Photo Gallery (U.S. National Park Service)

Geology

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As can be seen here, Padre Island is composed of quatenary deposits.

Geologic Map of Texas

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The back of the island near the Mansfield Channel consists of extensive sand flats.

Back of island near the 54 mil...

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Barren dunes may be blown across the island at as fast as 35 feet per year until they become covered over with vegetation, which arrests their progress. They are then known as "stabilized blowout dunes".

Vegetated blowout dunes

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This unusually large piece of fulgurite is about four inches in diameter. It was part of a larger piece found during construction of the Malaquite Visitor Center, where it is currently on display.

Large fulgurite specimen

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This small channel formed sometime between 2000-2005 after a series of high tides and storms. It cut from the the Gulf into the island for about a mile or more. Within a few months it had disappeared. The amount of sand carried in by the currents can repair damage to the Padre Island topography relatively quickly.

Small channel

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Troughs, known as blowouts, can be cut into the fore-island dune ridge by the Gulf breezes. Note the dark pattern in the lower right foreground. This is formed from large sand grains, after the wind has sorted them out from the smaller grains. These patterns feel like a hard crust when trod upon. The large grains can reflect light making them noticeable from some distance.

Trough in fore-island dunes

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Like sand roses, selenite is a crystal that forms from gypsum. Selenite is one of the few naturally occurring stones at Padre Island.

Selenite crystal

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"Sand roses" also known as "gypsum roses" are rocks that form as water rises and falls depositing layer upon layer of gypsum crystals into sand. The gypsum crystals grow, trapping the sand into patterns resembling flowers. The Laguna Madre is the only place in Texas where sand roses may be found. However, they are rare.

Sand rose

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This broken specimen makes for an excellent illustration of a fulgurite cross section. The center of the sand was vaporized by the lightning resulting in a tube.

Fulgurite 3

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This large fulgurite sample shows how the exterior of a fulgurite column. Note that the broken ends indicate this was a section of a larger piece. Fulgurite may extend deep into the ground and form branches just as a lightning bolt may.

Fulgurite 2

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