The Upper Cretaceous section at Schmilka in

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The Upper Cretaceous section at Schmilka in

Saxony (Elbsandsteingebirge, Germany) – syntectonic sedimentation and inverted zircon age populations revealed by LA‑ICP‑MS U/Pb data

Das Oberkreide‑Profil bei Schmilka in Sachsen

(Elbsandsteingebirge, Deutschland) – syntektonische Sedimentation und inverse Zirkon‑Alterspopulationen offengelegt durch LA‑ICP‑MS U/Pb‑Daten

Mandy Hofmann

¹

, Ulf Linnemann

¹

and Thomas Voigt

²

1 Senckenberg Naturhistorische Sammlungen Dresden, Museum für Mineralogie und Geologie, Sektion Geochronologie,

Königsbrücker Landstraße 159, 01109 Dresden, Germany; mandy.hofmann@senckenberg.de — ² Friedrich-Schiller-Universität Jena, Institut für Geowissenschaften, Burgweg 11, 07749 Jena, Germany

Revision accepted 19 June 2013.

Published online at www.senckenberg.de/geologica-saxonica on 10 September 2013.

Abstract

Mesozoic sediments in Saxony are represented by few limited occurrences of Lower Triassic and Middle to Upper Jurassic deposits but mainly by Upper Cretaceous predominantly clastic units filling the Elbe Zone (Pietzsch 1963, Voigt & Tröger in Niebuhr et al. 2007, Tröger in Pälchen & Walter 2008). The latter ones are confined by the Lausitz Block (part of the West-Sudetic Island) in the NE and the Erzgebirge (part of the Mid-European island) in the SW. The Upper Cretaceous sedimentation in the area of the Elbsandsteingebirge starts with the Upper Cenomanian marine transgression. Sediments of the Elbsandsteingebirge were deposited in marine environment in a narrow strait connecting northern cold Boreal water of N – NW Europe with the Tethyan warm-water areas in the S. The West-Sudetic Island (Lausitz- Krkonosze High) was the most possible source area for the Upper Cretaceous sediments of the Elbe Zone (Voigt 1994, Wilmsen 2011).

Composition of sandstones and conglomerates indicate erosion and redeposition of older sediments which covered initially the basement of the Lausitz.

We analysed six samples representing a 400 m thick sandstone succession (Schmilka, Postelwitz and Schrammstein formations) of Early Turonian to Early Coniacian age from the area around Schmilka (Elbsandsteingebirge) regarding their U/Pb-ages of detrital zircon grains. A significant change in the age spectra occurs from the Upper Turonian to the Lower Coniacian. We found a sudden input of Meso- and Palaeoproterozoic ages in the uppermost part of the Schmilka section that represent typical Baltica ages. As the whole region of northern Germany was covered by marine Cretaceous sediments, a direct input from Baltica (Scandinavia?) is impossible. Facies distribution and recent investigations suggest that during Middle Jurassic a major part of sandstones derived from uplifted parts of Paleoproterozoic and Mesoproterozoic units of Baltica. Therefore, we interpret the presented Coniacian age spectra as a signal of redeposited Middle Jurassic sandstones. Erosion of Jurassic sediments started not earlier than Early Coniacian (higher Schrammstein Formation, Sandstone e).

The limited amount of ca. 540 Ma ages and predominance of variscan ages in all samples confirm covering of the Cadomian basement units of the Lausitz Block by Mesozoic sediments, originally derived from the Bohemian massif during the first depositional cycle. The basement rocks of the Lausitz Block were not available for erosion until at least Middle to Late Coniacian time.

Further, our data confirm the inversion of the Lausitz Block relative to the Elbe Zone during Late Cretaceous time as already proposed by Voigt (1994).

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1. Introduction and geological setting

Apart from some scattered occurrences of Lower Triassic in some shallow synclines and Zechstein to Upper Ju- rassic at the margins of the Lausitz Block, Upper Cre- taceous sediments represent the major part of Mesozoic deposits in Saxony. They are mainly restricted to the Elbe Zone and represent the subsidence axis of the extended Bohemian Cretaceous basin which covers the Bohemian Massif in the Czech Republik. In the Elbsandsteinge- birge sediments range from the Middle Cenomanian to the Lower Coniacian and were summarized as Elbtal Group. Thickness and facies distribution indicate syntec- tonic deposition in the front of an uplifting source area (Pietzsch 1963, Voigt 1994, Tröger in Pälchen & Walter 2008).

1.1. Mesozoic sedimentation in Saxony

Jurassic and Triassic sediments are only known from very few localities, but these scattered remnants support the assumption that there had been a Triassic as well as a Jurassic cover on the pre-Mesozoic basement of Saxony (e.g. Tröger in Pälchen & Walter 2008). Triassic sedi- ments show the same characteristics as the very uniform basin-fill of the Triassic Germanic Basin. The lower Tri- assic time is characterized by continental red beds (Bunt- sandstein). Sediments are only known from drill holes

in northeastern Saxony (Spremberg-Weißwasser, Lausitz Block) and from some occurrences in western (Zeitz- Schmölln Syncline) and northern (Mügeln and Düben- Mühlberg Syncline) Saxony (Pietzsch 1963, Friebe in Pälchen & Walter 2008). Additionally, Lower Triassic sandstones of limited thickness are exposed in the central part of the Elbezone around Meißen.

Jurassic sediments in Saxony are even rarer than the Triassic ones and only known from some occurrences along the Lausitz Thrust (Tröger in Pälchen & Walter 2008), where they underlie Upper Cretaceous deposits and got incorporated into the partly overturned sediments along the thrust (Fig. 1).

Sedimentation started in the Middle to Late Jurassic, as at this time the marine transgression reached the area of today’s Saxony. A general fining trend is observed in the sedimentary record, forming a succession that grades from sand- into silt- and limestones (according to Cotta 1838 in Pietzsch 1963: 360). Earlier investigations pro- posed a narrow sea strait in the Elbezone but pelagic limestones and marls point to an extended shallow basin at least during Late Jurassic.

The Late Jurassic to Early Cretaceous time is char- acterized by widespread and extensive erosion. This lead to general subsidence and is assumed to explain the transgression of Cenomanian deposits on the meta- morphic basement of the Erzgebirge and the Elbe Zone (Tröger in Pälchen & Walter 2008). A first transgression happened during the Early Cenomanian (Meißen Forma-

Kurzfassung

Mesozoische Sedimente sind in Sachsen durch wenige vereinzelte Vorkommen der unteren Trias und des mittleren bis oberen Jura in der Umrandung des Lausitzer Massivs vertreten. Den Hauptanteil bilden aber die oberkretazischen vorwiegend klastischen Einheiten, welche in der Elbtal-Gruppe zusammengefasst sind und das Elbtal ausfüllen (Pietzsch 1963, Voigt & Tröger in Niebuhr et al. 2007, Tröger in Päl- chen & Walter 2008). Diese werden im NE durch den Lausitz-Block (als Teil der Westsudetische Insel) und im SW durch das Erzgebirge (als Teil der Mitteleuropäischen Insel) begrenzt. Die oberkretazische Sedimentation im Elbsandsteingebirge beginnt mit der obercenoma- nen Transgression. Die hier diskutierten Sandsteine wurden in einem engen Meeresarm abgelagert, welcher das kältere boreale Nordmeer mit der südlichen wärmeren Tethys verband (Wilmsen et al. 2011). Die Westsudetische Insel (Lausitz-Riesengebirge Block) stellt das Hauptliefergebiet für die oberkretazischen Sedimente der Elbezone dar (Voigt 1994, Wilmsen 2011). Die Zusammensetzung der Sandsteine und Konglomerate legt nahe, dass der Lausitz-Block als ein Teil der Westsudetischen Insel mit Sedimenten bedeckt war, welche während der Oberkreide erodiert wurden.

