Paleo-palynology: The study of ancient plant spores and pollen, and marine plankton that have been fossilized in rock, and which can be extracted from that rock using chemicals and laboratory techniques. The fossil spores and pollen are then mounted on slides and studied using high power optical microscopes.
Srivastava (1981) published a detailed palynostratigraphy for the Albian, showing the known age ranges of 84 spore and pollen species. The known age ranges come from type sections where marine invertebrate fossils have been used to establish the relative ages of those rocks. Isotopic dates have been used to establish the actual age range for Albian rocks (97.5-113 mya: Harland et al., 1982), whereas the relative age (i.e. Albian) is the sequential position of these rocks relative to younger and older rocks.
Srivastava (1981) was interested mainly in dating the Frederickburg Group of northern Texas, which is slightly younger than the Glen Rose Formation of Early Albian age. The yellow band in the three graphs below shows how the age ranges of palynomorphs can be used to determine and refine the relative age of the Fredericksburg Group (F-9,10,11). Because Fredericksburg rocks lie on top of Glen Rose rocks, the Glen Rose Formation must be older. The red band shows the age of the Glen Rose Formation, and what spores and pollen it contains. Note how younger rocks contain many spore and pollen species not found in the Glen Rose, while other species disappear in the Albian. This was a period of major floral change and diversification in the Cretaceous. This change in composition and diversity (turnover) was probably due mostly to climatic change, which allowed immigration of species from other regions, as well as created the conditions necessary for the rapid evolution of new plant species. It was during the Albian that flowering plants (angiosperms) began their adaptive radiation to become the dominant vegetation of the world. For more information on this subject, see Paleobotany.
It is therefore of interest that the footprint layers of the lower Glen Rose Formation contain foreign visitors from perhaps another world, who left humanoid tracks and artifacts as testimony that they were there just when angiosperms began their rapid evolution.
Srivastava, Satish K., 1981. Stratigraphic Ranges of Selected Spores and Pollen from the Fredericksburg Group (Albian) of the Southern United States. Palynology. American Association of Stratigraphic Palynologists Foundation, pp. 1-27
Harland, W.B., Cox, A.V., Llewellyn, P.G., Pickton, C.A.G., Smith, A.G., and Walters, R., 1982. A geologic time scale. Cambridge University Press, Cambridge, 131 p.
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