Correlation Between High-Resolution Remote-Sensing Imagery and Detailed Field Mapping in Cordilleran Miogeocline
Sandra C. Feldman, James V. Taranik
Selected areas were mapped at a scale of 1:6,000 in the southern Hot Creek Range (south-central Nevada), which is underlain by Paleozoic autochthonous limestone, shale, and sandstone, Paleozoic allochthonous chert and siltstone, and Tertiary rhyolitic to dacitic ash flow tuff. The mapping was compared with computer-processed Airborne Imaging Spectrometer (AIS) data and Landsat Thematic Mapper (TM) imagery.
The AIS imagery of the Hot Creek Range was acquired in 1984 by a NASA C-130 aircraft; it has a spatial resolution of 12 m, and swath width of 380 m. The sensor was developed by the Jet Propulsion Laboratory and is the first in a series of NASA imaging spectrometers. The AIS collects 128 spectral bands, having a bandwidth of approximately 9 nm, in the short-wave infrared between 1.2 and 2.4 µm. This part of the spectrum contains important narrow spectral absorption features for the carbonate ion, hydroxyl ion, and water of hydration. Using computer-processed AIS imagery, therefore, we can separate calcite from dolomite, and kaolinite from illite and montmorillonite as well as differentiate geologic units containing these minerals.
On the AIS imagery, the Upper Mississippian Tripon Pass Limestone shows a distinctive calcite absorption feature at 2.34 µm; this feature is not as pronounced in Cambrian and Ordovician limestones. The dolomitized Nevada Formation exhibits the dolomite absorption feature at 2.32 µm. Clay mineral absorption features near 2.2 µm can be distinguished in altered volcanics. Mineralogic identification was confirmed with field and laboratory spectoradiometer measurements, thin-section examination, and x-ray analysis.
AIS results and field mapping were also compared to computer-processed Landsat TM imagery, the highest spectral and spatial resolution worldwide data set currently available.
AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.