Eine Sammlung zur Erläuterung des «Windschliffes»

Ohne ZusammenfassungDer Verfasser ist in der Nacht vom 25./26. September 1915 in der Champagne gefallen.     

The Cenomanian—Turonian Anoxic Event in Southern Tibet：A Study of Organic Geochemistry

The Cenomanian-Turonian oceanic anoxic event(C/T OAE) is developed in southern Tibet.Organic geochemical study of the Cenomanian-Turonian sediments from the Gamba and Tingri aress shows that the mid-Cretaceous black shales in southern Tibet are enriched in organic carbon.Te molecular analyses of organic matter indicate marine organic matter was derived from algae and bacteria.In the Gamba area,the organic matter is characterized by abundant tricyclic terpanes and pregane,which are predominant in 191 and 217 mass chromatograms,respectively,Pristane/phytane(Pr/Ph)ratios in the C/T OAE sediments are less than 1, demonstrating the domination of phytane.The presence of carotane can be regarded as a special biomarker indicating oxygen depletion in the C/T OAE sediments in the Tethyan Himalayas.In anoxic sediments,β-carotane and γ－carotane are very abundant.The β-and γ-carotane ratios relative to nC17 in the Cenomanian-Turonian anoxic sediments vary from 32.28-42.87and 5.10-11.01.     

The masquerade of alkaline–carbonatitic tuffs by zeolites: a new global pathfinder hypothesis

Rapid and progressive reaction of alkaline–carbonatitic tuffs with magmatic and crustal fluids disguises their initial character and origin. This is collectively indicated from (a) the extensive literature on zeolite formation from volcanic glass precursors and alkaline fluids, (b) mineralogical characteristics of specific zeolite species, (c) a comparative review of global distributions of alkaline–carbonatite suites and of zeolite minerals, and (d) new trace element data from zeolite samples. A unifying conceptual model based on tectonic and geological settings, hydrological regime and mineralogy is presented that helps to explain the global distributions and current understanding of occurrences. The model will assist in resource exploration by contributing deeper understanding of the economically important bedded zeolite deposits and further, serve as a guide to the discovery of new alkaline–carbonatitic suites, potentially of economic significance (metallic ores and rare earth elements). It follows that future testing of the hypothesis will impact on models of natural carbon cycling as volcanic contributions of CO₂ are reviewed.     

Quo vadis neoliberalism? The remaking of global capitalist governance after the Washington Consensus

The Washington Consensus, through which neoliberal global capitalist governance gained hegemony over the third world, entered a crisis in the late 1990s. Triggered by the 1997 Asian financial crisis, and by contestations of neoliberal governance from global civil society, two remakings of global capitalist governance can be identified: A ‘post-Washington consensus’ whose relation to neoliberalism is complex; and a ‘new development economics’ that advocates Keynesian principles. Irrespective of the trajectory of this emergent phase of re-regulation, particularly after the 2008 global finance crisis, these remakings can be conceptualized as supplements reinforcing an imaginary of capitalism as the solution to, rather than progenitor of, uneven development. Through discourses of capitalist development as a sequential trajectory to be followed by all countries, as flattening the world to enable catch-up by backward countries, and as incorporating socio-spatial difference via its commodification, this socio-spatial imaginary functions to legitimate expertise located in the first world, and global capitalist governance, irrespective of serial policy failures.     

The Witputs diamictite in southern Namibia and associated rocks: constraints for a global glaciation?

The Witputs section of the Gariep Belt (S Namibia) comprises a sequence of clastic and chemical sediments, which have been interpreted as representative of a Late Neoproterozoic global or near-global ice age event, and recent biostratigraphic work in the upper rocks of the Witputs suggest a Late Ediacaran age. To further characterise this sequence and provide additional age constraints, a detailed sedimentological and detrital zircon study has been carried out. The petrographic, sedimentological and geochemical characteristics of the Witputs diamictite determined in this study are homogenous and indicative of debris flow or palaeo-valley infill sediments, deposited in an oxic environment with no glaciogenic evidence. This homogeneity is also reflected in the detrital zircon age spectra with most ages falling between 1.0 and 1.3?Ga, representing the local geology, with the youngest grain at 1030.2?±?10.9 (2??) (n?=?92?<10% discordance), despite the fact that mid and Late Neoproterozoic volcanic activity is known in the local region. The overlying carbonate rocks, often considered to be ??cap carbonates??, show high Mn (up to 60% MnO), with base metal precipitation (Zn, V, Co), and are recrystallised. Their ??¹³C_VPDB isotope ratios are homogeneous at around-3. Major and trace element ratios reach values which indicate that C?CO isotopes may be disturbed and might not reflect primary global seawater composition, thus questioning their use for global correlation and comparison with composite chemostratigraphic curves. The contact to the overlying Late Ediacaran Sanddrif Member is not exposed, and the rocks dip in a different direction than the underlying carbonate rocks. The c. 40-m-thick section is characterised by rapid lithology changes including shales, calcareous sandstones and wackes, fine-grained conglomerates and rare clean quartz-rich sandstones, all of which have strikingly similar detrital zircon populations, and the youngest zircon is dated at 1082.8?±?10?Ma (2?? errors, from 72 grains with <10% discordance). Acritarchs earlier found in the Sanddrif Member, however, indicate a post-570?Ma depositional age. If the diamictites are glacio-marine deposits, then an interesting conclusion is that the clastic sediments can display a very immature geochemical signature, indicating a localised provenance, with derivation purely from the local basement rocks, which is also reflected in the detrital zircon populations. However, we would hesitate to assign a glacial origin to the deposits as no glacial indicators, other than a diamictitic texture, were observed. Clearly, far more work on the detailed mapping and sedimentology of the Neoproterozoic Gariep Belt deposits is required, particularly as many are currently used for global correlation. Age constraints derived from extensive detrital zircon work can only constrain the deposits as being post 1.03?Ma with the detritus being purely locally derived.     

