4-Facies peritidal-subtidal-shoal. Nearshore and Subtidal carbonate environments

peri-tidal - environments are affected by daily movement of tide

supra-tidal - permanently above tide, exposed to open air

inter-tidal - area between high tide and low tide, alternately exposed to air and covered by seawater.

Sub-tidal - permanently submerged, higher diversity of organisms.

Supra tidal zones:

• desiccation cracks

• flat-pebble conglomerate

• fenestrae

Intertidal zone

+ stromatolites

+ mangroves

-darker layers represent organic rich

-whitish layers are carbonate sediment.

-distinct organic and carbonate detrital layers after storm event

High energy environment, get granular sediment.

As evaporite crystallise and precipitate, can disrupt original depositional texture.

Rudist shell - on top right - made my aragonite.

Aragonite is metastable - forms quickly but is not stable and will dissolve quickly.

Karstification - chemical dissolution of soluble rocks (especially limestone and dolomite) by slightly acidic water.

Sea-level goes up and down, distinct cyclicity.

Micritisation is the process by which shells are bored and altered so that only a thin rim of micrite remains, with the original shell interior commonly replaced by sparry (blocky) calcite, typical for shallow water