The Middle Jurassic succession in the central sector of the Pieniny Klippen Belt (Sprzycne Creek): implications for the timing of the Czorsztyn Ridge development

Abstract

Abstract:In this study, we revisit the stratigraphic age and discuss sedimentary characteristics of the lower Middle Jurassic turbidite deposits ("black flysch") of the Szlachtowa Formation, as well as the under-and overlying members of the Sprzycne Creek section situated in the central sector of the Pieniny Klippen Belt (Poland). We show that the succession captures the lower Middle Jurassic marine sediments of the pre-Late Albian Magura Basin, located to the north of an ancient submarine swell (Czorsztyn Ridge). The turbidite deposits of the Szlachtowa Formation and marly shales of the Opaleniec Formation yield dinoflagellate cysts indicative of the latest Aalenian or learliest Bajocian to Early Bathonian. The character of these deposits, and their location below the overthrusted Subpieniny Nappe show that this succession does not belong to the successions of the Oravicum domain, located on the southern side of the Czorsztyn Ridge. The Szlachtowa Formation is underlain by the Skrzypny Formation, which is reported for the first time outside the Oravicum domain. It suggests that the pre-Late Albian Magura Basin came into existence not earlier than during the latest Aalenian, following the rising of the Czorsztyn Ridge. The marly shales assigned here to the Opaleniec Formation of Late Bajocian-Bathonian age and younger marly deposits of Cretaceous age were distinguished in the past as the so-called "Sprzycne beds" of Cretaceous age. However, the combination of these two rock units into a single lithostratigraphic unit is unsuitable because they represent two separated stratigraphical intervals and their contact is tectonic.

The tectonics and stratigraphy of the transitional zone between the Pieniny Klippen Belt and Magura Nappe (Szczawnica area, Poland)

“…Barski et al 2012, see also Gedl 2008, 2013. The stratigraphic order of dinoflagellate cyst assemblages (Segit et al 2015) and the unique finding of Graphoceratidae ammonite (Gedl et al 2012) testified to the in situ occurrence of Middle Jurassic palynomorphs and macrofossils in the Szlachtowa Fm. (i.e.…”

“…Disparate opinions in favour of the Jurassic age involve two overlapping stratigraphic ranges: upper Lower to lower Middle Jurassic, with some hiatuses (Gedl 2008) and exclusively lower Middle Jurassic (Barski et al 2012, Segit et al 2015.…”

“…is overlain by the spotted-marly Opaleniec Fm., which yielded rich and well preserved palynomorph assemblages of the lowermost Upper Bajocian to Lower Bathonian (with no data on the uppermost part of the formation; Segit et al 2015) or the uppermost Lower Bajocian to Callovian interval (Gedl 2008(Gedl , 2013. Oszczypko et al (2012) referred the Opaleniec Fm.…”

“…at Jaworki/Szlachtowa to the Sprzycne beds from the Spisz sector of the Pieniny Klippen Belt (Sikora 1962(Sikora , 1971) of alleged Cenomanian age. The Sprzycne beds, however, proved to comprise tectonically amalgamated Jurassic and Cretaceous strata, erroneously attributed entirely to the Cretaceous by Sikora (1972) (Segit et al 2015).…”

“…These beds yielded phosphatic nodules, lithoclasts of green micritic limestones and ammonites diagnostic of the uppermost Lower Bajocian (see . (stratigraphy after: Birkenmajer 1970, 1977, Wierzbowski 1994, Wierzbowski et al 1999, Barski et al 2012, Segit et al 2015. A) Czorsztyn Succession (Pieniny Klippen Basin), A B C…”