EARTH121 Lecture Notes - Lecture 5: Sea Level Rise, Wind Wave, Sedimentary Structures
25 Aug 2016
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Document Summary
Sediment is unconsolidated material (fragments of rocks or minerals) and the rock has been lithified into a hard consolidated material. Size of fragments from different rocks vary: boulders (more than 256mm, cobbles (64mm 256mm, pebbles (2mm 64mm, sand (1/16 mm 2 mm, silt (1/256mm and 1/16mm, clay (less than 1/256mm) Sediment can be the result of evaporated solutions that leave behind precipitates (these rocks are known as evaporates) Organic matter (shells, fecal matter, corals that over millions of years accumulate produce rocks) Material such as silica are very strong cements. Detrital fragments: conglomerate rock: rounded particles (carried by water that round the particles, these rocks are described by size of fragments. Clastic clasts: classified by minerals, can be bioclasts (shells, skeletal components, plant fragments) or inorganic (non biochemical) Sediments are studied to understand sedimentary rock and the processes that lead to its creation. 3 depositional zones: continent(terrestrial), transitional, marine: when studied sediments can reveal past conditions under which they formed.
