Pollen dating method
Palynofacies studies are often linked to investigations of the palynology and organic geochemistry of sedimentary rocks.Palynofacies can be used in two ways: Both types of palynofacies studies are used for geological interpretation of sedimentary basins in exploration geology, often in conjunction with palynological analysis and vitrinite reflectance. Initially the only chemical treatment used by researchers was treatment with potassium hydroxide (KOH) to remove humic substances; defloculation was accomplished through surface treatment or ultra-sonic treatment, although sonification may cause the pollen exine to rupture.Once samples have been prepared chemically, they are mounted on microscope slides using silicon oil, glycerol or glycerol-jelly and examined using light microscopy or mounted on a stub for scanning electron microscopy.Researchers will often study either modern samples from a number of unique sites within a given area, or samples from a single site with a record through time, such as samples obtained from peat or lake sediments.Acetolysis was developed by Gunnar Erdtman and his brother to remove these fine cellulose materials by dissolving them.In acetolysis the specimen is treated with acetic anhydride and sulfuric acid, dissolving cellulistic materials and thus providing better visibility for palynomorphs.Early investigators include Christian Gottfried Ehrenberg (radiolarians, diatoms and dinoflagellate cysts), Gideon Mantell (desmids) and Henry Hopley White (dinoflagellate cysts). Weber 1918) appear to be among the first to undertake 'percentage frequency' calculations.Quantitative analysis of pollen began with Lennart von Post's published work. The term palynology was introduced by Hyde and Williams in 1944, following correspondence with the Swedish geologist Antevs, in the pages of the Pollen Analysis Circular (one of the first journals devoted to pollen analysis, produced by Paul Sears in North America).
Another treatment includes kerosene flotation for chitinous materials.
Pinus (Pine) and Picea (Spruce) pollen was found in such profusion that he considered them to be serviceable as "index fossils". They are extracted from sedimentary rocks and sediment cores both physically, by ultrasonic treatment and wet sieving, and chemically, by chemical digestion to remove the non-organic fraction.
Palynomorphs may be composed of organic material such as chitin, pseudochitin and sporopollenin.
Palynomorphs, however, generally have been destroyed in metamorphic or recrystallized rocks.
Typically, palynomorphs are dinoflagellate cysts, acritarchs, spores, pollen, fungi, scolecodonts (scleroprotein teeth, jaws and associated features of polychaete annelid worms), arthropod organs (such as insect mouthparts), chitinozoans and microforams.