Bulletin Volume 62 – 2014

Rinkite–nacareniobsite-(Ce) solid solution series and hainite from the Ilímaussaq alkaline complex: occurrence and compositional variation

Rønsbo, J.G., Sørensen, H.†, Roda-Robles, E., Fontan, F. & Monchoux, P., 2014-03-14. Rinkite–nacareniobsite-(Ce) solid solution series and hainite from the Ilímaussaq alkaline complex: occurrence and compositional variation*.
©2014 by Bulletin of the Geological Society of Denmark, Vol. 62, pp. 1–15.
ISSN 2245-7070. (www.2dgf.dk/publikationer/bulletin).

*Erratum to original version published on 14 March 2014.

On p. 4, right column, line 12, the sentence “All sample numbers are GGU numbers.” should be replaced by “All sample numbers are Geological Institute numbers except 154346 which is a GGU number.”
A corrected version of the article has been posted on 4 June 2014.

Abstract: In the Ilímaussaq alkaline complex, minerals from the rinkite–nacareniobsite-(Ce) solid solution series have been found in pulaskite pegmatite, sodalite foyaite, naujaite and naujaite pegmatite from the roof sequence, and in marginal pegmatite, kakortokite and lujavrite from the floor sequence.

The electron microprobe analyses embrace almost the full extension of the solid solution series and confirm its continuity. The solid solution series shows similar compositional variations in the roof and floor sequences: Rinkite members of the series are found in the less evolved rocks in the two sequences, whereas nacareniobsite-Ce members occur in the most evolved rocks and pegmatites in the two sequences.

The REE (+Y) content varies from 0.83 atoms per formula unit (apfu) in rinkite from pulaskite pegmatite to 1.31 apfu in nacareniobsite-(Ce) from naujaite pegmatite. The main substitution mechanisms in the solid solution series investigated in this work are 2Ca2+ = Na+ + REE3+ and Ti4+ + Ca2+ = Nb5+ + Na+. The increased contents of Nb5+ and REE3+ are only to a minor degree compensated through the F1– = O2– substitution. The chondrite normalised REE patterns of the minerals develop in a similar way in the two sequences, showing relative La-enrichment and Y-depletion from the less to the most evolved rocks.

Hainite has not previously been found in the Ilímaussaq complex. It was here identified in a pulaskite pegmatite sample by a combination of X-ray diffraction giving the unit cell dimensions a = 9.5923(7) Å, b = 7.3505(5) Å, c = 5.7023(4) Å, α = 89.958(2)°, β = 100.260(1)°, γ = 101.100(2)°, and X-ray powder pattern and electron microprobe data giving the empirical formula (Ca1.62 Zr0.16Y 0.22) (Na0.87Ca1.11) (Ca 1.65 REE0.35)Na(Ti0.81Nb0.09Fe0.08 Zr0.02)(Si2O7)2O0.99F2.96. Based on published and the present data it is documented that minerals from the hainite-götzenite solid solution series show a compositional variation between the ideal end members (Y,REE,Zr)Na2Ca4Ti(Si2O7)2OF3 and NaCa6Ti(Si2O7)2OF3.

Keywords: Ilímaussaq, rinkite, nacareniobsite-(Ce), hainite, götzenite.

Addresses:
Jørn G. Rønsbo [ jornronsbo [at] gmail [dot] com ] , Henning Sørensen, Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Encarnacion Roda-Robles,[encar [dot] roda [at] ehu [dot] es] Departamento de Mineralogia y Petrologia, Universidad del Pais Vasco/EHU Apdo. 644, E-48080, Bilbao, Spain.
François Fontan, Pierre Monchoux, Université de Toulouse, UPS (FSI-OMP), CNRS, IRD-GET, 14 Avenue Edouard Belin, F-31400 Toulouse, France.
* Contribution to the Mineralogy of Ilímaussaq no. 145
† Deceased

Corrected version as of 4 June 2014
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A new eusuchian (Crocodylia) tooth from the Early or Middle Paleocene, with a description of the Early–Middle Paleocene boundary succession at Gemmas Allé, Copenhagen, Denmark

Schwarz-Wings, D., Milàn, J. & Gravesen, P., 2014: A new eusuchian (Crocodylia) tooth from the Early or Middle Paleocene, with a description of the Early–Middle Paleocene boundary succession at Gemmas Allé, Copenhagen, Denmark.
© 2014 by Bulletin of the Geological Society of Denmark, Vol. 62, pp. 17–26.
ISSN 2245-7070. (www.2dgf.dk/publikationer/bulletin).

Abstract: A recently found crocodylian tooth crown from the basal conglomerate of the Middle Paleocene (Selandian) Lellinge Greensand Formation, differs morphologically from other finds of crocodylian teeth from the Paleocene of southern Scandinavia. The tooth is conical and blunt with a narrow rounded apex, and slightly curved along the axis of its length.

