Geological Christmas Gift - Coal Bags

 Last year I thought it would be fun to put together some coal bags for those of us who really enjoy getting coal for Christmas (or any of the season's holidays). I have the bag available up on Etsy right now for anyone interested.

While living in Utah, we lived close enough to a prolific coal seam that jutted out along a road cut on a highway, so I collected a few samples to be used in the gift bags. 

Coal along the Helper, UT roadcut. The coal belongs to a geological formation known as the Blackhawk Formation. 

Stratigraphic column of the Blackhawk Formation and neighboring formations from the Geological Survey publication on the rock units.

The Blackhawk Formation, specifically the coal bearing member, is Late Cretaceous in age. Specifically it is from the Campanian, ~80 million years ago. Coal forms in swamps. Living plant matter dies over time in the swamp, but there is so much decaying plant matter in a swamp that there's not enough oxygen in the water to break it all down. So the plant material builds up over time, and eventually gets buried by mud, sand, silt, or other sediment. This preserves the plant matter that slowly gets buried and cooked over time. The cooking process removes all of the other materials in the plants than the carbon, which is what the coal is.

For the gift bags, I wanted to include as much of that information as possible. 

Text on the inside of the tag:

Type of rock: Bituminous Coal

Rock Source: Blackhawk Formation (coal bearing member)

Age: Late Cretaceous (Campanian, ~80 million years old)

Environment: The coal you hold was once plant matter in a swamp. There was so much life in the swamp, that when the plants died there wasn’t enough oxygen in the water to break them down, so the plant matter built up. Eventually this plant matter was buried by sand and mud, and over time the plant matter was slowly “cooked” below the surface of the earth until all that was left was the carbon from the plants, creating coal.

I also wanted to include two varieties of gift tags that you can choose from.  

The traditional "Naughty" version, where the person getting the coal was bad:

Someone was naughty,

And made Santa mad.

So, this coal is your gift,

Cause let’s face it; you were bad!

Or the geology version, where the person getting it just likes rocks. 

Not everyone who’s been bad gets coal.

Sometimes that may be one’s very goal.

So here is a gift to stuff your sock.

As someone who really love rocks.

Each gift bag available here comes with:

- 2 to 4 pieces of coal that total about 6 ounces in weight.

- A red felt gift bag with draw string

- A naughty or nice tag, complete with geological information about the coal on the inside.

So if you are interested, or know someone who is interested, please pass the word along :-).