Gaps in this area were examined by Ken Karle in an article in Journal of Creation [free pdf]. This is a sea-level-rise picture at 180m asl (red), 240m asl (orange) and 320m asl (yellow) of the Susquehanna River basin of Pennsylvania, USA. The large river whose channel is marked by red is the Susquehanna River.
The image shows very clearly how Blue Mountain, the long SW-NE trending ridge that transects the picture, could have acted as an impoundment, which was overtopped by receding waters through what are now the water gaps (marked with arrows). Closer inspection also reveals many water gaps in the basin itself.
Karle’s article is a fascinating one and you can use Google Earth and Google Maps, with the Google Earth filled-in contours, yourself, to visualize water gaps in the region. There are hundreds of gaps in the basin.
Karle’s article was first published in Journal of Creation. It’s a great periodical to keep you at the cutting edge. The cover of the latest issue is displayed above right, with a link where you can obtain your own subscription. (Here’s the link for you to subscribe. If you are not from the US, click “Stay here” if a message box appears.)
Michael Oliver
Tas: I am a seasonal Fire Lookout in the Snake River’s Hell’s Canyon, between Oregon and Idaho, USA. During the summer, I converse with a lot of Geologists. I’d be happy to share some photos of the geography if you want. This place, like Arizona’s Grand Canyon, is a loud and clear testimony to what massive amounts of water can accomplish. My pics are large, let me know where to send a few, (if you want)…
Michael
Feedback
Here are some tangible and remarkable examples of the erosive power of water:
1) A youtube demonstration of detonation-powered water slicing a propane canister in half, which is being utilized by the US military to defuse IEDs: http://www.youtube.com/watch?v=Ybxken-YU6A&feature=youtube_gdata_player. Note at 1:12 minutes how cleanly the canister has been cut.
2) The wikipedia article on water jet cutters, which have the capability to carve even granite by the use of abrasive-loaded, highly pressurized water: http://en.wikipedia.org/wiki/Water_jet_cutter
When you look at the lengths and depths some of the large-scale water gaps around the world, such as the Grand Canyon and Hell’s Canyon, and the resistance of the rocks that they’re cut through, it really brings home the enormous power that the recession-stage currents must have had.