The high-resolution Holocene sea-level curve for Northwest Germany: global signals, local effects or data-artefacts?

A few years ago, a new relative sea-level curve for northwest Germany was constructed for the entire German North Sea coast. It is characterised by several suspected sea-level fluctuations. To test this curve for local effects, it was broken down into five relative sea-level curves representative for five coastal sections. The relative sea-level curves were corrected for tidal effects and also, a rough first correction for compaction was applied. The five curves all differ from the original curve and from each other. Most of the suspected sea-level fluctuations in the original curve cannot be supported and are discussed as data-artefacts or local effects. Around AD 800–1000 all curves show stagnation or drop of sea-level. Thus, this signal is discussed as of over-regional stratigraphic meaning. This study is a first step (1) to show that several curves are needed to demonstrate the Holocene sea-level history of such a big area as the entire German North Sea coast and (2) to establish reliable relative sea-level curves for the German North Sea coast. Further research is necessary to apply detailed corrections especially with respect to compaction-prone data and to improve the individual curves.     

The world’s by-product and critical metal resources part III: A global assessment of indium

Indium has considerable technological and economic value to society due to its use in solar panels and liquid crystal displays for computers, television and mobile devices. Yet, without reliable estimates of known and potentially exploitable indium resources, our ability to sustainably manage the supply of this critical metal is limited. Here, we present the results of a rigorous, deposit-by-deposit assessment of the global resources of indium using a new methodology developed for the assessment of critical metals outlined in Part II of this study (Werner et al., 2017). We establish that at least 356 kt of indium are present within 1512 known mineral deposits of varying deposit types, including VMS, skarn, epithermal and sediment-hosted Pb-Zn deposits. A total of 101 of these deposits have reported indium contents (some 76 kt of contained In) with the remaining 1411 deposits having mineralogical associations that indicate they are indium-bearing, yielding ∼280 kt of contained indium. An additional 219 deposits contain known indium enrichments but have unquantifiable contents, indicating that our global resource figure of 356 kt of contained indium is therefore most certainly a minimum. A limited number of case studies also indicates that a further minimum of ∼24 kt indium is present in mine wastes, a total that is undoubtedly smaller than reality given the minimal reporting of mine waste indium concentrations, and the extensive volume of historical mine wastes.These quantities are sufficient to meet demand for indium this century, assuming current and projected levels of consumption. However, given indium’s classification as a critical metal, its supply still remains a concern, and hence we have also discussed the economic viability and spatial distribution of the indium resources identified during this study to further our understanding of the geopolitical scarcity of this critical metal. Our results suggest that the global indium supply chain is fairly adaptable, primarily as the spatial distribution of indium resources deviates significantly from the current supply chains for this metal. Our study provides a stronger basis for future studies of indium criticality, provenance, supply chain dynamics, and stocks and flows in the fields of economic geology and industrial ecology.     

The First U–Pb (SHRIMP II) Evidence of the Franklin Tectonic Event at the Western Margin of the Siberian Craton

Doklady Earth Sciences - Geochemical and isotope–geochronological evidence of Late Riphean intraplate magmatism within the Chernorechenskii massif at the western margin of the Siberian Craton...     

