The first meeting for 2001 of the BC Geophysical Society will be this Thursday, January 11th. The society plans 3 meetings this winter - on the second Thursday of January, February and March. The meeting will be in the Bentall Center conference room - room 205 Bentall 2 tower 555 Burrard St., Vancouver, BC. The meeting will start at 4:10 pm. The room is booked from 4:00 to 6:00 for us. Dr. Gary Borstad of Borstad Associates will present the following talk: An overview of the SFSI-2 (SWIR Full Spectrum Imager) and some examples of its use for mapping clay alteration minerals at Cuprite Nevada Abstract: Electronic and vibrational processes at the atomic scale create narrow diagnostic features in the visible and particularly in the Short Wave Infra-Red (SWIR) reflectance spectra of rocks (e.g. Hunt and Ashley, 1979) and SWIR spectroscopy can be used to identify sulfates, carbonates, chlorites, silicates and phosphates. Minerals, such as kaolinite, dickite, alunite, muscovite, jarosite and illite, which are present in gold-bearing alteration systems can be identified through their absorption spectra. These minerals are important constituents of altered rocks and there are now several commercially manufactured hand-held SWIR spectrometers in common use on the ground. A number of airborne SWIR sensors have also appeared, with the aim of producing detailed image maps of much larger areas than can be produced by a geologist walking the terrain. Much of the science of airborne mineral mapping has come from a NASA program involving the AVIRIS (Airborne Visible/Infrared Imaging Spectrometer). AVIRIS acquires 224 channels in the Visible and Near Infra-Red (VNIR) and SWIR, and has been shown in a long series of scientific papers to be a very effective mineral mapping tool (e.g. Goetz, et al., 1985). It has become the standard by which all other SWIR instruments are measured. The Canada Centre for Remote Sensing (CCRS) of Natural Resources Canada has designed and constructed another SWIR airborne sensor, called the SWIR Full Spectrum Imager (SFSI). SFSI was originally intended to provide an alternative source of SWIR data for research and to provide higher spatial resolution imagery than the 20 m pixels produced by AVIRIS (Neville et al, 1995). Borstad Associates Ltd took over the SFSI in 1996 and have redeveloped it for commercial survey purposes. SFSI-2 also operates in the Short Wave range, from 1220 nm to 2420 nm and has the ability to simultaneously acquire the full spectrum (230 bands) at high spatial (4 m) and spectral (10.4 nm) resolution. The instrument utilises a two-dimensional detector array, refractive optics and a transmission grating with an angular field of view of 32 degrees. The sensor has been in commercial operation since 1998 and has now flown in Siberia, Nevada, Utah, Arizona, Peru, Chile, North West Territories, British Columbia and Saskatchewan. In this talk we will present examples of image maps made from SFSI-2 in Utah and Nevada, and compare mineral maps produced by the SFSI at 4 m ground resolution, using a process of spectral unmixing, with maps produced from 20 m resolution AVIRIS data, using the TRICORDER 3.3 algorithm. _______________________________________________________ List archive: http://www.mail-archive.com/[email protected]
