Biostratygrafia famenu z profilu wiercenia Gozd 2 (Pomorze Zachodnie)

Abstract

Biostratigraphy of the Famenian from the borehole Gozd 2 (Western Pomerania)

The stratigraphic position of Upper Devonian sediment from the column Gozd 2 has been revised on the basis of conodont fauna, and referred to the conodont Palmatoiepis crepida and Palmatolepis rhomboidea Zones. In the ammonite division they correspond to the lower and upper part of the Cheiloceras (do llα - do IIβ). Zone. The proposed stratigraphical division of the Famenian sediments from the column Gozd 2 is the first attempt of distinguishing conodont zones in the boreholes of the Gozd area. The here described material comes from the Gozd 2 borehole profile. At the depth between 2992.0 and 3203.0 m underlying Carboniferous deposits there is a series of Upper Devonian deposits, 211.0 m thick. They are composed of marly limestones partially nodular. The top of this series consists of grey-yellow mudstones and limy claystones. The brachiopods found in the deposits described by Łobanowski (1970) has determined the stratigraphical position of the series in Middle and Upper Fransian. The encountered conodont assemblage has enabled the autor to more accurately determine the stratigraphic position of the deposits. They comprise two Famenian conodont Zones - Palmatolepis crepida and Palmatolepis rhomboidea with their subzone. The typical forms found in the Palmatolepis rhomboidea zone are: Palmatolepis rhomboidea Sannemann, P. klapperi Sandberg & Ziegler, P. glabra pectinata Ziegler, P. glabra prima Ziegler & Huddle, Polygnathus semicostatus Branson & Mehl. In the Palmatolepis crepida Zone only two forms: Palmatolepis crepida Sannemann and P. circulans Szulczewski have been found. The re-occurrence of a part of the Palmatolepis rhomboidea Zone suggests the possibility of a reverse high-angle fault with vertical separation c.150m.