Spectral Remote Sensing

What is at surface, and what structures control it?

Alteration minerals, structures and rock boundaries mapped from satellite, from regional scale to camp scale, matched against laboratory spectra and tied to the structures that control them.

Cuprite, Nevada: alteration mineralogy from a 30 m EnMAP hyperspectral acquisition, matched against laboratory reference spectra. Cuprite is the published USGS reference site we benchmark against.

  • U.S. Geological Survey
  • British Geological Survey
  • CSIRO
  • European Space Agency
  • AuScope National Virtual Core Library
  • Geological Survey of Finland (GTK)
  • German Aerospace Center (DLR)
  • Geological Survey of Japan (AIST)
  • GNS Science
  • Council for Geoscience, South Africa
  • Alberta Energy and Minerals
  • Alberta Geological Survey
  • Botswana Geoscience Institute
  • British Columbia Geological Survey
  • Bureau of Land Management
  • EuroGeoSurveys
  • Geological Survey of Brazil (SGB)
  • Geological Survey of Denmark and Greenland (GEUS)
  • Geological Survey of Norway (NGU)
  • Geological Survey of Sweden (SGU)
  • GeoSphere Austria
  • Guyana Geology and Mines Commission
  • Manitoba Geological Survey
  • Mineral Resources Authority, Papua New Guinea
  • Minerals Commission of Ghana
  • Nova Scotia Department of Natural Resources and Renewables
  • ONHYM, Morocco
  • Polish Geological Institute (PGI-NRI)
  • Saskatchewan Geological Survey
  • Saudi Geological Survey
  • SERNAGEOMIN, Chile

Data published by 80 organisations ·Names and logos belong to their owners; no endorsement or partnership is implied. All 80 sources

Three scales

From a province to a prospect.

Choose the scale the decision needs. Each step narrows the ground the next one has to cover.

10 to 90 m

Regional

ASTER, Sentinel-2, Landsat, EMIT

Mineral groups, iron oxides, silica and the major structures across a province or a licence package.

Choose where to look.

30 m

District

EnMAP, PRISMA

Individual alteration minerals, from alunite and pyrophyllite to chlorite and carbonate, and the zoning between them.

Find the system and read its zoning.

0.3 to 3.7 m

Camp

WorldView-3, Pléiades Neo, airborne surveys and LiDAR

Mineral groups, veins, dykes, faults and rock boundaries at the scale of a prospect.

Put field teams on the right outcrop.

Our spectral projects are delivered with GeoSpectra, from free imagery to commercial camp-scale acquisitions.

Talk to us

The approach

A colour composite is an interpretation. A spectral match is a measurement.

Each pixel's absorption features are fitted against laboratory reference spectra, with thresholds calibrated per instrument. Every clean acquisition is compared: a class that flips between passes is noise and is withheld, and ground that matches nothing stays unmatched.

30 m
Hyperspectral
EnMAP and PRISMA; EMIT at 60 m; airborne surveys finer
1.2 m
Camp scale
WorldView-3 in the visible and near infrared, 3.7 m in the shortwave infrared; Pléiades Neo at 0.3 m for structure
11
Mineral families
Each mapped on its own evidence
489 million
Drill-core spectra
Raw spectra from 6,546 scanned holes in the national core library

The review

An interactive review that works offline.

Every mineral layer, natural colour, a drawing tool for the geologist's own interpretation and the written evaluation beside the map, in a folder that opens on any laptop in the field.

The MineDSS spectral site evaluation review interface, showing the Cuprite, Nevada mineral map and evaluation report
Cuprite, Nevada: the spectral site evaluation as delivered, with layer controls, the mineral map and the plain-language evaluation report. Data: NASA EMIT · Imagery © Esri

What it produces

The output.

What the engine produces, in formats a GIS and a geologist can both open.

Mineral maps by family

Each family at two intensities, detected and strong, as GIS-ready rasters.

Alteration layers as vectors

One layer per mineral assemblage, ready for the geology, drill collars and tenure.

Structure and rock boundaries

Faults, lineaments and contacts, with the sense of movement where the imagery resolves it.

Imagery and composites

Natural colour and mineral composites; at camp scale, a 0.3 m base image.

An integrated target map

Combined with your geology, geochemistry and geophysics: first and second priority areas for field follow-up.

An offline review and a written report

The interactive review, a plain-language report, and every layer as data.

Read more: the mineral families we map, and what they point to

Colours on our maps show which mineral matched at each place. They do not measure quantity or grade: the geology is in the pattern.

Alunite group

Acid-sulphate alteration, formed in hot, acidic hydrothermal fluids.

Kaolinite group

Argillic alteration. Kaolinite also forms by weathering; dickite does not.

Pyrophyllite

High-temperature, advanced argillic alteration.

White mica

Phyllic (sericitic) halos, and a common rock-forming mineral, so pattern matters more than extent.

Smectite

Argillic alteration and weathering.

Chlorite and epidote

Propylitic alteration: the cooler, outer halo of many systems.

Carbonate

Carbonate alteration and carbonate host rocks.

Iron oxides

Oxidised sulphides and gossans, and red soils, which is why context matters.

Jarosite

Acid oxidation of sulphides.