Wir analysierten sechs Sandsteinproben aus dem Gebiet um Schmilka (Elbsandsteingebirge) hinsichtlich ihrer U/Pb-Alter detritischer Zirkone. Die etwa 400 m mächtige Abfolge (Schmilka-, Postelwitz- und Schrammstein-Formation) repräsentiert das Untere Turon bis Untere Coniac. Es gibt eine auffällige Veränderung der Alterssprektren vom späten Turon bis ins frühe Coniac. Wir fanden einen plötzli- chen Eintrag meso- und paläoproterozoischer Alter im obersten Niveau der Schmilka-Sandsteinabfolge. Diese Alter sind typisch für eine Baltika-Herkunft. Da aber ganz Norddeutschland während der Oberkreide von Meer bedeckt war, ist eine direkte Lieferung von Baltica (Skandinavien) ausgeschlossen. Die Faziesverteilung und neueste Provenienzstudien indizieren, dass während des Mittleren Jura ein großer Teil der Sandsteine aus gehobenen Einheiten Baltikas herzuleiten ist. Deshalb interpretieren wir das Altersspektrum als Wiederaufarbeitung jurassischer Sandsteine. Die Erosion dieser Jura-Sedimente auf dem Lausitz-Block begann erst im Unterconiac (höhere Schrammstein- Formation, Sandstein e). Die geringen Mengen an 540 Ma alten Zirkonen in allen Proben und die Vorherrschaft von variszischen Altern, die für das Böhmische Massiv typisch sind, bestätigen, dass das cadomische Grundgebirge des Lausitz-Blocks von Sedimenten bedeckt war, die im ersten Ablagerungszyklus vom Böhmischen Massiv geliefert wurden. Die Grundgebirgseinheiten standen nicht vor dem unteren Coniac (vermutlich erst später) an der Oberfläche an.

Die Untersuchungen bestätigen die Inversion des Lausitzer Massivs in der späten Oberkreide (Voigt 1994).

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tion), but did not reach the area of the Elbsandsteinge- birge. After a fluvial phase a new transgression during the Late Cenomanian strongly influenced the whole area including all sediments of the Elbe Zone (Voigt & Tröger in Niebuhr et al. 2007). Therefore, sediment accumula- tion and subsidence in the Elbezone started not before Cenomanian.

The Upper Cretaceous sediments in the surroundings of the Lausitz Block are mainly restricted to the north- ern margin of the Lausitz and the Elbe Zone but covered also the eastern Erzgebirge (Tröger in Pälchen & Walter 2008). The Meißen Formation (marine) contains the old- est sediments of the Elbtal Group. The fluvial deposits of the Niederschöna Formation represent the chronologi- cal next unit, which is followed again by marine sedi- ments due to the Middle to Late Cenomanian transgres- sion. During this second transgression the sandstones of the Elbsandsteingebirge where deposited (Oberhäslich, Schmilka, Postelwitz, and Schrammstein formations).

Sedimentation continued at least until the Santonian in the Bohemian Cretaceous, but these youngest deposits were not preserved in Saxony.

Sedimentation occurred in a narrow sea strait con- necting the cold Boreal of N–NW Europe with the warm Tethyan areas in the S. This strait was confined by the Mid-European Island comprising the Bohemian Mas- sif in the SW and the West-Sudetic Island including the Lausitz Block in the NE (Tröger 1964, Wilmsen et al.

2011). Therefore, the Erzgebirge (Bohemian Massif, part of the Mid-European Island) and the Lausitz Block (part of the West-Sudetic Island) are likely source areas for the Cretaceous sediments in Saxony. Due to tectonic activity and the development of the Lausitz Thrust, the area be- tween these two islands evolved as an asymmetric basin (marginal trough) deepening towards the Lausitz Block (Voigt 1994). Thickness maps of the Upper Cenomanian sediments show first evidence of differential subsidence due to the tectonic activity. From Turonian time onwards, the sedimentation was clearly syn-tectonically controlled by the relative uplift of the Lausitz Block and enhanced subsidence in an axis running parallel to the recent Lausitz thrust (Voigt 1994).

From the NW to the SE, the Saxon Cretaceous sedi- ments become more and more siliciclastic, changing from hemipelagic limestones and marly dominated units around Meißen and Dresden (NW) to massive sandstones in the Elbsandsteingebirge (SE).

The Schmilka-Großer Winterberg section (Elbsand- steingebirge, for location see Fig. 2) represents the thick- est undisturbed succession, ranging from the Lower Tu- ronian Schmilka-Formation to the Upper-Turonian/Low- er Coniacian Schrammstein-Formation. The total thick- ness of the Upper Cretaceous in Saxony is in the order of 550 to 650 m (Tröger in Pälchen & Walter 2008) in the Elbsandsteingebirge and possibly 1000 m in the Zittauer Gebirge, where the Lower Coniacian is represented by thick sandstones of the Waltersdorf Formation. Further towards the SE, the sandstones pass over into the Upper Cretaceous of the Bohemian Basin (Czech Republic).

1.2. Schmilka section

The Schmilka – Großer Winterberg section is mainly char- acterised by thick marine sandstone packages compris ing a complete 400 m thick succession of the Lower to Mid- dle Turonian Schmilka Formation, the Middle to Upper Turonian Postelwitz-Formation and the Upper Turonian to Lower Coniacian Schrammstein For ma tion. The labia

tus Sandstone marks the base of the section (Schmilka Formation). The overlying Postelwitz- and Schramm- stein formations can be further subdivided in distinct units which have member status: Sandstones a, b and c according to Lamprecht 1928, 1931 and 1934 are sum- marized as Postelwitz Formation (Prescher 1981), d and e as Schrammstein Formation (Voigt & Tröger 2007) at the top of the Großer Winterberg (Fig. 2 and 3).

2. Samples and methods

2.1. Samples

The completely exposed Schmilka – Großer Winterberg section forms the type locality of the lithostratigraphic subdivision of the Cretaceous in the Elbsandsteinge- birge. Sampling covered the whole succession within a vertical distance of about 30 to 70 meters between the sample points. These samples represent all Upper Creta- ceous sandstone units from the Schmilka-, Postelwitz-, and the Schrammstein formations (see Fig. 3). The sedi- ments are represented by fine- to coarse grained quartz sandstones with a relatively low content of feldspar in the Schmilka Formation and the Sandstones b and d, respectively; and a higher amount of feldspar in the Sand stone a and e. Heavy mineral spectra are mainly dominated by tourmaline, zircon, and rutile. In total six sandstone samples were analysed regarding their zircon U/Pb ages. The sample localities for the sandstones used for zircon dating are marked in figures 2 and 3. Sample coordinates are given in table 1.

2.2. Methods

Zircon concentrates were separated from 1–3 kg sample

material at the Senckenberg Naturhistorische Samm lun-

gen Dresden. After crushing the rocks in a jaw crusher,

the material was sieved and washed. The heavy mineral

separation was realized by using heavy liquid LST (sodi-

um heteropolytungstates in water) and a Frantz magnetic

separator. Final selection of the zircon grains for U/Pb

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dating was achieved by hand-picking under a binocular microscope. Zircon grains of all grain sizes and morpho- logical types were selected, mounted in resin blocks and polished to half their thickness. The zircon grains where examined regarding their cathodoluminescence signal using an EVO 50 Zeiss Scanning Electron Microscope (Sen ckenberg Naturhistorische Sammlungen Dresden) prior to U/Pb analyses. This helps to distinguish differ- ent growth and maybe metamorphic zones within the single grains. For U/Pb analyses the laser spots where placed in zones with monophase growth patterns that show no metamorphic overprint. Zircons were analyzed for U, Th, and Pb isotopes by LA-SF ICP-MS techniques at the Senckenberg Naturhistorische Sammlungen Dres- den (Museum für Mineralogie und Geologie, GeoPlasma Lab), using a Thermo-Scientific Element 2 XR sector field ICP-MS coupled to a New Wave UP-193 Excimer Laser System. A teardrop-shaped, low volume laser cell constructed by Ben Jähne (Dresden, Germany) and Axel Gerdes (Frankfurt am Main, Germany) was used to en- able sequential sampling of heterogeneous grains (e.g.

growth zones) during time resolved data acquisition.

