THE OCCURRENCE OF LAACHER-SEE-TEPHRA IN POMERANIA, NW POLAND

A millimetre-thick bed of highly vesiculated pumiceous clasts was foun d in two peat bogs in Pomerania (NW Poland). Their phonolitic composit ion confirms the correlation with the Laacher See Tephra (LST). Based on the various CaO-Na2O-K2O content, most of these clasts can be linke d with the Lower Laacher See Tephra (LLST), and some with the Middle L aacher See Tephra B (MLST-B). C-14 dates obtained on peat samples are in agreement with an Allerod stratigraphic position of that tephra. In several localities in NW Poland, it was found that there was no occur rence of tephra in peat bogs. Thus the presence of the LST is restrict ed to the northwestern fringes of Pomerania.