A. Depositional contact of sandstone over conglomerate.
B. Depositional contact of conglomerate over tuff.
* No visible faulting--instead the overlying rock appears "glued" to
the underlying rock. Photo A above.
* May show erosion or scouring along the base. Photo B above.
* May contain clasts of the underlying rock. Photo B above.
* May have a conglomerate immediately overlying the contact.
Photo B above.
* May truncate structures in underlying rock. Click here
unless it's a buttress unconformity, bedding above depositional contacts always lies parallel to the contact.
* May or may not show development of soils at contact.
If part of the stratigraphic record is missing at a
the contact is an unconformity. The criteria listed above generally apply to unconformities.
To see a variety of unconformities, click here.
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