468 MICROFOSSILS/Palynology by the astronomical position of Earth relative to the sun The problems of reconstructing complex Quaternary environments have led palynologists to use a wide range of fossil groups in order to provide multiproxy evidence that can allow more accurate models of past changes Pre-Quaternary Palynology Hydrocarbon exploration provided the main impetus for palynological biostratigraphy (or ‘palynostratigraphy’) in the second half of the twentieth century, due largely to the realization that small fragmentary rock samples, such as ‘ditch cuttings’ from drilling, could yield thousands of intact palynomorphs The erection of zonal schemes for non-marine successions based on spores and pollen in the Carboniferous (Figure 4) was followed rapidly by the publication of similar schemes for the Devonian and later systems The stratigraphic resolution of these palynological zonations compares very favourably with many schemes based on invertebrates; the average duration of Upper Palaeozoic spore and pollen biozones/sub-biozones is less than Ma Detailed zonations of marine Palaeozoic rocks have been erected, based mainly on acritarchs (see Microfossils: Acritarchs) and chitinozoa (see Microfossils: Chitinozoa), whereas palynostratigraphic work on marine Mesozoic and Tertiary successions has relied principally on dinoflagellate studies In relatively recent times, palynological investigations of Precambrian rocks have produced spectacular results in terms of both enabling much needed biostratigraphic correlation and shedding light on the nature of early life in Earth’s oceans The limited palaeogeographical distribution of many pre-Quaternary spore and pollen species restricts the applicability of most palynological zonations to specific regions, and in most cases rules out any possibility of ‘global’ correlation However, the converse of this obvious disadvantage is that floral provinces can be recognized, which can complement palaeomagnetic and other evidence in making large-scale palaeogeographical reconstructions Other Geological Applications Not all Phanerozoic palynological research has been biostratigraphic Inspired by palaeoecological studies of Quaternary peats, pioneering work on spore and pollen assemblages from Palaeozoic coal seams led to convincing interpretations of the gradually changing environmental conditions responsible for the accumulation of the peat More comprehensive Figure Part of the miospore zonation for the Late Devonian and Early Carboniferous of western Europe, showing the stratigraphic ranges of selected miospore taxa