Biostratigraphy, Phytogeography and Evolution of Middle Ordovician-Earlier Silurian Land Plants Based on their Spores

中奥陶世/早志留世陆生植物孢子可以 有助于解决两个重要问题。 土地 植物孢子提供了进入陆地和新鲜 H2O环境。 的 本提案中描述的研究是第一次尝试 建立一个晚奥陶世/早志留世非海相 生物地层学和植物地理学。 在整个后志留纪古生代，陆地植物 孢子/花粉已被证明是至关重要的地层分带 非海相和浅水近岸海相岩石。 只有当地 尝试将孢子生物地层学扩展到 晚志留世，而没有有效地进入前晚志留世。 现在似乎有可能建立一个连续的生物地层学 对于浅水近岸海洋和非海洋岩石， 中奥陶纪到泥盆纪 这将是第一个可能的非海洋分区 岩石;它也将提供唯一精确的方法， 浅水、近岸、晚奥陶世-志留纪地层 海洋无脊椎动物/有机微体化石是否缺失 目前在近岸相生物地层学上有用。 同样重要的是， 植物代表了一组迄今未知的陆地植物， 将重要的植被资源 早在传统的早泥盆世基准之前， 通常被认为标志着主要的，最初的辐射， 维管植物

Mid-Ordovician/Early Silurian land plant spores can contribute to the resolution of two important problems. Land plant spores provide the only entrance into terrestrial and fresh H2O environments in this interval of Phanerozoic time. The research described in this proposal is the first to attempt to establish a Late Ordovician/Early Silurian nonmarine biostratigraphy and phytogeography. Throughout the post-Silurian Phanerozoic, land plant spores/pollen have proved vital in stratigraphic zonation of nonmarine and shallow-water, nearshore marine rocks. Only local attempts have been made to extend spore biostratigraphy into the Late Silurian, and none effectively into the pre-Late Silurian. It now appears possible to establish a continuous biostratigraphy for shallow-water nearshore marine and nonmarine rocks from the mid-Ordovician to the Devonian. This will be the first zonation possible for nonmarine rocks; it will also provide the only precise means of correlating shallow-water, nearshore, Late Ordovician-Silurian strata since marine invertebrates/organic microfossils are absent or not presently biostratigraphically useful in the nearshore facies. Equally important is the fact that the spore-producing plants represent a hitherto unknown group of land plants that placed an important source of vegetation into continental habitats well before the traditional Early Devonian benchmark commonly considered to mark the major, initial radiation of the tracheophytes.