An unconformity is an erosional or non-depositional gap in the geologic record. They typically form when an older layer is subject to a period of erosion before the deposition of new sediments. This road cut near Payson, Arizona shows a pretty cool unconformity. Can you find where it is? Check the jump below to see… Continue reading Can you find the unconformity?
Types of unconformities
Unconformities—erosional or non-depositional gaps—are abound in the geologic record. These erosional surfaces separate a lower, older strata from a younger, upper one (unless the sequence has been overturned). An unconfomity will typically form when an older layer is subject to a period of erosion before the deposition of new sediments. For example, the “Great Unconformity” of… Continue reading Types of unconformities
Can you spot the unconformity?
This photo displays a pretty spectacular unconformity—an erosional/non-depositional surface where rock units deposited during different intervals of time appear to be continuous. In the bottom half of the image, you can see Paleoproterozoic pink quartzite ~1.7 Ga in age, while in the top half of the image—directly overlying the quartzite—is Cambrian sandstone conglomerate ~540 Ma… Continue reading Can you spot the unconformity?