Title Information

Münchner Geowissenschaftliche Abhandlungen
Reihe A: Geologie und Paläontologie

Volume 31

VOIGT, Silke: Paläobiogeographie oberkretazischer Inoceramen und Rudisten. Ozeanographische und klimatologische Konsequenzen einer neuen Paläogeographie 1996. [in German] – 101 pp., 55 figures, 2 appendices. 29.7 x 21.0 cm. Paperback ISBN 978-3-931516-06-2 Euro 30.00 series: MGA, Reihe A: Geologie und Paläontologie order now

Abstract

Recently published rotations based on paleomagnetic lineations and digitized outlines of continents and terranes were used to create new maps of Late Cretaceous palaeogeography. The biogeographic distribution of framebuilding rudists and inoceramids was plotted on these maps. The occurrences of rudist reefs data show a stable northern boundary of distribution along 30°N paleolatitude. In this zone was the transition from arid to humid climate. Negative fresh water balances of the tropics and subtropics favoured lagoonal circulation and caused oceanographic conditions like nutrient-poor water, warm temperatures, hypersalinity and deep penetration of light, promoting the formation of carbonate platforms. The humid climate north of 30°N latitude caused an increase of terrigeneous input. The higher supply of nutrients favoured eutrophic conditions in the water. Reduced temperatures and a higher turbidity of water inhibited the formation of bioconstructions. Late Cretaceous inoceramids were characterized by rapid evolutionary rates and a high diversity. The high sea level inhibited the formation of oceanic fronts above the shelf edges and favoured the migration possibilities of the larves. Third order sea level changes influenced changes in diversity in early Late Cretaceous. The number of endemic species increased during regressions and subsequent lowstands.