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Lower and Middle Cenomanian ammonites from the Morondava Basin, Madagascar

Kennedy W. J., Walaszczyk I., Gale A. S., Dembicz K., Praszkier T.

Acta Geologica Polonica

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2013

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Vol. 63, no. 4

625--655

EN

Lower and Middle Cenomanian ammonite assemblages have been collected on a bed-by-bed basis from localities at Vohipaly and Mahaboboka, Madagascar, as well as from outcrops around Berekata, all in the Morondava Basin, southwest Madagascar. These collections demonstrate the presence of the upper Lower Cenomanian Mantelliceras dixoni Zone and the lower Middle Cenomanian Cunningtoniceras inerme Zone of the north-western European standard sequence. These records indicate that the striking anomalies in the zonal assemblages of the classic divisions of the Madagascan Cenomanian are based on mixed assemblages, rather than a succession that differs radically from that elsewhere in the world. The dixoni Zone fauna is: Desmoceras cf. latidorsatum (Michelin, 1838), Pachydesmoceras kossmati Matsumoto, 1987, Forbesiceras sp., F. baylissiWright & Kennedy, 1984, F. largilliertianum (d'Orbigny, 1841), Mantelliceras cantianum Spath, 1926a, M. dixoni Spath, 1926b, M. mantelli (J. Sowerby, 1814), M. picteti Hyatt, 1903, M. saxbii (Sharpe, 1857), Sharpeiceras sp., S. falloti (Collignon, 1931), S. mocambiquense (Choffat, 1903), S. cf. florencae Spath, 1925, Acompsoceras renevieri (Sharpe, 1857), A. tenue Collignon, 1964, Calycoceras sp., Mrhiliceras lapparenti (Pervinquičre, 1907), Mariella (Mariella) stolizcai (Collignon, 1964), Hypoturrilites taxyfabreae (Collignon, 1964), Turrilites scheuchzerianus Bosc, 1801, Sciponoceras cucullatum Collignon, 1964, and Sciponoceras antanimangaensis (Collignon, 1964). The presence of Calycoceras in a Lower Cenomanian association represents a precocious appearance of a genus typically Middle and Upper Cenomanian in occurrence, and matches records from Tunisia. The inerme Zone yields a more restricted assemblage: Pachydesmoceras kossmati, Forbesiceras baylissi, Acanthoceras sp. juv., Cunningtoniceras cunningtoni (Sharpe, 1855) and Hypoturrilites taxyfabreae.

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Biostratygrafia i paleośrodowisko środkowej jury z kamieniołomu Ogrodzieniec

Barski M., Dembicz K., Praszkier T.

Volumina Jurassica

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2004

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Vol. 2, no. 1

61-68

EN

The uppermost Bathonian and Callovian deposits from the newly exposed section of Ogrodzieniec were studied. The biostratigraphical analysis was based on both ammonite and dinocyst zonations. The uppermost Bathonian Orbis and Discus and the Callovian Herveyi, Jason, Coronatum, Athleta, Lamberti zones were distinguished. State of preservation of ammonites and lack of dinocysts made it impossible to distinguish Koenigi and Calloviense zones of the lowest Callovian. The position of the Bathonian/Callovian boundary was found in the clayey part of the section. Earlier the boundary was thought to be erosional. The new data indicate, however, the presence of continuous sedimentation, with low sedimentation rate, during Discus and Herveyi chrons. The presence of Gtenidodinium combazii in Orbis, Discus and Herveyi zones shows normal sea conditions in this time. The change of the dinocyst assemblage the Bathonian/Callovian boundary indicates the sea water cooling.

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Zróżnicowanie litofacjalne osadów keloweju w rejonie Zawiercia

Dembicz K., Praszkier T.

Volumina Jurassica

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2003

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Vol. 1, no. 1

49-52

4

Stratygrafia, mikrofacje i środowisko sedymentacji osadów keloweju z profilu Włodowic koło Zawiercia

Dembicz K., Praszkier T.

Volumina Jurassica

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2003

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Vol. 1, no. 1

35-48