Re: Moorad's assumed timeline

From: Michael Roberts <michael.andrea.r@ukonline.co.uk>
Date: Fri May 21 2004 - 02:45:57 EDT

The Ediacaran period is as newsworthy as the election of Reagan as
president. There have been attempts to divide the Precambrian into discreet
periods for a century, but it is difficult due to mashed up rocks and a lack
of fossils.

Many have called this new period the Vendian for decades.

To be personal in 1970 I was working in the Precambrian of South Africa and
most was late PC sediments with glacial material at the top - though then
some questioned its glacial origin. It was relatively easy to work out the
sequence and I am sure I walked over fossils without seeing them. The
Ediacaran is just the top of the sequence I worked on and it makes sense.
Hopefully with some world-wide correlation the older strata will be given a
world-wide classification. Meanwhile we can only note approximate parallels
between the stinkfontein of S Africa and the Torridonian of Scotland which
are of very simialr age.

I still do not understand your timeline as geologists just dont think like
that.

Michael

P.S. Always take the BBC with a pinch of salt (preferably Permo-triassic),
it often gets things wrong.

> No one says that geologists do not use experimental science to set up
their timeline. In fact, that is what I said that historical sciences are
sciences owing to the use of experimental science. There are all sorts of
data that one takes from different sites and sources and thus must
coordinate the timeline according to all existing data. Perhaps you can help
us understand the recent work where the geological time gets a new
period----Ediacaran organisms appear after a series of ice ages that covered
the Earth. Geologists have added a new period to their official calendar of
Earth's history - the first in 120 years.
http://news.bbc.co.uk/1/hi/sci/tech/3721481.stm
<http://news.bbc.co.uk/1/hi/sci/tech/3721481.stm>
>
>
>
> Moorad
>
> -----Original Message-----
> From: Glenn Morton [mailto:glennmorton@entouch.net]
> Sent: Thu 5/20/2004 10:44 PM
> To: Alexanian, Moorad; 'Michael Roberts'; asa@calvin.edu
> Cc:
> Subject: RE: Moorad's assumed timeline
>
>
>
>
>
> > -----Original Message-----
> > From: asa-owner@lists.calvin.edu
> > [mailto:asa-owner@lists.calvin.edu] On Behalf Of Alexanian, Moorad
> > Sent: Thursday, May 20, 2004 12:58 PM
> > To: Michael Roberts; asa@calvin.edu
> > Subject: RE: Moorad's assumed timeline
> >
> >
> > An attorney sets up a scenario in time and fits the known
> > data into that scenario. Doesn't the geologist fit data in a
> > scenario in time? How else can you talk about past events in
> > a time orderly fashion and not fit them in a time sequence?
>
> Sorry Moorad, what you are saying is pure misunderstanding and
> poppycock. Geologists have radiometric dating to pin certain points in
> the timeline via the laws of physics. And as Michael noted, there is
> relative dating, there is the observed rates of sedimentation for
> various rock types today, which if applied to the thickenesses of
> sediments we see in the geologic record fits remarkably well with the
> radiometric dates. When it comes to oceanic sediments we can
> radiometrically tie certain dead nannoplankton to age dates. These
> nannoplankton are found in an invariable order throughout the world's
> ocean basins. There have only been a few hudnred species of these type
> of plankton. They float in the ocean waters and float along with the
> currents which take them all over the world. So we know that these
> plankton form timelines in the sediments of the worlds oceans. Today
> our timelines are based upon the laws of physics. So you can't act as if
> this is just mere speculation.
>
>
>
>
>
Received on Fri May 21 05:30:37 2004

This archive was generated by hypermail 2.1.8 : Fri May 21 2004 - 05:30:39 EDT