Geothermometry of eclogites and other high pressure (HP)/ultrahigh‐pressure (UHP) rocks has been a challenge, due to severe problems related to the reliability of the garnet–clinopyroxene Fe–Mg ...exchange thermometer to omphacite‐bearing assemblages. Likewise, reliable geobarometers for eclogites and related HP/UHP rocks are scarce. In this paper, a set of internally consistent geothermobarometric expressions have been formulated for reactions between the UHP assemblage garnet–clinopyroxene–kyanite–phengite–coesite, and the corresponding HP assemblage garnet–clinopyroxene–kyanite–phengite–quartz. In the system KCMASH, the end members grossular (Grs) and pyrope (Prp) in garnet, diopside (Di) in clinopyroxene, muscovite (Ms) and celadonite (Cel) in phengite together with kyanite and coesite or quartz define invariant points in the coesite and quartz stability field, respectively, depending on which SiO2 polymorph is stable. Thus, a set of net transfer reactions including these end members will uniquely define equilibrium temperatures and pressures for phengite–kyanite–SiO2‐bearing eclogites. Application to relevant eclogites from various localities worldwide show good consistency with petrographic evidence. Eclogites containing either coesite or polycrystalline quartz after coesite all plot within the coesite stability field, while typical quartz‐bearing eclogites with no evidence of former coesite fall within the quartz stability field. Diamondiferous coesite–kyanite eclogite and grospydite xenoliths in kimberlites all fall into the diamond stability field. The present method also yields consistent values as compared with the garnet–clinopyroxene Fe–Mg geothermometer for these kinds of rocks, but also indicates some unsystematic scatter of the latter thermometer. The net transfer geothermobarometric method presented in this paper is suggested to be less affected by later thermal re‐equilibration than common cation exchange thermometers.
The history of predation is recorded primarily from drilling in Cenozoic invertebrates. Quantitative data are uncommon from the Triassic, a period before the appearance and radiation of many known ...drill hole producers such as various gastropod families and octopods. We present quantitative evidence of drilling from the Late Triassic (Carnian) Cassian Formation of Italy and the Middle Triassic (Anisian) Lower Muschelkalk of Poland, documenting the first drill holes in Triassic brachiopods. A single brachiopod with a cylindrical, complete drill hole was found in a brachiopod sample from of Poland (drilling percentage=0.3%, n=365). The Cassian Formation yielded drill holes in gastropods, bivalves, and brachiopods, indicating that more species are drilled than was known previously. The minimum drilling percentage exclusive of incomplete drill holes of a sample from the Stuores Wiesen (Cassian Formation) is 1.7% (n=116.5). Prey selectivity is evident: complete drill holes are primarily present in one gastropod species, Polygyrina lommeli (11.8% of specimens with a complete drill hole), whereas other common species were not drilled. Single drill holes in brachiopods are cylindrical and complete and may be predatory in origin. Multiple drill holes in mollusks are common, and drill holes are parabolic and often incomplete with a central boss, resembling the shape of drill holes produced by extant naticid gastropods. A survey of the Paleozoic literature showed that such drill holes are also present in Devonian and Carboniferous brachiopods. However, naticids did not evolve until the Cretaceous so we propose the term “drill hole convergence” for similar-shaped drill holes produced by different organisms. The Triassic parabolic drill holes are not caused by domicile-seeking or boring organisms. Instead, we favor a predatory origin of these drill holes, but we cannot entirely rule out parasitism. Surveying other Triassic invertebrate assemblages should yield more evidence of drilling.
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•We report on rare drill holes in mollusks and brachiopods from the Triassic.•The drill holes are most likely made by predators or, perhaps, parasites.•Most drill holes resemble those produced by modern naticid gastropods.•Similar holes also occur in the Paleozoic, when naticids were also absent.•“Drill hole convergence”: similar-shaped holes drilled by different organisms.
