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High-resolution Campanian-Maastrichtian carbon and oxygen stable isotopes of bulk-rock and skeletal components: palaeoceanographic and palaeoenviron-mental implications for the Boreal shelf sea

Wilmsen M., Niebuhr B.

Acta Geologica Polonica

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2017

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Vol. 67, no. 1

47--74

EN

A high-resolution latest Early Campanian to Early Maastrichtian carbon and oxygen stable isotope record from the northern German Boreal shelf sea based on 537 analyses of co-occurring belemnites, brachiopods, inoceramids, oysters, and bulk rock samples is presented. All samples are precisely related to their stratigraphic, systematic and facies backgrounds and form an integrated, nearly 10-myr-long dataset with considerable palaeoenvironmental and palaeoceanographical implications. Petrographic studies indicate that low-magnesium calcitic coccoliths and calcispheres (i.e., planktic carbonate) predominate the bulk-rock data (marl-limestone rhythmites and chalks), thus representing a sea-surface water signal, and that only minor diagenetic alteration of the carbonate muds took place. Based on TL and CL microscopy, the investigated belemnites are extraordinarily well preserved, which may in part be explained by their early diagenetic surficial silicification (container effect), while the other macroinvertebrate groups are all less well preserved. The (plankton-dominated) δ13C values of the marl-limestone rhythmites and chalks (+1.1 to +2.5‰), recording a surface water signal, compare well with the δ13C data of inoceramids while δ13C brach.values (+1.5 to +3.0‰) are heavier than the bulk rock data. The large variation in the δ13Cbel. (-0.1 to +3.6‰) is attributed to isotopic disequilibrium of the biogenic carbonate formed by the belemnite animal. The bulk rock δ18O values show a remarkable low scatter, supporting petrographic observation of only minor diagenetic stabilisation/cementation, and can be approximated with northern German shelf sea-surface temperatures of ca. 20°C for the Late Campanian (ca. -2‰ δ18O), being slightly cooler during the Early Maastrichtian. The δ18O values of the belemnite rostra are even less variable and quite rich in heavier 18O (-0.7 to +0.6 with a mean of -0.1‰ δ18Obel.) in comparison to bulk rock and other skeletal components. Based on their excellent microstructural preservation and non-luminescence, we conclude that the belemnite rostra are diagenetically unaltered and have preserved the primary δ18O signal of ambient seawater (12±2°C). In the absence of any indication for migration from cooler water masses and evidence for authochtonous populations we assume that the belemnites of the genera Belemnitella and Belemnella lived as nektobenthos near the sea-floor and thus record the temperature of the bottom mixed layer of the seasonally weakly stratified north German shelf sea at water depths of 100 to 150 m; the temperature gradient was thus 12.5–18.75 m/1°C. A conspicuous latest Campanian cooling event is evident in both sea-surface and bottom-water temperatures. The δ18O values of nearly all investigated benthic fossils lie between the isotope values of pristine belemnites and bulk rock, and, therefore, should be used for palaeotemperature reconstructions only with great care.

2

Luminescence Dating of Fluvial Deposits from the Weser Valley, Germany

Roskosch J., Tsukamoto S., Frechen M.

Geochronometria

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2015

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Vol. 42, no.1

126--138

EN

Luminescence dating was applied on coarse-grained monomineralic potassium-rich feldspar and polymineralic fine-grained minerals of five samples derived from fluvial deposits of the River Weser in northwestern Germany. We used a pulsed infrared stimulated luminescence (IRSL) single aliquot regenerative (SAR) dose protocol with an IR stimulation at 50°C for 400 s (50 μs on-time and 200 μs off-time). In order to obtain a stable luminescence signal, only off-time IRSL signal was recorded. Performance tests gave solid results. Anomalous fading was intended to be reduced by using the pulsed IRSL signal measured at 50°C (IR50), but fading correction was in most cases necessary due to moderate fading rates. Fading uncorrected and corrected pulsed IR50 ages revealed two major fluvial aggradation phases during the Late Pleistocene, namely during marine isotope stage (MIS) 5d (100 ± 5 ka) and from late MIS 5b to MIS 4 (77 ± 6 ka to 68 ± 5 ka). The obtained luminescence ages are consistent with previous 230Th/U dating results from underlying interglacial deposits of the same pit, which are correlated with MIS 7c to early MIS 6.

3

Latest Campanian to Early Maastrichtian (Cretaceous) nautiloids from the white chalk of Kronsmoor, northern Germany

Wilmsen M., Esser K. J.

