How does a monzogranite turn into a trachydacitic extrusion mantled by basinal volcaniclastics and peperites? The case of South-Ouessant, Armorican Variscides (France)

2020 ◽  
Vol 177 (6) ◽  
pp. 1161-1167
Author(s):  
Martial Caroff ◽  
Bernard Le Gall ◽  
Christine Authemayou
Keyword(s):  
Sedimentary Basin ◽  
Coarse Grained ◽  
Soft Substrate ◽  
Volcanic Origin ◽  
Pillow Lavas ◽  
Magmatic Body ◽  
Load Effects ◽  
New Perspective ◽  
Armorican Massif ◽  
Highly Strained

How many volcanic bodies are being confused with plutonic ones worldwide? The purpose of this study is not to provide an answer to this question, but rather to illustrate this issue through an example from the French Armorican Variscides. It concerns a magmatic body cross-cutting highly strained terranes in the Ouessant Island, regarded for decades as a granitoid (monzogranite) on the basis of both its coarse-grained texture and its mineralogy. However, the volcanic origin of the metamorphosed series flanking this foliated body is here recognized by pillow lavas, deposit layers, and fiamme-bearing volcaniclastics, all emplaced onto the soft-substrate floor of a fault-bounded basin. Among other things, similarities between feldspar megacrysts/porphyrocrysts in both the volcaniclastics and the adjoining (formerly) monzogranitic massive body lead us to reinterpret the latter as a trachydacitic extrusion. In our model, the corresponding viscous lava progressively flowed in the basin, recovering the earlier volcanic formations and inducing load effects on the underlying soft sediments, along with compaction of the previously deposited pumices, to produce fiamme. The interpretation of the South-Ouessant area as a Visean transtensional volcano-sedimentary basin provides a new perspective on the distribution of the Variscan pull-apart basins in the Armorican Massif.

Age and depositional environment of the Sainte-Anne Formation (Armorican Massif, France): the oldest (Emsian) evidence for mountain erosion in the Variscan belt

2009 ◽  
Vol 180 (6) ◽  
pp. 529-544 ◽  
Author(s):  
Céline Ducassou ◽  
Christine Strullu-Derrien ◽  
Michel Ballevre ◽  
Marie-Pierre Dabard ◽  
Philippe Gerrienne ◽  
...  
Keyword(s):  
Depositional Environment ◽  
Source Area ◽  
Variscan Orogeny ◽  
Variscan Belt ◽  
Delta Front ◽  
Volcanic Origin ◽  
Sedimentary Sequences ◽  
Erosion Level ◽  
Continental Area ◽  
Armorican Massif

Abstract The palaeogeography of the internal zones of the Variscan belt during the early stages of the convergence remains unclear. Sedimentary sequences that recorded the denudation of an early relief have generally been removed by erosion. In the Chalonnes area (southeast of the Armorican Massif), the reefal carbonates of the Chalonnes Formation (Fm) are overlain by the immature, poorly-sorted sandstones of the Sainte-Anne Fm. This formation is characterised by the occurrence of gravity flow deposits and contains immature and poorly sorted sandstones with a large amount of plant debris and lithic fragments, suggesting a depositional environment in a delta front dominated by floods. A revision of the palaeoflora content allows to assign an Emsian age to the Sainte-Anne Fm. Lithic fragments are mainly of sedimentary and volcanic origin, suggesting moderate erosion level of the source area. Palaeocurrent data indicate a southern origin for the sediments. These features collectively demonstrate that the Sainte-Anne Fm is the record of the erosion of a continental area located farther south, and experiencing incipient tectonic uplift during the Emsian. The Sainte-Anne Fm could represent therefore the earliest record in France of the very first stages of the Variscan orogeny.

scholarly journals Relations between basalts and adakitic–felsic intrusive bodies in a soft-substrate environment: the South Ouessant Visean basin in the Variscan belt, Armorican Massif, France

2016 ◽  
Vol 53 (4) ◽  
pp. 441-456 ◽  
Author(s):  
Martial Caroff ◽  
Bernard Le Gall ◽  
Christine Authemayou ◽  
Denise Bussien Grosjean ◽  
Cyrill Labry ◽  
...  
Keyword(s):  
High Pressure ◽  
Early Stage ◽  
Variscan Orogeny ◽  
Variscan Belt ◽  
Soft Substrate ◽  
Mafic Intrusions ◽  
Partial Remelting ◽  
Pressure Fractionation ◽  
Peraluminous Granites ◽  
Armorican Massif