Little is known about water in nominally anhydrous minerals of orogenic garnet peridotite and enclosed metabasic rocks. This study is focused on peridotite‐hosted eclogite and garnetite ...(metarodingite) from the Erzgebirge (EG), Germany, and the Lepontine Alps (LA), Switzerland. Newly discovered, peridotite‐hosted eclogite in the Erzgebirge occurs in the same ultra‐high pressure (UHP) unit as gneiss‐hosted coesite eclogite, from which it is petrologically indistinguishable. Garnet is present in all mafic and ultramafic high pressure (HP) rocks providing for an ideal proxy to compare the H2O content of the different rock types. Garnet composition is very similar in EG and LA samples and depends on the rock type. Garnet from garnetite, compared to eclogite, contains more CaO (garnetite: 10.5–16.5 wt%; eclogite: 5–11 wt%) and is also characterized by an anomalous REE distribution. In contrast, the infrared (IR) spectra of garnet from both rock types reveal the same OH absorption bands that are also identical to those of previously studied peridotitic garnet from the same locations. Two groups of IR bands, SW I (3,650 ± 10 cm−1) and SW II (3,570–3,630 cm−1) are ascribed to structural hydroxyl (colloquially ‘water’). A third, broad band is present in about half of the analysed garnet domains and related to molecular water (MW) in submicroscopic fluid inclusions. The primary content of structural H2O, preserved in garnet domains without fluid inclusions (and MW bands), varies systematically—depending on both the location and the rock type. Garnet from EG rocks contains more water compared to LA samples, and garnet from garnetite (EG: 121–241 wt.ppm H2O; LA: 23–46 wt.ppm) hosts more water than eclogitic garnet (EG: 84 wt.ppm; LA: 4–11 wt.ppm). Higher contents of structural water (SW) are observed in domains with molecular water, in which the SW II band (being not restricted to HP conditions) is simultaneously enhanced. This implies that fluid influx during decompression not only led to fluid inclusions but also favoured the uptake of secondary SW. The results signify that garnet from all EG and LA samples was originally H2O‐undersaturated. Combining the data from eclogite, garnetite and previously studied peridotite, H2O and CaO are positively correlated, pointing to the same degree of H2O‐undersaturation at peak metamorphism in all rock types. This ubiquitous water‐deficiency cannot be reconciled with the derivation of any of these rocks from the lowermost part of the mantle wedge that was in contact with the subducting plate. This agrees with the previously inferred abyssal origin for part of the rocks from the LA (Cima di Gagnone). A similar origin has to be invoked for the Erzgebirge UHP unit. We suggest that all mafic and ultramafic rocks of this unit not only shared the same metamorphic evolution but also a common protolith origin, most probably on the ocean floor. This inference is supported by the presence of peridotite‐hosted garnetite, representing metamorphosed rodingite.
Rad sagledava ranije poznate i nepoznate grobne nalaze kasnog
10. i 11. stoljeća iz Šenkovca, Sv. Jurja u Trnju i Sv. Martina na
Muri u Međimurju. Njihovom, prvi put cjelovitom obradom, na
jednome ...mjestu upotpunjena su saznanja o procesima koji se
događaju između Drave i Mure te širem prostoru istočnih Alpi
i Panonske nizine. Za prepoznavanje i utvrđivanje regionalnog
okvira bilo je potrebno kartiranje analogija za grobne nalaze.
Stavljanje u povijesni kontekst pružilo je neophodne determinante
za razumijevanje tog prostora, a dodatni ekskursi o transformacijama
ranoga srednjeg vijeka u međurječju Drave i Mure
upotpunili su interpretaciju grobnih nalaza.
The late Eocene-to-early Oligocene Taveyannaz Formation is a turbidite series deposited in the Northern Alpine Foreland Basin (close to the Alpine orogenic front). Double dating of zircons with the ...fission-track and the U–Pb methods is applied on samples from the Taveyannaz Formation to reconstruct the exhumation history of the Central-Western Alps and to understand the syn-collisional magmatism along the Periadriatic lineament. Three samples from this unit show similar detrital zircon fission-track age populations that center at: 33–40 Ma (20%); 69–92 Ma (30–40%); and 138–239 Ma (40–50%). The youngest population contains both syn-volcanic and basement grains. Combined with zircon U–Pb data, it suggests that the basement rocks of Apulian-affinity nappes (Margna Sesia, Austroalpine) were the major sources of detritus, together with the Ivrea Zone and recycled Prealpine flysch, that contributed debris to the Northern Alpine Foreland Basin. Furthermore, the rocks of the Sesia–Lanzo Zone or of equivalent units exposed at that time presumably provided the youngest basement zircon fission-track ages to the basin. The Biella volcanic suite was the source of volcanogenic zircons. Oligocene sediment pathways from source to sink crossed further crystalline basement units and sedimentary covers before entering the basin from the southeast. The lag times of the youngest basement age populations (volcanic zircons excluded) are about 11 Myr. This constrains average moderate-to-high exhumation rate of 0.5–0.6 km/Myr in the pro-side of the orogenic wedge of the Central Alps during the late Eocene to early Oligocene.
