Geophysical
Characteristics of
Shale Domes
Seismic | Shale domes are readily located by conventional
reflection seismic methods. They may be distinguished
from salt domes 1) by conventional Dt
analysis because the interval velocities in shale are
lower than in salt and 2) by the crestal sag as suggested
in the seismic line shown below. |
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Gravity | Gravity surveys are less definitive because newly
emplaced shale generally have low densities but older
shale bodies which have dewatered are usually much more
dense than the surrounding rocks. Thus, shale domes may
cause gravity minima, gravity maxima or no discernible
anomalies. The diagram below demonstrates this phenomena.
The cylinders represent shale diapirs. |
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Other
Effects on Shale Structure ![]() |