The morphology of the tooth suggests it belongs to either the longirostrine eusuchian Aigialosuchus, which is known from the Campanian of southern Sweden, or to a member of the Alligatoridae which are the most common crocodylians in northern Europe in the Late Cretaceous. Gavialoid crocodylians, in particular Thoracosaurus which is known from the Danian limestome of the Limhamn quarry in southern Sweden and from the Faxe quarry in eastern Denmark, can be excluded because of their deviating tooth morphology.

Regardless of its assignment, the tooth is interesting in a stratigraphic context as it demonstrates the existence of at least two crocodylian taxa in Scandinavia during the Early and Middle Paleocene.

Keywords: Crocodylian diversity, Eusuchia, Middle Paleocene, Danian/Selandian boundary, Echinoderm conglomerate, Lellinge Greensand Formation.

Authors’ addresses:
Daniela Schwarz-Wings, Museum für Naturkunde, Leibniz Institute for Research on Evolution and Biodiversity, Invalidenstrasse 43, DE 10115 Berlin, Germany.
Jesper Milàn, Geomuseum Faxe/Østsjællands Museum, Østervej 2, DK-4640 Faxe, Denmark; also Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Palle Gravesen, Det Sorte Geomuseum, Skolegade 2B, DK-4874 Gedser, Denmark; also Natural History Museum, Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark.

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Manganiferous minerals of the epidote group from the Archaean basement of West Greenland

Katerinopoulou, A., Balic-Zunic, T., Kolb, J., Berger, A. & Secher, K. 2014: Manganiferous minerals of the epidote group from the Archaean basement of West Greenland.
© 2014 by Bulletin of the Geological Society of Denmark, Vol. 62, pp. 27–37.
ISSN 2245-7070. (www.2dgf.dk/publikationer/bulletin).

*Erratum to original version published on 10 October 2014.

In Fig. 1 the sample number 177979 is incorrect. It should be 177975.
A corrected version of the article has been posted on 29 October 2014.

Abstract: The chemical compositions and crystal structures of Mn3+-containing minerals from the epidote group in Greenland rocks are investigated and described in detail. They occur in hydrothermally altered Archaean mafic sequences within the gneissic complex of the North Atlantic craton of West Greenland.

The Mn-containing minerals have a characteristic red to pink colour. A detailed microchemical study shows a significant inter- and intra-sample variation in Mn content. The samples from different parageneses can be classified as Mn-bearing epidote and Mn-bearing clinozoisite. The intra-sample variation in the content of Al, Fe and Mn is on a very fine scale, but still allows for identification of a negative correlation between Mn and Fe. Textures indicate different stages of growth.

Crystal chemical data are compared with literature data and illustrate the basic systematic differences between the influence of Fe and Mn on the crystal structure of the epidote group minerals.

Keywords: Epidote, clinozoisite, Greenland, manganiferous minerals.

Authors’ addresses:
A. Katerinopoulou [annak [at] snm [dot] ku [dot] dk], Natural History Museum of Denmark, Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark;
current address: [ akat [at] topsoe [dot] dk ], Haldor Topsøe, Nymøllevej 55, DK-2800 Kgs. Lyngby, Denmark.
T. Balic-Zunic [toncib [at] snm [dot] ku [dot] dk], Natural History Museum of Denmark, Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark.
J. Kolb [jkol [at] geus [dot] dk] and K. Secher [kse [at] geus [dot] dk], Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
A. Berger [ab [at] geo [dot] ku [dot] dk], Department of Geography and Geology, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark;
current address: [alfons [dot] berger [at] geo [dot] unibe [dot] ch], Institute of Geological Sciences, University of Bern, Switzerland.

Corrected version as of 29 October 2014:

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A study of the sharks and rays from the Lillebælt Clay (Early–Middle Eocene) of Denmark, and their palaeoecology

Carlsen, A.W. & Cuny, G. 2014: A study of the sharks and rays from the Lillebælt Clay (Early–Middle Eocene) of Denmark, and their palaeoecology.
© 2014 by Bulletin of the Geological Society of Denmark, Vol. 62, pp. 39–88.
ISSN 2245-7070. (www.2dgf.dk/publikationer/bulletin).

Abstract: Elasmobranch assemblages from the Eocene Lillebælt Clay Formation (Late Ypresian to Middle Lutetian) at Trelde Næs in Denmark yielded teeth of 31 different genera/species from surface collecting as well as from bulk sampling.
The fauna is dominated by lamniform pelagic sharks and deepwater genera like Hexanchiformes, Centrophorus, Isistius, Echinorhinus and Pristiophorus.

