This is an archive of CompuServe forum messages from 1985 to 1995, as saved in transcripts by John Foust.
Search Results (26 messages)
> No big argument here either, just a qualification that the several orogenies we've discussed here which formed the mountain chain apparently proceeded from north to south over time. Devonian beds are clearly involved in the folding in northeast PA and southern New York, and these had to have come…
> I see what you're saying here, and I think you're basically right, but I don't see your "roots" going down very far. Remember, these are sediments which have overflowed the edge of the continental craton being pushed back by the plate collision like you'd push back the cuticle of…
I agree with you, Doug. As deep and complete as the erosion of a faulted and folded region could ever be, it would still be differential between layers. Resilient beds, and/or inclined beds, will always produce relief. Nothing in the Central Appalachians, at least, has been eroded flat. The inverted…
Always great to see another Geographer! Best of luck to him. If he hasn't checked the MAPFORUM, there's always some interesting cartographic chat over there. Most Physical Geography postings are in the various sections here; the best Environmental and Human Geography discussions are over in EARTH. The thread subjects often…
Ahh, yes … Waterpocket Fold. That and a waitress in Flagstaff nearly prevented me from returning to my beloved Central PA.
Agreed with most of your post, but I understood the collision BEGAN at this time or a little earlier and progressed southward. Or else a brief mountain building event in the early Devonian in what is presently New England was followed by a longer, more involved event sometime later in…
Arrrgh! Out of 457 geologic paradises to check out when I was in the SW two years ago, I had time for all too few, and this was one. Time to go again. I'll check the maps. I always wondered about rubble in the classic karst topography. Where does it…
I agree, Doug, and tend to go with (b) because if we take the simple case of a resilient layer uniformly overlying a softer layer, warp them into a gentle, symmetrical (read this as "ideal") anticline, there would be no differential erosion between layers since that softer layer was not…
Maybe we should carry this to a new thread, Kamron, since we're out of the ocean now. It surprises me to this day, even though I accept the theory and explanation. It comes down to the fact that the high exposed points are eroded faster, and the time scale is…
Interesting thread, Jeff! The above statement, particularly, is something I hadn't run across before. It is interesting that a formation will recharge in a time scale that we can measure. How substantial is this recharging? My very basic, 15 year old geology training made me believe that these oil-bearing deposits…
>>That the deep cuts in the shelf have a rough one-to-one correspondence with major modern rivers suggests that they were cut by flows not hugely greater than modern river flows.
My understanding is that in the case of a denser oceanic crust subducting under the edge of a less dense continental crust and the subsequent flow of magma to the surface, we should remember that at the boundary, both plates are in compression. As the edge of the continental crust…
> Haven't heard of anything like this. I'd find it very unlikely given the geology of NE PA … that being the hardcoal country. I wouldn't normally think of warm springs in an area like that either. As a whole, the region is quite inactive. It would be a lot…
I hadn't heard about this. It seems a little South and West for such an extensive anthracite seam. Please tell me more.
> This, that you've mentioned, is one of the hypothetical scenarios I was trying to put together in my head before posting the question. I can imagine this redeposition of fossils (what I meant by my term "washing down") occurring where large fossils such as the dinosaur remains you mentioned,…
> I guess I didn't make clear my term "washing down". I was attempting to describe a process in which, for example, fossils from an exposed Pennsylvanian bed would be freed from the matrix by erosion or solution and re-deposited more or less intact along with other sediments into a…
Just as an aside on this discussion, Jim … something that has always bothered me when I allowed it to do so is this: Do fossils from one time period ever appear preserved in sediment of a later time period as the rock in which they were originally present erodes…
Thanx, Richard. I was looking for info on a water cavern in Mifflin County PA called Alexander's Cave. I read a newspaper article awhile back on this cave, which used to be a popular place in the 30s … so popular in fact that folks began breaking off the formations…
Thanx, Doug! I realize I'm talking about a bygone era when Alexander's Cavern was open to the public, but as I understood from the article, groups of cavers are occasionally allowed to go inside. It must be a mighty dedicated landowner in this day and age who has hold of…
Doug et al, Is anyone on-line familiar with a large water-cavern in Mifflin County PA called Alexanders Cavern? All along I've been led to believe Penns Cave is the only live water cavern in PA, but I happened to run across an old article from the local paper about a…
Thanks, Doug. It sure would be nice to think so. I don't aim to speak for anyone else, but it's always seemed to me that you're not really ready to learn when you hit college out of high school. It's a step toward a job, more than anything. Or for…
Earth Science Schools?
Message #124141
What are the best schools these days for a bloke to pursue a graduate degree in the Earth Sciences? I graduated from Penn State in '81 with a BS in Geography, with emphasis on on the Physical side of things … climates, oceans, landforms, geology, cartography. I never had a…