Dr. Nichols.

1) We may examine  different places in the world and see where rocks
are currently forming. We use trained people to document exactly how
rocks are forming currently.  We use well studied records as modern
analogs, or models. [I had visited a place where pyroclastic rock was
freshly deposited on my head.  I went to that place knowing fully
well that "the environment selects the type of rocks that would form
in it", a kind of natural selection thing. We know that  igneous
rocks form at plate boundaries or above hot spots.  We know that
calcareous critters swim in clear tropical waters at which they die
and are later fossilized. Swimming critters do no abound in murky
waters.  We know that glaciers of higher latitudes transport assorted
rocks and deposit those as the glaciers melt away.  Such is how Cape
Cod, Mass., formed. We also infer that, before 15,000 years ago,
during the ice age, the continental shelf was exposed, explaining how
glaciers advanced from the north through Massachusetts to New York,
and further south of that. Sea level has been rising over the last
15000 years and the major coastal cities in the east will be
challenged by that rise whether or not humans contribute to global
warming. The point to underscore here is  that different  environment
select the type of rocks that are formed in them.  There are places
where deltas deposit muds, and underwater rises are covered by
turdidites.  Such explanations in no way contradict the role of
intelligent design, however.]

2) We are also aware that the world has not been the same throughout
time.   We use trained people to document rock records that are
different from those which we have assembled from the modern
environment, and use these records as ancient analogs.

3) We perform experiments with different environmental parameters
(temperature, pressure, fluid type, fluid pressure, oxygen tension,
etc.) as a way of understanding stability field of igneous and
metamorphic minerals, and (redox potential, fluid flow rate, sediment
load, angle of repose of flume, subsidence rate of basin, uplift rate
of provenance, etc.) to asses textures and fabrics developed in the
sedimentary rock record. However, Such experiments are conducted in
larger institutions.

We then use modern and ancient analogs as well as experimental work
to better explain the rock record.  Sedimentary rocks have features
that help us determine the applicable rates of sedimentation. We  can
examine rocks and determine if they were hurricane, tsunami, or other
catastrophic deposits. We can readily recognize such sedimentary
deposits, as we can determine if ancient igneous rock formed above a
subduction zone, or a divergent zone, etc. Our undergraduate students
use major, trace,  and rare earth element chemistries of rocks, XRD
signatures of minerals  and apply appropriate discrimination diagrams
to infer the environment at which igneous rocks had formed.  I am
proud of them and the training my colleagues administer.  In due
course, I intend to apply for a grant that will allow one of our
students to obtain radiometeric age dates for one particular outcrop
that our students commonly use in the study of hard rocks.  Such data
have been determined fby others for the formation elsewhere. However,
I want our program to furnishing the dates so that our  students will
not have fear or aversion to such useful methods of deciphering the
age of rocks. It is not a trivial matter to extricate the appropriate
materials for age dating purposes. Thus, such training will be
worthwhile, and our discussion on raven might result in such
worthwhile consequences.

Returning to the story that made us communicate, as any one can see,
Lookout Mountain is now a mountain.  It used to be a valley a couple
of million years ago, while Lookout Valley and Sequatchie Valley used
to be mountains.  These inferences are based on sound evidence.
Equally, astonishingly, there separate rivers, flowing in different
directions now constitute the Tennessee river by means of river
piracy.  I will quit here.

Meanwhile, I want to assure you that we read our literature and also
contribute to it.

Have a nice weekend, and a profitable spring situation.

HG

>Dr. Churnet,
>
>I thought that "the present was the key to the past" and that there
>is evidence in the geologic record of periods of significantly
>greater volcanic activity worldwide.  Is it impossible that large
>sedimentary rock formations could be formed during such periods?
>
>Even if this not the scenario under which Lookout Mountain itself
>was actually formed, the bigger point in all of this is that 30
>millions years is not "required" to explain 300 meters of
>sedimentary rock.  There are alternate accumulation rates, other
>than 1 cm per 1000 years, that are backed up by observation and have
>been reported in NON-creationist peer-reviewed literature.
>
>Catastrophic events such as earthquakes, volcanic activity, tsunamis
>and hurricanes occur frequently in the present.  Is it reasonable to
>exclude their profound effects when interpreting the past?  Assuming
>a rate of sedementation that is roughly linear and constant may not
>treat the problem appropriately.
>The results are only as good as the assumptions.
>
>I have tried to make this point as clear as possible.  Hope this
>helps.  I'm going back to work now.
>
>Stephen
>
>Habte Giorgis wrote:
>
>>Dr. Nichols,
>>Thanks for clarity of the following reply. What has any of it got to
>>do with sedimentation rates of Lookout Mountains strata? Please do
>>not tell us that it has any relevance to an estimation of rate of
>>sedimentation of Lookout Mountain strata.
>>
>>HG.
>>
>>>Dr. Churnet,
>>>
>>>Observation #1: The volcanic eruption of Mt. St. Helens caused a mud
>>>flow that was observed to form 762 cm of stratified sediment.
>>>Observation #2:  In laboratory experiments, water flow laid down and
>>>sorted heterogeneous sand mixtures into multiple strata similar to
>>>that seen in sedimentary rock formations.
>>>Observation #3:  Sandstone and limestone type sedimentary rocks have
>>>been observed to form in a timespan ranging from 5-78 years.
>>>
>>>Conclusion: It is possible for multiple centimeters of sedimentary
>>>strata to accumulate and lithify in short periods of time.
>>>
>>>I'm sorry for any confusion.
>>>
>>>Stephen