GEOL 1003 Lecture : Ch5 Sedimentary Environments With Notes
Document Summary
Patch reefs within a shallow lagoon next to a reef front in australia. When you look at a sedimentary structure, you can deduct what the past environment looked like. = geography of the past: ancient environments reconstructed from geologic evidence using the concept of actualism. Paleoenvironmental reconstruction: e. g. , dinosaur habitat, mainly aquatic? containing their fossils. Biotic organisms and processes: vertical sequence of sediments from a meandering river. The lateral shifting environments produces a vertical sequence that changes from coarse to fine sediments associated with adjacent environments. Walther"s law: when depositional environments migrate laterally, sediments of one environment come to lie on top of sediments of an adjacent environment. Weathering processes and decay of plant material: type depends on climatic conditions. E. g. , caliche (desert soil accumulation of caco3: oxidized seds (reddish-color) Recognized by: plant roots, animal burrows. Fine sediments at center; coarsest sediments along margins: sometimes bordered by stream and river deposits. Indicative of abundant precipitation within that area.
