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Sedimentology of the Early Jurassic terrestrial Steierdorf Formation in Anina, Colonia Cehă Quarry, South Carpathians, Romania

Kędzior A., Popa M. E.

Acta Geologica Polonica

2013

Vol. 63, no. 2

175--199

Authorship issues are clarified, new photographic documentation is provided and emended systematic descriptions are presented for the oldest Cambrian trilobite taxa from the Holy Cross Mountains (Poland). Biostratigraphic analysis of the fauna allows correlation with the traditional Holmia kjerulfi-group Zone of Scandinavia, the Callavia Zone of Britain and Newfoundland, the lower and middle part of the Sectigena Zone of Morocco and the Marianian Stage of Spain. The trilobites display a strong biogeographic signal linked with West Gondwana and Avalonia and a suggestion is made that the TESZ margin of Baltica with the Malopolska Massif was liable to currents from those areas that distributed planktonic trilobite larvae.

Patterns of occurrence and distribution of crustacean ichnofossils in the Lower Jurassic-Upper Cretaceous of Atlantic occidental margin basins, Portugal

Carvalho C., Baucon A., Rodrigues N., Santos V., Viegas P.

Acta Geologica Polonica

2010

Vol. 60, no. 1

19-28

Crustacean ichnofossils are most abundant in the stratigraphic record of Portugal. In this paper is presented a study on crustacean ichnoassemblages from the Sinemurian to middle Cenomanian, during the opening and subsequent filling of Atlantic occidental margin basins (Lusitanian Basin and western part of Algarve Basin). Thalassinoides dominates the lagoonal and inner shelf facies from the late Sinemurian at least to the Turonian, generally defining all of the carbonate sequence with its dense, "nodular" ichnofabric since the Late Jurassic. Asequence is described in the lower Barremian of Cabo Espichel in which burrow mazes of Thalassinoides suevicus occur, containing hundreds of Mecochirus rapax as an obrution lagerstatte. The Cretaceous of the Lusitanian Basin is rich in marly limestones mottled with Thalassinoides but almost devoid of Rhizocorallium. Fairly common in dark marls and biomicrites from the Jurassic, Rhizocorallium irregulare locally occurs in dense monospecific fabrics. Slipper-shaped and oblique forms (Rhizocorallium jenense) as well as spiral and lobate forms are rhizocoralliid foraging modifications usually developed in deeper tiers than Thalassinoides and sometimes evidencing bioimprints in Glossifungites preservation. Siliciclastic facies related to rifting subsidence along major fault scarps and fan deltas/braided river depositional systems show pervasive bioturbation with Psilonichnus tubiformis.Another crab-style behaviour ascribed to Macanopsis plataniformis is described for the first time in Portugal, associated with a coarse-grained sandstone episode in a tidal flat setting from the Kimmeridgian, where monospecific brachyuran burrows were developed in a firmground.