Earth tides and joints

gus horsley

New member
I remember reading many moons ago that the gravitational pull of the Moon was (partially) responsible for jointing in certain rocks, including Carb limestone.  I haven't seen any recent research on this subject.  Has anyone done any?
 

Les W

Active member
I recall a paper about earth tides affecting water levels by closing and opening joints but not sure they are strong enough to form joints.
Could be wrong though...  :-\
 

RobinGriffiths

Well-known member
Wasn't the Bilston Tidal experiment as set up in Parc Mine - level2 supposed to measure the deflection of the crust or something along those lines ?
 

ChrisJC

Well-known member
RobinGriffiths said:
Wasn't the Bilston Tidal experiment as set up in Parc Mine - level2 supposed to measure the deflection of the crust or something along those lines ?

Yes it was. I recall the results being inconclusive however. But I don't think that's quite what the OP is asking.

Chris.
 

jarvist

New member
Mmm, sounds a bit suspicious, but who knows.
The tidal bulge in the crust is tiny, a few 10s of cm. Even in the open ocean the water only rises a meter or so.

The differential force as the moon orbits is almost infinitesimal, compared to the kind of forces generated by weather systems, tectonic plate movements etc.
 

langcliffe

Well-known member
Not recent work, but I think that the original suggestion was proposed in 1961 by Hodgson: "Regional Study of Jointing in Comb Ridge - Navajo Mountain Area, Arizona and Utah". It worked on the basis of semi-diurnal tides working on immature sediments, and creating joints by fatigue cracking. The only times I have ever seen references to Hodgson's paper in the literature is when authors say that it is not necessary to resort to such an explanation in their own  specific joint study cases.
 
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