Abstract

A three-dimensional (3-D) laser scanner is a type of land-based LIDAR (Light Detection and Ranging) instrument. It sweeps the surrounding environment with optical rays. The rays produce reflections when they encounter solid objects. The instrument records the angle of each ray and measures the travel time of the corresponding reflection. The survey data can be displayed on a computer screen as a cloud of reflection points that delineate the geometrical shape of the scanned objects. A series of scans around the target object yields a 3-D digital geometrical model of the object. We believe that 3-D laser scanning is useful in environmental monitoring, geologic, and geomorphologic studies of natural caverns, because, using this technology, researchers can digitally capture the complex internal architecture of the caverns quickly and accurately without physically touching fragile speleothems. Here we present 3-D scan data and preliminary topographic models for speleothems obtained in the Carlsbad Caverns. Eight sets of scan are performed on a flowstone feature called “Frozen Niagara Falls”, which yielded almost 8 million topographic measurements with most of them spaced within 1 cm from one another. These point measurements have been interpolated into tessellated surfaces and yielded continuous, digital topographic models of the speleothems.