Is Sandstone well sorted or poorly sorted?

Sandstone: Is it a Hodgepodge or a Harmonious Blend?

So, you’re wondering about sandstone and whether it’s a well-organized rock or a bit of a jumbled mess? The truth is, it’s not a simple yes or no answer. Sandstone, that sedimentary rock we see all over the place – making up a good chunk of the Earth’s crust, actually – can be either. It really boils down to where it came from and how it was formed.

Think of it like this: sandstone is basically a bunch of sand grains, mostly silicate, glued together by other minerals. Now, how uniform those sand grains are in size? That’s what we call “sorting.”

If you’ve got a well-sorted sandstone, it’s like a perfectly organized toolbox where all the wrenches are the same size. But a poorly sorted sandstone? That’s more like the junk drawer in your kitchen – a chaotic mix of everything from tiny screws to oversized spatulas.

So, what makes the difference? Well, a few things:

• The Delivery Service: Was the sand delivered by a gentle breeze, a raging river, or a lumbering glacier? Wind and water are pretty good at sorting things out, while glaciers? Not so much. They’re more of a “grab everything and go” kind of transporter.
• The Final Destination: Was the sand dropped off on a calm beach, a fast-flowing riverbed, or a quiet lagoon? A high-energy environment, like a wave-battered beach, tends to create well-sorted sandstones because the waves wash away the smaller particles, leaving behind the larger ones. A low-energy environment? Not so much.
• The Journey: The longer the trip, the better the sorting, generally speaking. It’s like a rock tumbler – the rough edges get smoothed out, and the weaker particles get broken down and carried away.

Now, let’s talk about different types of sandstone. This is where it gets interesting.

• Quartz Arenites: These are the crème de la crème of sandstones, made up of mostly quartz. They’re usually super well-sorted, the result of a long and arduous journey. Imagine those pristine white sand beaches you see in travel brochures – that’s the kind of environment where these guys are born.
• Arkosic Sandstones (Arkose): These sandstones are a bit rougher around the edges, with a good dose of feldspar thrown in. They tend to be poorly sorted because they come from places where rocks are breaking down quickly, like near mountains.
• Wackes (Graywackes): These are the dark and mysterious sandstones, packed with a mix of everything – rock fragments, feldspar, quartz, and a whole lot of mud. They’re usually poorly sorted, like a sediment stew. You often find them in deep-sea environments, the result of underwater landslides called turbidity currents.

Think about it this way: a sandstone’s sorting is like a window into its past. A well-sorted sandstone tells a tale of a long journey and a calm resting place. A poorly sorted sandstone? It speaks of a wild ride and a hasty burial.

So, next time you see a sandstone, take a closer look. Is it a harmonious blend of similar-sized grains, or a chaotic hodgepodge of everything imaginable? The answer will tell you a lot about where it’s been and how it came to be. It’s all part of the story that rocks can tell, if you know how to listen!