Acta Geologica Polonica

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2004

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Vol. 54, no. 4

489-498

EN

A well preserved and stratigraphically tightly constrained nautiloid fauna consisting of two species is described from the uppermost Campanian to Lower Maastrichtian white chalk section of Kronsmoor, northern Germany. Cymatoceras patens (KNER, 1848) occurs rather frequently in the Kronsmoor section; one specimen is from the Upper Campanian Micraster grimmensis/Cardiaster granulosus Zone, one from the upper Belemnella pseudobtusa to lowermost Belemnella obtusa Zone. The bulk of the material (nine specimens) is from the Early Maastrichtian B. obtusa and Belemnella sumensis zones. The species is known from the Upper Campanian to Lower Maastrichtian of northern Germany, The Netherlands, Poland, the Ukraine, and possibly Denmark. Cymatoceras loricatum (SCHLUTER, 1876) occurs in Kronsmoor (four specimens) in an interval comprising the Early Maastrichtian upper B. obtusa to B. sumensis zones.The species was hitherto only recorded from the uppermost Lower and Upper Campanian of Westphalia and Lower Saxony, Germany. Both species appear to be restricted to the Central European Subprovince of the temperate North European Province (Boreal Realm).

4

Early Late Campanian ammonite fauna from Busko Zdrój (Nida Trough, southern Poland)

Machalski M., Kennedy W. J., Kin A.

Acta Geologica Polonica

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2004

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Vol. 54, no. 4

447-471

EN

Sixteen ammonite taxa are recorded from four temporary exposures of lower Upper Campanian deposits in the town of Busko Zdrój, NE limb of the Nida Trough, southern Poland. These are: Phylloceras (Neophylloceras) cf. bodei, Tetragonites obscurus, Desmophyllites sp., Pachydiscus (Pachydiscus) subrobustus, P. (P.) cf. subrobustus, Hoplitoplacenticeras (Hoplitoplacenticeras) dolbergense, H. (H.) sp., H. (Lemfoerdiceras) lemfoerdense, Glyptoxoceras cf. retrorsum, G. sp., Lewyites elegans, Pseudoxybeloceras (Pseudoxybeloceras) riosi, Ps. (Ps.) sp. juv., Baculites sp., Scaphites gibbus, and Trachyscaphites spiniger spiniger. Many specimens lack precise provenance data, but co-occurrence of T. obscurus, P. (P.) subrobustus, H. (H.) dolbergense, H. (L.) lemfoerdense, Ps. (Ps.) riosi, Baculites sp., S. gibbus, and T. s. spiniger is documented from a single opoka bed in one of the exposures.The ammonites allow correlation with standard sections in northern Germany: the ammonite-bearing sequence of Busko Zdrój corresponds to a part of the interval from the basiplana / spiniger to roemeri zones in Lńgerdorf and Kronsmoor (Schleswig-Holstein), and from the stobaei / basiplana to vulgaris / stolleyi zones in the Lehrte West Syncline (Lower Saxony). It can also be correlated with the lower part of the Neancyloceras phaleratum Zone in Vistula valley, central Poland.

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Late Campanian and Early Maastrichtian ammonites from the white chalk of Kronsmoor (northern Germany) - taxonomy and stratigraphy

Niebuhr B., Esser K.

Acta Geologica Polonica

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2003

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Vol. 53, nr 4

257-281

EN

Hypophylloceras (Neophylloceras) velledaeforme (Schluter, 1872), Anagaudryceras lueneburgense (SCHLUTER, 1872), Saghalinites wrighti BIRKELUND, 1965, Pachydiscus (Pachydiscus) neubergicus (VON HAUER, 1858), Menuites cf. wittekindi (SCHLUTER, 1872), Diplomoceras cylindraceum (DEFRANCE, 1816), Baculites vertebralis LAMARCK, 1801, Baculites knorrianus DESMAREST, 1817, Acanthoscaphites tridens (KNER, 1848), and Hoploscaphites constrictus (J. SOWERBY, 1877) are described for the first time from Kronsmoor, the only continuous Campanian-Maastrichtian boundary succession of northern Germany. Combined with the slightly younger section at Hemmoor (30 km SW of Kronsmoor), thirteen ammonites species in all are known to date from the Maastrichtian. The material studied comprises species from the Upper Campanian Belemnitella langei to the Lower Maastrichtian Belemnella sumensis zones. Three species (Baculites vertebralis, Baculites knorrianus, Hoploscaphites constrictus) occur earlier here than elseswhere (e.g. Denmark). Menuites cf. wittekindi, formerly known only from the Nostoceras polyplocum Zone (Upper Campanian), occurs in the Belemnella lanceolata Zone at Kronsmoor. Pachydiscus neubergicus and Diplomoceras cylindraceum, two of twelve markers for the base of the Maastrichtian at Tercis (GSSP, southwestern France), have their first occurrences at Kronsmoor significantly above that of Belemnella lanceolata, the belemnite marker for the base of the stage. Compared with Tercis, were the stage boundary was recommended between the FOs of both ammonite species, the Campanian - Maastrichtian boundary at Kronsmoor seems to be located within the Belemnella pseudobtusa Zone. Thus, the first occurrence of the genus Belemnella is of Late Campanian age, appearing c. 540 ky earlier than the base of Maastrichtian as defined at the GSSP at Tercis.

