USE OF A 3D INFRARED-RANGE CAMERA IN MESOSCALE GEOLOGIC INVESTIGATIONS: A CASE STUDY USING THE WINDOWS KINECT

Rapid and accurate three-dimensional (3D) analyses and characterization of geologic and paleontologic features is increasingly in demand. Many studies employ terrestrial Light detection and Ranging (LiDAR) to characterize geologic features that are often inaccessible for traditional study at high precision (< 1 cm-resolution). Geologic features are also studied in three-dimensions at the microscale with very high precision (μm-Å) techniques. Many of these methods however, require significant funding, are time consuming, or are logistically, technically, or analytically challenging to obtain, or do not bridge the cm-m scales of observation. Here we present examples of the use of an inexpensive and user-friendly infrared range camera (Windows Kinect™) to demonstrate its utility as a tool for examining geologic features. The Kinect ™ emits a pattern of infrared dots and references this pattern to a calibrated pattern for depth calculations. These xyz data are then combined with RGB images to generate 3D models of samples. Previous studies report error between ≤ 1 mm to 75 mm depending on the distance from the sample to the detector. We discuss the advantages and limitations of this new method in the earth sciences and produce example data sets in structural geology and sedimentology. Roughness analysis of small faults in the footwall of the Wasatch fault, and sedimentary analysis of syn-tectonic sediments in the hanging wall of the East Cache fault in northern Utah were conducted using data collected with the Kinect™.

An analysis of slip-surface roughness from the mm- to m-scales reveals a broad range in roughness in the slip-parallel and slip-perpendicular directions for small faults in the footwall of the Wasatch fault. The RMS roughness of slip surfaces varies from 0.6 to 9.8 mm at lengths between 0.13 to 1.0 m. 3D imaging of liquefied and slumped sediment in the hanging wall of the East Cache fault allow rapid for measurement of faults, clast shape and size, clast orientation, wavelengths of ripples and flame structures, and attitudes of cross beds and ripples. Combining 3D images into a mosaic ~10 m-wide, 3 m-high, and with 3 m of depth range allows for the measurement of features over multiple scales. These test cases illustrate the utility of the Kinect™ for measuring mesoscale geologic features.