Each analysis consisted of 15 s background acquisition followed by 20 s data acquisition, using a laser spot-size of 20 to 25 µm, respectively. The signal was tuned for maximum sensitivity for

²⁰⁶

Pb and

²³⁸

U. A common-Pb correction based on the interference- and background-

Abb. 2. Die geologische Karte des Untersuchungsgebietes (leicht verändert nach Lobst 1993) zeigt die oberkretazischen Sandsteine der Schmilka- (labiatus-Sandstein), der Postel- witz- (Sandsteine a – c) und der Schrammstein-Formation (Sandsteine d und e). Die Probenahmepunkte sind ein ge- tragen.

Fig. 1. The cross-section of the Saxonian Cretaceous Basin shows the thrusting of the Lausitz Block on the Mesozoic deposits (based on Lobst 1993). The sediments are overthrust- ed. Important are the Jurassic deposits that are preserved along the fault. They are in general absent below the Cre- taceous deposits elsewhere in Saxony. Their occurrence and facies indicate a widespread Jurassic cover and the inversion of a Jurassic-Early Cretaceous graben which was established in the area of the recent Lausitz Block.

Abb. 1. Schnitt durch das sächsische Kreidebecken, der deutlich die Aufschiebung des Lausitz-Blocks auf die mesozoischen Sedimente des Elbtals zeigt. Die Sedimentschichten wurden dabei überkippt. Wichtig ist das Vorkommen jurassischer Sedimente im Liegenden der kreidezeitlichen Ablagerungen. Sie sind nur im Störungsvolumen erhalten geblieben und fehlen im Untergrund des Sächsischen Kreidebeckens. Ihre Existenz und ihre Ausbildung las- sen auf eine ehemals weite Verbreitung jurassischer Sedi- mente und die Inversion eines Grabens schließen, der ur- sprünglich auf dem Lausitzer Massiv angelegt und in der Oberkreide invertiert wurde.

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was taken for interpretation for all zircons >1.0 Ga, and the

²⁰⁶

Pb/

²³⁸

U ages for younger grains. For further details on analytical protocol and data processing see Gerdes &

Zeh (2006) and Frei & Gerdes (2009).

3. Results

The U/Pb zircon ages show very similar results for the first five samples (Sk 6-2, Sk 1s, Sk 5, Sk 4-1, 3-1) repre- senting the sandstone units labiatus Sandstone (Schmil- ka Formation), Sandstone a, b, c (Postelwitz Formation), and Sandstone d (Schrammstein Formation) (Fig. 3).

The youngest concordant measurement for each sample is given in the AgeDisplay diagrams in Figure 3. For all samples, the age spectra start at ca. 300 to 330 Ma and go on more or less continuously until ca. 800 Ma. The youngest single zircon grain was found in sample Sk 5, giving an age of 258 ± 6 Ma (2 σ error). There are abun- dant (for samples Sk 6-2, Sk 1s, Sk 5, Sk 4-1, Sk 3-1) or many (sample Sk 2-2) Meso- and Palaeoproterozoic zir- con ages up to ca. 2000 to 2100 Ma. Archean ages were only found in the base of the section in sample Sk 6-2 (labiatus Sandstone, Schmilka Formation), represented by one zircon grain with an age of 2969 ± 76 Ma (2 σ error). There is only one more grain older than 2100 Ma found in sample Sk 4-1 (Sandstone c, Postelwitz Forma- tion) giving an age of 2441 ± 34 Ma (2 σ error, Fig. 3).

The most important result is the striking difference in abundance and distribution of age spectra of the Meso- and Palaeoproterozoic zircon in sample Sk 2-2 (Sand- stone e, Schrammstein Formation) compared to all other samples. The increasing number of Proterozoic ages in the upper part of the section is associated with a decrease in Palaeozoic ages (Figs. 3 and 4).

4. Interpretation and discussion

The recent geology of the Lausitz Block is dominated by early Cambrian granodiorites which intruded Late Neo- proterozoic greywackes. The age spectra of these units are well known and represent the following ages: The sedimentation age of the greywackes is assumed to be ca. 570 Ma, given by youngest detrital zircon grains and ash layers. In addition to this, the greywackes contain few detrital zircon grains of Archean ages (up to 3.5 Ga) and abundant zircons of Palaeo- and Neoproterozoic/Cadomi- an ages. Important is the lack of detrital Mesoproterozoic zircon grains in these sediments. The intruding granodi- orites are summarized as Lausitz Granodio rite Suite and

show zircon ages of ca. 540 Ma. Only the Rumburg Gra- nite with ca. 490 Ma is younger. On top of these Cadomi- an units lie Lower Ordovician shallow marine sediments represented by the Dubrau Formation (Tremadoc, ca. 480 Ma; Linnemann 2008, Linnemann et al. 2011).

The ages are different from observed ages of the Cretaceous sandstones in the Schmilka-Großer Winter- berg section. We did not find a prominent peak of ca.

540 Ma old zircon grains, as expected due to the direct neighbourhood to the 540 Ma old granodiorites of the Lausitz Block. Ages of this time were found in all sam- ples, but not with increased amounts relatively to other age groups. Nevertheless, this age group occurs both in the Variscan deformed basement of the Bohemian Massif as well as in the units of the Lausitz Block. Therefore, we conclude that these sandstones were derived from sedi- mentary units which covered the inverted Lausitz Block during the Cretaceous and were originally derived from the Bohemian Massif.

We interpret the Neoproterozoic to Paleozoic ages of all samples as the influx of reworked units of the Avalo- nian/Armorican and Variscan basement units (Hofmann et al. 2009). The youngest concordant U/Pb zircon age of 258 ± 6 Ma (sample Sk 1s, sandstone a, Fig. 3) shows that there had been magmatic activity in the uppermost Permian, maybe representing the first break-up activities of Pangea and opening of Permian basins.

— Zircons of Triassic, Jurassic and Cretaceous sandstones in Germany indicate a distinct change in source area of the Jurassic sediments compared to Triassic and Cretaceous sediments. Middle Jurassic sandstones (Dogger) show a distinct age peak in the Meso- and Paleoproterozoic ages (Hofmann et al. 2009). These ages are representative for a Baltica provenance (Hofmann et al. 2009) and correlate to the regional uplift of the North Sea Dome during the Middle Jurassic which resulted in the widespread erosion and resedimentation of Early Jurassic and Triassic sand- stones of the Northsea Basin which were originally shed from the Baltic shield.

There is no potential source area providing big amounts of zircon ages between 900 and 1900 Ma in Cen- tral Europe. Therefore it is likely, that the high amount of Proterozoic ages in the uppermost sample (Sk 2-2, Sand- stone e, see Fig. 4) derived from eroded and reworked Ju- rassic siliciclastic sediments covering the Lausitz Block at that time. The samples Sk 6-2 to Sk 3-1 were taken below Sk 2-2 (Fig. 3) and do not show this massive in- put of Proterozoic ages. They prove that Middle Jurassic deposits where not at the surface at that time. Probably, they had still been covered by younger sediments (Upper Jurassic to Lower Cretaceous). The erosion of units with the Meso-/Proterozoic age spectra started in the Conia- cian. Therefore the basement units of the Lausitz Block were not at the surface and not available to erosion dur- ing Turonian – Coniacian time (Fig. 5).

— Apatite cooling ages of the Lausitz Block (Lange et al.

2008) and of the Karkonosze Mts. (Danišik et al. 2010)

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prove an enormous Late Cretaceous uplift of the Lausitz Block ca. 50 to 85 Ma ago (Lange et al. 2008). Uplift and fast cooling happened in two stages also in the Karko- nosze Mts. at ca. 82 – 90 Ma and at 77 – 91 Ma (Danišik et al. 2010). This uplift resulted in the removal of about 3 – 4 km of overburden (estimated denudation rate of ca.

100 m/1 Ma for the Lausitz Block, Lange et al. 2008).

