An exceptionally preserved conulariid from Ordovician erratics of Northern European Lowlands

A conulariid preserved in three dimensions from Ordovician fluvioglacial erratics of the Northern European Lowlands (North German Plain) is described under open nomenclature. It is assigned to the genus Conularia with similarities to Baltoscandian conulariids. The lithology of the erratic boulder and fauna contained in it provide important information on the origin and transport direction of the sediment preserved in a kame from the Saalian glaciation. This paper deals with the site of origin of the boulder in Baltoscandia analysing the comprised palaeofauna, from a palaeostratigraphic and palaeogeographic point of view, from its deposition in Ordovician times until its arrival at its current location in the Late Pleistocene. It also reveals for the first time the internal structure of the conulariid aperture.

¹⁰Be-based exploration of the timing of deglaciation in two selected areas of southern Norway

We present new 10Be surface exposure ages from two selected locations in southern Norway. A total of five 10Be samples allow a first assessment of local deglaciation dynamics of the Scandinavian Ice Sheet at Dalsnibba (1476 m a.s.l.) in southwestern Norway. The bedrock ages from the summit of Dalsnibba range from 13.3±0.6 to 12.7±0.5 ka and probably indicate the onset of deglaciation as a glacially transported boulder age (16.5±0.6 ka) from the same elevation likely shows inheritance. These ages indicate initial deglaciation commencing at the end of the Bølling–Allerød interstadial (∼ 14.7–12.9 kyr BP) and ice-free conditions at Dalsnibba's summit during the Younger Dryas. Bedrock samples at lower elevations imply vertical ice surface lowering down to 1334 m a.s.l. at 10.3±0.5 ka and a longer overall period of downwasting than previously assumed. Two further 10Be samples add to the existing chronology at Blåhø (1617 m a.s.l.) in south-central Norway. The 10Be erratic boulder sample on the summit of Blåhø sample yields 20.9±0.8 ka, whereas a 10Be age of 46.4±1.7 ka for exposed summit bedrock predates the Late Weichselian Maximum. This anomalously old bedrock age infers inherited cosmogenic nuclide concentrations and suggests low erosive cold-based ice cover during the Last Glacial Maximum. However, due to possible effects of cryoturbation and frost heave processes affecting the erratic boulder age and insufficient numbers of 10Be samples, the glaciation history on Blåhø cannot conclusively be resolved. Comparing the different timing of deglaciation at both locations in a rather short west–east distance demonstrates the complex dynamics of deglaciation in relation to other areas in southern Norway.

SAFEGUARDING OF MINERAL RAW MATERIALS DEPOSITS – A CONCEPT OF VALORIZATION AND SELECTION OF MINERAL DEPOSITS OF PUBLIC IMPORTANCE

The article presents a proposal for the new rules for the selection of deposits, which due to their value should be protected as Mineral Deposits of Public Importance (MDoPI) on national level. It was assumed that safeguarding should cover only the largest recognized deposits in terms of resources located in areas not excluding exploitation, which meet jointly two criteria: the total resources of the largest deposits should cover at least 50% of national geological resources and simultaneously they should meet the criterion of security of supply minerals for at least 50 years, with average demand calculated based on data from the last 10 years. Using the above criteria, analysis of the following deposits was performed: gypsum and anhydrite, basalt, granite, granodiorite, erratic boulder and syenite, dolomite, marl, travertine, limestone and dolomitic limestone, quartzite, greywacke, sandstone, quartzite sandstone, marl and limestone for the cement industry as well as limestone and marl for the lime industry. In total, 828 deposits were analyzed, and the assumed criteria were fulfilled in this group of deposits by a total number of 82 deposits. Among them, 6 deposits are very conflict, 71 – conflict, and 5 – partly conflict. In the case of several very conflict deposits, there is a high probability that their exploitation will not be possible, so meeting the criteria will require extending the list of deposits by 6 other ones. It was proposed that the verification of valorisation of deposits classified as MDoPI should be carried out periodically – not more often than every 5, but not less than every 10 years. This task should belong to the duties of the geological survey.

Special Structure and its Geological Significances of WZD Bauxite

Through systematically geologic survey and observation of drills and rock slices this paper have a comprehensive research on special structure of bauxite in Wuchuan-Zheng,an-Daozhen (WZD) area. Special structure mainly includes directional structure of clast, leaching structure and colloid structure. Clast is erratic boulder indicating high energy environment. Leaching structure shows there is an eluvial process in mineralizaton process, and leaching is important for the formation of high grade bauxite. Appearance of colloidal in WZD bauxite shows that agglutinate of gel is one of the reasons for the formation of WZD bauxite. Clastic structure, leaching structure and colloidal structure demonstrate that mineralizaton process of WZD bauxite is a very complicated process.

