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General physical features of the Fulgurites from
PECOS PLAINS, NEAR MONAHANS, WARD COUNTY, WEST TEXAS
TYPE I (Light gray-white, glassy, tubular)
| GENERAL INFORMATION ABOUT THE LOCALITY: | |
The fulgurites from West Texas are found in the sand dunes of the Pecos Plains. The dune field is approximately 70 miles long and 20 miles wide, and stretches in a narrow band from 20 miles northeast of Crane, Texas, to the southeast corner of New Mexico. The dune field runs parallel to an area called the Llano Estacado, Spanish for "staked plains" where the early travelers passing through this area had to mark their way with stakes. The sand in these dunes is composed of very uniform near white Quartz sand, with traces of iron-rich clay. The sand was laid down about 16,000 years ago. These dunes are the highest points in the surrounding area, and are natural targets for lightning strikes. The fulgurites are typically found in the dunes with no vegetation -- far removed from power lines, telephone poles, windmills, etc., and other items which would attract the lightning. The dunes shift as much as 70 feet per year due to the seasonal change of prevailing winds. The erosion of the dunes due to the shifting winds exposes the fulgurites. At a typical lightning strike site, one larger diameter fulgurite will often be found sticking up from the sand as much as 6 inches, and several much smaller diameter fulgurites will then be found in an area within 20 to 30 feet of the main strike. It is not uncommon to find as many as 5 of the smaller fulgurites radiating out of the sand as if someone had stuck them in the sand in a random pattern. If there is not much clay in the sand the fulgurites can be excavated. They are very fragile, and most break off in lengths of 3 to 4 inches or less. |
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| OUTSIDE SURFACE: | |
| FORM: | Fairly straight, with a slight curvature down the length on some specimens, nearly equidimensional diameter, tubular. Some specimens exhibit undulating ridges running down the length of the tube. Items TX-06 and TX-11 are open down the length of the fulgurite, i.e., the lightning bolt was so hot, and the walls of the tubes were thin enough, so that the tubes collapsed before cooling. Extremely pronounced ridges run down the length, on the backs of both specimens -- the back of TX-11 is shown in the accompanying photo. The fronts (i.e., the interiors of the fulgurites) of TX-06 and TX-11 are very glassy and shiny -- the front view of TX-06 is shown in the accompanying photo. Item TX-08 has a pearl-like, fused silica bead closing the tube on one end of the specimen. Item TX-13 has both ends about 90% closed -- again, due to high heat and partial collapse of the tube before cooling. The pricing schedule, which follows the photographs of the specimens, is based upon the openness of the fulgurite tubes, as well as upon their size. |
| COLOR: | Light gray-white, to pale tan. |
| TEXTURE: | Fairly smooth, glassy, with some specimens exhibiting pronounced ridges. |
| SAND GRANULES: | Modest amount, sometimes practically nonexistent, i.e., the sand granules were mostly fused, during formation, by the extreme heat. |
| GLASSY INTERIOR: | |
| COLOR: | Colorless-white, to pale gray (sometimes mottled), translucent to transparent. |
| TEXTURE: | Smooth, glassy, semi-botryoidal. |
| BUBBLES (GAS POCKETS) PRESENT: |
Numerous, microscopic. |
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