Carbonate Reefs and nano organisms Flashcards
What are coccolithophores and how big are they?
They’re nano Plankton
When did the coccolithophores arise?
Triassic but they became abundant in the late cretaceous.
Below what depth does calacite dissolve?
Compensation depths - around 4 to 5 km
What are the Cnidarian?
They Phylum Cnidarian are jellyfish.
What symmetrical features do the cnidarian have?
Radial/bilateral symmetry - bicycle wheel symmetry
Describe the life cycle of the cnidarian?
They start of reproducing via sperm and egg, then they turn in to a polyp with a sexual reproduction. Then the medusa (jellyfish) release from the polyp (facing up).
Zoantharian Corals Skeleton composition?
Their membrane secrates calcium carbonate skeletons.
Features of Rugose Corals?
Bilaterally Symmetry Calacite Skeletons Ordovician to Permian Weakly anchored to the sea floor Colonian or Solitary Well developed septa
Tabulate Coral Features?
Always Colonial Ordovician to Permian Radial Symmetry Calcite Skeletons Weak or absent septa
Scleactinian Coral Features?
Triassic to recent Colonial to solitary Well developed septa Aragonite Skeleton Radial Symmetry
Stromatolites Features?
Live by sharks (i.e shark bay) to stop being eaten by grazing metazoans
They’re buried occasionally - leading to strongly reinforced calcitic skeletons
They precipitate calcite which binds sediment together
Porifeans meaning
Sponges
Features of Porifeans
Decay quickly after death, leads to sponge skeleton
Held together by Spongen
They form chert - microcrystalline quartz that replaces calcite
What are stromatolites?
They’re laywers of photosynthetic cyanobacteria that precipitate calcite that bind sediment together.
What is chert in sponges?
Chert is microcrystalline quartz that replaces caco3 grains
