Anna Fonseca – Infrared Spectroscopy Applied to Alteration Mapping

By: Anna Fonseca, Principal Consultant (Geology) with SRK.

ABSTRACT

Infrared spectroscopy is a key technique for vectoring mineralized centres in hydrothermal ore deposits. The technology was developed by astronomers in the 1800s and has become widespread across the sciences since the 1950s.

This presentation will cover topics such as:

• causes of infrared absorptions in minerals;
  
• important infrared-active mineral groups;
  
• how to interpret infrared spectra of minerals;
  
• vectoring with crystallinity and compositional zoning;
  
• spectroscopic sample collection and description;
  
• instruments that are applicable to mineral exploration.
  

After the presentation, there will be an instrument demonstration. Attendants are welcome to bring their altered samples for infrared spectroscopic analyses.

BIO

Anna Fonseca is a Principal Consultant with SRK and has over 20 years of international mineral exploration experience in mapping, geochemical survey and QA-QC protocols design, regional GIS compilations and targeting, and drilling in various hydrothermal deposit types including porphyry-epithermal, Carlin, IOCG,CRD, skarn, and VMS. In the past eight years Anna has focused on alteration mapping and modeling of porphyry and epithermal deposits, aided by infrared spectroscopy, petrography and geochemistry.  Her laboratory at SRK includes two petrographic microscopes and a high-resolution portable infrared spectrometer.