EPEIRIC SEAS: A CONTINENTAL EXTENSION OF SHELF BIOTAS
1. Overview 1.1. Controls 1.2. Temporal Distribution 1.3. Geographic Distribution 1.4. Sedimentology 1.5. Climatic Impact 2. The Environment of Epeiric Seaways 3. Origin and Evolution of the Epicontinental Sea Biota 3.1. Nature of the Epicontinental Fossil Record 3.2. Measuring Biodiversity in Epicontinental Seas 3.3. The Endemism Question 3.4. Precambrian 3.5. Paleozoic 3.5.1. Cambrian 3.5.2. Ordovician–Permian 3.6. Mesoand Cenozoic 3.6.1. Triassic–Cretaceous 3.6.2. Paleocene–Recent 3.7. Mass Extinctions Glossary Bibliography Biographical Sketch
The birth and demise of the vast epicontinental Permian Irati-Whitehill sea: Evidence from organic geochemistry, geochronology, and paleogeography
Abstract Organic-rich shale deposits of the Irati (Brazil) and Whitehill (South Africa) formations represent the most important sedimentary remnants of a huge Permian sea that occupied an estimated 5 million km2 before drying out and disappearing. To unravel the evolution and final demise of the Irati-Whitehill sea, we present a paleogeographic and organic geochemical characterization as well as a precise tephrochronology of the sea. Constrained by new high-resolution chemostratigraphic data (biomarker data combined with carbon and nitrogen isotopes) of two boreholes from central and southern areas of the Parana Basin (Brazil), the evolution of the sea is divided into five stages. These stages reflect the transition from a marine realm (stage I) to an environmentally restricted sea characterized by major ecosystem changes (stages II and IV) where water renewal controlled the post-salinity environmental dynamics (stages III and V). A zircon U Pb TIMS age of 277.26 ± 0.62 Ma of stage V correlates with the age of the San-Rafaelic orogeny along the paleo-Pacific South American margin and the rising of the Cape Fold Belt. We conclude that the convergent tectonic dynamics may have acted as the main agent in the entrapment and disappearance of the sea, ending a history of no more than four-million-year of the Irati-Whitehill sea.
Regional Aspects of Carbonate Deposition
It was customary during many recent years for the Research Committee of the Society of Economic Paleontologists and Mineralogists (SEPM) to sponsor research symposia on special topics at the annual meetings. In addition to the regular Research Committee Symposium presented in 1954 at the St. Louis meeting, a special symposium was also held on Regional Aspects of Carbonate Deposition. This carbonate symposium was organized in response to a special request by H. N. Fisk, who was president of SEPM at that time. During the symposium, special question cards were distributed to the audience and collected after each paper. These questions, together with questions and comments from the floor, formed the basis for the Panel Discussion which followed the symposium. The panel consisted of Moore, Ginsburg, Rodgers, and Walter Bucher, who presented the paper on the Bahamas in the absence of Newell. In addition, two authorities in the field of carbonate deposition, L. V. Illing and R. W. Fairbridge, were invited to join the panel and participate in the discussion.