sedimentary geology geos 240 – chapter 3-2 sedimentary petrology-2 dr. tark hamilton camosun...
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Sedimentary Sedimentary GeologyGeology
Geos 240 – Chapter Geos 240 – Chapter 3-23-2
Sedimentary Sedimentary Petrology-2Petrology-2
Dr. Tark HamiltonDr. Tark Hamilton
Camosun CollegeCamosun College
QFLQFL++
GraiGrainn
SizeSizePrisPrismm
F
Q
L
Provenance
Sandstone
DolostoneBreccia
Provenance from Clasts & Provenance from Clasts & Accessory MineralsAccessory Minerals
Conglomerates & coarse grained lithic sands afford Conglomerates & coarse grained lithic sands afford provenance & tectonic setting to be interpreted provenance & tectonic setting to be interpreted from lithic clasts: granitic, regional metamorphics, from lithic clasts: granitic, regional metamorphics, volcanics, second cycle sediments…volcanics, second cycle sediments…
Even fine sands and silts contain rare accessory Even fine sands and silts contain rare accessory minerals which are heavy, hard & chemically minerals which are heavy, hard & chemically resistant like: zircon, baddeleyite, monazite, apatite, resistant like: zircon, baddeleyite, monazite, apatite, garnet, tourmaline, hornblende, epidote, topaz, garnet, tourmaline, hornblende, epidote, topaz, corundum, ilmenite, native gold. These are corundum, ilmenite, native gold. These are concentrated using heavy liquids, panning or concentrated using heavy liquids, panning or centrifugation. Zircons can even be dated. Mapping centrifugation. Zircons can even be dated. Mapping of past drainages has been accomplished for many of past drainages has been accomplished for many units in the Phanerozoic section of Western Canada units in the Phanerozoic section of Western Canada because of unique assemblages from each upstream because of unique assemblages from each upstream shield terrane. Zirconium and titanium could be shield terrane. Zirconium and titanium could be economically recovered from tar sands tailings.economically recovered from tar sands tailings.
•Deep sea micro- & nannofossil ooze & cold carbonate vent moundsDeep sea micro- & nannofossil ooze & cold carbonate vent mounds*Diagenetic carbonate cements from sub- & anaerobic bacterial processes*Diagenetic carbonate cements from sub- & anaerobic bacterial processes
Bio-&
The Biochemistry of The Biochemistry of CarbonatesCarbonates
Photo/chemosynthesis life makes hydrocarbons or Photo/chemosynthesis life makes hydrocarbons or carbohydratescarbohydrates atmospheric atmospheric carbon dioxidecarbon dioxide and and waterwater in the presence of in the presence of energy energy (sunlight, chemical bonds)(sunlight, chemical bonds) And And enzymesenzymes or or mineral substratesmineral substrates to catalyze reactions to catalyze reactions Prokaryotes: Archea, Eubacteria or Eukaryotes, Plant lifeProkaryotes: Archea, Eubacteria or Eukaryotes, Plant life 6CO6CO22 (g)(g) + 6H + 6H22O O (l)(l) C C66 H H1212OO6 (aq)6 (aq) or cellulose or cellulose Some Archea (methanogens), since 4 Ga, don’t require oxygenSome Archea (methanogens), since 4 Ga, don’t require oxygen COCO22 (g)(g) + 2H + 2H22 (g)(g) CH CH4 (g)4 (g) or or
Aerobic or anaerobic metabolism of organic molecules Aerobic or anaerobic metabolism of organic molecules (food/fuel source) regenerates carbon dioxide with or (food/fuel source) regenerates carbon dioxide with or without free oxygen:without free oxygen: CHCH22O O (aq)(aq) + O + O22 (g)(g) H H22COCO33 (aq)(aq) HCO HCO33 ––
(aq)(aq) + H + H++(aq)(aq) aerobic aerobic
CHCH44 (aq)(aq)+ SO+ SO44‑2‑2
(aq)(aq) => S=> S‑2‑2(aq)(aq) + H+ H++
(aq)(aq) + HCO3 + HCO3‑‑(aq)(aq) + H + H22OO(l)(l) anoxic anoxic
Add dissolved CaAdd dissolved Ca+2 +2 and Feand Fe+2+2 to make Calcite and Pyrite to make Calcite and Pyrite
Inorganic carbonate precipitation happens in evaporties and Inorganic carbonate precipitation happens in evaporties and hydrothermal settings but even there closer examination hydrothermal settings but even there closer examination usually seems to involve archaeausually seems to involve archaea
Limestone ComponentsLimestone Components Foraminifera Foraminifera
MicriteMicrite Sparry Cemented CalcareniteSparry Cemented Calcarenite
The “Godfather” of Carbonate Geology
Robert Lewis (Luigi) Folk San Salvador, BahamasJune 2008 Age ~73 (Upper Holocene)
(The logo on the dirty ball cap is an ad for a local backhoe companyin Austin Texas)
LLRR
MudMud
Silty MudSilty Mud
Sandy Sandy MudMud
Muddy Muddy Silt/SandSilt/Sand
Breccia/ Breccia/ ConglomerConglomerateate
Field
Lab