Sediments & Climate Proxies

1.         MAJOR CONTROLS OF SEDIMENT FLUX

2.         Interpreting Ancient E.O.D.'s

            a.         Coloration

                        i.         Black - organic carbon (absence of organisms that oxidize compounds) or iron (combining with sulfur forming FeS₂ (pyrite).

                        ii.        Red (brown & green) - oxidation of iron and iron- bearing minerals. Red beds from source material, post- burial, or subaerial oxidation.

                                    iii.       Ferric minerals (hematite) – red, brown, or purple

                                    iv.       Ferrous minerals – gray and green.

3.         Paleosols – Soils that formed on past landscapes

            a.         Material forming planet’s surface and altered in place by physical, chemical, +/- biological processes

            b.         Roots require oxygen for respiration and subsurface pattern controlled by water table

4.         Histosols – EverWet

            a.         Any type of peat or organic-matter accumulation; ≥ 50% TOC by weight (e.g., coal)

5.         Gleysols – Wet

            a.         Surface or subsurface horizon experienced low redox conditions

            b.         Low chroma coloration

            c.         Carbonaceous material & Pyrite

            d.         Red-yellow mottled in fluctuating water conditions

6.         Calcisols – Wet/Dry cycles

            a.         Prominent subsurface calcic (CaCO₃) horizon

            b.         Vadose textures

            c.         Carbonate natural part of paleosol (not diagenetic)

7.         Vertisols – Seasonal Wet/Dry

            a.         Homogenized soil profile

            b.         Shrinking & swelling of expandable clays

            c.         Dessication cracks

            d.         Wedge-shaped peds

            e.         Hummock & swales

            f.         Slickensides

            g.         Clastic dikes

8.         Gypsisols – Arid

            a.         Gypsum or Anhydrite in surface or subsurface

            b.         Gyp/Anhyd-filled dessication cracks

            c.         Displace & replace nodular texture

            d.         Tepee structures

9.         Evaporites

            a.         Crystallize from hypersaline solutions (brines)

                        i.         High temperature, low precipitation

            b.         Few evaporite minerals in marine & non-marine settings

            c.         Terrestrial playa lakes (trona [hydrous NaHCO₃], anhydrite [CaSO₄], gypsum [CaSO₄2H₂O], & halite [NaCl]) may show lamination

            d.         Shallow marine sabkha, saltpans, estuaries, lagoons