1.7k likes | 4.21k Views
Carbonate sediments, facies, & depositional environments. http://smu.edu/earthsciences/academics/courses/geol3472/. Carbonate Platforms.
E N D
Carbonate sediments, facies, & depositional environments http://smu.edu/earthsciences/academics/courses/geol3472/
Carbonate Platforms A carbonate platform is a sedimentary body which possesses topographic relief, and is composed of autochthonous calcareous deposits (Wilson, 1975).
Carbonate platforms: Ramps progressive increase in water depth basinward
Modern carbonate ramp: southern Persian Gulf arid climate
The majority of the world’s oil reserves occur in carbonate ramp facies of the Middle East World Oil Reserves
Progradation of carbonate ramp facies results in an overall coarsening-upward succession, perhaps capped by evaporite facies if arid climate
Great Barrier Reef, Northeast Australia - reef-rimmed shelf
South Florida Shelf (infrared satellite image) Florida Bay - muddy inner shelf Florida Keys - exposed Pleistocene reef
Geologic map of Guadalupe Mtns.- west Texas and southern New Mexico
Oblique aerial view of Guadalupe Mountains - looking north
Interpretation of Permian facies belts, Guadalupe Mountains
Rimmed carbonate shelves - Oolite sand shoal facies Forereef facies
Submersible photo of cemented slope beds, Bahamas - 40° angle
Idealized progradational • carbonate rimmed • shelf succession • overall coarsening-up • pattern from fine-grained • toe-of-slope muds • to forereef slope (reef talus) to reef boundstone • or oolite shoal deposits (perhaps with finer-grained shelf-lagoon facies on top)
Response of carbonate platforms to changing sea level 1 - transgressive response to rising sea level
Response of carbonate platforms to changing sea level 2 - regressive response to falling sea level
Response of carbonate platforms to changing sea level 3 - exposure during maximum sea level fall
Formation of karst landforms, caverns and cave systems during exposure of carbonate terrain
karst topography of Florida (exposed carbonate platform) with numerous sinkholes
Superimposed scales of stratigraphic cyclicity, Cambrian Nevada
Meter-scale carbonate cycles, Cambrian, Nevada - alternation of dark, shallow subtidal limestones with light, dolomitized tidal flat facies