N.Wells
Posts: 1836
Joined: Oct. 2005
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| Quote | | None of the cross sections appear to run through my location. |
F is close enough to show the structure of the rift valley in your region.
| Quote | | And I am relatively certain that the angle at my site is greater than at the lower (Portland Formation) elevations, to the east. |
I'm not disputing that. I'm not even disputing that some of the difference may reflect local intrusion of magma, although the bits of the "Metacomet Ridge" that I know about are layer-cake surficial basalt lava flows that have been tilted, and not laccoliths and other intrusions capable of tilting the strata. I am saying that uplift is not primarily responsible for the dip, because what you are seeing is primarily differential subsidence, with greater subsidence in the east due to the nature of the rift valley.
If your beds dip 12-13 degrees east, the New Haven Arkose underneath the lava flows underneath you dip about the same. The stuff to the east may well dip 2 or 3 degees less, but that's 10 degrees of regional dip, only two or three degrees possible due to local magmatism and/or local folding and faulting, and none due to tectonic uplift (differential or otherwise).
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