Structures and other features within sedimentary rocks - clues to the past environments Paleoenvironments Environment of deposition Direction of water or wind Strength or energy of transport agent The “up” side of a sedimentary bed Life that existed and the environment they lived in Climate conditions

Facies Set of conditions that lead to a particular rock type or group of rocks.

Chemical Sedimentary Environments –Shallow marine (salt water) areas (usually carbonates and evaporites form) –For example – Limestone, Halite, Gypsum

Clastic Sedimentary Environments Marine –Beaches, tidal flats, deltas, deep seas, lagoons. Continental –Rivers, deserts, alluvial fans, playa lakes, glacial areas.

Transgression – ocean advancing over areas that were once dry land (happening today) Regression – opposite, land migrates further out into ocean. (or ocean level dropping)

Typical ocean sediments beach sand mud carbonate sediments sandmud Dissolved ions

Typical ocean sediments beach sand mud carbonate sediments Process of transgression sandmud carbonate

Typical ocean sediments beach sand mud carbonate sediments Process of transgression sandmud carbonate sandmudcarbonate Typical sediment sequence would show Carbonate Mud sand