6 Flashcards
Bioclast Limestone
Coquina: Forms from the cementation of shells and coarse shell fragments
Chalk: Fine grained white limestone formed of the shells of planktonic microorganisms
Oolitic Limestone
Formed by cementation of sand seized ooids (small calcite spheres inorganically precipitated in warm shallow sea water)
Travertine
Formed by a process of rapid precipitation of calcite often in a limestone cave
Tufa
Precipitated from solution in the water of continental spring, lake or from groundwater, more porous and cellular
Peat
Uncolidated deposit of moss and other plant remains
Coal
Sedimentary rock forming from compaction of partially decayed plant material
Shallow swamps or bogs:
Organic Material deposited in water with low oxygen content
Sedimentary structures:
features developed during or shortly after deposition of sediment, but before lithification
Bedding:
A series of visible layers within rock
Principle of original horizontality
Most water laid sediment is deposited as horizontal or near horizontal layers
Principle of superposition
The olderst layer on the bottom and the layers becoming younger upward
Cross bedding
Thinner beds at an angle to main thicker beds
Graded-bedding
The layer with vertical change in partical size
Ripple Marks:
Small ridges formed on sediment surface exposed to moving wind or water
Mud Cracks
A polygonal pattern of cracks formed in very fine grained sediment as it dries
