Scientific Fact versus Interpretation

Think about how easily sand can be made into sand castles by just adding a little water. Desert environments appear to be dry, but can have quite a bit of moisture in the early morning air. And obviously, sand and silt in the marine environment is invariably moist, so suddenly a windstorm blows sediment into a shallow pond/creek/calm ocean/lagoon with ripples on the bottom and soon the ripples are covered in a cm thick layer of silt. And viola! Preserved ripples.Same basic processes for fossil track preservation.This is just one of several preservation processes, however.

I've only posited one possible way to preserve tracks or ripples. I think we discussed this once before in another thread and there were several processes which seemed plausible. I think clay, silt, and cement components were mentioned as 'setting' agents. The new layer does not have to be a different size or type of sediment. I think all you really need is for the tracks, ripples, mudcracks, raindrops, etc. to form in sediment that can retain an impression long enough to survive in any particular environment. Are you referring to a specific location or is this a general question?Thing is, the way geologists interpret the stratigraphic record is to compare what we see in the rocks to what we see today. Perfect analogues are not always necessary or possible, but all it really takes is making some pretty simple observations of the modern landscape and see if we can see the same or similar things in the rock record. Or vice versa. And we do.

Thanks for that paper, holmes, it actually has applications to both my projects. Karlstrom has been doing similar work since the 70s and I wouldn't be surprised if he alone had more than 50 published papers on similar topics.

I guess I'm just delusional like that.

My background is economic geology, specifically mineral exploration/mining work in the precious metals industry. That's where I started out and I later went back for a Master's when the price of gold took a dive in the late 90s (when many geos were laid off).The paper you linked discusses regional structural trends/shear zones in Colorado that are probably related to arc accretion in the Proterozoic.One of my projects is an intrusion located in southern Wyoming about 15 km south of the Archean-Proterzoic suture. In the past, I was unaware of the presence of those two thrusts located up north as they are not present on any of the maps I have.The second project is located in the vicinity of the Black Canyon. I've been mapping pediment surfaces (and structure when I can find it) out there in an attempt to reconstruct the geomorphic and erosional history of the area, basically paleolandscape reconstruction. The pediment surfaces, which are comprised of unconsolidated gravels up to boulder size, occur at different elevations similar to river terraces, and probably represent different pulses of stream formation/deposition at the end of at least two glacial periods.The pediment project is only one portion of a larger project involving studying rocks deposited in the Western Interior Seaway. We recently recovered 500+ feet of core drilled into Cretaceous rocks (located near the Black Canyon) that were deposited in the seaway and I am logging that right now.The paper you linked specifically discusses structure in the Black Canyon area. Just based on a quick perusal of the paper, the authors appear to have re-interpreted some of the major structures, so it will be interesting to see why.This message has been edited by roxrkool, 03-17-2006 09:40 AM

Faith, that is the language of science. Geologists speak and write about geology in the present tense. If the geologic community overwhelmingly accepts a theory based on the weight of the evidence, then we speak as if it is fact. If less data exists to support a theory, then we add words like "indicates," "suggests," etc.Additionally, calling scientific theories 'conjecture' is misleading if not patently false. Because you personally refuse to acknowledge the data, is not a good enough reason to impugn the intellectual capabilities, professional integrity, and motives of all scientists who don't follow your particular brand of logic.