#All
2 messages in this thread
Hi, Howard–
Thanks for the details I was missing!
I was trying to distinguish for Kamron cases where the entire crust (and
lithosphere) is being pulled apart (a spreading center like the Rift Valley of
Africa) and uplifts driven by an igneous intrusion. I neglected to speak of
the latter as also involving stretching of the older top layers. I also used
the term "graben" solely for the former case – I hope it does not apply also to
stretch marks due to an uplift.
–Doug
Doug–
>> I also used the term "graben" solely for the former case – I hope it does
not apply also to stretch marks due to an uplift.<<
A graben is *any* elongate, downthrown block caused by "normal" faulting. I
mean "normal" as opposed to "reverse" faults. Normal faulting results from
*tension* in the crust (generally due to uplifting). Reverse faulting is caused
by *compression*. The term graben is not restricted to spreading centres, but
can be applied in any normal faulting situation, at any scale. Graben is German
for "ditch".
–Howard