Term
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Definition
-Sedimentary Structure
-carbonate rock classification
-skeletal allochem identification |
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Term
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Definition
-Most abundant particle type + Dunham name
-Grain size and sorting
-mineralogy
-cement
-porosity
(cross-stratified ooid-peloid grainstone) |
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Term
| Platform Interior Fossil assemblage |
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Definition
RESTRICTED (ELEVATED SALINITY)
low diversity
Dasyclads, Mizzia
Stromatolites, algae mats
Green algae |
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Term
| Mid Platform Fossil Assemblage |
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Definition
OPEN SHALLOW SHELF
high diversity
fauna is age-dependent, but brachs, bivalves, crinoids, bryozoans, green algae, corals are all common |
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Term
| Platform Margin Fossil Assemblage |
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Definition
REEF SYSTEM
corals, stromatoporoids, green algae, rudist clams, highly dependent on age
high diversity index, large size, organisms that show attachment
massive highly calcified structures for wave resistance |
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Term
| Fore-Slope Fossil Assemblage |
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Definition
Brachs, crinoids,platy stromatoporoids or corals for maximizing light penetration
some fusilinid or other forams, commonly transported |
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Term
| Fore-Slope Fossil Assemblage |
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Definition
Brachs, crinoids,platy stromatoporoids or corals for maximizing light penetration
some fusilinid or other forams, commonly transported |
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Term
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Definition
| only delicate forms, brachs, others that can live in muddy substrate |
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Term
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Definition
| not good for and specific setting, occur widely by local generation and get transported |
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Term
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Definition
-energy indicator
shelf
high energy shelf margin
tidal currents
mix of hypersaline platform top water with open ocean water |
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Term
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Definition
-2 general types
soil pisolites indicate exposure, erosion, and rainfall
Depositional formation in marine vadose zone associated with teepee formation |
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Term
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Definition
inraclasts
ripped up mud-crack tidal flats
rip-up flat-pebble conglomerate from storm-generated erosion on the shelf |
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Term
| Aggregate Grains or Grapestone |
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Definition
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Term
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Definition
high energy
massive burrowed and cross stratified
cross stratified = higher energy |
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Term
| Packstone (grain dominated) |
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Definition
typically good indicator of mixed environment
likely a grainstone shifted into a lower energy environment and then burrowed |
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Term
| Wackestone (mud dominated) |
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Definition
| lower energy setting, large range of water depths from subtidal lagoons and tidal flats to outer shelf, slope, and toe-of-slope |
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Term
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Definition
common in tidal flats where too restricted for fossils or other burrowing forms
occur in deep water basinal settings |
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Term
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Definition
| current laminations, algae laminations, mud cracks, rip-up clasts, fenestral lamination, low-relief stromatolites |
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Term
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Definition
| cross-bedded sands, storm deposits, burrowing |
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Term
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Definition
| few sed structures, massive framestones or bafflestones, early marine cement |
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Term
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Definition
| soft sed folds, breccia deposits, graded bedding, turbidites |
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Term
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Definition
| thin bedded mudstone, fine mm-lamination, absence of burrowing |
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Term
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Definition
| Facies adjacent to one another in a CONTINUOUS vertical sequence also accumulated adjacent to one another laterally (only for section without unconformities) |
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Term
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Definition
Develop in isolation from clastic influx
best between 30 degrees north and south of equator (australia, gulf of mexico) |
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Term
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Definition
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Term
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Definition
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Term
| Isolated Platform Example |
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Definition
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Term
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Definition
Isolated Platform
-pure carbonate system since jurassic
-5km thickness
-series of trending platforms and lows
-humid equitorial setting
-flat topped platform
-modern sed average <5m thick |
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Term
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Definition
Isolated platform with windward/leeward ASYMMETRY
-tidal flux only important where focused by reentrants
-four main facies: coralgal, oolite, oolite grapestone, peller/mud
-no evaporites
Reef along windward side; mud along leeward |
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Term
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Definition
derived from coral and red algae
intertidal to 50m
high wave energy, strong currents
subfacies:
-platform margin reef (windward)
-Lagoonal patch reefs
-Backreef sands |
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Term
| Platform Margin reef subfacies |
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Definition
| formed by Acropora palmata, Acropora cervicornis, red algae lithothamnium, Goniolithon, Halimeda |
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Term
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Definition
occur around reefs and much of the platform margin
5km wide at belt
sands reworked by wave and tidal currents forming large bedforms
