A New Silurian (Llandovery, Telychian) Sponge Assemblage from Gotland, Sweden

A New Silurian (Llandovery, Telychian) Sponge Assemblage from Gotland, Sweden

Author: Freek Rhebergen

Publisher: John Wiley & Sons

Published: 2014-02-27

Total Pages: 161

ISBN-13: 1118906640

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A newly discovered, diverse sponge fauna of early Silurian age, is described from Gotland, Sweden. This is the first Silurian sponge assemblage known from Baltica, and the only diverse Llandoverian assemblage known worldwide. The fauna includes 20 genera and 29 species, of which three genera and six species are new. Eighteen species are new to Baltica. The fauna shows strong similarities to later Silurian assemblages in Arctic Canada, but one endemic species comprises ca. 50% of the fauna. The fauna shows that lithistid sponges recovered well from the late Ordovician extinction in some areas, and became widely spread in the early Silurian. In contrast, non-lithistid sponges like, such as hexactinellids, appear to have evolved rapidly during the Late Ordovician – early Silurian interval, and some modern groups probably originated in inshore habitats.


Silurian Reefs of Gotland

Silurian Reefs of Gotland

Author:

Publisher: Elsevier

Published: 1971-01-01

Total Pages: 554

ISBN-13: 0080869246

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The Swedish island of Gotland, in the Baltic, has attracted much attention of many geologists. Gotland is built up by a Middle Palaeozoic table-land, with an average height of 20-30 m, but with some higher hills in the inland and with steep cliffs along part of the coast. The Middle Palaeozoic strata consist primarily of limestones and marlstones. For a good understanding of the sedimentary succession of Gotland, it is important that the distribution of all the different kinds of sediments should be carefully mapped, and their faunal contents to be intensively studied. This book includes the survey and ideas gathered along with important data about the stratigraphy and reefs of Gotland. It presents description of the Baltic area, development of the stratigraphical subdivision of the Middle Palaeozoic of Gotland, and some tectonic and pseudo-tectonic phenomena. Stratified and unstratified sediments are presented along with a number of palaeoecological observations on Gotlandian fossils. Some comparisons of the reefs of Gotland with reefs in a few other areas are also examined.


The Earlier Stone Age Settlement of Scandinavia

The Earlier Stone Age Settlement of Scandinavia

Author: Grahame Clark

Publisher: CUP Archive

Published: 1975-01-09

Total Pages: 320

ISBN-13: 9780521204460

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During the Ice Age Scandinavia was submerged under thick ice sheets, and it was only in the subsequent warmer conditions, as the ice receded, that colonisation by plants, animals and men became possible. In this book Grahame Clark examines the expansion of human settlement into this area, with particular emphasis on the economic aspects of the societies under discussion. The account is carried down to the time (3500-3000 BC) when mixed farming, including cereal agriculture, was being introduced into the area. The book is fully illustrated and documented by many maps and tables. It provides a rounded picture of the economy of the first settlers and their descendants in an area whose archaeological past has been exceptionally fully investigated and documented. The colonisation of Scandinavia is considered in its European context, but the main emphasis lies on the process of change and the continuity of settlement in the territory itself.