On Tue, 09 Jan 2001 16:22:51 +1100 Jonathan Clarke
<jdac@alphalink.com.au> writes:
> These features can be subtle in cross section. Mussman et al. noted
> that the Knox surface is a was in some places a disconformity, missing
only a
> few m The equivalent post-Romaine surface in Quebec is extremely
planar for
> the most part. However, it still shows features of subaerial
dissolution, as
> described by Desrochers and James.
Having fought through the coal-origin issue and realizing that obvious
empirical data is being unintentionally overlooked because it doesn't
allow conformance with the reigning uniformatarian paradigm, I would have
to say that your conclusion of subaerial dissolution is suspect (by
analogy with conclusions about the origin of coal ). I would have to
study the outcrops and literature for myself, but just at this distance I
am thinking that "extremely planar" is incompatible with "subaerial
dissolution." I am not saying that you are not right, just that I am
skeptical.
> I did a quick search using Georf and material in the AGSO library, but
> uncovered little that dealt with the contact relationships of these
units.
> The exception was one paper which did mention that there was quite
> significant relief along the contact Jefferson and Lousiville
Limestones, but
> did not clarify whether this was depositional relief (the Louisville
contains
> numerous reefs), post depositional erosion, or some combination of
these.
> However the contract regionally is not as planar as the photos in
Whitcomb
> and Morris would suggest.
I know the depositional relief can be high. I have seen high-angle talus
deposits against bioherms in the Holston Marble near Knoxville,
Tennessee. My thesis area had been mapped as structurally complex. I
showed that the area was only gently deformed but depositionally complex.
Bill
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