Re: Tides Record 18-Hour Earth Days

Stephen Jones (
Thu, 11 Jul 96 22:10:05 +0800


On Sun, 07 Jul 1996 20:11:05, Glenn Morton wrote:

GM>I am back. I decided I better stay on if I was going to reply to
>Stephen's critiques.
>I have just recieved word that the July 5 Science will have an article on
>the evidence for an 18 hour day from the pre-cambrian era. For any
>young-earther's that might be lurking, evidence of a drastically more
>rapid spin of the earth in the past is quite widespread.

I am not sure why Glenn links my name with "young-earther's". For
the benefit of newcomers (and Glenn?) I am an "old-earther"! :-)

GM>The article is by Charles P. Sonett and Aramais Zakharian. A
>couple of quotes from the note I received. This is from
>> They studied sediments left by tides preserved in four
>> exceptional formations: the Big Cottonwood Formation near Salt
>> Lake City, Utah, deposited 900 million years ago; the Elatina
>> Formation near Adelaide, Australia,deposited 650 million years
>> ago; the Pottsville Formation of northern Alabama from 312
>> million years ago; and Indiana's Mansfield Formation from 305
>> million years ago. The ages of these formations are known by
>> their geological context.
> The discovery of "tidalites" from southern Australia in
>> the late 1980s alerted scientists like Sonett to a new way to
>> examine how the moon's orbit has evolved through time.
>> Layers of tide-deposited sedimentary rock, called
>> tidalites,are records of daily tides.Dark bands that
>> periodically occur in the layers clearly mark the semi-monthly
>> "neap" tides, or lower tides that form during the waxing and
>> waning phases of the moon, i.e., when the moon is farthest from
>> aligning with the sun and Earth. Lighter areas between the dark
>> bands mark the semi-monthly "spring" tides, or the higher tides
>> that form when sun, Earth and moon are most nearly aligned, at
>> full moon and new moon.
>They go on to note that the moon will reach synchronous orbit with the
>earth in 15 billion years (given the present rates of recession). That
>assumes, of course that the earth and moon are not swallowed in the death
>of the sun in about 5 billion years or so.

Nothing in the above says anything about an "18 hour day from the
pre-cambrian era", so preumably Glenn has inadvertently left it out?
But in any event it is nothing really new. Old-earth creationist
Alan Hayward in 1985 wrote of evidence of 21.8 hour days in the

"Recent research has shown that the days and nights are getting
longer. Because of friction, mostly that of the tides, our spinning
earth is gradually slowing down. The rate of deceleration has been
measured against atomic clocks, and it averages 0.000 015 seconds per
day per year at present, although there is reason to think that over
long periods in the past the slightly higher figure of 0.000 020
would be more appropriate. So a million years ago the days would
have been about 20 seconds shorter than nowadays. But measurements
indicate that the length of the year is no hanging. This is what
might be expected. There is no appreciable action in outer space to
slow down the forward motion of the earth as it orbits the sun.
These two facts together - a lengthening day and a constant year -
mean that the number of days in a year must gradually decrease so as
to balance the books.

Now let us go back in our imagination to the Devonian period, which
geologists believe was about 400 million years ago. The days then
would have been about 400 x 20 seconds shorter than they are now,
which would make them about 21.8 hours long. But the years then
would have contained 365 1/4 x 24 hours (= 8766 hours), just as they
do today. So if we divide the number of hours in the Devonian year,
8766, by the number of hours in the Devonian day, 21.8, we arrive at
an estimate of the number of days in the Devonian year. It comes to
just over 400 days.

Surprising though it may seem, we have ways of seeing whether this
really was so. Certain living species of coral and of shellfish not
only have annual growth bands like tree rings; they also exhibit
daily growth bands. With experience, researchers can pick out about
365 of the daily growth bands between the yearly ones. Fortunately
(or should we say, providentially?) certain fossil corals and fossil
shellfish from the Devonian period display the same phenomenon.(16)
And in both the corals (17) and the shellfish (18) there are about
400 daily bands between the annual ones. This provides an unexpected
and striking confirmation that the conventional geological date for
the Devonian period is reasonably correct.

(16) D. E. Wonderly, in an appendix to R. C. Newman and H. J.
Eckelmann, Genesis One and the Origin of the Earth. Baker, Grand
Rapids, 1981, p. 96.

(17) C T. Scrutton, 'Periodicity in Devonian coral growth.'
Paleontology, 1965, vol. 7, pp- 552-8.

(18) S. J. Mazzullo, 'Length of the year during the Silurian and
Devonian periods-new values.' Geol. Soc. Amer. Bull. vol. 82, 1971,
pp. 1085-6.

(Hayward A., "Creation and Evolution: Rethinking the Evidence from
Science and the Bible", 1985, Bethany House: Minneapolis MN, 1995
reprint, pp95-96)

I am not sure how YECs relate the six days of creation to the
conventional geological eras, but presumably they could accept this
evidence if they maintained either that the six days of creation
were not all exactly 24-hour days or they resorted to an appearance
of age argument?

God bless.


| Stephen E (Steve) Jones ,--_|\ |
| 3 Hawker Avenue / Oz \ |
| Warwick 6024 ->*_,--\_/ |
| Perth, West Australia v (My opinions, not my employer's) |