Provenance of the detrital garnets and spinels from the Albian sediments of the Czorsztyn Unit (Pieniny Klippen Belt, Western Carpathians, Slovakia)

Abstract

According to earlier concepts, the Czorsztyn Unit (Oravic Superunit, Pieniny Klippen Belt, Western Carpathians) sedimented on the isolated Czorsztyn Swell which existed in the Middle Jurassic-Late Cretaceous time in the realm of the Outer Western Carpathians. This paper brings new data providing an alternative interpretation of its Cretaceous evolution. They are based on heavy mineral analysis of the Upper Aptian/Lower Albian sediments of the Czorsztyn Unit. They rest upon a karstified surface after a Hauterivian-Aptian emersion and are represented by condensed, red marly organodetritic limestones with some terrigenous admixture (Chmielowa Formation). The heavy mineral spectrum is dominated by spinels, followed by garnet, with lesser amounts of zircon, rutile and tourmaline. The composition of the majority of the detrital garnets shows that they were derived from primary HP/UHP parental rocks which were recrystallized under granulite and amphibolite facies conditions. The garnets were most probably derived directly from the magmatic and metamorphic rocks of the Oravic basement, as the high-pyrope garnets are known to be abundant in Mesozoic sediments all over the Outer Western Carpathians. The presence of spinels is surprising. According to their chemistry, they were mostly derived from mid-oceanic ridge basalts (MORB) peridotites, supra-subduction zone peridotites (harzburgites) and transitional lherzolite/ harzburgite types. Only a lesser amount of spinels was derived from volcanics of BABB composition (back-arc basin basalts). The presence of this ophiolitic detritus in the Czorsztyn Unit is difficult to explain. Ophiolitic detritus appeared in the Aptian/Albian time only in the units which were considered to be more distant, because they were situated at the boundary between the Central and the Outer Western Carpathians (Klape Unit, Tatric and Fatric domains). The hypothetical Exotic Ridge which represented an accretionary wedge in front of the overriding Western Carpathian internides was considered to be a source of the clastics. In previous paleogeographical reconstructions, the Czorsztyn Unit was situated north of the Pieniny Trough (considered to be one of the branches of the Penninic-Vahic Ocean). In the trough itself, the ophiolitic detritus appeared as late as in the Senonian and there was no way it could reach the Czorsztyn Swell which was considered to be an isolated elevation. The new results presented herein show that these reconstructions do not fit the obtained data and infer a possibility that the Czorsztyn sedimentary area was not isolated in the Cretaceous time and it was situated closer to the Central Carpathian units than previously thought. A new paleogeographical model of the evolution of the Pieniny Klippen Belt is presented in the paper: Oravic segment was derived from the Moldanubian Zone of the Bohemian Massif by the Middle Jurassic rifting which caused block tilting where most of the Oravic units were arranged north of the Czorsztyn Swell. The Oravic segment was situated in...

Sedimentological study of the Nikolčice Formation - evidence of the Middle Jurassic transgression onto the Bohemian Massif (subsurface data)

“…Data can be com pared, more over, with re sults from the Juras sic de pos its of the West ern Carpathians (Aubrecht and Méres, 2000;Aubrecht et al, 2009) and the Pol ish Plat form (Méres et al, 2012). Al though high-pyrope gar nets are known to be abun dant in Me so zoic de pos its of the Outer West ern Carpathians, the dis tri bu tion of the gar net types and com par ison of discriminant di a grams shows only slight sim i lar ity to the data from the NF.…”

“…The PRP-ALM+SPS-GRS di a gram (Mange and Mor ton, 2007) in Fig ure 10A re flects the dom i nant (76.7%) of gar nets from high-grade granulite fa cies metasedimentary rocks and inter me di ate fel sic ig ne ous rocks; sig nif i cantly less com mon (19.5%) are gar nets from in ter me di ate to fel sic ig ne ous rocks and gar nets from am phi bo lite-fa cies metasedimentary rocks are rare (3.8%). The PRP-ALM-GRS di a gram (Aubrecht et al, 2009) in Fig ure 13B in di cates the dom i nant (46.9%) pri mary source of gar nets de rived from eclogite-and granulite fa cies rocks and also (31.6%) gar nets de rived from gneiss es metamor phosed un der pres sure and tem per a ture con di tions tran si - A -dis crim i na tion di a gram ac cord ing to Mange and Mor ton (2007) (1 -py rox enes and peri dot ites, 2 -high-grade granulite fa cies metasedimentary rocks and in ter me di ate fel sic ig ne ous rocks, 3 -in ter me di ate to fel sic ig ne ous rocks, 4 -am phi bo lite fa cies metasedimentary rocks); B -dis crim i na tion di a gram ac cord ing to Aubrecht et al (2009) (1 -py rox enes and peri dot ites, 2 -fel sic and in ter me diate granu lites, 3 -gneiss es and am phi bo lites meta mor phosed un der pres sure and tem per a ture con di tions tran si tional to granulite and am phi bo lite fa cies meta mor phism, 4 -gneiss es meta mor phosed un der am phi bo lite fa cies con di tions); C -ter nary di a gram of the chem is try of de tri tal gar nets in com par i son with pos si ble source ar eas; data from source rocks ac cord ing to Otava et al (2000), Èopjaková et al (2002, 2005), Èopjaková (2007) and Buriánek et al (2012) tional to granulite-and am phi bo lite-fa cies meta mor phism. Garnets from am phi bo lite-fa cies rocks (mostly am phi bo lites less com monly gneiss es) are less com mon (21.5%).…”

Lower Badenian coarse-grained Gilbert deltas in the southern margin of the Western Carpathian Foredeep basin

“…Only garnets from high-grade mafic rocks are exceptional (4.4 %). The PRP-ALM-GRS diagram (Aubrecht et al 2009) in Figure 10B indicates the most dominant (84.5 %) primary source of garnets derived from gneisses and amphibolites metamorphosed under amphibolite-facies conditions. Garnets reflecting the source from gneisses or amphibolites metamorphosed under pressure and temperature conditions transitional to granulite-and amphibolite-facies metamorphism are not common (8.5 %), similarly to garnets derived from granulites (7.0 %).…”

“…Classification diagrams (Mange & Morton 2007;Aubrecht et al 2009;Krippner et al 2014) were used for evaluation of the potential primary sources. The PRP−ALM+SPS−GRS diagram (Mange & Morton 2007) in Figure 10A reflects the most important role (59.6 %) of garnets from amphibolitefacies metasedimentary rocks; significantly less common are garnets from intermediate to felsic igneous rocks (24.0 %) or garnets from high-grade granulite facies metasediments and intermediate felsic igneous rocks (12 %).…”

High (ultrahigh) pressure metamorphic terrane rocks as the source of the detrital garnets from the Middle Jurassic sands and sandstones of the Cracow Region (Cracow-Wieluń Upland, Poland)

“…To construct the original triangular diagrams, the compositions of garnets from various metamorphic conditions were plotted (Aubrecht et al 2009;Méres 2008Méres , 2009. Representative analyses of the garnets from various rocks (kimberlites, garnet peridotites, UHP eclogites, eclogites, HP granulites, LP granulites, retrograde eclogites), were taken from the following papers: garnets from HP granulites in the Góry Sowie Mts.…”