Cambrian Fossils of Central Europe and Their Palaeogeographic Constraints
摘要
Fossiliferous Cambrian rocks are generally rare in Central Europe and spatially restricted, but in total they yield an astounding plethora of skeletal faunas with trilobites, brachiopods, molluscs and mollusc-like animals, echinoderms, chancelloriids, archaeocyaths and various groups of other early skeletal fossils as well as ichnofossils, calcimicrobes and palynomorphs. Strata which offer biostratigraphically significant successions and record distinctive depositional histories are known from the Franconian Forest in northeastern Bavaria, the Delitzsch–Torgau–Doberlug syncline in northern Saxony, the Görlitz area in eastern Saxony, and the Barrandian region of Bohemia. The patchily distributed Lower Cambrian rocks from northeastern Bavaria and Saxony include significant archaeocyath-calcimicrobial limestones of probably Cambrian Stage 3 age and Mediterranean-type fossil-bearing shale and recessive coarser siliciclastic successions with a Cambrian Stage 4 age, all typical for Western Gondwana. Faunas of the uppermost Stage 4 and the lower and middle part of the Middle Cambrian/Miaolingian are surprisingly frequent and diverse given the limited outcrop conditions of the rocks. They indicate a complete succession with at least six different biostratigraphic levels distinguishable in the Franconian Forest. Five out of these biostratigraphic levels can be correlated between the areas and into other regions of the palaeocontinent or even on an intercontinental or subglobal scale, such as a Hupeolenus, a Kingaspidoides frankenwaldensis/Morocconus, Ornamentaspis, Badulesia tenera and Solenopleuropsis “zone”. Guzhangian strata are recorded by skeletal fossils in the Bergleshof Formation of the Franconian Forest and apparently by palynomorphs of the Delitzsch Formation in the Delitzsch–Torgau–Doberlug area, but the Furongian appears to have been a period of non-deposition and erosion (except for volcanic episodes known from the Franconian Forest and the Barrandian region).