Introduction

Recent studies and investigations have agreed that paleomagnetic polarity changes are the most expedient criteria for establishing the main divisions of Quaternary stratigraphy and for tracing the “N/Q” limit between Neogene and Quaternary (actually, the Pliocene–Pleistocene boundary). In Hungary, there are two viewpoints as to where to mark the N/Q boundary: at the Gauss–Matuyama paleomagnetic boundary (Rónai, 1984), dated to 2.5 Ma, or at the top of the Olduvai event (Pasini and Colalongo, Chapter 2, this volume), dated to 1.8 Ma. Each of these reversals is close to the initiation of a period of global cooling.

If we accept the paleomagnetic polarity changes as signposts of stratigraphic boundaries, it is still necessary to reach consensus on which of the cooling events should be recognized as the lower boundary of the Quaternary. Both reversals have been recognized in Hungary, but most Hungarian scientists have long favored the view that the beginning of the Quaternary should be determined by a major stratigraphic and paleontological change, which we now know to have been almost coincident with the Gauss–Matuyama paleomagnetic boundary – see Rónai (1984) and the references cited therein.

There are several reasons to prefer this date, but the main one is that it corresponds to the most impressive change in the Carpathian Basin during the past 5–10 million years, namely, the epirogenetic uplift of that great territory in the middle of the European continent, and the regression of the Pannonian Lake, comparable to regression in the Dacic Basin (Ghenea, Chapter 20, this volume). This event changed the geomorphology of the entire region and seems also to have been coincident with the starting point of a new tectonic cycle.