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Readings from Sediments & Basins: (8:1-67)

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Presentation on theme: "Readings from Sediments & Basins: (8:1-67)"— Presentation transcript:

1 Readings from Sediments & Basins: (8:1-67)
Sedimentary Geology Geos 240 – Chapter 8 Depositional Environments Part 5 Shallow Carbonates & Evaporites Dr. Tark Hamilton Readings from Sediments & Basins: (8:1-67) Camosun College


3 Bahamas Platform & Fringing Reefs
. La Habana

4 Transgression & Optimal Carbonate Factory

5 Continental Shelf Eastern Nicaragua

6 Florida Keys: Shallow Back Reef – Lagoon – Mangrove Swamps
20 km

7 The Great Barrier Reef: Cretaceous through Recent! Queensland OZ

8 Lateral Progradation Bahamas Bank
Reflection Seismic Section & Interpretation

9 Cross Section of Redwater Reef, Dev. NW of Edmonton flexed later

10 Devonian Reef, Gyrfalcon Bluff, Banks Is

11 Devonian Crinoid Reef, Princess Royal Is

12 Fossiliferous Producing Dev Kee Scarp Reef Norman Wells

13 Devonian Coral Reef, Norman Wells NWT

14 Dev. Reef: Dolomite/Stromotoporoid Norman Wells

15 Ordovician Bioherm, Niagara Falls

16 Devonian Reef: Dolomitized Stromotoporoid Cairns Formation, Grassi Lakes Reef, Canmore

17 Devonian Reef: Dolomitized Stromotoporoid Cairns Formation, Grassi Lakes Reef, Canmore

18 Devonian Reef: Dolomitized Stromotoporoid Cairns Formation, Grassi Lakes Reef, Canmore


20 Proterozoic Stromatolites, Dismal Lakes NWT

21 Silurian Stromatolites, Somerset Island NWT
Supertenuous Drape Tidal Scour Algal Mound Buildup

22 Sabkha DepositionalModel, Persian Gulf Arid Tidal Coast

23 Ancient Tidal Limestone Facies

24 Mississippian Lisburne Limestone Tidal Crossbeds Diagenetic Chert

25 Ordovician Intraclast Dolomite Breccia, Somerset Is. NWT

26 Silurian Ripples & Flasers Dolomites, Somerset Is. NWT

27 The New Conservative Ordovician Burrow Mottled Limestone Ottawa

28 Ordovician Tyndall Stone, Burrow Mottled Dolomite, Red River Fm Manitoba

29 Ripups & Scours Silurian Dolomites, Somerset Is. NWT

30 Transgressive Phase Rising System Tract

31 Seds can come from Out of plane Regressive Phase
Falling System Tract

32 C-Ord. Cow Head Turbidites, NF

33 C-Ord. Cow Head Debris Flow, NF

34 C-Ord. Cow Head Deformed Clast

35 Anhydrite, Shale, Detrital Carbonates
Exhumed Carboniferous Facies Transition Sverdrup Basin, Ellesmere Island Sverdrup Basin Rim Bioclastic Debrites Anhydrite, Shale, Detrital Carbonates

36 Evaporites & Evaporite Basins
Geographically Enclosed Water Bodies Tropics +/- 30° Latitude, descending dry air Sabkhas, Playas, Salinas, Salt Lakes Incipient Rift Basins – Triassic Margins of Atlantic Restricted Back Reef Basins: Carb’s + Anhydrite Evaporated Cratonic/Epicontinental Seas: Devonian of Alberta, Sask., Michigan & Zechstein Perm/Penn of North Sea Basin Often alternate climatically with humid clastics

37 Usiglio’s Experiment: Evaporation of Sea Water & Sequence of Salts
s.g. = 1.035 Calcite Anhydrite Halite Bitterns

38 Development of Evaporite Basin

39 Development of Evaporite Basin

40 Evaporite Minerals Dominant Evaporite Minerals include: Carbonates, Chlorides, Sulphates, Borates & Nitrates Marine systems dominantly produce Carbonates, Chlorides & Sulphates Arid Terrestrial Systems produce unusual diagenetic minerals in pore spaces and beds of Borates & Nitrates additional to the Carbonates, Chlorides & Sulphates. Additional to the unusual Continental anion Chemistry, salts of metals form some unusual brine minerals, Cu, Ni, Zn, Pb, Ag and even (NH4)+ ! Salts precipitate in inverse order depending on their solubility. (solubility in strong/odd brines is empirical) Salts in vadose zone porosity are important in soils

41 Textures in Resedimented Evaporites, Italy Messinian (~5Ma) Mediterranean Basin

42 Evaporite Minerals Carbonates: Mineral Formula Calcite CaCO3
Dolomite CaMg (CO3 )2 Siderite FeCO3 Natrite Na2CO3 & Natron•6(H2O) Trona Na3(CO3)(HCO3)•2(H2O) (Green River, WY; Lake Magadi, Kenya)

43 Carbonate Minerals Trona Natrite

44 Sandstone with Cubic Halite Casts Jurassic, Utah

45 Evaporite Minerals Chlorides: Mineral Formula Halite NaCl Sylvite KCl
Carnallite KMgCl3 · 6H2O

46 Chloride Minerals Sylvite Halite Hopper Crystals Carnallite Halite

47 Cyclic & Crossbedded Devonian Halite, Goderich ON
Q1) Cyclic evaporation and minor recharge. Q2) Brine is denser and has more momentum than typical sea water. Pure Halite has a S.G. of 2.07, lighter than calcite or quartz. As a result, lower current velocities might produce X-bedded halites just as shallow but also in deeper, quieter water than carbonate shoals or siliciclastic bars. In what kind of Basin would “Cyclic Halite” beds form? In what sort of flow regime would Halite X-beds form?

48 Evaporite Minerals Sulphates: Mineral Formula Anhydrite CaSO4
Gypsum CaSO4· 2H2O Langbeinite K2Mg2(SO4)3 Polyhalite K2Ca2Mg(SO4)4 · 2H2O Kieserite MgSO4· H2O Kainite KMg(SO4)Cl · 3H2O

49 Interbedded Gypsum & Calcsiltite, Silurian Somerset Island
? Solutional Collapse

50 Interbedded Anhydrite & Shale Ellesmere Island

51 Sulphate Minerals Polyhalite Langbeinite Kieserite Kainite

52 Evaporite Minerals Nitrates: Mineral Formula Niter KNO3
Nitratine NaNO3· 2H2O Nitrocalcite Ca(NO3)2 · 4H2O Nitrobarite Ba(NO3)2 Gerhardtite Cu2(NO3)(OH)3 Some of these were done from memory so you may wish to check

53 Nitrate Minerals Niter Nitratine Nitrobarite Gerhardtite Nitrocalcite

54 Borax Mines Death Valley CA

55 Evaporite Minerals Borates: Mineral Formula Boracite Mg3[ClB7O13 ]
Borax Na2[B4O7]2 · 10H2O Colemanite Ca[B3O4(OH)3] · 3H2O HydroBoracite CaMg [B3O4(OH)3]2 · 3H2O Larderellite (NH4 )B5O6(OH)4 Tincalconite Na2[B4O7] · 5H2O Ulexite NaCa[B5O6(OH)6]· 5H2O Some of these were done from memory so you may wish to check

56 Borate Minerals Boracite Colemanite Hydroboracite Borax Larderellite
Ulexite Tincalconite

57 Salar de Atacama, Antofagasta Chile

58 The End: Chapter 8 Part 5!

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