Preservation of fossils 0.0 / 5 ? GeologyF795A2/A-levelOCR Created by: Maria5Created on: 27-05-17 18:16 246315 Across 1. An infilled fossil void, usually with another mineral (4) 4. 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. (12) 5. An impression of the outside or inside of a fossil (5) Down 2. Occurs during burial as overlying mass of rocks increases pressure and temperature. Volatiles are driven off, increasing carbon content (13) 3. Occurs when percolating groundwater rich in silica dioxide moves through the rock. The minerals dissolved crystallise out of solution and fill pores or voids. (14) 6. Occurs when the original material is dissolved atom by atom and substituted with another mineral. E.g. Aragonite to Calcite (11)
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