On the base of pebble composition close to the Lausitz Thrust and these cooling ages, Voigt (2009) concluded that eroded units were initially represented by a thick sedimentary pile of Triassic to Early Cretaceous sedi- ments which were redeposited in an upside-down suc- cession (first youngest, last oldest). As the uppermost Cretaceous sandstones show no evidence of a granodi- oritic source and most cooling ages indicate a Santonian to Campanian uplift, a much thicker primary thickness of Cretaceous sediments can be assumed.

Triassic sandstones were assumed as source for the higher parts of the Late Cretaceous succession in the Elbsandsteingebirge (Voigt 1994). But the predominance of Baltica ages (Meso-Palaeoproterozoic) in the high-

est preserved units indicates that they did not provide a significant amount of sands to the basin fill until the early Coniacian. We propose a later redeposition of Tri- assic sands. This is in agreement with cooling ages of the Lausitz Block (Lange et al. 2008) and the Karkonosze Mts. (Danišik et al. 2010) and the comparison with bet- ter preserved basins, proving a Santonian to Campanian peak of inversion tectonics.

Unfortunately, there are no younger Upper Creta- ceous sediments than Lower Coniacian left in the study area. Because of that, we can only assume that the Tri- assic and Permian sediments, lying below the Jurassic deposits, got eroded later too, and, maybe, even a part of the granodiorite of the Lausitz Block itself, in the up- permost Cretaceous. These “evidences” where probably eroded during the big Late Cretaceous to Early Palaeo- gene weathering.

Additionally, we assume regional uplift of the Lausitz and the Bohemian Massif after inversion, because most of the Cretaceous deposits of the Bohemian Cretaceous Basin had been removed before the Miocene.

Fig. 3. Section of the Elbsandsteingebirge around Schmilka (Großer Winterberg region) based on Lamprecht (1928), Tröger (in Pälchen

& Walter 2008) and own field observations. One sample of each sandstone unit was analysed. Sample points are indicated. Age- Display diagrams of all samples showing concordant U/Pb zircon ages (x-axis) versus probability and frequency (y-axis) after Sircombe (2004) are based on 1 σ errors. All measurements with a degree of concordance between 90 and 110 % were regarded as concordant and used for the diagrams. ²⁰⁶Pb/²³⁸U-ratios were used for age calculation of all ages below 1000 Ma. For older grains

207Pb/²⁰⁶Pb-ratios were used for age calculation. Youngest concordant single zircon age of each sample is given with 2 σ error.

Abb. 3. Geologischer Schnitt durch das Elbsandsteingebirge bei Schmilka (Region Großer Winterberg) basierend auf Lamprecht (1928), Tröger (in Pälchen & Walter 2008) und eigenen Geländeaufnahmen. Pro Sandsteineinheit wurde eine Probe analysiert. Die Probenahmeniveaus sind durch weißen Sternchen markiert. Das AgeDisplay Diagramm jeder Probe zeigt die U/Pb-Zirkonalter (x- Achse) aufgetragen gegen die Wahrscheinlichkeit und Häufigkeit (y-Achse), basierend auf einem 1-σ-Fehler (Sircombe 2004). Alle Messungen mit einer Konkordanz zwischen 90 und 110% wurden als konkordant angesehen und zur Erstellung dieser Diagramme genutzt. Zur Altersberechnung für Alter unter 1000 Ma wurden die ²⁰⁶Pb/²³⁸U-Verhältnisse verwendet. Für höhere Alter wurde das

207Pb/²⁰⁶Pb-Verhältnis herangezogen. Das jüngste konkordante Einzelzirkonalter für jede Probe ist angegeben (2-σ-Feh ler).

Fig. 4. Diagrams showing change in age classes (Archean, Proterozoic and Palaeozoic) for all analysed sandstones. Note the sudden increase of Proteorzoic ages in the uppermost sample (Sk 2-2, Sandstone e, Schrammstein Formation) in comparison to the five samples below.

Abb. 4. Darstellung der Veränderung der Altersklassen für alle analysierten Sandsteine. Auffällig ist die plötzliche Zunahme proterozoi- scher Alter in der obersten Probe (Sk 2-2) im Vergleich zu den fünf darunterliegenden Proben.

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5. Summary

The main results of this study can be summarized in sev- en points:

The Lausitz Block was a part of the West-Sudetic Island and covered with Triassic, Jurassic and probably Lower Creataceous sediments. It was the most probable source area for the Upper Cretaceous sandstones of the Elbtal Group.

— The determined zircon ages from the Palaeozoic to Late Neoproterozoic are interpreted as signals of reworked lo- cal material, such as the Variscan and Cadomian base- ment units and their Palaeozoic cover sequences.

— The zircon U/Pb-age spectra show a sudden input of Meso- and Palaeoproterozoic ages in the uppermost part of the Schmilka section (sample Sk 2-2, Sandstone e, Fig. 3), that can only be interpreted as reworking of si- liciclastic Jurassic material (Middle Jurassic).

— Erosion of these Jurassic sediments started not earlier than in the Coniacian (Fig. 5).

— Most zircon grains represented in this study experienced at least their second cycle of recycling during the Late Cretaceous sedimentation.

— The minor amounts of ca. 540 Ma ages in all samples confirm the Mesozoic cover of the Cadomian basement units of the Lausitz Block. The latter ones were not avail-

Fig. 5. Model of inversion and syntectonic redeposition of the Mesozoic cover of the Lausitz Block (based on Voigt 2009 and the recent study) showing sedimentation and tectonic activity along the Lausitz Thrust during the Mesozoic. Uplift of the Lausitz Block started in the lower Upper Cretaceous (Middle Cenomanian). From that time on, the Mesozoic cover of the Lausitz Block was the main source area for the sediments of the Saxonian Cretaceous Basin. Erosion of Middle Jurassic siliciclastic sediments started in the Coniacian. Older (Triassic) sediments and early Cambrian granodiorites did probably not contribute to the formation of Upper Cretaceous deposits in Saxony.

Abb. 5. Model zur Sedimentation und tektonischen Aktivität ent- lang der Lausitzer Überschiebung während des Mesozoi- kums (basierend auf Voigt 2009 und den Ergebnissen dieser Studie). Die Hebung des Lausitz-Blocks begann in der unteren Oberkreide (mittleres Cenoman). Die auflagernden mesozoischen Sedimente des invertierten Lau sitz-Blocks waren die Hauptquelle für die Sandsteine des Elbsandsteingebirges. Die Abtragung mitteljurassi- scher siliziklastischer Sedimente begann im Coniac. Äl- tere (triassische) Sedimente und der heute in der Lausitz dominierende Granodiorit trugen vermutlich nicht zur Sedimentbildung der sächsischen Oberkreide bei.

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able for erosion until at least Middle to Late Coniacian times (most probably even later).

— The presented section does not show a real inversion with Cadomian ages (mainly ca. 540 and ca. 570 Ma) of the Lausitz Block on top. According to cooling ages and compared with better preserved basins this inversion took place during the Santonian to Campanian, which is too young for the Schmilka – Großer Winterberg section.

6. Acknowledgement

We would particularly like to thank Dr. Jan-Michael Lange (Sen- ckenberg Naturhistorische Sammlungen Dresden) for various cor- rections, advises, and references that helped to improve this paper.