The metasedimentary and magmatic terranes in the southern part of the Ouessant Island (Western Brittany, France) are the offshore prolongation of the Léon Variscan metamorphic domain. They mainly consist of micaschists and subordinate amphibolitic lenses (meta-pillow lavas and volcaniclastic successions) cut by a swarm of trondhjemite sills, together with a large porphyritic monzogranite body, newly dated at 336 Ma, and later syeno-leucogranitic intrusions. A large spectrum of fluidal peperites, including spectacular “fiamme”-bearing breccias, is observable at the contact between metasediments and most of the intrusives. The coexistence of amphibolitized basalts, adakitic trondhjemites, and peraluminous granites in the inferred South Ouessant basin is assigned to a variety of deep subcontemporaneous processes, including asthenospheric partial melting, high-pressure fractionation in lithospheric reservoirs (or partial remelting of deep crystallized mafic intrusions), and continental crust melting. Implications of these new results are discussed in the Visean basinal framework of the Armorican Massif, formed at an early stage of the Variscan orogeny.

A Vessel of the Funnel Beaker Culture at Salgótarján-Pécs-Kő

2020 ◽  
Vol 24 (1) ◽  
pp. 177-203
Author(s):  
Tünde Horváth ◽  
Attila Kreiter ◽  
Orsolya Viktorik
Keyword(s):  
Conclusive Evidence ◽  
Complex Situation ◽  
Volcanic Origin ◽  
Petrographic Analyses ◽  
Phase Iiib ◽  
Place Of Origin ◽  
Non Local ◽  
Funnel Beaker Culture ◽  
New Perspective

Abstract This study describes and discusses an old find from a wholly new perspective. The non-local fragment or fragments represent imports or imitations that can be linked to the Funnel Beaker culture and not to Kostolác, Coţofeni, Livezile or Bošáca as originally suggested by József Korek. The hallmarks distinctive to the culture are the ornamented rim exterior and rim interior, the zigzag motif under the rim and the ladder motif on the belly. However, the channelling on the belly is a typical Baden trait, which has not been noted on Funnel Beaker vessels to date. The best and closest analogies can be cited from the Baden settlement at Oldalfala/Stránska–Mogyorós, where they were erroneously identified as Coţofeni/Livezile imports. The occurrence of Funnel Beaker pottery on several sites on the southern fringes of the Western Carpathians suggests a more complex situation; however, their stratigraphic contexts on these multi-period, stratified sites remain unclear due to the field techniques employed during the old excavations. The determination of the exact place of origin is rather difficult within the culture’s vast distribution, although they can most likely be assigned to the Funnel Beaker eastern group, Wiórek phase (IIIB – IIIB-C in the current terminology), whose absolute dates fall between 3700/3600 and 3200 BC. The petrographic analyses revealed that the clay and the tempering agents are of local volcanic origin, providing conclusive evidence that Funnel Beaker vessels had been made locally. In this sense, the pottery fragment discussed here can be best described as a local hybrid product.

scholarly journals A new perspective on membrane-embedded Bax oligomers using DEER and bioresistant orthogonal spin labels

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Markus Teucher ◽  
Hui Zhang ◽  
Verian Bader ◽  
Konstanze F. Winklhofer ◽  
Ana J. García-Sáez ◽  
...  
Keyword(s):  
Hela Cell ◽  
Quaternary Structure ◽  
Coarse Grained ◽  
Spin Labels ◽  
Cell Extracts ◽  
Protein Label ◽  
New Perspective ◽  
The Stability ◽  
Double Electron Electron Resonance

Abstract Bax is a Bcl-2 protein crucial for apoptosis initiation and execution, whose active conformation is only partially understood. Dipolar EPR spectroscopy has proven to be a valuable tool to determine coarse-grained models of membrane-embedded Bcl-2 proteins. Here we show how the combination of spectroscopically distinguishable nitroxide and gadolinium spin labels and Double Electron-Electron Resonance can help to gain new insights into the quaternary structure of active, membrane-embedded Bax oligomers. We show that attaching labels bulkier than the conventional MTSL may affect Bax fold and activity, depending on the protein/label combination. However, we identified a suitable pair of spectroscopically distinguishable labels, which allows to study complex distance networks in the oligomers that could not be disentangled before. Additionally, we compared the stability of the different spin-labeled protein variants in E. coli and HeLa cell extracts. We found that the gem-diethyl nitroxide-labeled Bax variants were reasonably stable in HeLa cell extracts. However, when transferred into human cells, Bax was found to be mislocalized, thus preventing its characterization in a physiological environment. The successful use of spectroscopically distinguishable labels on membrane-embedded Bax-oligomers opens an exciting new path towards structure determination of membrane-embedded homo- or hetero-oligomeric Bcl-2 proteins via EPR.