Volcanic Event Layers-A Marker Bed of Correlation of Coal Measures

Upper Carboniferous-Lower Permian volcanic event deposits from two cross sections in Nanpiao, Liaoning Province, and the Daqing Mountains, Inner Mongolia, were examined by systematic rock and mineral identification, differential thermal analysis, X-ray diffraction, scanning electron microscopy and trace element and rare earth element quantitative analysis. According to the results, twelve sequences of volcanic event deposits have been distinguished from bottom to top, including 34-39 volcanic event layers. As these layers each have their own distinctive petrological, mineralogical and geochemical characteristics and were derived from the same source, they provide new evidence for further ascertaining the distribution characteristics of volcanic event deposits on the northern margin of the North China plate and carrying out the stratigraphic correlation using volcanic event layers as marker beds.     

Changshanian Maximum Flooding Event in China and Its Global Correlation

Various orders of condensed sections are recognized in the Cambrian of North China Carbonate Platform. Study of comparative sedimentology proves that CS4-CS5 in the Changshanian age is the maximum sea flooding sediments in the Cambrian, regardless of the distribution, thickness, internal structure of the condensed section series and K2O abundance. It is a two-layered composite condensed section series, characterized by the enrichment of such elements as K, P, Mn, Ti, Co, V, Cr, Cu, Zr, Ni, Li, Th, La, Ce, Nd, Dy, Y, Sc and Be. The Changshanian maximum flooding event can be correlated on a global scale, and the corresponding sedimentary records are discovered in 26 intercontinental sections in N. Europe, N. America, and Tarim and the Yangtze Platform of China. Through detailed sedimentological research, meter-scale cycle analysis and Fischer plots, it is concluded that the Changshanian maximum flooding was a composite effect of the second-order eustacy superimposed by the third-and fourth-order eustacy,     

Geological Evidence for the Presence of the Emperor Event in China

The presence of the reversals of the geomagnetic field within the Brunhes is indicated by paleomagnetic stuides on Cenozoic volcanic rocks in the Leizhou Peninsula, loess strata and Quaternary marine sediments in the Pearl River Mouth basin in China. These regional reversals occured at 0.58±0.13 Ma, 0.45 Ma and 0.47—0.48 Ma respectively according to the results of K-Ar isotopic dating and climatostratigraphic and biostratigraphic analyses. The reversals equivalent to the Emperor Event is suggested.The reversals revealed in different regions with various lithologic characters in China prove that the Emperor Event is a global reversal event rather than a geomagnetic excursion, and its confirmation will permit a precise definition of the Middle/Late Pleistocene boundary.     

The legal meaning of Lefebvre’s the right to the city: addressing the gap between global campaign and scholarly debate

There is a growing consideration globally of a right to the city in urban policies, strategies and legislation. The mention of this concept in the UN’s New Urban Agenda vision statement, in relation to human rights, both acknowledges and encourages this trend. It is also a result of lobbying and contestation. In the Anglo-American scholarly literature, there has been caution as to whether Henri Lefebvre intended a legal and institutionalized meaning for his ‘right to the city’. This paper reviews these debates and from that perspective examines Lefebvre’s positions on law, rights and the right to the city. It locates this within his wider political strategy and in particular the three-pronged strategy he put forward in The Urban Revolution to address the urban question—political foregrounding of the urban, promotion of self-management, and introduction of the right to the city into a transformed contractual system. By contextualizing and reviewing Everyday Life in the Modern World (published immediately before Right to the City), the paper examines Lefebvre’s thinking on rights formation, within ‘opening’, or the process of inducing change. The paper engages with meanings Lefebvre provides for rights in his concept of the right to the city, including his later conception of a contract of citizenship. The paper suggests that engagement with a fluid role of law and rights, in combination with Lefebvre’s other strategies, is important in opening the pathway he charts for the realization of this right, whether through local or global initiatives.     

Study of a Neogene basin dynamics: The “Bizerte basin”, northeastern Tunisia: relevance to the global Messinian Salinity Crisis

The Messinian sediments of northeastern Tunisia were deposited under an active tectonic setting. They are organized in sequences indicating a transitional deposit from margin – littoral to lacustrine – continental facies. These series unconformably overlie the Serravallian–Tortonian silty clays packages, and are overlain by the transgressive Early Pliocene marl (Zanclean). The presence of evaporitic strata points out to the Messinian Salinity Crisis described in the peripheral basins of the western Mediterranean. The Messinian sedimentation was found to have been closely controlled by transtensive tectonics and differential subsidence at a large spatio-temporal scale. It is organized in sequences typical of a depositional environment controlled by eustatism, tectonic and maybe by climate changes. Despite the existence of some local specific sedimentological characteristics, our results corroborate previous findings that pointed out to the Messinian times as a singular period all around the Mediterranean Basin. Field and subsurface seismic profile data helped reconstructing either the sedimentary or tectonic unconformities existing between the studied Messinian series and older Neogene successions.     

