Studia Geologica Polonica  vol. 114 (Abstracts)

New data on the Lower Cretaceous microfossil and nannoconid stratigraphy in the Guaniguanico terrane of western Cuba

Andrzej PSZCZÓŁKOWSKI

Abstract
The age of some Lower Cretaceous lithostratigraphic units and their boundaries in the Guaniguanico terrane, western Cuba, is modified on the basis of calpionellids, foraminifers and nannoconids. In the Northern Rosario belt, the Artemisa/Polier formations boundary is diachronous (upper Lower Berriasian to Lower Valanginian). In the studied sites located in the Southern Rosario belt, the topmost part of the Sumidero Member of the Artemisa Formation is latest Valanginian to Hauterivian in age. Comparing this result with previous data, the Artemisa/Santa Teresa formations boundary ranges from Lower Valanginian to Hauterivian. The Late Valanginian to earliest Hauterivian age of the lowermost part of the Pons Formation in the Río Las Piedras section, Sierra de los Organos, is accepted on the basis of the planktonic foraminifers, calpionellids and nannoconids. The presence of Tintinnopsella carpathica Murgeanu et Filipescu is characteristic for the Tintinnopsella Zone. Nannoconus truittii Brönnimann, 1955, subsp. truittii Deres et Achéritéguy, 1980, is present in the Barremian-Lower Aptian assemblages. Comparing the Lower Cretaceous stratigraphic record from the Guaniguanico terrane to that registered at the Southern Gulf of Mexico basin site (Hole 535), some similarities, as well as differences, can be discerned.

Studia Geologica Polonica, 114: 35-75.

Nannoconid assemblages in Upper Hauterivian-Lower Aptian limestones of Cuba: their correlation with ammonites and some planktonic foraminifers

Andrzej PSZCZÓŁKOWSKI & Ryszard MYCZYŃSKI

Abstract
The nannoconids are abundant in the Lower Cretaceous pelagic limestones in western and central Cuba. In some limestone beds, these nannofossils occur together with ammonites or planktonic foraminifers. Our samples were collected from the Polier, Veloz and Paraiso formations. The Late Hauterivian to Early Aptian age of the studied samples is based mainly on ammonites. The nannoconids identified in these samples are grouped in 4 assemblages: Late Hauterivian, Early Barremian, Late Barremian and late Early Aptian. In the Early Barremian assemblage, the narrow- canal nannoconids are by far more frequent than the wide-canal ones. Small specimens, classified herein provisionally as N. truittii truittii, occur also in this assemblage. On the other hand, the representatives of the Nannoconus steinmannii group are absent in the late Early Aptian assemblage, which includes the wide canal forms only. Nannoconids found in one sample may represent an assemblage of the earliest Aptian age.

Studia Geologica Polonica, 114: 77-92.

Inoceramids and buchiids in the Tithonian deposits of western Cuba: a possible faunistic link with South-Eastern Pacific

Ryszard MYCZYŃSKI

Abstract
Occurrence of the “Boreal type” bivalves: inoceramids (represented by the genera: Inoceramus Parkinson, 1819; Retroceramus Koshelkina, 1963 and Anopaea Eichwald, 1861) and buchiids (Buchia Rouillier, 1845) in the Tithonian sections of the Sierra de los Organos and Sierra del Rosario belts, western Cuba, is described. Anopaea and other “Boreal” bivalves probably migrated to the Cuban Jurassic basin over the South American shelf and probably throught Southern Mexico. Their occurrence might reflect cooler temperature in the proto-Caribbean basin caused by oceanic currents and/or upwelling, rather than tectonic transport from Southern Boreal province.

Studia Geologica Polonica, 114: 93-112.

Some ammonite genera from the Tithonian of western Cuba and their palaeobiogeographic importance

Ryszard MYCZYŃSKI

Abstract
Ammonites of the genus Hybonoticeras Breistroffer, 1947, described here as: Hybonoticeras (Hybonoticeras) sp. ex. gr. beckeri (Neumayr) and Hybonoticeras (Hybonotella) cf. mundulum striatulum Berckhemer & Hölder, derive from Lower Tithonian deposits of the Sierra de los Organos and Sierra del Rosario belts (Guaniguanico terrane, western Cuba). The presence of the genus Hybonoticeras Breistroffer, 1947, in Cuba, confirms the palaeobiogeographical connections between Spain, Cuba and Mexico during Early Tithonian time, as proposed earlier by the present author. A direct marine connection between Mediterranean Tethys and the proto-Caribbean basin at that time had probably occurred through the “hispanic corridor” sensu Westermann (1984). The taxonomic position of the endemic Cuban genera (Salinites, Protancyloceras - hondense type, Vinalesites, Butticeras, and Paralytohoplites) is specified. These ammonites can be used only for regional correlation, limited to the Gulf of Mexico (Eastern Mexico and Southern part of the United States) and the Caribbean (Cuba). The new data caused modification of local ammonite biozonation.