scholarly journals From marginal outcrops to basin interior: a new perspective on the sedimentary evolution of the eastern Pannonian Basin

2021 ◽  
Author(s):  
István Róbert Bartha ◽  
Dániel Botka ◽  
Vivien Csoma ◽  
Lajos Tamás Katona ◽  
Emőke Tóth ◽  
...  
Keyword(s):  
Pannonian Basin ◽  
Sedimentary Facies ◽  
Time Frame ◽  
Well Logs ◽  
Coarse Grained ◽  
Small Satellite ◽  
Sedimentary Evolution ◽  
Seismic Sections ◽  
New Perspective ◽  
Uplift And Erosion

AbstractSedimentary successions exposed at basin margins as a result of late-stage inversion, uplift and erosion usually represent only a limited portion of the entire basin fill; thus, they are highly incomplete records of basin evolution. Small satellite basins, however, might have the potential of recording more complete histories. The late Miocene sedimentary history of the Șimleu Basin, a north-eastern satellite of the vast Pannonian Basin, was investigated through the study of large outcrops and correlative well-logs. A full transgressive–regressive cycle is reconstructed, which formed within a ca. 1 million-year time frame (10.6–9.6 Ma). The transgressive phase is represented by coarse-grained deltas overlain by deep-water lacustrine marls. Onset of the regressive phase is indicated by sandy turbidite lobes and channels, followed by slope shales, and topped by stacked deltaic lobes and fluvial deposits. The deep- to shallow-water sedimentary facies are similar to those deposited in the central, deep part of the Pannonian Basin. The Șimleu Basin is thus a close and almost complete outcrop analogue of the Pannonian Basin’s lacustrine sedimentary record known mainly from subsurface data, such as well-logs, cores and seismic sections from the basin interior. This study demonstrates that deposits of small satellite basins may reflect the whole sequence of processes that shaped the major basin, although at a smaller spatial and temporal scale.

scholarly journals Microstructure of Plasma Nitrided AISI420 Martensitic Stainless Steel at 673 K

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 60 ◽  
Author(s):  
Tatsuhiko Aizawa ◽  
Tomoaki Yoshino ◽  
Kazuo Morikawa ◽  
Sho-Ichiro Yoshihara
Keyword(s):  
Stainless Steel ◽  
Martensitic Stainless Steel ◽  
Nitrided Layer ◽  
Nitrogen Concentration ◽  
Coarse Grained ◽  
Two Phase ◽  
Fine Grained ◽  
Chromium Nitrides ◽  
Initial Stage ◽  
Highly Strained

Martensitic stainless steel type AISI420 was plasma nitrided at 673 K for 3.6 ks to investigate the initial stage of the nitrogen supersaturation process without the formation of iron and chromium nitrides. SEM-EDX, electron back-scattering diffraction (EBSD), and TEM analyses were utilized to characterize the microstructure of the nitrided layer across the nitriding front end. The original coarse-grained, fully martensitic microstructure turned to be α’- γ two phase and fine-grained by high nitrogen concentration. Below this homogeneously nitrided layer, α’-grains were modified in geometry to be aligned along the plastic slip lines together with the α’ to γ-phase transformation at these highly strained zones. Most of these α’-grains in the two-phase microstructure had a nano-laminated structure with the width of 50 nm.

A new perspective on the coarse-grained dynamics of fluids

2004 ◽  
Vol 120 (9) ◽  
pp. 4074-4088 ◽  
Author(s):  
Gary S. Ayton ◽  
Harald L. Tepper ◽  
Dina T. Mirijanian ◽  
Gregory A. Voth
Keyword(s):  
Coarse Grained ◽  
New Perspective

scholarly journals ORIGIN AND QUALITY OF THERMAL GROUNDWATERS IN THE REGION OF FARSALA (E. THESSALY/GREECE)

2007 ◽  
Vol 40 (2) ◽  
pp. 570 ◽  
Author(s):  
G. Stamatis ◽  
K. Parpodis ◽  
N. Lambrakis ◽  
E. Zagana
Keyword(s):  
Chemical Composition ◽  
Geothermal Field ◽  
Coarse Grained ◽  
Thermal Waters ◽  
Pillow Lavas ◽  
Geothermal Potential ◽  
Low Salt ◽  
Temperature Ranges