No proof from carbon isotopes in the Francevillian (Gabon) and Onega (Fennoscandian shield) basins of a global oxidation event at 1980–2090 Ma following the Great Oxidation Event (GOE)

Highly depleted C isotope composition of organic matters from the Onega (Fennoscandian shield) and Francevillian (Gabon) basins are differently interpreted. Kump et al. (2011) suggested the occurrence of a massive and global oxidation event during the period of 1980–2090 Ma, which follows the Great Oxidation Event (2450–2320 Ma) (Bekker et al., 2004). Inversely, Gauthier-Lafaye and Weber (2003) invoke the possible action of methanotrophic microorganisms to explain the δ¹³C values as low as –46‰ measured in the Franceville basin. Here we present the isotope data available in the Franceville basin in order to discuss these two interpretations. The lack of any δ¹³C correlation between organic matter and carbonate in the Franceville basin does not allow the consideration of a massive and global oxidation event.     

Silica dust and non-occupational silicosis——A global perspective

Health risk from various particulates of dust has been of public health concern for many years and scientific observations on dust have been going on for the last 200 years. Diseases resulting from exposure to dust are generally known as pneumoconiosis and have been primarily associated with occupational exposure to silica dust. Silica, which induces silicosis, has been recognized as far back as the Hippocratic times. The aim of the research is to try to assess the nature and scale of health risks from environmental exposure to silica on a global scale, with particular emphasis on non-occupational silicosis （pneumoconiosis）. Thorough literature reviews included studies and literature from non-occupational and occupational silicosis studies along with papers from Geology and Medicine. Non-published studies and local knowledge from Ladakh were used in pertinent of the review. The commonest form of silica （SiO2） is quartz. Other particulates in the atmosphere and finer particles 〈10 when inhaled with oxygen endanger human health; silica is the most threatening for non-occupational silicosis because of its high fibrogenicity. Aerosol minerals can often travel from continent to continent creating a health risk not just in the area of dust source, but also to secluded humans. When emitted into the air environmental exposure to （silica） quartz can occur as component of particulates emissions produced by natural-industrial-agricultural activities. Human exposure to environmental （silica） quartz can be summarized into direct and indirect pathways. Health risk from exposure to silica （quartz） has been widely studied in occupational settings; however there is a scarcity of studies on environmental/non-occupational exposure. Review of epidemiological studies on environment/non-occupational silicosis showed that all the studies lack a good control group and represent a small sample size. Many of these studies are case reports with retrospective histopathology, focusing only on the prevalence and lacking robust exposure measurement. Non-occupational/environmental silicosis is a global public health concem and the areas of dust source could be modified with climate changes. Literature is very scarce in relation to health risks from environmental dust （silica/quartz）, nevertheless the review of occupational studies links silica exposure to numerous diseases in humans.     

Reply to Discussion of «Relative sea level fluctuations in Aegean coastal areas from middle to late Holocene» by Kosmas Pavlopoulos [Geodinamica Acta 23/5–6 (2010) 225–232]

Abstract

This paper gives an answer to the criticism of Jussereta and Baeteman to the paper Discussion of “Relative sea level fluctuations in Aegean coastal areas from middle to late Holocene” by Kosmas Pavlopoulos [Geodinamica Acta 23/5–6 (2010) 225–232]. Jussereta and Baeteman were critical about how the peat beds can be regarded as certain sea level indicators. It is evident that the method adopted for the determination of the mean sedimentation rate of the peats beds is the dating of two distinct (usually basal and uppermost) layers.

A common inaccuracy that some researchers do when they refer to relative sea level changes, is to focus only on eustatic component of this process, and to ignore the rest two (isostatic and tectonic). Jussereta and Baeteman do not believe that a particulate site could suffer alternate stages of subsidence and uplift. However, Aegean Sea is an area of high tectonic potential, which has shaped by the interplay compression and extension forces.

Finally, this answer gives evidence that the observational data concerning the Holocene RSL stands in unstable localities can be compared with those data extracted from a hydro-isostatic model to estimate rates of vertical displacement and, therefore, to detect uplifting, relative stable and subsiding regions. This approach is followed by many researchers who study various Mediterranean coasts

© 2011 Lavoisier SAS. All rights reserved     

Lake Cheko and the Tunguska Event: impact or non‐impact?

Several lines of evidence were presented in Gasperini et al. [Terra Nova (2007), vol. 19 , pp. 245–251] suggesting that Lake Cheko, a small lake close to the alleged epicentre of the 1908 Tunguska Event, might be a secondary impact crater. Collins et al. [Terra Nova (2008), this volume] argue against this hypothesis. We reply here arguing in favour of an impact origin for Lake Cheko.