GEO 103 Lecture Notes - Lecture 11: Bioturbation, Ripple Marks, Graded Bedding

• School: Stony Brook University
• Department: Geosciences
• Course: GEO 103
• Professor: Mc Lennan

Document Summary

Composition tells us about the source rocks, weathering history. This involves some lithification process so there can be overlap between this and chemical sedimentary rocks since the rock can also be formed through precipitation. Ex: quartz sand may have been deposited in river, on beach or in sand dunes. Limestone deposited mostly in warm, shallow seas (small amount originates in lakes) Evaporates (ex: rock salt, rock gypsum) indicate arid environments where evaporation rates are high. Coal originates in swamps and bogs on land - usually marginal marine with very little oxygen from a lot of organic activity (decomposition). Organic matter is preserved better in these environments. Detrital grain size gives indication of energy conditions during transport and deposition. Small particles (silt/clay) transported by weak currents and accumulate under low-energy conditions. Silt is also transported by wind and is the primary constituent in loess deposits. Two textural features reflecting particle size distributions and shapes.