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Table1.LA-SF-ICP-MS U, Pb, and Th data of single zircon grains from the Upper Cretaceous sandstones of the Schmilka section (Elbsandsteingebirge). Name of the sample as well as GPS coordinates, geological formation, stratigraphic age, amount of measured zircon grains and amount of concordant (within 90 to 110% of concordance) analyses are given for each sample as first line on top of the data. — Italic/grey: discordant analyses (not in the range of 90–110 % of degree of concordance) Tabelle 1.LA-SF-ICP-MS U, Pb und Th Daten von einzelnen Zirkonen der oberkretazischen Sandsteine des Schmilka Profils (Elbsandsteingebirge). Der Probenname, die GPS Koordinaten, geologische Formation, stratigraphisches Alter, Anzahl der gemessenen Zirkone und Anzahl der konkordanten (innerhalb einer Konkordanz von 90 bis 110%) Analysen sind für jede Probe in der ersten Zeile über den jeweiligen Daten angegeben. — Kursiv/grau: diskordante Analysen (außerhalb des 90–110% Bereichs der Konkordanz) Sk 1s (Sandstone a, Postelwitz Formation, Middle Turonian) — 50° 54′ 06.7″ N; 14° 13′ 07.5″ E, measured single zircon grains: 111, concordant within 90 – 110% of concordance: 108 Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] a216879233151.1662980.055631.90.41172.60.053681.80.74349735083584098 a318147253140.3229040.057272.00.42502.50.053821.50.79359736083643499 a417190190110.678540.055933.70.41694.30.054062.00.8835113354133744694 a516084105131.3047710.102642.10.85712.80.060561.80.75630126291362439101 a6125845690.6850080.138222.11.28273.70.067313.00.5783517838218476398 a846665730.1456110.062032.20.46603.50.054492.80.623888388123916299 a960717514440.705190.081632.00.65133.40.057862.80.5750610509145256296 a1015228217120.4697010.055942.00.41382.80.053651.90.73351735283564298 a1112284177100.49136540.054552.10.40092.90.053302.10.713427342934247100 a1313431148110.3689380.078951.90.62032.90.056982.20.6649094901149148100 a1449012422320.389840.074791.90.58623.10.056842.40.634659468124855396 a1617982256150.54335750.056602.30.41993.30.053812.40.713558356103635398 a1714674157111.296540.055812.20.41207.10.053546.70.31350835021352152100 a1833982419230.348240.053522.10.39344.40.053323.80.493367337133428798 a1973965111370.68276750.303342.14.84342.40.115801.20.8717083117922018922190 a204568094250.60532100.243832.02.89722.50.086181.40.83140726138119134227105 a2111687171111.3322860.056631.90.42582.80.054532.10.67355736093934790 a2229757321280.6924560.084211.80.68822.40.059271.60.745219532105773690 a24662976491410.43106030.0614310.00.458910.10.054181.20.99384383843337926101 a252664735140.9114780.342512.45.74943.20.121742.20.7418994019392819823996 a27104466580.6445280.111332.30.94494.50.061563.80.52680156752265982103 a2823721420.778810.124422.21.10224.60.064254.10.47756157542575087101 a2921211295170.4227190.055161.90.40603.20.053392.50.613467346934657100 a3058748661.1531460.056082.00.41413.90.053553.30.5335273521235274100 a3167876350.1521030.089193.00.71734.30.058323.10.70551165491854267102 a3260099050.4531500.058492.30.43693.40.054162.50.673668368103785697 a3327608281260.4749870.091072.40.74772.80.059541.60.8456213567125873496 a3511322171100.49124480.057221.90.42382.70.053722.00.683596359835945100

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Table 1 — Sk 1s (Sandstone a, Postelwitz Formation, Middle Turonian) continued. Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] a363519660190.7957070.299383.64.42493.80.107201.40.9316885317173217522596 a3747847251.5689170.056902.00.42143.30.053712.70.593577357103596199 a3844295930.2015040.057192.30.42353.90.053703.20.5935983591235971100 a4021425104110.6128680.101372.11.05753.20.075662.40.66622137331710864957 a4156891231.0614960.201922.52.18283.70.078402.80.67118627117626115755102 a421042811170.83197560.056012.00.41433.20.053652.50.643517352103565599 a4317671196120.6768070.056792.90.42033.30.053681.60.88356103561035835100 a44124311030.9017250.298013.14.05154.10.098602.60.77168146164534159849105 a4772306440.6353980.060513.00.45184.00.054162.60.75379113791337859100 a4920094130100.81105880.071031.90.54582.40.055731.40.794428442944232100 a501792913080.2686070.064012.10.48262.80.054681.80.754008400939941100 a5172599333120.331700.029684.30.23226.00.056724.10.721898212114819139 a52146956940.137080.061143.10.458310.20.054369.70.31383123833338621899 a5354144301150.432370.048592.20.35284.60.052664.00.473067307123149297 a547236541180.87611270.391021.96.41012.20.118901.10.87212834203419194019110 a55206427570.6957630.085681.90.68073.40.057622.90.55530105271451563103 a5796125641.10176840.061991.90.46423.20.054312.60.6038873871038458101 a5810326042170.8689330.356952.05.74562.30.116741.00.90196835193820190717103 a59202717150.08136740.080691.90.63734.00.057293.50.4850095011650376100 a6067033531.9316330.065692.20.50113.10.055322.10.734109412104254696 a6270273421.18128490.063392.10.47723.90.054603.30.5339683961339675100 a6365781730.329560.171192.41.66193.50.070412.60.681019239942294052108 a65298957250.227420.076905.20.59966.20.056553.30.84478244772447473101 a66105644430.25195760.061072.40.45553.00.054101.80.7938293811037541102 b242987650.708960.056982.60.42094.00.053583.10.6535793571235369101 b348296184300.06140760.171342.31.68922.60.071501.20.8910192210041797225105 b443002140300.40521150.209172.22.35042.60.081491.30.8612242512281912332699 b543619416350.3726530.082332.40.64943.30.057212.20.75510125081350047102 b640464185340.67563970.172592.31.67293.00.070301.90.771026229981993739110 b712801204120.22235600.060042.40.44373.20.053602.00.7737693731035445106 b819599352190.23118250.056322.40.41614.40.053583.70.5435383531335383100 b975797780.7031270.102852.70.85906.10.060575.50.446311663029624118101 b1096237280.07100750.125713.11.10153.90.063552.30.80763237542172750105 b1316392160110.354600.064802.90.489310.30.054769.90.284051140435403222101 b1527243317270.20152870.090012.20.71222.90.057381.80.78556125461250640110 b1658077550.2314890.064653.30.49164.90.055143.60.6740413406174188197

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Table 1 — Sk 1s (Sandstone a, Postelwitz Formation, Middle Turonian) continued. Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] b1729449217280.61452560.123862.31.08913.30.063782.40.69753167481873451103 b1824206196281.8914520.119113.31.02944.70.062683.30.70725237192469771104 b1916395265170.7327600.059582.40.44634.50.054323.90.533739375143858797 b2065001119481.99142470.307692.24.26972.50.100641.20.88172934168821163622106 b2126419447260.5624650.055982.20.41503.80.053763.10.573517352113617097 b22116528210720.89116150.309562.44.30472.60.100851.10.91173936169422164020106 b24694313080.6320440.057632.50.42984.00.054093.10.633619363123757096 b251077395102.124830.071972.60.54977.80.055397.40.334481144528428164105 b2651029467560.4653030.121153.01.04813.20.062751.00.95737217281770022105 b2711579239140.92214070.054772.30.40443.20.053562.10.74344834593524898 b2864355670.8119860.114192.60.97573.60.061972.50.72697176911867353104 b2924865131.1912000.056952.70.42325.60.053894.90.49357103581736611097 b30612711480.7387140.061522.90.46196.10.054465.40.48385113862039012099 b3147114450.4877730.102992.60.84614.00.059582.90.67632166221958864107 b3217813176150.269610.088822.30.71134.00.058083.30.56549125451753373103 b3317231245181.084410.067002.60.51105.50.055324.90.46418104191942510998 b36725913280.3324310.062182.30.46573.10.054322.10.7438993881038447101 b3712672112130.9177810.105312.50.88563.90.060993.00.63645156441963965101 b3831886455290.4124720.062542.20.46683.50.054132.70.6339183891137762104 b3911016189110.4836670.057352.20.42284.10.053473.40.5436083581234977103 b4010963117121.9833050.085702.20.67903.20.057462.40.68530115261350952104 b411312694121.20210810.109842.30.92662.90.061181.80.79672156661464638104 b421097710590.8920150.082662.40.65773.20.057712.20.7451212513135194899 b4367693740.9440720.087982.70.69863.90.057592.70.71544145381651460106 b4421435283160.62118040.055742.20.40992.50.053331.30.873508349834329102 b4623982198170.4022890.085892.60.68613.80.057932.80.69531135301652760101 b4717831208120.35327500.059852.40.44363.30.053762.20.7437593731036150104 b4846668040.8189550.040802.10.28883.20.051332.40.662585258725655101 b491766915490.4518280.056442.60.41914.90.053864.20.533549355153659497 b5064697252.14120130.054492.30.39863.30.053052.30.7134283411033152103 b5120305184100.4711640.051722.10.37914.20.053173.60.503257326123368297 b5236046354190.23668530.056282.20.41292.80.053221.70.803538351833838104 b5379637440.5534740.058292.40.43553.30.054182.30.723658367103795196 b5459562830.8417200.100142.30.85063.40.061602.50.6861514625166605393 b55124369160.0211400.071582.60.55026.70.055746.20.394461144524442137101 b5736980304160.17681520.057142.30.42002.80.053311.70.813588356934237105

