Ledger Stone - Bedrock Granite

Hi, I'm Tim Carter. Ask the Builder

I'm here in Center, New Hampshire, right on my own street. They're getting ready to build a new home

And you can see how they've scraped. They got rid of all the trees, a lot of trees here

This is where the house is going to go. They're going to have to do a lot of blasting

There's a lot of, they're right here. They're into the ledge. And that's what this video is about

Ledge. I want to show you what ledges. If you've ever watched the old Carrie Grant movie, Mr. Blandings

builds his new home. It's really, really funny part about 45 minutes into the video

But right here, I'll try to point my finger, this is solid bedrock that, you know, that continues

down through the earth. Once you get into the mantel, it's pretty plastic. It's like taffy

But that is the Meredith porphyritic granite. And there's more of it. It's all over the place

But this is actually an exposed part of the bedrock. And you can see the same

There was a little bit of soil on it right here, maybe a couple inches thick

But that's solid bedrock. So when you go to buy a lot, a building lot in New England, you better be paying attention

You better understand what the bedrock geology is. I do phone coaching, so if you need help with it, my college degree, I'm a geologist

But this is a really great example. I'll actually walk up to it so you can get a little bit closer look

but this is uh you can see how the leaves and stuff have been on for a long time this is actually

considered uh the most beautiful rock i know it doesn look that way right here in new england it got all these giant white felt spark crystals Some of them are huge as big as my thumb They just massive And what this was this was some

seafloor sediment miles thick that got subducted underneath a continental edge. And then

it started to melt and then it started to kind of come up to the surface like a hot air balloon

you know, floats up into the sky. Here's a nice piece of. of the Meredith Porphyretic gran

I'm going to walk over to you so you can really see the crystals. Look at those crystals

Here's a really good piece. Here's where it's been cracked. Yeah, but that's the

look at those beautiful crystals there. Look at that big piece of felds floor. Pretty amazing

But anyway, this piece of seafloor, there's another big piece of the ledge

That's solid bedrock. That goes all the way, you know, to China, so to speak. Anyway, this miles of seafloor sediment

that got sucked. underneath the edge of a continent. It got pulled down, started to melt, and then it became

less dense than like a hot air balloon. It started to kind of come up to the surface. And sometimes

it makes it, sometimes it doesn't. And eventually, through plate tectonics, it gets brought to the

surface like it is here. So this is a giant, huge piece of granite. And it's many, many square

miles. Big area here of where I live. My house is built on this. I live just about a half mile away

All right, so now you know what ledge is. It's not that thing that's up on your closet

You know, that's a shelf. This is ledge. All right, I'm Tim Carter. Remember, if you need help, geology-wise, building-wise

I do phone consulting. I'm Ask the Builder. Bye