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The AAPG/Datapages Combined Publications Database
AAPG Bulletin
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Marine sediments were deposited in western Libya during most of Paleozoic time. The resulting rock section consists of a thick sequence of detrital rocks, largely dark gray shales and sandstones, ranging in age from Cambrian to Permian. A high proportion of the fine-grained rocks in all of the Paleozoic systems contain spores, pollen, hystrichospheres, and (or) chitinozoans.
Various hystrichospheres occur in most of the marine Paleozoic rocks. Although some hystrichospheres are stratigraphically significant throughout the Paleozoic, they are particularly, important in the Cambro-Ordovician section, where pollen and spores are absent. Chitinozoans are found most commonly in Silurian and Devonian strata.
The earliest occurrence in Libya of spores of vascular plants is in rocks of Early Silurian age. The Silurian microflora is dominated by smooth trilete spores. Spores constitute less than 10 per cent of the total palynological assemblage in the lower part of the Silurian, but generally comprise a larger proportion of the total assemblage in upper Silurian rocks; the remainder of the population is composed primarily of hystrichospheres.
An abundant and diverse microflora is encountered in Devonian rocks. This assemblage is characterized by trilete spores with a variety of sculpturing and ornamentation. Smooth, spinose, and reticulate spores are common, as are zonate and monosaccate spores. Trilete spores with radiating ridges are also found.
The Carboniferous microfloral assemblage is distinguished by spores with an equatorial flange, triangular zonate spores with distal spines, trilete reticulate spores, and monosaccate forms.
The frequent occurrence and excellent preservation of these palynological assemblages, commonly where other fossils are rare or absent, permit zonation and correlation of Paleozoic strata in Libya. These rocks also provide a source of material that can contribute to an over-all understanding of the stratigraphic ranges, evolution, and phylogeny of spores, pollen, and certain groups of microplankton during Paleozoic time.
Representative microfossil assemblages are illustrated together with range charts showing the stratigraphic distribution of the more common and diagnostic forms.
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