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Table 1 — Sk 1s (Sandstone a, Postelwitz Formation, Middle Turonian) continued. Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] b582105312980.21376250.063332.50.48352.70.055361.20.90396940094272793 b591331712260.208200.054073.30.39676.20.053225.20.543391133918338118100 b6074695340.686180.063102.20.47885.60.055035.20.3939483971941311695 b616178641130.73107120.289842.44.37762.60.109541.00.9216413417082217921992 b62117223940.82186940.106812.50.90454.00.061423.20.61654156542065469100 b6331154145121.0410130.071853.40.55744.40.056262.80.7744715450164636197 b6490146241.33167080.055642.30.40743.00.053111.90.773498347933443105 b6564004220.57117810.056102.80.41443.50.053582.20.783529352113545099 b66205517270.7330690.084292.80.67043.90.057682.70.73522145211651859101 Table 1 — aSk 2-2 (Sandstone e, Schrammstein Formation, Lower Coniacium) — 50° 54′ 32.9″ N; 14° 14′ 33.4″ E, measured single zircon grains: 120, concordant within 90 – 110% of concordance: 59 Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] a14331310.928360.047973.70.347612.70.0525612.20.29302113033431027898 a223935140.9541300.060913.50.49006.30.058345.20.55381134052154311570 a340808650.2467990.051483.60.42758.90.060228.10.40324113612761217653 a49367151110.12164020.077703.50.61745.40.057634.10.6548216488215169094 a544329260.3315790.058113.90.53104.80.066272.80.8136414432178155945 a647663650.895940.099693.61.498936.50.1090536.40.1061321930251178466334 a73683996290.2755420.285934.63.86115.30.097942.50.88162167160643158547102 a81790997180.20169700.184183.31.91924.10.075582.50.80109033108828108450101 a9864118990.28132010.046604.00.42917.00.066795.70.58294123632283111935 a108190137120.4816330.081385.00.67436.80.060104.70.73504245232860710183 a1145278070.2523450.086713.20.70855.90.059264.90.54536165442557710793 a12416410860.3067470.055773.90.42045.70.054674.20.6835013356173999388 a1312024195150.2033650.078494.30.63005.20.058213.00.8248720496215386591 a143863168270.31125680.370452.46.47203.60.126712.70.6720324320423220534799 a1565648290.7212400.091535.50.78986.60.062593.60.8356530591306947781 a1623706040.1619480.063373.70.51258.10.058657.20.45396144202855415871

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Table 1 — aSk 2-2 (Sandstone e, Schrammstein Formation, Lower Coniacium) continued. Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] a17607116690.3081060.052083.40.39214.70.054603.30.7232711336143967383 a1871867294710.3972030.223112.62.58493.00.084031.40.88129831129622129328100 a1928878650.1850950.059814.20.47296.70.057345.30.62374153932250511674 a20520812570.0322630.060404.30.50017.20.060055.80.60378164122560512562 a2135357150.1414290.063704.20.65567.70.074656.50.543981651232105913138 a222186366220.51220240.296452.84.12974.40.101033.30.65167442166036164362102 a2372921970.7069220.314632.24.61914.60.106484.00.49176335175339174073101 a2432836105330.3998290.288684.33.99294.80.100322.10.90163563163340163039100 a25895621.5211940.184964.61.93569.50.075908.20.491094471093651092165100 a266318122100.1637330.080135.80.66016.70.059753.40.8649728515275947484 a2711173170150.359350.083355.90.80126.20.069721.90.9551629597289203956 a2873061236680.1137510.287372.74.01904.00.101432.90.6816283916383316505499 a292739591300.3087620.314675.24.66827.70.107605.70.671764801762661759103100 a3013114106200.2823670.178973.91.76695.30.071603.60.7310613810333597574109 a3130738370.4954780.077404.30.60447.00.056635.50.624812048027477121101 a3219391495240.087140.049643.10.45425.50.066364.50.5731210380188189438 a3321997340.3940490.058114.70.44127.00.055075.20.67364173712241511788 a3440406170.4365480.111245.40.95857.40.062495.00.73680356833769110798 a355490101100.2213570.094926.40.86797.60.066324.00.8558536634368178472 a3625085960.1342670.097055.20.79646.90.059524.60.75597295953158699102 a3710983188180.2334160.096454.30.86366.50.064944.90.66594246323177210377 a389072520.5016730.062016.40.46709.70.054627.40.65388243893239716698 a3929969469450.478760.081593.70.79726.00.070864.70.6150618595279539753 a40406110870.1819390.061594.30.50447.50.059406.10.57385164152658213366 a4118486330.7834330.038956.70.293710.40.054697.90.65246162612440017762 a4238634860.9125020.093538.70.73819.50.057233.80.92576485614250184115 a436685169100.2655360.056734.20.42695.30.054573.20.8035615361163957190 a442158550160.28210410.300196.84.31989.30.104376.30.731692101169779170311699 a4515798227190.173190.084674.40.70167.50.060106.00.60524225403260713086 a4658053660.4281940.165294.91.63446.10.071713.60.80986459843997874101 a477494166100.28137520.057245.00.43489.10.055107.50.56359183672841616886 a4835557850.4228600.056465.60.41777.20.053654.50.78354193542235610299 a4921624210.1238730.0311812.40.242314.50.056367.50.85198242202946716642 a5028912630.3219160.109184.70.93498.00.062106.50.58668306704067813999 a51531500.192970.089814.20.862316.80.0696316.20.25554236318291833360 a52108855570.292610.100482.51.469015.60.1060315.40.166171591899173228236

(15)

Table 1 — aSk 2-2 (Sandstone e, Schrammstein Formation, Lower Coniacium) continued. Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] a5386849770.293270.064276.50.79898.30.090155.20.784022559638142910028 a54529610.896460.064105.30.720925.80.0815725.30.2040020551116123549632 a5518165170190.0165440.123604.51.06796.20.062664.30.72751327383369792108 a5647983950.3922610.113038.80.894411.30.057397.10.786905864956506157136 a5731634630.5746820.065398.10.616112.50.068339.50.65408324875087919846 a581501824100.4858520.379626.55.52567.90.105574.40.832075117190570172480120 a5950097930.2921020.040726.60.34309.60.061097.00.69257172992564215040 a6053195540.1193650.079564.60.63256.60.057664.70.70494224982651710496 b112976030.1723610.045116.50.34489.50.055436.90.68284183012543015466 b2188811550.5136000.041883.00.30585.90.052945.10.5126582711432611581 b314475362310.2515470.084785.40.73696.80.063034.20.7952527561307099074 b45196259140.0397280.059343.20.44344.50.054203.20.7137211373143797198 b515760463300.414110.056173.50.79004.60.102013.00.77352125912116615521 b615633650.6721000.112413.00.96866.10.062495.30.50687206883169111399 b7520059100.3270820.164945.71.68876.90.074263.90.829845210044510487894 b817957550.2028980.061573.80.53115.50.062564.10.6838514433206938756 b9247513970.3446020.050423.30.37675.70.054194.60.58317103251637910484 b1036685480.2550630.150765.01.52006.90.073134.80.72905429384310179889 b114163193120.1714140.064064.70.55526.80.062865.00.68400184482570310657 b12651895180.2392420.181514.71.80006.20.071924.10.7510754710454198483109 b139636840.3420500.049577.70.327011.60.047848.70.66312242872992205340 b146635408190.1311330.047707.20.420011.50.063868.90.63300213563573718941 b154223264150.2326420.056016.10.41427.40.053634.10.8335121352223569499 b16519558140.5063550.212185.42.39517.40.081875.10.731240611241551242100100 b17237011780.1140380.069603.70.56966.40.059355.20.59434164582458011275 b185252820.099340.073756.20.585316.10.0575614.90.39459284686251332789 b19668372200.3115170.278665.33.33306.60.086754.00.80158575148953135577117 b2016578850.2325420.056645.20.52109.70.066728.20.53355184263482917143 b2124247870.1717140.087455.50.73518.20.060976.10.67540295603663813085 b223395143130.2757200.092676.90.75798.60.059315.10.81571385733857811099 b235163259230.1385320.094186.80.78278.20.060274.70.82580385873761310195 b24978841.9810530.287967.83.783510.90.095297.60.7216311141589911534143106 b251380783340.1064450.412996.26.91557.30.121453.90.842229118210167197870113 b261997170100.2837560.057404.90.42807.10.054075.20.69360173622237411696 b2719577490.6030090.099777.90.89479.70.065045.70.81613466494877612079 b284682196270.5677730.123514.41.03755.60.060923.40.78751317232963674118

