sedimentary geology geos 240 – chapter 3-2 sedimentary petrology-2 dr. tark hamilton camosun...

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

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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