Coupatezia miretrainensis, Centrophorus aff. granulosus and Chlamydoselachus cf. fiedleri are reported for the first time from the Ypresian. The record of Coupatezia miretrainensis extends its stratigraphic record from the Lutetian back to the Late Ypresian, whereas the record of Centrophorus aff. granulosus extends the origin of the Centrophorus granulosus group back to the Late Ypresian from its hitherto known origin in the Lutetian. The possible presence of the sparsely known Bartonian genus Turania awaits further sampling to be confirmed.

The Ichthyofauna suggests deposition in a deep-water environment in subtropical to temperate waters on the middle or outer continental shelf and upper slope at water depth down to 350 m. This is in agreement with depositional depths inferred from fossil molluscs and fish otoliths from Trelde Næs.

Keywords: Denmark, Lillebælt Clay Formation, Eocene, Elasmobranchii, fossil teeth, palaeoecology.

Authors’ addresses:
Agnete Weinreich Carlsen [ agnetecarlsen [at] mail [dot] dk ], Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350 København K, Denmark.
Gilles Cuny [ gilles [dot] cuny [at] gmail [dot] com ], Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5–7, DK-1350 København K, Denmark;
current address: UMR CNRS 5276 LGLTPE, Université Claude Bernard Lyon1, Campus de la Doua bât. Géode, 2 rue Raphaël Dubois, F-69622 Villeurbanne Cedex, France.

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The lower Maastrichtian Hvidskud succession, Møns Klint, Denmark: calcareous nannofossil biostratigraphy, carbon isotope stratigraphy, and bulk and brachiopod oxygen isotopes.

Jelby, M.E., Thibault, N., Surlyk, F., Ullmann, C.V., Harlou, R. & Korte, C. 2014: The lower Maastrichtian Hvidskud succession, Møns Klint, Denmark: calcareous nannofossil biostratigraphy, carbon isotope stratigraphy, and bulk and brachiopod oxygen isotopes.
© 2014 by Bulletin of the Geological Society of Denmark, Vol. 62, pp. 89–104.
ISSN 2245-7070. (www.2dgf.dk/publikationer/bulletin).

Abstract: A new calcareous nannofossil and δ13C stratigraphy is established for the chalk exposed in the lower Maastrichtian Hvidskud succession, Møns Klint, Denmark. It is based on 21 nannofossil samples and analysis of 82 stable isotope samples, allowing correlation with a previously established brachiopod zonation.

The succession, which belongs to the brachiopod spinosa-subtilis to pulchellus-pulchellus zones, extends upwards from calcareous nannofossil subzone UC16ii to UC19ii and encompasses δ13C events M1+ to M2+. A new chronostratigraphic and geochronological age model is proposed based on correlation with the cored boreholes Stevns-1 (Denmark) and ODP Site 762C (Indian Ocean).
Hvidskud encompasses the 405 kyr eccentricity cycles Ma40513 – Ma40511 within magnetochron C31r.

A sedimentation rate of 5.0 cm kyr-1 can be inferred from correlation to geochronological tie-points in ODP 762C, suggesting an age of ~70.9 Ma for the base of the succession and a duration of >680 kyr for the investigated interval. The Hvidskud succession is well-exposed, easily accessible, and the new stratigraphic framework and precise age model suggest that it can be used as a key locality for stratigraphic correlation of the lower Maastrichtian in north-western Europe.

Information on palaeo-seawater temperatures can be drawn from oxygen isotope records obtained from bulk rock samples and 24 micromorphic brachiopod specimens (Terebratulina faujasii).
The brachiopod data show a clear diagenetic trend but point to an upper range of unaltered values between –0.4 and –0.6\\\\\\‰. Assuming a δ18O value of –1\\\\\\‰ for seawater in a Cretaceous ice-free world, this would indicate bottom water temperatures of 13.6 to 14.3°C of the Danish Chalk Sea (45°N) during the early Maastrichtian cooling.

Keywords: lower Maastrichtian, calcareous nannofossil biostratigraphy, δ13C stratigraphy, Danish
Basin, brachiopod zonation, oxygen isotopes, Hvidskud.

Authors’ adresses:
Mads Engholm Jelby [ madsjelby [at] hotmail [dot] com ], Nicolas Thibault [nt [at] ign [dot] ku [dot] dk], Finn Surlyk [finns@ign. ku.dk], Clemens V. Ullmann [cu [at] ign [dot] ku [dot] dk], Rikke Harlou [rikke [at] harlou [dot] dk], Christoph Korte [korte@ign. ku.dk], Department of Geosciences and Natural Resource Management, University of Copenhagen, ØsterVoldgade 10, DK-1350 Copenhagen K, Denmark.

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