(16)

Table 1 — aSk 2-2 (Sandstone e, Schrammstein Formation, Lower Coniacium) continued. Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] b295280234220.3537020.085257.00.73628.60.062635.00.82527365603869610676 b3014722160.476090.238404.42.77268.50.084357.30.511378551348661301142106 c1784659110.36110960.174961.91.73153.30.071782.70.5810391810202298055106 c212985242210.27226680.083422.10.66593.00.057892.10.6951710518125264798 c325677540.4148590.055732.00.40814.50.053114.00.4535073481333491105 c4820260120.64114430.179081.81.79173.00.072562.40.59106217104220100249106 c56304167110.3328480.060492.20.49553.50.059412.70.623798409125825965 c61040728110.98102860.308131.84.35452.80.102502.10.66173128170423167039104 c741954560.1764690.138012.01.24944.20.065663.70.48833168232479677105 c8117344980.3233890.125362.32.39093.70.138322.90.637611712402722065035 c9692743100.3594660.212951.22.17433.20.074052.90.39124514117322104359119 c1013461414210.10203600.053132.10.39232.90.053562.10.72334733683524795 c1131594461.1838020.105731.40.89164.10.061163.90.3564896472064583100 c1250052184580.6448930.269903.33.64895.20.098054.00.6315404515604215877697 c1358109262690.2923250.252662.43.14772.80.090361.60.84145231144422143330101 c1434693350.6552370.142243.21.30865.80.066734.80.568572685034829101103 c1565132570.2974540.257981.83.15183.80.088613.30.48147924144530139663106 c161669610.2917530.212683.12.84157.50.096906.80.42124335136758156512879 c17875238100.50101940.237892.02.84823.50.086832.90.58137625136827135756101 c1833920104320.8845410.231153.43.29293.80.103321.70.9013414114793016853180 c191529351181.09168280.269491.23.41842.40.092002.10.49153816150919146740105 c207514112120.2949760.102792.30.85054.10.060013.40.57631146251960473104 c2185637990.852010.081772.51.594111.40.1413911.20.225071296874224419323 c2241568117380.32410000.304011.74.29302.20.102421.30.80171126169218166824103 c231191734120.64121420.299252.34.10153.40.099412.50.67168834165528161346105 c2450746380.7184410.109012.00.91923.00.061152.20.68667136621564547103 c2530928960.4957670.059482.40.44774.10.054593.30.593729376133957594 c2642219560.348800.055282.30.52746.70.069206.30.3434784302490512938 c273240883300.4974730.314522.14.57253.10.105442.20.70176333174426172240102 c281060342110.36120260.242922.72.98983.90.089272.80.6814023414053014105499 c29895483120.30134250.144001.21.33972.70.067482.50.4386798631685251102 c30698710.6610260.118333.11.13317.00.069456.20.44721217693891212979

(17)

Table 1 — Sk 3-1 (Sandstone d, Schrammstein Formation, Lower Coniacium) — 50° 54′ 31″ N; 14° 14′ 16.5″ E, measured single zircon grains: 115, concordant within 90 – 110% of concordance: 46 Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] a1201512260.5138070.048953.90.35356.80.052385.60.573081230718302127102 a225831550.7126740.298363.84.05126.40.098485.20.59168356164553159696105 a36448251180.41111930.072282.20.57863.40.058052.60.6645010464135325685 a421079770.5938370.068662.50.52394.70.055344.00.52428104281742690101 a54422310.567970.054314.50.41829.10.055858.00.49341153552844617776 a6300313570.269640.051083.40.48397.50.068706.70.45321114012589013836 a814874950.5624790.090383.00.74335.50.059644.60.54558165642459110194 a911006330.4321110.051353.30.37186.50.052515.60.513231032118308127105 a118250404210.4519970.050002.10.43716.50.063406.10.3331573682072213044 a12242110670.3213380.069703.20.57376.80.059705.90.48434144602559312973 a1310656340.5820690.054991.80.39305.40.051835.10.33345633715278116124 a1413048140.5523040.052862.20.37885.40.051975.00.40332732615284114117 a159865530.6918250.041593.70.31188.60.054377.70.44263102762138617368 a16353294121.2659060.107982.80.91945.30.061754.50.5366118662266669699 a17168610160.9914760.053503.60.40346.40.054695.40.56336123441940012084 a18263815480.3129660.055582.00.41224.70.053794.30.433497350143629696 a1914926940.447480.055894.20.523010.70.067869.80.39351144273886420341 a201545283420.91119140.464346.47.20129.70.112487.20.6724591332137901840130134 a2121176540.303010.060654.30.723813.30.0865612.50.333801655358135124228 a225727202120.272820.052902.20.73653.30.100972.50.6633275601416424620 a233398128100.4134400.076524.50.60456.20.057304.30.7247520480245039594 a2413878250.5724970.053832.10.42106.90.056726.60.3033873572148114570 a258035331.6815360.049692.90.36066.70.052636.00.43313931318313137100 a2615818050.4223990.057233.00.529410.40.067089.90.29359114313784020643 a2727547981.2012700.089933.30.88725.10.071553.90.6555518645259737957 a2812567440.6822620.056602.30.41715.10.053454.50.45355835415348103102 a2919118060.318490.075402.60.592010.90.0569410.50.24469124724248923396 a308072630.4813370.094412.60.78368.30.060197.90.31582155883861117195 a314145263140.4834320.053631.80.42146.60.056986.40.2733763572049114069 a32238513090.3541920.072763.00.58086.80.057896.10.44453134652652613586 a334694242180.1377170.077894.10.62236.80.057955.40.60484194912752811992 a343735183120.2620650.068712.70.52923.70.055862.50.7342811431134475696 a352901196110.3512670.056362.90.41497.30.053396.70.393531035222345153102 a366253921.1910700.053962.80.43808.20.058877.70.3433993692656216860 a378765230.5215590.049494.60.37988.30.055667.00.55311143272443915571 a38196911781.8036570.051783.20.38735.70.054244.70.56325103321638110685

(18)

