EvaporiteCarbonate Sediments of Abu Dhabi, UAE

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Evaporite/CarbonateSediments of Abu Dhabi, UAE

• C.G.St.C. Kendall

Departments of Geological Sciences University of
South Carolina Jackson School
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Outline of Presentation

• Carbonate - Controls
• Holocene Carbonate Settings of UAE
• Axial trough
• Pearl Bank Reefs
• Wave dominated barrier island coast
• Back barrier lagoon and shoals
• Cyanobacterial Mats
• Supratidal evaporites
• Aeolian
• Conclusions

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Major Controls on Carbonates

• Climate belt Tropical, temperate or polar
• Ocean circulation Dissolution or precipitation
• Nutrients Clastic influx ocean circulation
• Turbulence of water Oxygen, CO2 Clarity
• Bathymetry Sunlight, temperature sea floor
  slope
• Eustatic sea level Function of climate
  tectonics
• World atmosphere Aragonite or calcite ocean
• Tectonic setting Ocean width plate position
• Biologic community Beat of time (evolving
  party)

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Low Nutrient
Low Nutrient
Low Nutrient
TROPICS
TEMPERATE OCEANS
Low Nutrient
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Carbonate Tectonic Setting Examples

• Extension
• Major rifted, faulted (Break-up) trailing
  margin terrains
• Red Sea
• Bahamas
• East Africa
• Great Barrier Reef of Australia
• Cretaceous of Gulf of Mexico
• Compression
• Major fill of foreland basin
• West Texas New Mexico
• Paleozoic
• Arabian Gulf
• Holocene
• Mesozoic
• Appalachians
• Paleozoic
• Australia
• Murray Basin Tertiary

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CompressionalTectonic Setting
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Regional Drainage Into Basin
Restricted Entrance To Sea
Isolated linear Belt of interior drainage
Arid Tropics Air System
Wide Envelope of surrounding continents
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United Arab Emirate Coast
Arid Climate
Barrier Island Coast
Coastal Evaporite System
Reef Platform
Aeolian System
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United Arab Emirate Coast
Tidal Deltas
Arid Climate
Coastal Evaporite System
Reef Lagoon
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Carbonate DepositionalSystems

• Framework of genetically related stratigraphic
  facies geometries their bounding surfaces

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UAE - Carbonate Systems

• Carbonate depositional systems controls
• Depositional systems Axial Basin Ramp Shelf
  margin crest Shelf (Outer Inner restricted)
• Each described in terms of Critical
  characteristics Setting Dominant sedimentary
  processes Facies Subdividing surfaces
  Lithology Sedimentary Structures Geometries
  and Fauna Flora

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REEF MARGIN
BASIN
BARRIERS LAGOONS
OPEN MARINE RAMP
SLOPE
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Carbonate settings UAE

• Axial Basin
• Ramp Slope
• Reef Margin Crest
• Shelf
• Barriers of more normal marine waters
• Inner restricted higher salinity lagoons
• Aeolian intermittent alluvial

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Basin
Ramp
Open Shelf
Restricted Shelf
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Carbonate Basin Systems

• Critical characteristics of system?
• Geomorphologic setting
• Dominant sedimentary processes
• Facies
• Geometries Confined versus open
• Subdividing surfaces
• Lithology
• Sedimentary structures
• Fauna flora

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Lecture Critical Info!

• Basin- couplets of micrite, shale silt from
  mix of pelagic shelf sources very low faunal
  diversity
• Ramp- sheets that thin lose faunal diversity
  basinward thicken shoreward
• Reef Margin- massive heterogeneous sediments
  with high faunal diversity, porous but not prone
  to seal
• Shelf- often wide spread continuous sheets of
  shoaling upward heterogeneous facies bed
  thickness
• Outer shelf- bedded heterogeneous facies with
  mix of linear bodies parallel to basin
  perpendicular to it! Local build up lenses
  faunal diversity higher seaward
• Inner shelf- dominated by shoaling upward often
  micritic sheets alternating with evaporites / or
  incised carbonate filled channels low faunal
  diversity
• Isolated Basins- Evaporite/ carbonate couplets
  from isolation

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Facies of UAE
Axial Muds
Skeletal Sands
Ooid Tidal Deltas
Reefs Coralgal Sands
Pellets Grapestones
Coastal Sabkha
Cyanobacterial mats
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Facies Abu Dhabi - UAE
Skeletal Sands
Ooid Tidal Deltas
Reefs Coralgal Sands
Pellets Grapestones
Coastal Sabkha
Cyanobacterial mats
Cyanobacterial mats
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Facies of UAE
Skeletal Sands
Ooid Tidal Deltas
Coral Reefs
Coastal Sabkha
Pellets Grapestones
Cyanobacterial mats
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Carbonate settings UAE

