Academic literature on the topic 'Palynologie Pollen fossile'

Methods of paleovegetation analysis can be grouped into two broad categories. Those that use plant microfossils for reconstructing terrestrial vegetation, past environments, migrations, and evolutionary histories constitute a part of paleopalynology that includes the study of pollen, spores, other acid-resistant microscopic structures, and phytoliths (distinctive, microscopic silicate particles produced by vascular plants). Those that use plant megafossils such as leaves, cuticles, cones, flowers, fruits, and seeds constitute paleobotany. Two important subdisciplines of paleobotany are dendrochronology (fossil woods) and analysis of packrat middens. The latter are sequences of nesting materials, constructed by packrats of the genus Neotoma, preserved in arid environments of the American southwest. The study of fossil fruits and seeds is a specialized field within paleobotany, and it is also used in studies on Quaternary vegetational history in the preparation of seed diagrams accompanying pollen and spore profiles from bog and lake sequences. In 1916 Swedish geologist Lennart von Post demonstrated that pollen grains and spores were abundantly preserved in Quaternary peat deposits and could be used to trace recent forest history and climatic change (Davis and Faegri, 1967). The term palynology was subsequently introduced by Hyde and Williams in 1944 to include all studies concerned with pollen and spores. Paleopalynology has come to denote the study of acid-resistant microfossils generally, while pollen analysis designates those investigations dealing specifically with the Quaternary. In the early 1950s researchers in the petroleum industry began to routinely apply paleopalynology to problems of stratigraphic correlation and the reconstruction of depositional environments in Tertiary and older strata (Hoffmeister, 1959). This added a practical dimension to a mostly academic pursuit and fostered interest in applied palynology and its use as a paleoecological research tool. This important development is reflected in the increased number of publications after about 1955. As the history of other innovations might predict, there was a period of exuberant claims, isolated specialization, and exaggerated charges of deficiency in the method; but for palynology this seemingly inevitable period was mercifully brief. The different terminology, principles, and techniques involved in megafossil paleobotany and paleopalynology still result in specialization, but this limitation is frequently overcome by coordinated or collaborative projects, and an increasing number of practitioners work in both disciplines.