Detailed descriptions of acritarchs and trilobites found in the Cambrian strata of the Avalon Peninsula of eastern Newfoundland. A biostratigraphic zonation based on acritarchs is proposed, and an analysis of 7 previously described microfloras is refined and completed, enabling a more accurate correlation to be made with trilobite-bearing strata in Great Britain and Scandinavia, and with acritarch faunas in northern Norway, the Baltic area and the Gondwanaland region.
This work reviews the correlation of the British and Irish Cambrian with the current (though incomplete) international standard for the Cambrian. Since the earlier edition of 1972, the basal and upper limits of the Cambrian system have been internationally agreed; so this account excludes Tremadocian rocks but includes some that were formerly considered Neoproterozoic. Half of the series and stage subdivisions are internationally agreed, but for the undefined divisions of the Cambrian the standard used here makes use of data from Avalonian successions. Since the first edition was published, almost every aspect of the Cambrian in the British Isles has been subjected to new study. Here, the plate tectonic make-up of the British Isles is reviewed, new radiometric ages and isotopic studies are summarized and the biostratigraphy is enhanced by the study of acritarchs, especially in the Irish successions.
The Early Palaeozoic was a critical interval in the evolution of marine life on our planet. Through a window of some 120 million years, the Cambrian Explosion, Great Ordovician Biodiversification Event, End Ordovician Extinction and the subsequent Silurian Recovery established a steep trajectory of increasing marine biodiversity that started in the Late Proterozoic and continued into the Devonian. Biogeography is a key property of virtually all organisms; their distributional ranges, mapped out on a mosaic of changing palaeogeography, have played important roles in modulating the diversity and evolution of marine life. This Memoir first introduces the content, some of the concepts involved in describing and interpreting palaeobiogeography, and the changing Early Palaeozoic geography is illustrated through a series of time slices. The subsequent 26 chapters, compiled by some 130 authors from over 20 countries, describe and analyse distributional and in many cases diversity data for all the major biotic groups plotted on current palaeogeographic maps. Nearly a quarter of a century after the publication of the ‘Green Book’ (Geological Society, London, Memoir12, edited by McKerrow and Scotese), improved stratigraphic and taxonomic data together with more accurate, digitized palaeogeographic maps, have confirmed the central role of palaeobiogeography in understanding the evolution of Early Palaeozoic ecosystems and their biotas.
This textbook will appeal to students and graduates making their first steps in the application of both microfossils and stratigraphy. It presents, in detail, the historical development of microfossil biostratigraphy, from its birth to the emergence of sequence stratigraphy, including its roots in classical biostratigraphy. The interplay between the academic and economical challenges, on one hand, and developments in microfossil biostratigraphy, on the other, is explored thoroughly. The book also presents an introduction to the scientific concepts used in microfossil biostratigraphy practice, and the uses in microbiostratigraphy of 25 groups of microfossils, such as algae, protistans, reproductive plant debris, invertebrates, chordates and vertebrates, and microproblematica groups. It also provides a numerical method to calculate the biostratigraphical resolution of these microfossil groups.
