Trzeciorzęd i rzeźba podłoża czwartorzędowego rejonu Okuniewa w świetle profilu Hipolitów

Abstract

THE TERTIARY AND THE RELIEF OF THE BASEMENT OF QUATERNARY DEPOSITS IN THE VICINITY OF OKUNIEW ON THE BASIS OF BOREHOLE MATERIAL FROM HIPOLITÓWSummaryThe course of a ridge and furrow in the Cretaceorus basement and the following members of Tertiary deposits were traced in the vicinity of Okuniew on the basis of material from the Hipolitów borehole, which reached Cretaceous rocks.The hard ground that forms the top of Upper Maastrichtian carbonate rocks is overlain by gaizes, opokas and marls of theLower Palaeoceneat a depth of 256.3–234.4 m. Above, at a depth of 234.4–175.6 m, there is a bipartite complex of quartz glauconite sands, separated by silty-sandstone deposits. This complex is assumed to be of Eocene age, on the basis of Upper Eocene microfauna occurring in clays tones and silstones which separate the sands. At the top of the sands there are Middle Oligocene, sandy and silty-clayey, continental deposits, with charred plant remains. The overlying deposits, occurring at a depth of 164.2–126.4 m, consist of sands and silts with intercalations of brown coal, defined as Miocene on the basis of palynological studies. A series of sandy-silty rocks with traces of plant remains occurs at a depth of 126.4–82.0 m and is regarded as disturbed Miocene deposits and Pliocene deposits. At a depth of 82.0–10.6 m there are variegated clays and silts with sporadic intercalations of sands, assigned to the Pliocene. The upper part of these deposits, to a depth of51.9 m, represents disturbed Pliocene rocks with older Quaternary, mainly preglacial rocks.The results of investigations in the vicinity of Okuniew and materials from the Hipolitów borehole show for the first time the occurrence of older Palaeogene deposits in this area. They also provide evidence that the elevations and lowering of the basement, running from the south-east to the north-west, result from the remodeling of the structural-tectonic elements of the basement during the Tertiary and the Quaternary.This conclusion shows that it is necessary to revise the present opinions about the origin of ridges composed of Tertiary rocks and occurring at a high altitude (over100 mabove sea level).