Complex patterns in fossilized stromatolites revealed by hyperspectral imaging (400-2496 nm)

Area of Science:

• Geology
• Astrobiology
• Remote Sensing

Background:

• Stromatolites are layered structures formed by microbial communities, crucial for understanding early life.
• Determining biogenicity in ancient stromatolites is challenging without preserved biomarkers.
• Hyperspectral imaging offers a non-destructive method for analyzing mineral composition and texture.

Purpose of the Study:

• To assess the utility of hyperspectral imaging in identifying textural and compositional variations in ancient stromatolites.
• To determine if complex textures revealed by hyperspectral imaging can serve as evidence for biogenicity.
• To differentiate between biogenic and non-biogenic origins of stromatolite samples.

Main Methods:

• Hyperspectral imaging (400-2496 nm) was applied to four ancient stromatolite samples.
• Automated feature extraction quantified mineral reflectance and absorption features.
• Ferrous iron content was measured using specific reflectance ratios; mineral identification was confirmed by petrography and XRD.

Main Results:

• Shortwave infrared (SWIR) hyperspectral imagery revealed complex laminar and convoluted patterns, including textures resembling living microbial mats.
• Spectral analysis identified mineral compositions such as dolomite, calcite, chlorite, and illite.
• Distinct mineral distribution patterns and spatial statistics differentiated biogenic (calcite-rich, convoluted) from non-biogenic (chlorite-rich, laminar) stromatolite portions.

Conclusions:

• Hyperspectral imaging effectively maps textural and compositional variations in stromatolites.
• Complex textures identified by SWIR imaging can support biogenicity claims, especially in the absence of biomarkers.
• This technique is a powerful tool for geological and astrobiological investigations of stromatolites.