Table 1 — Sk 3-1 (Sandstone d, Schrammstein Formation, Lower Coniacium) continued. Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] a3911541580300.1329850.054603.10.45136.10.059965.30.51343103782060211457 a40949948160.4894660.329603.44.59274.50.101062.90.76183655174838164454112 a414161144110.1175150.079892.30.61474.70.055804.10.49495114861844491112 a424839161120.1988040.077623.80.59335.80.055434.40.65482184732243099112 a444771810.018100.060462.80.495312.90.0594112.60.22378104094458227365 a45478614180.215310.053653.00.58996.60.079735.90.453371047125119011728 a46489388100.6581450.103812.50.86723.40.060592.30.73637156341662550102 a478001220.9812800.113493.00.98217.40.062766.80.40693206953870014599 a4821307140.5713910.058122.30.46744.90.058334.30.473648389165429567 a4915044930.7721060.061523.40.47709.30.056238.70.37385133963146219283 a5012474220.1324910.058513.10.40896.00.050685.20.513671134818227120162 a5120345330.1113430.059912.50.543010.80.0657410.50.2337594403979822047 a5227498240.0751460.055462.40.41114.80.053764.20.503488350143619496 a5314844430.5016070.057273.30.42335.30.053614.10.62359113581635493101 a5423688140.1448440.050083.80.348415.20.0504514.70.253151230441216341146 a5513123320.0923730.060483.40.46545.30.055824.00.6537913388174458985 a56360410360.3665840.054714.20.41509.80.055028.80.43343143523041319783 a5743535440.139690.078407.80.759123.10.0702321.70.344873757310793544652 a5831121240.4221210.322693.83.89806.30.087614.90.61180361161352137495131 a5933044250.4653100.110053.10.95535.30.062964.30.5967320681277079295 a60821141101.2845380.197054.32.11016.10.077674.30.71115946115243113885102 b12086161251.5459580.316112.84.73993.20.108751.50.89177144177427177927100 b236544193500.39244100.251913.33.04203.80.087581.90.87144843141830137336105 b325281031.5327390.251282.83.23635.80.093415.10.4814453614664614969697 b45713165100.3211530.060512.30.56823.30.068112.30.703799457128724843 b56348244130.0951830.055054.40.40636.80.053535.20.64345153462035111798 b7282610250.0352990.058703.40.43645.50.053934.30.62368123681736898100 b86155175130.50112000.071242.20.54433.10.055412.20.7044494411142950103 b922487950.4819000.059302.80.51117.80.062507.30.35371104192769115554 b1026556250.5045780.078432.20.63533.80.058743.10.5948711499155586787 b11838945121.0792470.228902.92.89063.80.091592.50.7613293513792914594891 b1212894830.1624240.056182.70.41755.70.053915.10.4735293541736711496 b137672298150.2922100.051483.10.42025.10.059204.10.6032410356165748956 b145570150120.1394010.082202.30.68634.60.060553.90.5150911531196238582 b15253310760.6826170.056512.60.42847.20.054986.70.3635493622241115086 b165909117110.3098650.098142.90.81753.80.060422.50.7660317607186195398

(19)

Table 1 — Sk 3-1 (Sandstone d, Schrammstein Formation, Lower Coniacium) continued. Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] b17357715080.3034360.051123.00.40004.80.056753.70.633219342144828267 b1829486240.603700.060293.40.738211.90.0888111.30.293771356152140021727 b1914331202220.0793080.113704.41.11265.40.070973.00.8269429759299576273 b2023379971.1616280.056613.30.42065.80.053884.80.57355113561836610897 b21328014780.3256670.052582.40.38384.10.052933.40.5833083301232676101 b2228286113390.08114340.359402.24.97673.60.100432.80.61197937181530163252121 b23424712390.1510580.071722.40.58777.00.059436.60.34447104692758314377 b24238510350.0329520.055162.70.40584.60.053353.70.6034693461434483101 b2610914930.996080.053403.70.391410.10.053179.40.373351233529336213100 b2711084630.5612940.053222.90.38935.90.053065.10.49334933417331116101 b28305813380.8555170.052922.40.40824.30.055943.60.553328348134508074 b2947438380.443080.084233.21.20815.50.104024.50.59521168043116978231 b308814020.794960.057402.90.42715.50.053974.60.54360103611737010397 b313843177100.3772150.055612.20.41263.90.053813.20.563497351123637396 b3222505650.2638070.091242.60.75025.40.059634.70.49563145682459010195 b336116291160.3563590.053882.70.40483.70.054482.60.723389345113915887 b344809112110.2780990.102872.00.84983.20.059912.50.62631126251560054105 b355112254130.1335540.053965.50.41056.80.055174.00.8033918349204199081 b361225461210.89117580.312632.44.52513.30.104982.20.73175437173628171441102 b371653575260.51132370.334032.34.75733.10.103302.10.73185837177727168439110 b384557201110.1952870.055563.10.40954.40.053463.20.69349103491334971100 b39776245180.4484030.393912.35.07114.50.093373.80.52214142183139149572143 b4020978240.3418090.055733.10.41095.40.053474.40.58350113501634999100 b41432312790.3076890.074593.30.58383.90.056762.20.8346415467154824996 b426522113100.463150.079842.21.12906.70.102566.30.334951176737167111730 b43321312070.4459720.060021.60.44953.90.054323.50.413766377123847998 b4428499650.3517130.056052.40.47808.20.061867.80.2935283972766916853 b45559711790.1421530.078773.60.69185.20.063703.70.7048917534227327967 b4622797540.4511430.051452.70.38785.00.054664.20.533238333143999581 b4717257430.5931650.040713.10.30876.70.055006.00.4625782731641213462 b48144493050.9011510.124055.22.31426.50.135303.90.807543712174721686835 b49399311360.3846560.051332.50.41245.10.058274.50.483238351155409960 b5043846860.8210190.079102.60.83824.50.076863.70.57491126182111187544 b5153328160.514780.067852.80.81654.80.087273.90.58423126062213677631 b5211903120.6619490.054863.10.40595.00.053664.00.6134410346153579096 b5414812520.4427040.083852.80.64065.60.055414.80.505191450322429107121

(20)

Table 1 — Sk 4-1 (Sandstone c, Postelwitz Formation, Upper Turonian) — 50° 54′ 31.5″ N; 14° 14′ 17.1″ E, measured single zircon grains: 116, concordant within 90 – 110% of concordance: 67 Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] a16883321.2710930.049793.60.36848.20.053667.40.43313113182335716788 a2285713770.1147160.055832.80.41324.70.053673.80.6035010351143578598 a314426940.2727220.054663.10.40055.50.053144.50.573431034216335102103 a515137340.2028320.057782.90.42645.20.053524.30.55362103611635198103 a68152920.6612970.076353.60.58097.30.055186.40.494741646528420143113 a7873441150.8285750.306703.24.31164.30.101962.80.75172449169636166052104 a83326175100.3462080.056962.70.42214.50.053743.60.593579358143608299 a9233311170.2139520.062642.40.51155.30.059224.70.4539294191857510268 a10304815990.2257280.056403.00.41495.00.053363.90.61354103521534489103 a1110745241.0218650.063492.50.50469.10.057658.70.28397104153151619277 a125787191170.1298860.095562.70.77874.10.059103.10.65588155851857167103 a1312386640.8719360.058012.20.41996.00.052495.60.37364835618307126118 a1410665641.1520480.057803.50.41887.80.052566.90.453621235524310158117 a155799154140.2553430.091163.10.75354.20.059952.80.7556217570186026093 a1615027440.0727850.056643.40.42225.80.054064.60.59355123581837410595 a1733722115460.57106660.358054.06.43554.70.130362.40.8619736920374221034394 a1817789750.4316070.054893.70.40316.30.053265.10.593441234418340115101 a1910220565270.1312990.049633.20.42627.30.062286.50.44312103602268413946 a2035034990.5050680.171433.21.63774.60.069283.30.701020319852990767112 Table 1 — Sk 3-1 (Sandstone d, Schrammstein Formation, Lower Coniacium) continued. Isotope ratioscAges 207PbaUbPbbTh/Ub206Pb/204Pb206Pb/238Uc2σ207Pb/235Uc2σ207Pb/206Pbe2σRhod206Pb/238U2σ207Pb/235U2σ207Pb/206Pb2σconc Number[cps][ppm][ppm][%][%][%] [Ma][Ma][Ma][Ma][Ma][Ma][%] b5521705330.0339370.057312.60.43874.80.055514.00.543599369154339083 b5620825330.2017310.055163.20.42446.50.055815.60.49346113592044512678 b5728344340.3148590.082303.60.66996.00.059034.80.60510185212556810490 b5826876840.5852030.059382.00.42854.60.052344.20.4337273621430095124 b5947556960.5221580.083882.90.69956.00.060485.20.49519155392562111384 b6014613121.0625140.052623.80.41687.90.057456.90.48331123542450915265