We review the highlights of the 1988 symposium on Palaeozoic Biogeography and Palaeogeography, and present a revised set of 20 Palaeozoic base maps that incorporate much of the new data presented at the symposium. The maps include 5 major innovations: (1) A preliminary attempt has been made to describe the motion of the Cathaysian terranes during the Palaeozoic; (2) a more detailed description of the events surrounding the Iapetus Ocean is presented; (3) an alternative apparent polar wandering path for Gondwana has been constructed using the changing distributions of palaeoclimatically restricted lithofacies; (4) new palaeomagnetic data have been incorporated that places Laurentia and Baltica at more southerly latitudes, and adjacent to Gondwana, during the Early Devonian; Siberia is also placed further south in the light of biogeographic data presented at the symposium; (5) Kazakhstan is treated as a westward extension of Siberia, rather than as a separate palaeocontinent. The relationships between climatic changes, sea level changes, evolutionary radiations and intercontinental migrations are discussed

https://mem.lyellcollection.org/content/memoirs/12/1/1.full.pdf

Revised World maps and introduction

The Portscatho Formation, within the allochthonous unit of the Middle and Upper Devonian Gramscatho Group, is a thick sequence of deep-water sandstones and interbedded slates deposited by southerly-derived turbidity currents into the Gramscatho basin of south Cornwall. Throughout an approximately 3.5 km thick sequence, the Portscatho Formation is petrographically and chemically coherent, except that the upper section shows a higher proportion of metamorphic clasts, high, but variable Cr, and low, uniform Zr abundances. Complementary framework mode and bulk geochemistry indicate that the sandstones were derived from a dissected continental magmatic arc of predominantly acidic composition, similar to average upper continental crust, but with an admixture of minor intermediate/basic material. Flysch deposition took place in a fore-arc setting. The presence of an arc to the south of Cornwall during the Devonian implies that there was subduction at the margin of the Gramscatho basin, whose ultimate closure was accommodated by the northward stacking of flysch–ophiolite nappes.

Tectonic environment of the Devonian Gramscatho basin, south Cornwall: framework mode and geochemical evidence from turbiditic sandstones

Numerous climate models predict that the geography of the supercontinent Pangea was conducive to the establishment of a "megamonsoonal" circulation. In general, geologic evidence supports the hypothesis of a megamonsoon that reached maximum strength in the Triassic. Pangea in the Late Carboniferous had widespread peat formation in what is now central and eastern North America and Europe and relatively dry conditions on the Colorado Plateau. The equatorial region of the continent became drier through the end of the Carboniferous. By the Permian, the equatorial region of Pangea was dry, and indicators of aridity and rainfall seasonality became more widespread. Wind directions from Colorado Plateau eolian sandstones are consistent with an increasing influence of monsoonal circulation at this time. In the Triassic, climate in the Colorado Plateau region became relatively wet, though still seasonal, and the few eolian sandstones indicate a major shift in wind direction at that time. In addition, sedimentation ...

Climate of the Supercontinent Pangea

Plate tectonic reconstructions of the Cretaceous and Cenozoic ocean basins

Breakup of a supercontinent between 625 Ma and 555 Ma: new evidence and implications for continental histories

This paper contains 50 maps which have been designed for use by the geologic community in preparing paleogeographic, biogeographic, climatologic, and tectonic reconstructions of the Paleozoic periods. Seven maps for each of seven Paleozoic intervals are included, plus a suture map showing the outlines of the Paleozoic continents in their present positions. The intervals chosen are the Late Cambrian (Franconian), Middle Ordovician (Llandeilian-earliest Caradocian), Middle Silurian (Wenlockian), Early Devonian (Emsian), Early Carboniferous (Visean), Late Carboniferous (Westphalian CD), and Late Permian (Kazanian). The paleomagnetic information used to orient the continents is given. For each interval, three types of maps are included, one locality map with place names labelled, four paleogeographic maps with our interpretation of the distribution of mountains, lowlands, shallow seas, and deep oceans, and two outline maps for those who prefer to make their own paleogeographic interpretations. Several project...

Colleen Barton

Papers

Paleozoic Base Maps