• Axial Basin
• Ramp Slope
• Reef Margin Crest
• Shelf
• Barriers of more normal marine waters
• Inner restricted higher salinity lagoons
• Aeolian intermittent alluvial

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AXIAL BASIN
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Arabian Gulf Factory producing carbonates
storing products of cyanbacteria since Triassic.
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A big day for a bloom!!
Organics in the Gulf!
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Facies of Persian Gulf
After Wilkinson Drummond, 2004
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Facies of Persian Gulf
After Wilkinson Drummond, 2004
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Carbonate Basin Systems

• Tend to exhibit thin beds of alternating micritic
  carbonate, silts shales. Thinner beds distal
  from basin margin
• Set in deeper water down slope from basin crest
  or margin
• Sediment transport into basin function of gravity
• Facies
• Subdividing surfaces products of changes in the
  climatic changes experienced by the basin
• Basinal couplets of lime mud shale come from a
  mix of pelagic shelf sources
• Evaporites occur when basin is isolated
  Sedimentary structures
• Beds tend to be thin and homogeneous
• Cosmopolitan fauna from pelagic setting with a
  stressed benthic signal with both low numbers
  diversity

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AXIAL BASIN
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SHELF MARGIN SLOPE ITS BASE
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Carbonate settings UAE

• Axial Basin
• Ramp Slope
• Reef Margin Crest
• Shelf
• Barriers of more normal marine waters
• Inner restricted higher salinity lagoons
• Aeolian intermittent alluvial

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Ramp
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Shelf Ramp

• Critical characteristics of system?
• Geomorphologic setting
• Dominant sedimentary processes
• Facies
• Subdividing surfaces
• Lithology
• Sedimentary structures
• Geometries Confined versus open
• Fauna flora

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Ramp

• Beds are inclined down slope and thin, varying
  from sparse heterogeneous shallow water
  bioclastic grains and common lime mud in deeper
  water
• Gravity the dominant sedimentary driver
• Facies
• Subdividing surfaces are product of sea level
  lows, storms and earthquakes (Yes
• Lithology is heterogenous shallow to deeper water
  carbonates(Yes
• Sedimentary structures may include graded beds
  and debris flows (Yes
• Geometries Vary from sheets, stacked fans
  incised submarine valleys (No
• Fauna flora is has a mix of transported shallow
  water bioclasts to deeper water benthics and
  pelagic forms (No

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Stratigraphic signal of ramp system

• Heterogeneous cycles
• Irregular stratification that is thick in
  shallower crestal position but thins down slope
• High faunal, sediment and bedding character
  diversity in shallower portions
• Often capped by a erosion surfaces driven by
  changes in sea level
• Cycles may be initiated by a marine shale or marl
  or hardground surface

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REEF MARGIN
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Carbonate settings UAE

• Axial Basin
• Ramp Slope
• Reef Margin Crest
• Shelf
• Barriers of more normal marine waters
• Inner restricted higher salinity lagoons
• Aeolian intermittent alluvial

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Facies Abu Dhabi - UAE
Skeletal Sands
Reefs Coralgal Sands
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Reef Margin Systems

• Critical characteristics of system?
• Geomorphologic setting
• Dominant sedimentary processes
• Facies
• Subdividing surfaces
• Lithology
• Sedimentary structures
• Geometries Confined versus open
• Fauna flora

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Stratigraphic signals of Margin Systems

• Erosion bounded stratigraphic markers at break in
  slope
• Reefs and banks tend to have irregular to massive
  stratification formed in submarine setting
• Cross bedded reef carbonates found in hollows
• Major source of heterogeneous carbonate sediment,
  often cemented at deposition. If matrix coarse
  grained will often contain pebbles larger reef
  fragments. However matrix can be micrite too!
• Have high porosities and permeability's
• High faunal and sediment diversity

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Massive Bedded Greatest Faunal Diversity At Air
Water Interface
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SHALLOW RAMP MARGIN SETTING
Reef Body
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Geometry of Carbonates - Ramp
SHALLOW RIMMED MARGIN SETTING
Reef Body
3-4 Meters
SHALLOW
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Abu AlAbyadReefFront
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Dhabaiya Patch Reefs
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SHELF BARRIERS INNER LAGOONS
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Facies Abu Dhabi - UAE
Ooid Tidal Deltas
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Carbonate Barrier Systems

• Critical characteristics of system?
• Geomorphologic setting
• Dominant sedimentary processes
• Facies
• Subdividing surfaces
• Lithology
• Sedimentary structures
• Geometries Confined versus open
• Fauna flora

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Carbonate Barrier Setting

• Subject to waves on their seaward side and
  exposed to tidal exchange
• Develop where carbonate secreting organisms are
  stressed by carbonate precipitation
• Punctuated by exposure surfaces
• Cycles show a lag following the onset of marine
  transgression that starts the shoaling upward
  cycles
• Higher energy facies like oolite bodies parallel
  the basin margin as relatively narrow linear belts

