BIOLOGY 101 Study Guide - Quiz Guide: Baryte, Siderite, High Island
Document Summary
Warrawoona age: a rock group that existed 3. 5 bya. Was altered by heat and pressure and answered some of the first questions regarding the antiquity of life. What is found here: most rock is volcanic with only a few sedimentary deposits, and most of the area is made of lava flow. Different evidence for the oldest life-direct and indirect: Chert: hard, sedimentary rock that accumulates in volcanic rock. Examples: flint, jasper, agate, where most sediments are preserved. Ooids: scientists hypothesize that their formation is associated with early life. Are sometimes formed in the presence of life, sometimes not. Gypsum: a sulfate mineral that contains calcium and sulfur, was also around in the past. Stromatolites: colonies of bacteria made of low mounds of finely laminated sediment that are trace fossils. Cyanobacteria: grow, photosynthesize and form dense mats and thrive. Secretes slime that protects them against sunlight and allows them to stick to surfaces.
