Sand

By: Crunch
9/29/2019 6:57 PM

Pickle, you mentioned sand recently. That it runs out 20 or so miles from the beach before you run into any rocks. Could you expand on that, as much as you'd like?

Someone told me an oil well was drilled decades ago on OBX, went down 10,000 feet, didn't hit a single rock, sand all the way. Is that correct?

Curious as to what the geography and geology are like.

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By: Grim_Smoker
9/29/2019 9:59 PM

Well I've learned that the island has a bunch of "peet" as I was told it was called under it, even 'built' on it. See a ton of it on 55, it looks like hard packed dirt/plant/etc crap. It washes up in smooth rock like chunks.

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By: Crunch
9/30/2019 12:05 AM

Grim, you mean ramp 55 near Hatteras?

We were told last year that the lake where Buffalo City used to be was actually an old peat bog that caught fire and burned, later filled up with water from springs.

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By: Pickle
9/30/2019 7:34 AM

Sand, sand and more sand! My experience has been gained from running a Charter Fishing Boat here on the Outer Banks for 20 years or so. Although we do all types of fishing, we specialize in Wreck and Bottom Fishing. In order to do this type of fishing you have to learn the bottom composition (Sand, Mud, Hard) and the locations of "Bottom Structure" and Wrecks. This is not only true for Recreational Fishing but Commercial fishing as well. Fish congregate around structure for sources of food. Commercial Fishermen have to be careful of "Hanging" there nets on Wrecks or certain types of "Broken" Bottom. I did get some PM's on my comments so I'll give a quick overview here. From Corolla all the way to Buxton the Atlantic Ocean Bottom slopes quite gradually. You can go out almost 20 miles off Nags Head and it will only be about 100 feet deep and the bottom will be all sand. Inshore of that there are several distinct Sloughs that parallel the beach might drop 20 feet from the surrounding bottom but these Sloughs are only 50 to 60 feet deep. In that Zone there are quite a few Shipwrecks some locations are known but many are coveted secrets which fisherman do not divulge. Now all that bottom out 20 miles is Sand mostly, hard packed. There are some rocks off Avon a bit closer, but that is very concentrated. That gradual slope will maintain it's 100 foot depths to the "50 Fathom Curve" (30 Miles out) which have some scattered rock and lots of "Pebbly and Broken Shell Bottoms interspaced with some hard mud and dark black sand. That 300 foot Bottom continues to the 100 Fathom Curve (about 35 to 40 miles out) and the Gulfstream. Beyond the 100 Fathom Curve there are spots especially about 40 miles Southeast of OI that will drop to 1000 or more. Rock is kind of a Collective term and can be interpreted or vary from pebbles to "Baseball" sized rocks to Boulders and then you have solid Rock which we have very little of. And for the record there are no coral reefs out there, this is not Florida and our very temperate but wildly fluctuating water temps are proof.

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By: Tim-OBX
9/30/2019 9:00 AM

The peat marsh fires from 2008 were a real nasty mess. At one point we had one near Stumpy Point on fire and one in the dismal swamp so it did not matter which way the winds blew we got ash and smoke. It lasted a month or two until they pumped in millions of gallons of salt water and we got some heavy rains.

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By: Crunch
9/30/2019 12:00 PM

Many thanks, Pickle. Very interesting.

Can you tell what kind of rock is there when you do find it? Sedimentary, igneous? Is it possible the Gulfstream is washing/rolling them north? Odd that there would be a concentrated bunch off Avon.

Where does all this sand come from? I'm guessing it must be washed up or blown in and that there are no glacier effects this far south?

Have you heard about the oil well drilling?

I assume any rock we see on OBX has to be imported from the mainland somewhere.

I do remember being told Cape Cod is wind-blown and it is constantly being blown closer to the rest of Massachusetts. I want to say the sand there came from "local" rock erosion but don't remember for sure.

Thanks, again, Pickle!

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By: Crunch
9/30/2019 12:03 PM

Thanks, Tim. Didn't know there were still peat marshes in the area. Makes sense that there are.

Where is the peat coming from that Grim is referring to? That would be ocean-side, right?