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Stratigraphic signal of barrier systems

• Homogeneous shoaling upward cycles
• Regular uniform stratification formed in a
  shallow marine to intertidal setting
• Wide spread high porosities and permeabilities in
  grain carbonates
• Low faunal, sediment and bedding character
  diversity
• Often capped by a subaerial exposure surface
• Cycles may be initiated by a marine shale or marl
  or hardground surface

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Barrier Island Geometries

• Sediment types are homogeneous ooids grain
  shoals , with local patch reefs
• Shoaling upward cycles common
• Bedding
• Unconfined sheets but heterogeneous character
• Inner portions may show tempestite beat
• Locally confined channel fill
• Local confined lens shaped build ups
• Fauna homogeneous to moderately cosmopolitan,
  becoming restricted away from open marine settings

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Ooid Shoals

• Form linear bodies parallel to basin
• Shoaling upward cycles common
• Sheets not uncommon
• Locally confined channel fill
• Fauna stressed but moderately cosmopolitan

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Reef Ooid ShoalsDhabaiya Halat Al BaraniUAE
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Khor Al Bazam Coastal Terrace UAE
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Halat Al Baraini Ooid Ebb Delta
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Halat Al Baraini Ooid Ebb Delta
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Abu Dhabi Ooid Ebb Delta
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Back Barrier Geometries

• Sediment types are heterogeneous Ooids,
  grapestones hardened pellets to bioclastic
  grain shoals to patch reef shoal build ups
• Shoaling upward cycles common
• Bedding
• Unconfined sheets but heterogeneous character
• Inner portions may show tempestite beat
• Inner portions may alternated with shale or marl
• Locally confined channel fill
• Local confined lens shaped build ups
• Fauna heterogeneous and moderately cosmopolitan,
  becoming restricted away from open marine settings

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Facies Abu Dhabi - UAE
Pellets Grapestones
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Facies Abu Dhabi - UAE
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Facies Abu Dhabi - UAE
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FaciesAbu DhabiUAE-Al Qala
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Angled Bars
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Angled Bars
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Grapestone Shoals

• Commonly grains form top of shoaling upward
  cycles
• Sheet-like geometry common
• Fauna moderately cosmopolitan

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Pelloid Shoals

• Grains occur within shoaling upward cycles
• Sheet-like geometry common
• Fauna low diversity

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Qala Bay Grapestone Flats
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Qala Bay Grapestone Flats
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Qala Headland Tertiary Outwash Fans
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Qala Bay Grapestone Flats
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Qala Bay Pellets
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Qala Bay Peneropolid
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Qala Bay Peneropolid
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Facies Abu Dhabi - UAE
Marine Travertine
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Coastal Bay J. Dhanna - UAE
Supratidal Crust Megapolygons
Purser Loreau Photo
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Jebel Dhanna Beach Travertine
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Jebel Dhanna Beach Travertine
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Coastal Bay J. Dhanna - UAE
Marine Travertine
Purser Loreau Photo
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Jebel Dhanna Beach Travertine
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Jebel Dhanna Beach Travertine
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Jebel Dhanna Beach Travertine
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Cement
Form on beaches of the UAE
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Facies Abu Dhabi - UAE
Mangrove Creeks
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Mangrove Creeks - Dhabaiya
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West of Dhabaiya Mangrove Swamp
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West of Dhabaiya Mangrove Swamp
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West of Dhabaiya Crab Burrows
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West of Dhabaiya Mangrove Swamp
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Shoaling Upward Inner Shelf Cycle
Shoaling Up Cycle
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Shoaling Upward Inner Shelf Cycle
Shoaling Up Cycle
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Mangrove lined beaches - Shelf Cycle
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Mangrovelined beaches-Shelf Cycle
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Shoaling Upward Inner Shelf Cycle
Shoaling Up Cycle
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CYANOBACTERIA MATS EVAPORITE FLATS
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"Facies adjacent to one another in a continuous
vertical sequence also accumulated adjacent to
one another laterally".
Walther's Law
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Major coastal provinces of United Arab Emirates
bathymetry of Southern Arabian Gulf in fathoms
(modified from Purser, 1973).
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Western Coastal Margin of the United Arab Emirates
Western Coast of the United Arab Emirates
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Eastern Khor Al Bazam Cyanobacterial Mats
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High Intertidal Cyanobacterial Flats
Intertidal Carbonate Flats
Earlier High Energy Beaches
Supratidal Sabkha Evaporites
Kendall Photo
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The Ancient Egyptians Knew This Before Walther
Or may be not?
Washover Sediments
Anhydrite
Cyanobacterial Peat
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Link between time, surfaces layers

