Zarys budowy geologicznej utworów trzeciorzędowych i czwartorzędowych w rejonie Zatoki Puckiej

Abstract

OUTLINE OF GEOLOGICAL STRUCTURE OF TERTIARV AND QUATERNARY FORMATIONS IN THE REGION OF THE PUCK BAY Summary Geological structure of the formations from the Silurian top (Ludlovian), through the Zechstein salt-bearing series, Triassic, Jurassic, and Cretaceous, up to the Tertiary formations and the whole Quaternary overburden has been penetrated by drillings in the E part of the Łeba elevation. The Tertiary deposits rest down to a depth of 147 m unconformably on the quartz-glauconite sands of Cenomanian age, locally on the Turonian siltstones. These are represented by marine sediments of Upper Eocene-Lower Oligocene age, and probably by brackish Middle Oligocene sediments, as well as by those of freshwater origin, Miocene in age. The faunistically evidenced Upper Eocene is represented at the bottom by a siltstone-marly series with fauna and phosphorites, some metres in thickness. It is overlain with a series of non-calcareous clayey siltstones of a deeper basin, with traces of fauna representatives, among them of mud-eating organisms. The next, overlying sandy-silty series, some ten metres in thickness, of an again shallowed basin, probably of Lower Oligocene age, contains fauna representatives, glauconite, single phosphorite fragments and redeposited amber particles. The upper parts of the Tertiary formations are built up of the arenaceous-silty sediments with glauconite admixtures, and disclose the nature of brackish deposits of the Middle Oligocene time. The Quaternary consists mainly of the arenaceous-gravel deposits and of boulder clays that represent the formations of the Older Middle Polish glacial time and ort the Baltic Glaciation, and the Holocene formations. To explain the geological structure more in detail, to define a detailed lithostratigraphical section of the Cainozoic cover, and to determine the deposits occurring at shallow depths the present author suggests a development of further detailed geological investigations in the area considered.