Weathering:  "rock rot"; breaking down solid rock into pieces, compounds, new minerals
    Physical/Mechanical Weathering; abrasion, freeze-thaw, exfoliation/pressure release
    Chemical Weathering; dissolving rocks in fluids; mineral transformation
    Products of Weathering;
        1: sediment;
        2: elements/ions in solution;
        3: new minerals
            "weathering minerals": clay minerals (e.g. kaolinite), oxides (e.g. rust), hydroxides

Sediment: loose/unconsolidated particles or minerals formed by different processes
    (a) clastic/fragmental sediment: particles/fragments/clasts of rock and mineral
        classification by size: clay, silt, (mud = clay+silt), sand, pebble, cobble, boulder
        classification by shape: angular, irregular versus rounded, smooth
    (b) biogenic sediment: plants and/or animals, usually their skeletons/hard parts
    (c) precipitated/evaporitic sediment: minerals grown from ions dissolved in water
        evaporitic minerals:  salts (halite, sylvite), carbonates (calcite, dolomite), sulphates...

Loose Sediment to Solid Rock;  aka diagenesis  or lithification  (rockification)
    to rockify loose sediment, need: 1.  THICK pile of sediment (> 1 mile).  2.  long TIME.  3.  circulating WATER.
        three processes that contribute to lithification/rockification
    (a) cementation; growth of cementing minerals in spaces between particles
        cementing minerals: quartz, calcite, hematite (rust), gypsum
        cement is not the same as precipitated sediment; cement bonds sediment
    (b) compaction; welding particles together under mild temperature and pressure
    (c) recrystallization:  typically associated with evaporitic minerals like salt.  "crystallize again"
 

Classification of Sedimentary Rocks: based on type of originally loose particles
    Clastic Sedimentary Rocks; made from fragments/clasts of rock and mineral
       Fine grained clastic rocks: claystones/shales, siltstones, mudstones
       Medium grained clastic: sandstones. "clean" sandstones are rich in quartz
       Coarse grained clastic: conglomerates (round bits) and breccias (angular bits)
    Biogenic Sedimentary Rocks; made from plants and/or animals. fossils usually visible
        Coal made from plants (no longer visible): lignite---bitumen----anthracite.
        Fossiliferous (biogenic) limestones; chalk, coquina, bioclastic limestone (fossil hash)
    Evaporitic Sedimentary Rocks; made from evaporated/precipitated minerals
        rock salt, carbonates (limestone, dolomite), sulphates (gypsum rock), etc.

Sedimentary Rock Associations: where sediment was originally accumulated
        **sediments accumulate in low spots, basins, depressions; not in mountains.
    Deep Ocean Floor:  mudstones, biogenic sedimentary rocks (chert, limestone)
    Continental Slope/Rise: dirty sandstones (graywackes), turbidites, mudstones
    Continental Shelf and Interiors: limestones, dolomites, quartz sandstones, shales
    Shallow Lakes and Seas:  evaporites (rock salt, limestone, dolomite), mudstones
    Deltas (Fresh and Salt): clastic sedimentary rocks, biogenic components
    Rivers Channels and Flood Plains: clastic sedimentary rocks + biogenic shale

Sedimentary Structures:  primary features formed in original sediment and preserved
    sed structures tell you many things about the original environment of deposition
       bedding = primary layering, originally horizontal.  cross bedding at an angle
       mudcracks (from drying), ripple marks (from wind or water)
       fossils themselves and other biogenic features like tracks and burrows
 
 

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