Re: Does anyone know how to define the fining upward sequences in field?

On 26 jan, 18:36, mirce...@xxxxxxxxxxx wrote:
On Sat, 26 Jan 2008 02:58:32 -0800 (PST), "basant...@xxxxxxxxx"

<basant...@xxxxxxxxx> wrote:
I am a student of geology and working in Himalaya. i am always facing
the problem to decide whether it is finning upward or coarsening
upward sequence. So can anyone help me to reduce this problem of mine.
I donnot know how long the strata has to take to decide because in
small scale it can be coarseing upward but in large scale it may be
finning upward. Just like, in Nepal Himalaya, as a whole the siwalik
is coarsening upward but in minor  scale there are so many finning
upward sequences.

Within the Siwalik Group the smaller-scale fining-upward successions
are due mainly to the lateral migration of fluvial channels. Overall,
at a much larger scale, the coarsening-upward trend reflects changes
in both tectonic and climatic factors.

Try to define, strictly on descriptive criteria, basic facies types,
organize them in facies associations, and use the latter to construct
facies successions.  You may recognize fining- and coarsening-upward
sequences during every one of these three steps, but most likely you
will have to move past strictly vertical grain-size trends to make
sense of your observations.

Regards,

Mircea

... and what sense will you make of such observations, knowing that
deposition is not related to time !
You can have 5 meters deposited in 5 minutes and a 1000m in a 12 hours
sequence indeed, according to the True Geology !

What can you derive further from any observations at all, especially
the ones to which Jo is pointing out i.e. fluvial & marine
sedimentation while what is considered as fluvial sedimentation is in
fact SECONDARY DEPOSITION OF ORIGINAL MARINE SEDIMENTS !
Further still the interweving of carbonate, clay ( mudstone etc) &
sandstone hand NO explanation in the literature, although it has in
real life since we observe it everywhere.

However you are correct in advising sieving routine to establish
granulometry distribution, the correct interpretation might then come
anytime later... once the detractors of the True Geology are dead !.

Best jpturcaud

.

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