Gypsum

Sulphate: evaporites and acid alteration.

Ammonium (buddingtonite)

Ammonium feldspar in some hot-spring systems.

Silica

From thermal infrared, reported as a lithological quartz signal and not as an alteration claim.

Instruments

Every acquisition over the ground, searched.

Every free acquisition over the area is catalogued first, with coverage and cloud measured, and only the instruments that can resolve the minerals in question are used. At camp scale, commercial imagery is acquired for the project.

InstrumentTypePixelRangeUsed for
EnMAP Hyperspectral satellite 30 m 0.42 to 2.45 µm Clays, micas, carbonates, sulphates, chlorite and epidote, iron
PRISMA Hyperspectral satellite 30 m 0.40 to 2.50 µm As EnMAP; archive acquisitions ordered per project
EMIT Imaging spectrometer, International Space Station 60 m 0.38 to 2.50 µm Broad mineral families over large areas
DESIS Hyperspectral, International Space Station 30 m 0.40 to 1.00 µm Iron oxides and vegetation; no shortwave clays
ASTER Multispectral with thermal infrared 15 to 90 m VNIR · SWIR · TIR Mineral-group ratios from the archive; silica from thermal infrared
Sentinel-2 Multispectral satellite 10 to 20 m 0.44 to 2.19 µm Iron-oxide indices at 10 m, and context
Landsat Multispectral satellite 30 m 0.43 to 2.29 µm Context and the long historical record
WorldView-3 Commercial multispectral satellite, acquired per project 1.2 m · 3.7 m VNIR · 8 SWIR bands Camp-scale mineral groups: clays and micas, carbonates, iron oxides
Pléiades Neo Commercial satellite, acquired per project 0.3 m Visible to near infrared Veins, dykes, faults and rock boundaries at prospect scale
Airborne Hyperspectral surveys where they exist and are licensed to 4.5 m VNIR · SWIR Detail at prospect scale
LiDAR Airborne elevation, where it exists or is flown 1 m or finer Elevation Faults and rock boundaries beneath vegetation

We do not identify individual mineral species from multispectral imagery. With a handful of bands it maps indices and mineral groups reliably; naming a species needs a hyperspectral measurement. Using the wrong instrument for that claim manufactures false identifications, and we do not do it.

62

Airborne products, Queensland

Hyperspectral mineral products at 4.5 m, cleared by the Geological Survey of Queensland for use in commercial deliverables.

23 m

National airborne maps, Afghanistan

The U.S. Geological Survey's airborne hyperspectral mineral maps, over the parts of the country that were flown, public domain, and the reference for our blind test.

489 million

Drill-core spectra, Australia

From 6,546 holes in the national core library, paired to laboratory assays in 2,746 of them: what the minerals look like below the surface the satellites see.

How it is tested

Benchmarked in Nevada. Tested blind in Afghanistan.

Scored against the published expert mapping of the USGS Cuprite reference site, on acquisitions from two different instruments.

Then tested blind in Afghanistan: the rule was frozen and the predictions recorded before the second area's reference mapping was read.

Spectral remote sensing partner

GeoSpectra

Our spectral projects are delivered with GeoSpectra, from free imagery to commercial camp-scale acquisitions. Australian specialists in spectral remote sensing and geospatial intelligence for mineral exploration. Their interpretation practice sets the standard our automated pipeline is held to.

geospectra.com.au

From every acquisition to a mineral map.
  1. 01

    Discover

    Every free multispectral and hyperspectral acquisition over the area catalogued, with the usable clear fraction measured, because catalogue cloud figures under-report cirrus. At camp scale, WorldView-3 or Pléiades Neo is acquired for the project.

  2. 02

    Hypothesis first

    The mineral-system hypothesis for the ground is written down and signed before any map is made, so the map is read against it.

  3. 03

    Match

    Continuum-removed spectral feature fitting against laboratory reference libraries, with detection thresholds calibrated per instrument.

  4. 04

    Corroborate

    Families compared across every clean acquisition. Vegetation, cloud and snow masked first; disagreement withheld.

  5. 05

    Interpret

    Faults, lineaments and rock boundaries interpreted from the imagery and elevation, and read against the alteration, as context for targeting and never as a rule that picks bodies on its own.

  6. 06

    Deliver

    The offline review, the written report and the data, with every served file checked before release.

Straight talk

What this is, and what it isn't.

We would rather say less than claim more than the evidence supports.

It is

  • Surface mineralogy measured from reflected light and matched against laboratory spectra
  • Mapped at the scale the decision needs, from a province to a prospect
  • Benchmarked against a published reference mapping, and tested blind
  • Honest about limits: vegetation, cloud and snow are masked, and unmatched ground stays unmatched

It is not

  • A measure of grade or quantity: colour shows which mineral matched, not how much
  • Species identification from multispectral imagery
  • A view below the surface: a satellite reads the uppermost skin of rock and soil
  • A drilling target on its own: alteration needs structure and context

Next in the workflow · 05

Due Diligence & Market Analysis

Can I acquire it, hold it, and what will it cost me?

Continue

Talk to us

Talk to us about spectral mapping.

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    The record, the models and the ground they point to.

  • Publishers and researchers

    Geological surveys, universities and programmes whose work the record is built on.