gen-define-the-formation-of-fossils-and-give-one-short-worked-ex-faeb

Define the formation of fossils and give one short worked example.

# Formation of Fossils **Fossils** are the preserved remains, impressions, or traces of organisms from past geological ages. Fossilization is a rare process that typically occurs when organisms are rapidly buried in sediment, protecting them from decay and scavengers. ## Main Steps in Fossilization: 1. **Death and burial** - Organism dies and is quickly covered by sediment 2. **Decay of soft tissues** - Soft parts decompose, leaving hard parts (bones, shells) 3. **Sediment accumulation** - More layers build up, creating pressure 4. **Mineralization** - Minerals from groundwater replace or fill organic materials 5. **Lithification** - Sediments harden into sedimentary rock 6. **Exposure** - Erosion or geological activity brings fossils to the surface --- ## Worked Example: Marine Trilobite **Scenario:** A trilobite dies on the ocean floor 450 million years ago. 1. **Burial:** The trilobite's body settles into soft mud on the seafloor and is quickly covered by sediment during a storm. 2. **Preservation:** The hard exoskeleton (shell) resists decay while soft internal organs decompose. 3. **Mineralization:** Over millions of years, mineral-rich water seeps through the sediment, and minerals like silica gradually replace the original shell material. 4. **Rock formation:** Continued sediment deposition creates pressure, compressing layers into shale rock. 5. **Discovery:** Geological uplift and erosion eventually expose the rock layer, revealing the trilobite fossil.