Occurs when the original material is dissolved atom by atom and substituted with another mineral. E.g. Aragonite to Calcite
Replacement
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Occurs when percolating groundwater rich in silica dioxide moves through the rock. The minerals dissolved crystallise out of solution and fill pores or voids.
Silicification
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Occurs in anaerobic conditions where sulfer is reduced to bisulfide which reacts with iron in the environment to form iron pyrite which replaces the fossil material.
Pyritisation
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Occurs during burial as overlying mass of rocks increases pressure and temperature. Volatiles are driven off, increasing carbon content
Carbonisation
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An impression of the outside or inside of a fossil
Mould
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An infilled fossil void, usually with another mineral
Cast
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Other cards in this set
Card 2
Front
Occurs when percolating groundwater rich in silica dioxide moves through the rock. The minerals dissolved crystallise out of solution and fill pores or voids.
Back
Silicification
Card 3
Front
Occurs in anaerobic conditions where sulfer is reduced to bisulfide which reacts with iron in the environment to form iron pyrite which replaces the fossil material.
Back
Card 4
Front
Occurs during burial as overlying mass of rocks increases pressure and temperature. Volatiles are driven off, increasing carbon content
Back
Card 5
Front
An impression of the outside or inside of a fossil
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