Regional scale exploration targeting with ASTER

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PhotoSat offers a geological alteration mapping package produced using ASTER satellite photos. In areas of sparse vegetation, ASTER photos are used to map opal/chalcedony, total silica, kaolinite, jarosite, sericite, chlorite, calcite and many other minerals for epithermal gold and silver and porphyry copper exploration.

ASTER ALTERATION MINERAL MAPPING

Depending on the presence of the alteration minerals on photo visible outcrops and subcrops the PhotoSat ASTER alteration mineral mapping will include the minerals listed below. If the mineral is not present it will not be included in the maps and report.

All Silica    SiO2

Opal/Chalcedony    SiO2•n(H2O)

Calcite             CaCO3

Chlorite/Epidote PhotoSat cannot differentiate between chlorite and epidote minerals with 16 band WorldView-3 photos.

Clay minerals

Alunite                    (Na,K)Al3(SO4)2(OH)6

Kaolinite                  Al2Si2O5(OH)4

Micas

Sericite: Sericite is hydrothermal alteration of orthoclase or plagioclase feldspars.  It may consist of each or a combination of the mica minerals Muscovite, Illite, and Paragonite.

PhotoSat cannot differentiate between these micas with 16 band WorldView-3 photos.

                 Muscovite   (KF)2(Al2O3)3(SiO2)6(H2O)

                 Paragonite  NaAl2[(OH)2|AlSi3O10]

                 Illite          K0.6(H3O)0.4Al1.3Mg0.3Fe2+0.1Si3.5O10(OH)2·(H2O)

Ammonium Minerals

Buddingtonite (ammonium feldspar)  NH4AlSi3O8

Iron Oxides

Hematite            Fe3+2O3

Goethite             Fe3+O(OH)

Jarosite              KFe3+3(SO4)2(OH)6

ASTER context images

Geology enhanced colour image

Vegetation intensity

Greyscale image

¹ SiO2 derived from the 5 ASTER thermal infrared bands which have 90 m pixels

² PhotoSat cannot differentiate between chlorite and epidote minerals with ASTER

³ Alunite or other minerals with an absorption peak at 2.2 microns.

4 Kaolinite or other minerals with an absorption peak at 2.16 microns

5 Sericite is not a specific mineral. It is hydrothermal alteration of orthoclase or plagioclase feldspars.  It may consist of each, or a combination of, Muscovite, Illite, and Paragonite.  ASTER cannot differentiate between these micas.

6 Ammonium feldspar NH4AlSi3O8

7 FeO many red, orange and brown coloured iron oxide Minerals

Deliverables:

Orthorectified images of all alteration minerals as RGB Geotiff files blue=possible, red=probable.

ESRI Shapefile polygons outlining the probable areas of alteration minerals.

ASTER Alteration Mapping Report: The report summarizes the alteration mineral processing results. This is not a Geological Interpretation nor an Exploration Targeting Report.​ The report is intended as a resource for qualified mineral exploration geologists.

ADVANCED PRODUCTS:

Spectral matching: Spectral matching uses the spectral signature of a pixel to look for other similar pixels. If there is an outcrop of significant interest, we can analyze the spectral signature of a pixel related to that outcrop and provide a map of other pixels in the ASTER scenes that are similar. We can work with only the exact location of the outcrop.  It is best if you can provide photographs and a detailed geologic description of the outcrop.

Lithological enhancement: Lithological enhancement is a statistical analysis of the spectral signature that reveals the strongest spectral differences over the visible, near infrared and shortwave infrared bands. Outcrops and soil will show differences in lithology, while vegetated areas will just show the differences in vegetation.  The process works best when there is a significant amount of soil and/or rock exposure.

ASTER ALTERATION mineral mapping PRICING

The alteration mapping data is provided on a project-by-project basis. Please provide us with the extents of your project area and we will prepare a quote.

For more information contact us at info@photosat.ca or 1-604-681-9770.

PhotoSat ASTER Alteration Deliverables

Up to 12 Alteration Deliverables if minerals are present and detectable in the ASTER satellite photos:

  • 12.5 m Opal/Chalcedony
  • 12.5 m Calcite
  • 12.5 m Chlorite/Epidote
  • 12.5 m Alunite
  • 12.5 m Kaolinite
  • 12.5 m Sericite
  • 12.5 m Buddingtonite
  • 12.5 m Iron Oxide Gossans
  • 12.5 m Hematite
  • 12.5 m Goethite
  • 12.5 m Jarosite
  • 75.0 m All Silica

3 Context images:

  • Geology enhanced colour image
  • Vegetation intensity
  • Greyscale image

Up to 12 ESRI Shapefiles (polygon):

  • Opal/Chalcedony
  • All Silica
  • Calcite
  • Chlorite/Epidote
  • Alunite
  • Kaolinite
  • Sericite
  • Buddingtonite
  • Iron Oxide Gossans
  • Hematite
  • Goethite
  • Jarosite

PhotoSat ASTER Alteration Technical Specifications

Map Projection: UTM, Others on request
Datum: WGS84, NAD27, NAD83 – Others on request
Raster Format: Alteration and Colour Images: GeoTIFF
Vector Format: Alteration minerals: ESRI Shapefiles (polygon)
Pixel Size: Color =12.5m, alteration=12.5m, silica=75m
Media: FTP
Image Resolution Pixel Size
Geology enhanced colour image

Vegetation intensity

Greyscale image

15m 12.5m
Opal/Chalcedony

Calcite

Chlorite/Epidote

Alunite

Kaolinite

Sericite

Buddingtonite

Iron Oxide Gossans

Hematite

Goethite

Jarosite

30m 12.5m
Silica Zones 90m 75m

License Agreement

  • PhotoSat General Terms of Sale