A zero-exposure time test on an erratic boulder: evaluating the problem of pre-exposure in Surface Exposure Dating

The method of surface exposure dating using in-situ produced cosmogenic nuclides has become an important and widely applied tool in Quaternary science. One application is the dating of erratic boulders on moraines. An important problem however remains: the evaluation of potential pre-exposure time for samples from boulder surfaces. We have tested pre-exposure by sampling all sides of a recently exposed boulder in order to measure inherited nuclides from prior exposure periods. The sampled erratic boulder rests on the right lateral moraine of the most recent advance of the Glacier de Tsijiore Nouve in the Arolla Valley, Switzerland. Mapping of the area was done to reconstruct the Holocene fluctuations of the glacier. This glacier is especially useful for such a test as it is characterized by an ideal geometric relationship between accumulation and ablation area and, therefore, responds rapidly to mass-balance changes. The sampled boulder was deposited in 1991. Assuming no prior exposure the expected concentration of a given cosmogenic nuclide should be near zero. The 10Be/9Be ratios of the five measured samples were indistinguishable from blank values within the given errors, demonstrating that the samples did not experience pre-exposure. Three samples measured for 21Ne reveal 21Ne/20Ne and 22Ne/20Ne ratios similar to those of air, with no detectable prior cosmogenic Ne accumulation.

Revision of the supposed Triassic, in fact Silurian genus Triadophyllum Weissermel, 1925 (Anthozoa, Rugosa)

The only existing type specimen of <i>Triadophyllum posthumum</i> Weissermel, 1925 is not a Middle Triassic (middle Anisian, Pelsonian) Scleractinia, but a Silurian Rugosa collected from a Pleistocene erratic boulder of Baltoscandian origin. First serial cross sections demonstrate a synonymy of <i>Triadophyllum</i> Weissermel, 1925 with the worldwide distributed ahermatypic genus <i>Palaeocyathus</i> Foerste, 1888 (including also <i>Enterolasma</i> Simpson, 1900) known from Llandoverian/Wenlockian – Eifelian times. The species <i>Palaeocyathus posthumus</i> as well as the genus are still unknown in the classical Silurian sequences of Gotland and Estonia, which may be the possible origin of the glacial drift. At present, a more precise age determination within the Llandoverian, Wenlockian, or Ludlovian can not be achieved. The nearest certain occurrence of the genus is the early Wenlockian <i>Palaeocyathus conicus</i> (Bul'vanker, 1952) of Podolia (Ukraine), situated likewise on the southwestern margin of the ancient Baltoscandian shield; other records such as the Ludlovian <i>Palaeocyathus bohemicus</i> (Počta, 1902) from the Barrandian (Czech Republic) and <i>Palaeocyathus radiatus</i> (Münster, 1839) from Upper Franconia (Saxothuringia, Germany) are more distant on Gondwana-derived terranes. <br><br> Das allein existierende Holotypus-Polypar von <i>Triadophyllum posthumum</i> Weissermel, 1925 ist kein Scleractinia-Vertreter der Mittel-Trias (mittleres Anis, Pelson), sondern ein silurisches Rugosa-Taxon, das aus einem Pleistozän-Geschiebe baltoskandischen Ursprungs gesammelt wurde. Eine erste Querschliffserie belegt die Synonymie von <i>Triadophyllum</i> Weissermel, 1925 mit dem weltweit verbreiteten ahermatypischen Genus <i>Palaeocyathus</i> Foerste, 1888 (einschließlich <i>Enterolasma</i> Simpson, 1900), das aus dem Zeitraum Llandovery/Wenlock – Eifel bekannt ist. Die Art <i>Palaeocyathus</i> <i>posthumus</i> und auch das Genus wurden in den klassischen Silur-Schichtfolgen von Gotland und Estland noch nicht gefunden, die als Herkunftsgebiete der glazialen Drift in Betracht kommen. Momentan lässt sich keine präzisere Altersbestimmung innerhalb des Llandovery, Wenlock oder Ludlow erreichen. Das nächste Vorkommen der Gattung, das ebenfalls am SW-Rand des alten Baltoskandischen Schildes liegt, ist <i>Palaeocyathus conicus</i> (Bul'vanker, 1952) im unteren Wenlock von Podolien (Ukraine). Andere Nachweise wie <i>Palaeocyathus bohemicus</i> (Počta, 1902) aus dem Ludlov des Barrandium (Tschechische Republik) und <i>Palaeocyathus radiatus</i> (Münster, 1839) aus dem Ludlow von Oberfranken (Saxothuringikum, Deutschland) gehören zu primär entfernteren Terranes, die von Gondwana herkommen. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.200700006" target="_blank">10.1002/mmng.200700006</a>

<i>‘Nodibeyrichia jurassica’</i> and associated beyrichiacean ostracode species and their significance for the correlation of late Silurian strata in the Baltic and Britain

Taxonomic revision reveals that the beyrichiacean ostracode ‘Nodibeyrichia jurassica’ can no longer be regarded as an index species for the uppermost (late Přídolí) ostracode ‘zone’ of the Silurian of the Baltic region embracing Estonia, Latvia and Baltic-floor derived erratic boulders. The taxon Nodibeyrichia jurassica Sarv, 1968 (non Gailite 1967) is regarded as a junior subjective synonym of Beyrichia protuberans Boll, 1862. Moreover, the material hitherto assigned to ‘Nodibeyrichia jurassica’ is herein considered to belong to two species: Nodibeyrichia protuberans (Boll, 1862) and Nodibeyrichia verrucosa Shaw, 1969. N. verrucosa occurs in England and Estonia, in the basal part and upper part of the Přídolí Series respectively. N. protuberans, as herein restricted, can be used to recognize the late Přídolí, uppermost ostracode assemblage level (N. jurassica Zone of previous literature) of the Silurian only in the central East Baltic (Latvia) and in erratic boulder material found in southern Baltic areas.