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Early Cenomanian (Cretaceous) inoceramid bivalves from the Kronsberg Syncline (Hannover area, Lower Saxony, Germany) : stratigraphic and taxonomic implications

Wilmsen M., Niebuhr B., Wood C.

Acta Geologica Polonica

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2001

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Vol. 51, nr 2

121-136

EN

An Early Cenomanian inoceramid bivalve assemblage collected from material excavated from a temporary exposure in the Kronsberg Syncline east of Hannover (northern Germany) is described. It consists of "Inoceramus" crippsi MANTELL, 1822, "I" hoppenstedtensis TROGER, 1967, Inoceramus virgatus scalprum BOHM, 1914 and I. virgatus virgatus SCHLUTER, 1877, as well as transitional forms between I. virgatus virgatus and I. virgatus scalprum and an apparently undescribed sulcate form. The inoceramid fauna is well preserved and very rich in individuals. Many of the inoceramids occur either as double-valved individuals or with the valves in close association and appear to be cocentrated in distinct layers. Co-occurring ammonites are Mantelliceras dixoni SPATH, Mantelliceras sp., Schloenbachia varians (J. SOWERBY), Hypoturrilities gravesianus (D'ORBIGNY) and Scaphites obliquus J. SOWERBY. Using event stratigraphy, the stratigraphic interval of the collected fauna can be assigned to the lower part of the Lower Cenomanian Mantelliceras dixoni ammonite Zone. It predominantly comprises material from the Inoceramus virgatus acme-event (the Schloenbachia/virgatus event of German event stratigraphy) at the top of the lower subzone (Mantelliceras dixoni & M. saxbii Subzone) of the dixoni Zone, which is known from the Lower Saxony, Cleveland (eastern England) and Anglo-Paris basins, where it invariably occurs in carbonate-rich rocks with low diversity faunas. The lithofacies and geochemistry of the strata are documented and the "Inoceramus" crippsi and Inoceramus virgatus groups are discussed, including the problematic provenance of the type series of Inoceramus virgatus scalprum.

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The Upper Cretaceous succession (Cenomanian - Santonian) of the Staffhorst Shaft, Lower Saxony, northern Germany: integrated biostratigraphic, lithostratigraphic and downhole geophysical log data

Niebuhr B.

Acta Geologica Polonica

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1999

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Vol. 49, no. 3

175-213

EN

The Cenomanian to Santonian succession of the Staffhorst shaft, ca. 50 km south of Bremen, because of its structural position in the northern German Upper Cretaceous basin, is intermediate in character and fossil content between the pelagic sediments characterizing the Pompeckj Block in the north and the proximal sediments of the Lower Saxony Block in the south. The biostratigraphic subdivision of the shaft is based on inoceramids, echinoids, belemnites and foraminifera. The various biozonations and zonal boundaries used in the Boreal Realm are compared and applied to the zonation of the shaft succession, and the biostratigraphy of the individual fossil groups is described. A new inoceramid zone, that of Inoceramus gibbosus, is proposed for the topmost Lower Coniacian; and an echinoid assemblage zonation is introduced. The existing benthic foraminiferal zonation of the Middle Turonian to Santonian has been modified, with changed age assignments based on the macrofossil zonation. The proposed basal stage boundary criteria of the "Second International Symposium on Cretaceous Stage Boundaries" (Brussels, 1995) could be applied only in some cases. The proximity of the Staffhorst shaft to the trial borehole, situated only 39 m away, has permitted the Self Potential (SP) and Resistivity (R) logs to be uniquely directly calibrated against the lithostraligraphical and biostratigraphic succession of the shaft. The previous identification of some stage and substage boundaries on the logs of northern German boreholes based on foraminiferal zonation will need to be shifted by several tens of metres as a result of thid calibration.