Valentine Pontifex

John Woodmorappe has the feature article today on AiG:

More evidence against so-called paleokarst

I am not a geologist but I find the illustration very interesting.

Correctly me if I am wrong: but don't I see at least three clear unconformities in it? On the top there is a local unconformity. Almost imediately below it is a nonconformity. Near the bottom is a disconformity.

Rhaedas

I'm no geologist either, but all I see is some pointing at possible conflicting data in some places. So what? Mountains move, and shuffle and even turn layers upside down...I see nothing here than allows him to do the typical YEC conclusion of "the Flood happened. QED".

Every YEC attack on science is based on the incorrect assumption that a scientific theory is "The Truth" and perfect, and one example of error somehow discounts the whole theory, and thus must lead to the conclusion that the bible is true, period. Never mind the overwhelming evidence that supports a multi-billion year old earth...

Joe Meert

JM: Well, he uses a sketch to make a non-point. Basically, he has to argue that this limestone was deposited underwater and solidified underwater in a short time period during the flood. Woody does not comment on what sort of temperature fluctuations happened because dissolution (and precipitation) of calcium carbonate is temperature dependent. However, based on the fact that there are cross-bedded sandstones immediately overlying and infilling the karst, I would guess that the deposition of this limestone was at fairly shallow depths (also strange for the flood). The intense heat release he proposes would not favor precipitation of calcium carbonate (limestone) so there would be no limestone to dissolve. The article is very sketchy on details (no surprise there) and this isn't exactly one of the 'best cases' ever presented for a global flood. I will ponder this some more in a couple of days when I clear my plate of other responsibilities.

Cheers

Joe Meert

ps418

I'll have a closer look at this in a few weeks, after I finish the article I'm writing on dinosaur lungs.

The main argument Woody seems to make is that some of the karst fills exhibit slickolites, and the presence of slickolites on the infill indicates that the overlying sediments were deposited before the karst formed. But that's not correct. Slickolites so indicate movement, but they don't show that the karst was formed post-burial. It is possible for instance that the slickolites were formed during early diagenetic compaction, as sediment infill is compacted a bit into the karst cavities. Woody's own explanation --that karst cavities were formed by hydrothermal properties-- is also a ripe target for refutation. It should be relatively easy to look for evidence of low-tempeature hydrothermal alteration of the associated rocks, as well as evidence for the hydrothermal plumbing that would have to have existed.

Patrick

N.Wells

There is a great paper on the strata discussed by Woodmorappe, by William J. Sando (1988, Madison Limestone, Mississippian, Paleokarst, in Noel P. James and Phil. W. Choquettte, Paleokarst, Elsevier).

Woodmorappe makes a big deal out of some work by L.W.D. Bridges. However, Sando's total comments on Bridges' suggestion (following a more standard "paleokarst" interpretation and many nice photos) are "A highly imaginative hypothesis of Laramide-Tertiary subsurface solution (Bridges 1982) to explain the Madison paleokarst features lacks verifiable evidence."

Sando describes complex surficial and near-surficial (vadose) karst features at the top of the Madison, and makes a case that the complex but different lower dissolution happened deeper below the surface, mainly below the groundwater table.

Woodmorappe makes a big deal about all paleokarst needing to be formed at the surface and prior to burial. In contrast, one would expect to find a variety of surficial and subsurface karst features in paleokarst, and one would also not be surprised to find karst processes continuing in one area while another is being buried or even during burial in the same location. Subjacent karst collapse sinkholes (sinkholes formed by cave collapse below noncarbonate sedimentary rocks and subsidence sinkholes (formed by dissolution of limestone under unlithified noncarbonate sediments) are well understood and would not be surprising if associated with paleokarst. His comments about paleorelief are also off the mark as karst surfaces range from tower karst (like the knobby hills in China) to karst plains. (See other papers in the James & Choquette book.)

Woodmorappe's claim that "a challenge to subaerial exposure here also challenges the entire sequence-stratigraphic concept" is just plain silly. It would barely even modify current ideas relative sealevel change in the midcontinent in that time period.

Woodmorappe indulges in one piece of out-of-context quoting that is so outrageous as to be worth detailing.
Here's Woodmorappe quoting two Geological Society of America abstracts by Jim Evans:

" ‘The Pennsylvanian [Upper Carboniferous] Molas Formation has long been considered as a terra rossa (residual) paleosol that developed above a paleokarst surface above the Mississippian [Lower Carboniferous] Leadville Limestone. A detailed field, SEM/EDS, XRD, and petrography study shows that this classic interpretation is untenable.’23

" The erstwhile paleosol, an obvious long-time indicator, is now considered a massive aeolian siltstone (loessite). In like fashion, the characteristic reddening of the Molas Formation, often attributed in the past to long-term near-surface weathering, is now regarded as a diagenetic feature.24 "

Woodmorappe's citations are:
23: Evans, J.E. and Reed, J.M., Reinterpretation of the Pennsylvanian Molas Formation (San Juan Basin) as a loessite, not as a terra rossa paleosol, Geological Society of America Abstracts with Programs 31(7):A–160, 1999. text.

24: Reed, J.M. and Evans, J.E., Diagenetic reddening of the Molas Formation (San Juan Basin): infiltration features in a Pennsylvanian loessite, Geological Society of America Abstracts with Programs 31(7):A–281, 1999.

Firstly, note that Evans work is in New Mexico, which is far enough from Wyoming that the overlying unit is completely different (the Molas Formation, as opposed to the Darwin Sandstone), and the Madison has become the Leadville. What holds in one area need not apply to the other.

Secondly, Jim's abstracts only refer to the interpretation of the Molas as untenable, not to the concept of Late Mississippian paleokarst. His second abstract (p.281) explicitly says "In the Molas Formation, the infiltration front can extend into the upper part ('karst towers') of Leadville Limestone, causing reddish fracture fills and red mottling within the paleokarst". Note that he refers to paleokarst in general and tower karst in particular. The paper after Sando's (by De Voto) in the James' book also talks about paleo tower karst at the top of the Leadville, and you can't get more surficial than tower karst. Woodmorappe clearly wants the reader to think that the 'untenable classic interpretation' includes the paleokarst features, but it absolutely and clearly does not.

Note also that Woodmorappe did a terrible job of citing and/or finding finding relevant literature, such as the Sando and De Voto papers.