Geochemical signatures and carbonate microfacies highlight contrasts between two distinctive mid–late Triassic reef communities in the Dolomite Alps, Italy. In the first community, sponges, ...bryozoans, calcified cyanobacteria and problematic organisms (Archaeolithoporella, Shamovella), together with a variety of micritic fabrics, formed compact reefs in high energy shallow-water at the margins of high-rise Ladinian–Carnian carbonate platforms. Debris from these margins created steep foreslopes, and some large blocks of the allochthonous material (Wengen–Cassian formations, Cipit Boulders) were buried in basinal shales that protected them from subsequent alteration and regional dolomitization. In the second and slightly younger community, small Carnian patch reefs (Heiligkreuz Formation, Alpe di Specie) developed in quieter shallow water, where they too were protected against alteration by enclosing shales. They were constructed mainly by scleractinian corals, sponges and red algae, and contain relatively large framework cavities with clotted-peloidal micrite. These early examples of coralgal reefs have broad similarities to present-day examples, whereas the community represented by the Cipit Boulders has more in common with Late Permian reefs.
Both bioconstructions preserve primary microfabrics and biomarkers. The Cipit Boulder samples contain bacterial, mainly cyanobacterial biomarkers, lack specific molecules typical of sulfate-reducing bacteria (SRB), and have Rare Earth Element (REE) values indicative of oxic conditions. These signatures are consistent with their original high-energy platform margin location, compact structure, and presence of calcified cyanobacteria such as Cladogirvanella and Girvanella. In contrast, the coralgal patch reefs contain SRB biomarkers, lack specific molecules typical of cyanobacteria, and have REE values indicative of sub-oxic conditions. These signatures are consistent with their lower energy depositional conditions and well-developed skeletal framework that created protected low-oxygen micro-habitats. The SRB biomarkers can be linked to the associated clotted-peloidal fabrics which resemble those commonly present in younger coral-reef frameworks. These details of redox conditions and bacterial processes underscore the important biotic, structural and environmental changes that affected shallow marine reefs during the Triassic.
•The first combined biomarker and REE analyses of contrasting Triassic reef types.•High rise reefs have cyanobacterial biomarkers and oxic (REE) distributions.•Quieter water reefs have BSR biomarkers and sub-oxic REE signatures.•These reefs mark a key transition from Paleozoic- to modern-type coralgal reefs.
En el bicentenario de la aparición de la bicicleta, este trabajo quiere ser una indagación en el lenguaje sectorial del ciclismo, más allá del que aparece en las crónicas periodísticas, que es el ...único que hasta ahora ha contado. Para ello, se analiza una novela que es un compendio ciclista. En El Alpe d´Huez (1994) de Javier García Sánchez se entrecruzan diversos códigos léxicos especializados a los que la creación literaria potencia con otro más abarcador: el mítico, de hondas raíces antropológicasOn The bicentenary of the bicycle’s origin, this work strives to be an inquest into the sectoral language of cycling, apart from that in the journalistic chronicles, which is the only one that has mattered so far. For that purpose, we will analyse a novel which is a cyclist compendium. In the Alpe d’Huez (1994), by Javier García Sánchez, different specialised lexical codes intertwine, and literary creation enhances them with yet another code, a more comprehensive one: the mythical one, with deep anthropological roots.
