other
radioactive mineralization are found in my samples of the 47 strata.
I have done two assays so far. Was U created first in rock A and then
migrated to rock B? Likewise for the Pb of decay. Both can migrate in
and out of rocks given millions and billions of years. How valid can
the ratio then be?
I have run a number of porosity tests on these slate-like strata.
Some samples are so porous (like the fossil wood) that you see many
tiny bubbles form in water and you can hear the bubbling. Minerals
migrate in and out because the strata are profoundly cracked,
fissured, faulted and some narrow strata are crumbled and powdered.
Imagine how much mineralization has been carried in and out over 100
Also I found a very crumbly and powdery stratum which contains a
large, fairly recent tree root. How recent? When did it get in there?
Maybe it is only.0001% fossilized but it surely has started. Do we
assume that the previous fossil sample is from 100+ mya? In 100 myf,
how will historical geologists know which sample of wood got
Clocks don’t lie but they have to be read honestly.