From: tcc@sentex.net (Douglas Cox) Newsgroups: talk.origins,alt.fan.publius,alt.atheism,alt.christnet Subject: Re: glaciers Date: Mon, 18 Mar 1996 22:52:30 GMT Organization: TCC Lines: 63 Message-ID: <4ikp3r$j75@granite.sentex.net> Reply-To: tcc@sentex.net In article <4ifraf$f9v@ray.atw.fullfeed.com>, John Hoffman writes: >Sir, >I read with interest your posting about the ice age in > Wisconsin. There are many local evidences of glaciation > in the area of Wisconsin in which I live, including such >landscape features as kames, eskers, and drumlins. Why do you think that drumlins, for example, are "evidence" of glaciation? Or, for that matter, kames, or eskers, etc? One of the interesting things about drumlins, which are streamlined hills, is that some of them consist of stratified gravel, similar to that which occurs in kames and eskers; however, since this stratified gravel is supposed (in the glacial theory) to have been deposited in streams that flowed from a melting glacier, that redeposited its load of debris, the glacial theory appears to require that the ice sheet was moving over the drift that was deposited when it melted. But, I wonder how the glacier could have streamlined the drift, if the ice had previously melted and flowed away in the streams? Seems to me there may be an inherent inconsitency in the theory here; shouldn't the streamlining (if continental glaciers are indeed capable of that sort of thing) have occurred on the bedrock below, rather than on the surface of the drift? But the bedrock is not streamlined. This is very curious. While the drumlins in some areas are composed of stratified drift gravel, others consisit of bedrock. Still others are part drift, and part bedrock; that is, there is a mantle of drift overlying a rock core in some of them, or the stoss end of a drumlin may be bedrock, while its tail consists of drift. All these types may occur together, in the same drumlin swarm, having the same general size and shape, and the same orientation pattern. It is very curious, IMO, that a glacier could erode drumlins consisting of hard bedrock into the same form as others in the vicinity that were presumably being formed from unconsolidated gravel and delicately stratified sands. At Rockwood, in Southern Ontario, there are hundreds of deep potholes in dolomite rock; there are signs posted in a park in the area that indicate the potholes formed when waterfalls called "moulins" plunged down through crevasses in the ice, and eroded the rock below, drilling deep, round holes, up to 20 feet in diameter. Now it seems that the glacialists want these waterfalls or "moulins" to sometimes construct great mounds of gravel, called "moulin kames." But here the same process is is invoked to drill holes in the bedrock. Again, there seems to be some inconsistency in the theory. What is really strange, though, is that the potholes at Rockwood are very near some large drumlins, composed of bedrock; the glacial theory, remember, says the drumlins were eroded as the hypothetical ice sheet moved across the region. In this case, it must have come from the southeast, and flowed northwest, climbing up out of the basin of Lake Ontario, creeping gently over the high cliffs of the Niagara Escarpment, towards Rockwood. Now, if the ice moved in this manner, how did all those waterfalls of moulins stay in one location long enough for all those deep potholes to be drilled? And why did hundreds of them form in such a small area? Hmmm... -- Douglas Cox