Conformable Contacts
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Conformable Contacts
Notes from the intersection of faith, reason and geology
Curated by YEC Geo
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Beach 4, Olympic Coast: folded rocks, overturned turbidite beds, an angular unconformity, seastacks, and a great beach walk.

Beach 4, Olympic Coast: folded rocks, overturned turbidite beds, an angular unconformity, seastacks, and a great beach walk. | Conformable Contacts | Scoop.it

Who knew there was such cool structural geology on the Olympic Peninsula?

 

There's even an angular unconformity, shown in the picture.  The blogger writes, "The rocks were then uplifted to sea level, where wave erosion could plane them off; this truncated the beds. The eroded rocks were later covered by flat-lying young sedimentary beds, which have yet to be lithified."

 

The blogger suggests that the tilted sediments were truncated by waves around 122,000 years ago then uplifted and later covered by unconsolidated sediments.  The time difference between the truncation and the deposition of the overlying beds is about 75,000 years. 

 

However, 75,000 years is a lot of time to maintain an uneroded truncation surface, especially in a coastal environment. Where are all the biological communities that would have formed on the seashore-mainland interface and should later have been buried by the glacial outwash that produced the overlying sediments?

 

As with other angular unconformities, the formation of this particular feature seems to me to be consistent with a much more compressed timescale than is currently hypothesized.

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Geology in Motion: Why did Sandy leave so much sand in Seaside Heights and even NYC?

Geology in Motion: Why did Sandy leave so much sand in Seaside Heights and even NYC? | Conformable Contacts | Scoop.it

A condensed explanation of sand transport mechanisms. 

 

We ourselves live steps from an accreting beach, and even though our dunes were wiped out when Sandy sideswiped us, I know that by next summer, we'll experience a net gain, while beaches several miles to the north may have to extend their boardwalks a few feet further down to meet the sand.

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