Asphaltum

By Katherine Pollock

Asphaltum has been washing ashore for thousands of years, long before any oil rigs existed

You may have seen or even stepped on a gooey tar-like substance on the beach. It’s generally in the sea grass and sometimes hard to spot because it blends in with the dark dried sea grass. On very hot days it can stick to your shoe; or, if you are barefoot, it will leave a hard-to-get-off black smudge on your foot. If it looks and smells like asphalt, then what you have found is Asphaltum. The little blobs are usually about three to six inches in diameter and about an inch thick but sometimes larger pieces wash up. Some of the older pieces are very hard, more like coal. You might find shells and sand imbedded into the surface. You can even find pieces shaped and rolled by hand.

Your first thoughts might be that an oil company was to blame for the stuff washing ashore. But this is one phenomenon that oil companies have no part of. Asphaltum has been washing ashore for thousands of years, long before any oil rigs existed. The stuff oozes up from the ocean floor naturally from the seepage far beneath the Gulf of Mexico. Since it hardens when it comes in contact with cold water and floats away in small amounts it most likely hasn’t caused any environmental threat to birds or sea life. Although I would imagine an unwitting sea turtle has probably swallowed a chunk and felt the ill effects.

The islands’ first beachcombers, the Karankawa Indians, were some of the first to find the tar useful. Five hundred years ago they gathered the gummy substance and melted it down. In the molten stage it had many uses. One important use was to coat the bottoms of their canoes, making them more waterproof and longer lasting. They also used it to decorate pottery. You might find shards of the sandy colored earthenware made of a sand and paste known as Rockport Pottery on the beach. Patterns of black, wavy and geometric lines, dots and triangles were used to adorn their bowls and vases. Some vessels used to hold liquids were coated with a thick black layer to help keep the liquids in.

Asphaltum was most widely used by Coastal Indians as an adhesive. They mended cracked pottery and glued broken pieces back in place. It has also been used to create tools similar to a hoe made out of a half quahog shell with asphaltum used to adhere it to a stick. Arrow heads have also been found along the coast with traces of black substance on the base where it appears the tar was used to help glue the arrowhead to the shaft.

So be careful where you step while you’re on the beach and take a closer look at it when you find it. Imagine how much you would need to coat your canoe!

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