Mapping the Piute Mountains, California, with thermal infrared multispectral scanner (TIMS) images

Abstract

Thermal infrared multispectral scanner (TIMS) data were acquired in 1990 over the Piute Mountains, California, to evaluate their usefulness for lithologic mapping in an area of metamorphosed, structurally complex, igneous and sedimentary rocks. The data were calibrated and atmospherically corrected, and emissivity variations in the form of alpha residuals were extracted from which color composite images were made. There was an excellent visual correlation between the units revealed in the color composite image and the lithologic units mapped in the eastern side of the area. It was also possible to correct, improve, and extend the recent map. For example, several areas mapped as granodioritic gneiss had TIMS alpha residual spectra consistent with mafic rocks and were subsequently mapped as amphibolite. The presence of a swarm of mafic dikes, of which only a few had previously been identified, was also revealed. The images also showed color variations in granitoid plutons that correlated with compositional variations previously determined by extensive field and geochemical work. The western Piute Mountains is an area that has proven to be especially difficult to map with field and air photographic methods, due to heterogeneous nature of certain units and various levels of desert varnish. The images permitted the extremely heterogeneous Proterozoic schists, gneisses, and granites to be easily mapped because the small‐scale compositional variability was averaged to the TIMS pixel size (12 m × 12 m square). Areal measurements from the images show that the Proterozoic rocks in the Piute Mountains consist of granitoids (∼50%), biotite gneiss (∼15%), pelitic gneiss (∼15%), quartzite (∼10%), and amphibolite (∼10%). TIMS data can dramatically increase the efficiency and the quality of geologic mapping in well‐exposed heterogeneous areas with minimal vegetation cover where detailed mapping of lithologic contacts by traditional methods is unusually difficult.

Multi- and hyperspectral geologic remote sensing: A review

“…In the early 1990s, Mike Abrams showed the added value of combined TIR and SWIR observations (Abrams et al, 1991;Hook et al, 1998). From TIR multispectral scanner data Simon Hook and co-authors showed the type of information that could be revealed (Hook et al, 1992(Hook et al, , 1994Hook and Kahle, 1996). The work on TIR spectroscopy of minerals and rocks (Salisbury and Daria, 1992; and mid infrared spectroscopy (Salisbury and Daria, 1994) of John Salisbury and his group has been instrumental to the development field of thermal remote sensing.…”

Two lithospheric profiles across southern California derived from gravity and seismic data

“…∼0.05 g/cm 3 lower than mid-crustal densities. This variant with no mafic rocks in the Mojave crust is not very probable because (1) the analysis of Quaternary basalts from two volcanic craters (Glazner et al, 1991) implies the existence of at least minor mafic rocks in the Mojave crust; (2) thermal IR multispectral scanning results yielded the following bulk composition of rocks in the eastern Mojave Province: granitoids ∼50%, gneisses ∼30%, quartzites ∼10%, and amphibolites ∼10% (Hook et al, 1994).…”

Use of Thermal Infrared Multispectral Scanner (TIMS) imagery to investigate upslope particle size controls on arid piedmont morphology

“…A number of investigations using the TIMS instrument have been performed for geologic mapping purposes (Gillespie et al, 1984;Abrams et al, 1991;Ondrusek et al, 1993;Hook et al, 1994;Crowley and Hook, 1996;Morrissey, 1999;Ramsey and Fink, 1999;Buongiorno et al, 2002;Ramsey, 2002;Michalski et al, 2004). Studies of unconsolidated materials using TIMS have been comparatively few (Weitz and Farr, 1992;Stefanov, 2000).…”