• Each layer no matter its dimension and whatever
  the time involved in its deposition, is bounded
  by surfaces that transgress time
• The interpretation of depositional setting for a
  section cut by diachronous surfaces must
  contravene Walthers Law
• However we simplify this by assuming the
• Bounding surfaces
• Layers of sediment
• have the same age

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Intertidal Sand Mud Flats
Tidal Channels
Hardgrounds
Beach Ridges
Cyanobacterial Mats
Sabkha
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Qanatir Traverse Seaward
Black Mangrove
Tidal Creek
Intertidal Muds Sands
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Qanatir Traverse Hardgrounds
Crumpled Polygonal Margins
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Qanatir Traverse Hardgrounds
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Qanatir Traverse Hardgrounds
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Tidal Channel
Intertidal Sand Mud Flats
Hardgrounds
Cyanobacterial Mats
Spits
Sabkha
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Qanatir Traverse Mats!
Intertidal Carbonate Flats
Cyanobacterial Mats
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Qanatir Traverse Cinder Algae
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Qanatir Traverse Mats!
Tidal Ponds
Tidal Creek
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Qanatir Traverse Mats!
Tidal Pond
Tidal Creek Cyanobacterial Megapoygons
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Qanatir Traverse Mats!
Cyanobacterial Peat
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Qanatir Traverse Mats!
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Qanatir Traverse Mats!
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Qanatir Traverse Mats!
Crinkled Algal Mat
Gypsum Mush
Cyanobacterial Peat
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QanatirTraverseAnhydritePolygons
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Qanatir Traverse Sahkha sequence
Anhydrite
Cyanobacterial Peat
Intertidal Muds
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Qanatir Traverse Sahkha sequence
Anhydrite
Cyanobacterial Peat
Intertidal Muds
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Qanatir Traverse Sahkha Halite
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Qanatir Traverse Sahkha sequence
Washover Sediments
Anhydrite
Cyanobacterial Peat
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Qanatir Traverse Sahkha sequence
Douglas Shearman
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Ras Al Aish Traverse Sahkha sequence
Gypsum after Anhydrite
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AEOLIAN FACIES OF UP-DIP CONTINETAL FRINGE
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Facies Abu Dhabi - UAE
Aeolian
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Carbonate Aeolian Systems signals

• Sediment Aeolian dunes and sheets
• Interbedded Sabkah and Playas Erosion
• Punctuated by Water table Stokes Surfaces marks
  limit
• Base level changes in ground water level
• Often associated with soils

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Wind Cross Beds in Carbonates
Kendall Photo
Pleistocene Near Abu Dhabi - UAE
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Wind Trough Beds Stokes Surface
Stokes Surface Erodes to Water Table
Pleistocene Near Abu Dhabi - UAE
Kendall Photo
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Wind Trough Beds Stokes Surface
Inferred successive formation of multiple
parallel bedding plane truncations of wind-blown
sand, matching water table position.
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Wind Cross Beds in Carbonates
Kendall Photo
Pleistocene Near Abu Dhabi - UAE
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Wind Blown Sediments - UAE
Barchan Dunes Rich in Carbonate
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Wind Blown Sediments - UAE
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Wind Blown Sediments - UAE
Geologist!
Barchan Dune of Red Quartz
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Wind Blown Sediments - UAE
Barchan Dune of Red Quartz
Vogue Model
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Facies Abu Dhabi - UAE
Skeletal Sands
Ooid Tidal Deltas
Reefs Coralgal Sands
Pellets Grapestones
Coastal Sabkha
Cyanobacterial mats
Cyanobacterial mats
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CARBONATE HIERARCHY - UNITS

• SHELF COMPLEX Mix of shelf, shelf margin
  adjacent basin facies evolving in response to
  complete complex cycles of changing base level
  paleogeography
• MARGIN COMPLEX Shelf, shelf margin adjacent
  basin facies evolving in response to a cycle in
  changing base level
• STACKED CYCLES OF BEDS Vertical character of
  beds from varying depositional settings
• BEDDING Internal character including lithology,
  geometry, sedimentary structures, fauna
• ALLOCHEMS Lthological components, their
  cementation diagenesis

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Lecture Conclusions

• Basinal couplets of mud shale from mix of
  pelagic shelf sources
• Down slope sheets that thin down slope may be
  grain prone in distal portions
• Margin Massive and heterogeneous, most porous
  but least prone to seal
• Shelf has wide spread continuous sheets that tend
  to shoal up
• Outer shelf- heterogeneous carbonates with mix
  of linear bodies parallel to basin
  perpendicular to it! Local build up form lenses
• Inner shelf- dominated by mud prone sheets with
  evaporites or clastic channels and sheets
  continental aeolian sheets
• Evaporites occur when basin is isolated

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Lecture Ends!!

• And so to lunch ?