molluscs, echinoids, green algae are only habitants |
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Term
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Definition
occur along platform margin locally
2types:
tidal bar belts (bars perpendicular to margin, wide but locallized)
marine sand belts (small sand waved in belt elongate parallel to shelf margin) |
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Term
| Oolitic and Grapestone lithofacies |
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Definition
Broad Belts 0-9m
Leeward Margin of platforms
behind and around true oolite belts
extensive Thallasia covered areas
mostly packstone made up of gastropods, echinoids, starfish, forams, small corals
Green algae |
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Term
| Pellet/Mud and Mud Lithofacies |
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Definition
protected platforms 0-4m
weak fair weather currents, only storm currents
aragonitic mud and fecal pellets
low diversity fauna of molluscs and echinoids |
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Term
| Intertidal-Supratidal Sediments |
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Definition
high energy shorelines (beaches on windward margin, skeletal sand from reef and backreef settings)
low energy tidal flats/reverse deltas (channels, levees, beach ridges, ponds, intertidal flats) |
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Term
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Definition
East facing rimmed shelf
environmental zones:
-platform interior Florida Bay
-Barrier inlet system around Pleistocene islands
-open shelf
-reef margin system
SAME 4 FACIES MAY BE APPLIED TO BAHAMAS
unique mud banks of Florida Bay
no evaporites, salinity range from 10-40 per mil |
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Term
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Definition
NNW facing ramp
main environmental zones:
-deep ramp
-pleistocene island and modern reef belt
-oolitic channel and tidal delta complexes
-restricted lagoon with salinities up to 70 per mil
-tidal flats, supratidal deposits with both carbonate and gypsum/anhydrite
wind and tidal processes dominant, no major hurricanes
supratidal deposits with complex mats, teepees, and sulphates is distinct to the setting |
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Term
| Major Facies in Carbonate Shorezone Systems |
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Definition
Eolian: like clastic, but commonly early cementation
Tidal Flat: supra, inter, subtidal
Barrier Island/Beach/Tidal Channel/Inlet
Upper and Lower Shoreface |
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Term
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Definition
-subtidal sed transported by tides and storm events
-accumulate sed and build across shelf
-result in Walther's Law type facies
-classic 'upward shallowing cycle' of carbonate rocks |
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Term
| Intertidal-Supratidal Sediments |
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Definition
High energy shorelines (beaches on windward margins, skeletal sand from reef and backreef settings)
Low energy tidal flats (reverse deltas)(channels, levees, beach ridges, ponds, intertidal flats) |
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Term
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Definition
Large bedforms (1-10s of m)
steep dips (30-34 degrees)
typically fine very fine sand sed
early cementation common |
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Term
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Definition
Gross Shape (barrier, fringing, Faro, Patch, Atoll, Table)
Stratigraphic character (bioherm, biostrome, reef core, reef flank)
nature of reef builders (skeletal reef vs reef mound) |
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Term
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Definition
primary frame (bafflestone, framestone, coral, algae, hydrozoans stromatops)
secondary frame (encrusters, bindstone, encrusters) |
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Term
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Definition
Physical (storms)
Biological (bioerosion, borers, raspers, crushers, burrowers) |
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Term
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Definition
| various syndep cements, microbial cements |
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Term
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Definition
| mud and grain producing 'critters' |
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Term
| Reef responses to Sea Level change |
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Definition
| drowning, backstepping, retreating, aggrading, prograding, give-up, catch-up, keep-up |
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Term
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Definition
Ramp
Distally Steepened Ramp
Rimmed Shelf
Isolated Shelf |
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Term
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Definition
Tropical/Photozoan: ramp, rimmed shelf, iso platform
Cool-Water/Heterozoan: ramp only
Mud-Mound/Microbial: distally steepened ramp |
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Term
| Attributes of Carbonate Slopes |
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Definition
-dumping ground for shallow water seds
-different timing and sed types than siliciclastic deposits
-seds deposited by combination of sediment gravity flow processes
-forms foundation for platform margin progradation
-rare setting for carbonate reservoirs |
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Term
| Selected Dolomite Occurences (2 of 5) |
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Definition
-Andros tidal flats
-Ambergis Cay, Belize
-Bonaire, Netherland Antilles
-Abu Dhabi sabkhas
-Coorong Lagoon, S. Australia |
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Term
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Definition
| dolomite cell smaller than calcite cell, so porosity increases due to transformation of a rock with a looser atomic packing to a tighter packing |
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Term
| Dolomite Textures and Occurence |
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Definition
Replacement Textures
-fabric destructive
-partial preservation
-mimetic
Cements
-simple rhombic rims
-highly zoned cements
-saddle dolomite rims |
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Term
| Controls on Formation of Evaporation Deposits |
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Definition
Brine Concentration
least evap most evap
CaCO3 CaSO4 NaCl Ksalts
1.8x 70x
Climate and flux crucial, coastal basins have humidity values too high to get Ksalts, thus these form only in continental settings or deep water |
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Term
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Definition
Mud Flats-displacive evap growth in preexisting sediments (dry and saline)
Shallow Water
Deep Water |
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Term
| Idealized Salinity Increasing Evaporite Cycle |
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Definition
3)Halite
2)Gypsum
1)Carbonate |
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Term
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Definition
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