Dajki neptuniczne w Rezerwacie Przyrody Nieożywionej Bonarka w Krakowie - świadectwo późno kredowych ruchów tektonicznych na Wyżynie Krakowskiej – replika

Józef Wieczorek, Thierry Dumont, Jean-Pierre Boullin, Barbara Olszewska

Abstrakt


NEPTUNIAN DYKES OF BONARKA - A TESTIMONY OF THE LATE CRETACEOUS TECTONIC MOVEMENTS IN THE CRACOW UPLAND - REPLY

Summary
The Late Cretaceous age of the fissures and faults at Bonarka is proved by our field and laboratory data [27]. The Gradziński's and Książkiewicz's drawings, formerly regarded as a decisive argument for Tertiary age of Bonarka faults, are in agreement with our interpretation, although these drawings were only secondary in our reasoning. The faults which cut the Jurassic basement grade upwards into the flexure, but they do not cut the top of well-bedded Lower Campanian marls. This fact justify doubts about their Miocene age. The Santonian marls which fill the fissures do locally show lamination [28, fig. 11] - contradictory to Felisiak's misinformation. Rare occurence of lamination do not exclude the sedimentary origin of fissure infilling! Similar, undoubtedly sedimentary infillings of bioerosional depressions are devoid of lamination (see discussion with Dżułyński [10], fig. 2-4). It is important to notice that we do not exclude the injection of already deposited plastic marls into large fissures during the Santonian [26]. However, it is hard to belive in the post-hardening tectonic injection mechanism - related to Tertiary movements - postulated by Felisiak [13], but not supported by field documentation. Not common (!) occurrence of Santonian microbreccia ilustrated in our paper [28, fig. 9, 12] is a result of Santonian polyphase infilling of some fissures. It should be stress that material younger than Santonian in age is absent in dyke infillings. Our interpretation does not negate the Tertiary tectonics on the Cracow Upland but focus attention on underestimated indications of pre-Tertiary instability of this peri-Carpathian region. The Santonian extension documented in our paper is fully compatible with the collapse of the Cracow swell recorded by Early Senonian sedimentation.