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By: Crunch
10/1/2019 1:37 AM

Grim,

Apparently the peat you are seeing on the ocean-side is ancient freshwater, sound-based, back-side peat from a forest or marsh that is slowly being uncovered as the OBX island migrates to the mainland. From an USGS publication on page 12 at Click to follow link...

Too tired to read the rest of it tonight, but it looks promising.

If the link doesn't work: Google "USGS The Outer Banks of North Carolina Pub 1177-B", published in 1986. A newer, more colorful updated version, publication 1827, was published in 2016. It mentions the peat deposits on page 57.

Crunch

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By: Grim_Smoker
10/2/2019 12:30 AM

Yes I was talking about ramp 55. When I first moved down there were large ledges of it uncovered down near the inlet on the ocean side of the beach. They're covered up again, but there are forever large hunks of it floating around, and I see bits of the ledges here and there as storms come through and whatnot. It's real hard packed, I was jumping up and down on it one day, even saw people driving over it. But of you put your foot on the edge and push down it crumbles away easily.

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By: Crunch
10/3/2019 10:31 AM

Grim,

Attached is a picture of the peat from the 1986 USGS booklet. Not a very high quality picture, but is that similar to what you see? Looks like a ledge, as you describe.

From the text, "Peat deposits and tree stumps, remnants of forest stands which generally occur on the back side of barrier
islands, are now being found on open ocean beaches"



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By: Grim_Smoker
10/3/2019 8:04 PM

Yup, just like that! I'll take a ride out tomorrow and take pics of some of the hunks that are everywhere. None of the ledges are currently exposed though.

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By: Crunch
10/3/2019 11:39 PM

Cool! I wonder how many thousands of years old it is. Look forward to your pics.

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By: obxmini
10/4/2019 7:45 AM

I've been following along on this one and appreciate the article. We've seen this sort of thing ourselves and now will be even more aware of the peat, as well as how it "got there."

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By: Crunch
10/5/2019 7:16 PM

OceanBlue,

I've been reading an excellent book recommended by Pickle, "How to Read a North Carolina Beach", available on Amazon. Only about 1/3rd through it, but very interesting.

The picture you posted a while back of Ocean City and Assateague, posted here again, is now coming into sharp focus, per the book on the evolution of barrier islands: the Assateague barrier beach in the lower left is "natural" and is migrating to the mainland; the Ocean City barrier beach on the upper half of the pic is not migrating nearly as much due to man-made impediments, all since a 1933 hurricane.

Many thanks for the post and sharing.

I assume I am just now discovering what you knew all along?



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By: J4yDubs
10/5/2019 10:27 PM

There's evidence of the NC barrier islands migration toward mainland all over the place. The peat mentioned is one (which is all up and down the NC coast). Go up north to the Carova area and you'll see stumps in the surf, the remains of a forest. Also, you'll find oyster shells in the surf. Oysters mainly live in sounds and bays. The shells you find are from when that area was bay or sound.

John

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By: Pickle
10/6/2019 7:44 AM

Just to take that post from John on Oyster Shells a bit further, the proof is in the Black Oyster Shells. Oysters are not Black, Dark Blue or Gray. Oysters are an off white color and when bleached by the Sun they become white. Why are they Black? They are Fossils. Just as John said, Oysters do not really live in the Ocean, they are a "Calm" water specie and need certain Salinity and Chemicals to prosper. They are Black because they have been buried with no exposure to Oxygen, just like Fossilized Shark Teeth. As the Beach migrates to the West, the rough Surf has uncovered ancient Shellfish beds that were in the Sound thousands of years ago. These Black Oysters are all over the beach and not worth anything, but come with a good story. The book "How to Read a North Carolina Beach" has a whole chapter (either 6 or 7) on this. I know in my Volunteer work I'll ask children to hold a Black, well worn Oyster Shell, the conversation goes on to you are holding something 10,000 years old. The usual reaction is "Wow" and disbelief. Just sayin.

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By: Crunch
10/6/2019 9:27 PM

Keep sayin, Pickle! Enjoy your posts!! Please share here.

Haven't gotten to Chapter 6 yet, but on my way. That USGS Publication 1827 was also very informative. Spouse is calling me for birthday cake. Gotta go!

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