The Post-Forum Study Tour following the 4th World Landslide Forum 2017 in Ljubljana (Slovenia) focuses on the variety of landslide forms in Slovenia and its immediate NW surroundings, and the ...best-known examples of devastating landslides induced by rainfall or earthquakes. They differ in complexity of the both surrounding area and of the particular geological, structural and geotechnical features. Many of the landslides of the Study Tour are characterized by huge volumes and high velocity at the time of activation or development in the debris flow. In addition, to the damage to buildings, the lives of hundreds of people are also endangered; human casualties occur. On the first day, we will observe complex Pleistocene to recent landslides related to the Mesozoic carbonates thrust over folded and tectonically fractured Tertiary siliciclastic flysch in the Vipava Valley (SW Slovenia), serving as the main passage between the Friulian lowland and central Slovenia, and thus also an important corridor connecting Northern Italy to Central Europe. A combination of unfavourable geological conditions and intense short or prolonged rainfall periods leads to the formation of different types of complex landslides, from large-scale deep-seated rotational and translational slides to shallow landslides, slumps and sediment gravity flows in the form of debris or mudflows. The second day of the study tour will be held in the Soča River Valley located in NW Slovenia close to the border with Italy, where the most catastrophic Stože landslide in Slovenia recently caused the deaths of seven people, and the nearby Strug landslide, which is a combination of rockfall, landslide and debris flow. The final day of the Post-Forum Study Tour will start in the Valcanale Valley located across the border between Slovenia and Italy, severely affected by a debris flow in August 2003. The flow caused the deaths of two people, damaged 260 buildings; large amounts of deposits blocked the A23 Highway, covering both lanes. In Carinthia (Austria), about 25 km west of Villach, the Dobrač/Dobratsch multiple scarps of prehistoric and historic rockslides will be observed. Dobratsch is a massive mountain ridge with a length of 17 km and a width of 6 km, characterized by steep rocky walls. The 3-day study tour will conclude with a presentation of the Potoška planina landslide, a slide whose lower part may eventually generate a debris flow and therefore represents a hazard for the inhabitants and for the infrastructure within or near the village of Koroška Bela.
The Alps are one of the most sensitive regions in Europe, and their future development represents a challenge that demands the cooperation of various experts, the business world, politics, and ...society, as well as the people living there. The Interreg IIIB project DIAMONT, which took place from 2005 to 2008, also addressed Alpine developmental challenges. This monograph presents the basic results of the project, supported by the broader theoretical framework of regional and sustainable development. We first present the cultural differences in the Alps and their influence on sustainable regional development. This is followed by the results of a Delphi analysis, which helped reveal the basic development tendencies in the Alps, and then we discuss appropriate indicators for regional development and harmonizing data. Attention is then dedicated to regional development instruments and the participative process, which is essential for attaining truly sustainable development. Finally, we present a Slovenian perspective on these issues.
Sodobna družboslovna in humanistična razmišljanja ter medijski diskurzi se pri iskanju rešitev za težave v centraliziranem, tehnologiziranem, kapitaliziranem in politično zastopniškem svetu pogosto ...zgledujejo po predindustrijskih ali etnografskih organizacijskih modelih, ki so jih zabeležili etnologi in antropologi. Pri tem prihaja do idealiziranja in posploševanja, saj se zanemarja številne konkretne okoliščine, ki so te modele omogočile ali jih še omogočajo. Razloge za oblikovanje kolektivnih institucij na izbrani mikrolokaciji avtor išče predvsem v okoljskih in demografskih danostih, ki so v slovenskih antropoloških spisih pogosto spregledane. K temu dodaja ekonomske, politične in kulturne dejavnike, čeprav jih ne postavlja v hierarhični odnos. Avtor išče znamenja skupnostnih prizadevanj v Trenti na ravni gospodinjstev, soseščin, vasi, agrarnih skupnosti, zadrug, kulturnih in turističnih društev ter praznikov. Ugotavlja, da je v majhni skupnosti recipročnost generalizirana ali uravnotežena, zelo redko pa je negativna v smislu tržnih menjav med njenimi člani, s čimer pritrjuje Sahlinsovi konceptualizaciji razmerij med družbenimi odnosi in materialnimi tokovi. Posebna pozornost je posvečena tržno-religioznemu lokalnemu prazniku Trentarski senjem. Z njegovo analizo je mogoče zelo plastično prikazati, kako na simbolni (prostorsko-časovni) ravni odsevajo spremembe v družbeno-ekonomski strukturi doline v 20. stoletju.
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