Mineral Composition: Silica

[Coming soon]

Created at: 
2023-01-12
Updated at: 
2023-04-20
Curator: 
Graham Lau
Authors: 
Graham Lau , Emma Johnson , Jose Morel  
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Definition
HIGH
LOW

Silica is a biogenically formed mineral when synthesized or created as a byproduct of organisms. [General]

Environments
Mars: Surface, Mars: Subsurface, Ocean Worlds: Enceladus Surface, Ocean Worlds: Enceladus Subsurface, Ocean Worlds: Europa Surface, Ocean Worlds: Europa Subsurface, Ocean Worlds: Titan Surface, Ocean Worlds: Titan Subsurface, Ocean Worlds: Other
eDiatoms have cell walls made of silica.

eIn the Waiotapu, New Zealand in the Champagne Pools, silica was often formed on EPS that was secreted by microorganisms.

 

Comparisons between silica features at El Tatio and Mars indicate a potential fossil origin of life. [General]

Environments
Mars: Surface
eThe biotic environment of El Tatio, Chile hosts opaline silica deposits that have many similarities to the ‘Home Plate’ deposits on Mars.

 
 

Loss of genes enabling silica transport may indicate a low prevalence of intracellular silica as a biosignature. [General]

Environments
All
eThe distribution of intracellular silica within bacteria is verified between different forms of silica in similar bacteria, indicating that some bacteria may have lost the genes enabling this silica in evolution or different strands vary in origin.

Definition
HIGH
LOW

Silicification is a process that often preserves biological organisms. [General]

Environments
Mars: Surface, Mars: Subsurface, Ocean Worlds: Enceladus Surface, Ocean Worlds: Enceladus Subsurface, Ocean Worlds: Europa Surface, Ocean Worlds: Europa Subsurface, Ocean Worlds: Titan Surface, Ocean Worlds: Titan Subsurface, Ocean Worlds: Other
eMany species of bacteria, algae, and micro-organisms are silicified in laboratory conditions in a manner that is consistent with authentic microfossils found in Precambrian cherts.

eSilicification in the Proterozoic commonly occurred in locations that had good silica availability, sediment permeability, and significant amounts of organic matter.

 
 

The process of silicification may make it hard to identify biogenic origin. [General]

Environments
All
eThe process of silicification can destroy features of organisms that indicate biogenic origin.

 

Silicification occurs more frequently in areas with organic matter, but the exact relation between these is unknown and can be hard to detect in areas with low amounts of organic matter. [Patchiness]

Environments
All
eSilicification in the Proterozoic commonly occurred in locations that preserved significant amounts of organic matter.

Definition
HIGH
LOW

Silica found in Apex Chert can be created abiotically through hydrothermal vents. [General]

Environments
All
eCarbonaceous material in cherts may exist in different phases (from different time periods), possibly resulting from pulses of hydrothermal silica of different temperatures.

 

Silica samples in the Apex Chert are found at depths where photosynthetic organisms can’t exist.  [General]

Environments
All
eSilica samples in the Apex Chert are found at depths where photosynthetic organisms can’t exist. 

 
 

Hydrothermal processes can create abiotic samples with morphological similarity to microorganisms. [General]

Environments
All
eChert samples taken from Mount Ada Basalt in Western Australia show evidence of hydrothermally altered organics, however they differ greatly from actual microfossils discovered in the same region.

Definition
HIGH
LOW