Farsala Basin presents a remarkable geothermal interest. Areas exhibiting geothermal potential are directly related to faulted zones, represented mainly by cross-faulted systems of E-W, NW-SE and NNE-SSW direction. Thermal waters occur in the areas of Ampelia and Krini in boreholes of 420 m depth. Their temperature ranges between 20,5° and 39,1° C. Thermal waters originate from meteoric waters, which have been infiltrated and heated in great depths, moved towards the surface through faults and hosted in the aquifers of coarse - grained formations find in the area. Their chemical composition is controlled by their contact with the volcanic parts (pillow lavas) of the ophiolithic series. They show alkaline character and low salts concentration. Waters of Ampelia region, which belong to Na-HCO^ type, exhibit temperatures from 27,9° to 39,1° C and low salt concentrations (405- 607 mg/l TDS). On the contrary, waters of Krini area present lower temperatures (20,5° -26,2° C) and higher salt concentrations (734-1850 mg/l TDS). These waters belong to Na-Mg-Ca-HCO^and Na-S04 -Cl-HCO} types. According to chemical geothermometers the study area can be classified to low enthalpy geothermal field, since the estimated thermal liquids temperature in great depths varies from 50° to 70° C.

scholarly journals CONDITIONS FOR THE FORMATION OF CLINOFORMS IN THE MIDDLE AND SOUTH CASPIAN MEGABASIN

2021 ◽  
Vol 2 (446) ◽  
pp. 82-89
Author(s):  
P. Z. Mammadov ◽  
R. Y. Ganiyevа
Keyword(s):  
Oil And Gas ◽  
Sedimentary Basin ◽  
Sedimentary Cover ◽  
Mobile Belt ◽  
South Caspian Basin ◽  
Stratigraphic Analysis ◽  
Central Segment ◽  
Specific Shape ◽  
New Perspective

The paper considers sedimentation process and objects of lateral development in deep-water uncompensated and shallow-water – epicontinental paleobasins developed at various evolution stages of South- Caspian and Middle-Caspian basins. The South Caspian megabasin is a great tectonic crustal element and a highly prospective sedimentary basin in the central segment of the Alpine-Himalayan mobile belt. The role of boundary structures of Scythian-Turan platform in the Middle Caspian (such as South-Caspian land and Karaboghaz arc) and avalanche sedimentation on the continental shelf in development of sedimentation units and specific shape objects of lateral development in many kilometers long sedimentary cover of South-Caspian basin has been shown. According to interpretation of seismo-stratigraphic data the inflow of paleodeltaic, avandelatic and turbidite objects of lateral development for infill of the Early Pliocene basin has been proved. Seismo-stratigraphic analysis, using other analyses (e.g. study of morphostructure of palaeorelief and thicknesses of the units and formations) and GSW, enabled the genesis of deposits in the underlying PS formations to be clarified from a new perspective and the favou- rable zones of formation of large lithological and stratigraphic traps for oil and gas accumulations to be identified.

Marginal marine depositional setting and correlation of the Devonian Sperm Bluff Formation (Taylor Group), southern Victoria Land, Antarctica

2013 ◽  
Vol 25 (6) ◽  
pp. 767-790 ◽  
Author(s):  
Jeni E. Savage ◽  
Margaret A. Bradshaw ◽  
Kari N. Bassett
Keyword(s):  
Sea Level ◽  
Sedimentary Basin ◽  
Coarse Grained ◽  
The West ◽  
Early Devonian ◽  
Sedimentary Environments ◽  
Late Precambrian ◽  
Victoria Land ◽  
Northern Side ◽  
Depositional Setting

AbstractAnalysis of conglomerates and sandstones of the Sperm Bluff Formation at the base of the Taylor Group (Devonian) between the Mackay Glacier and Bull Pass provides new insights into the nature of initial coarse-grained deposition on basement along the northern side of the McMurdo sedimentary basin. Six lithofacies are recognized in the Sperm Bluff Formation: conglomerate lithofacies, pebbly sandstone lithofacies, cross-bedded sandstone lithofacies, low-angle cross-stratified sandstone lithofacies, bioturbated sandstone lithofacies and interbedded siltstone/sandstone lithofacies. Sedimentary environments ranged from wave-dominated delta, estuary or lagoon to shoreface and inner shelf. The assemblage is thought to reflect changes in sea level. Rhyolite is the most abundant clast type in the coarse lithofacies, but is unknown in outcrop in southern Victoria Land. The rhyolites correlate in age and geochemistry with Cambrian granites in the basement. Coarse beds also contain numerous quartzite clasts, probably derived from the late Precambrian Skelton Group. Palaeocurrents on Mount Suess indicate a strong unimodal flow to the west, but other sites show polymodal palaeoflow. The Sperm Bluff Formation is correlated with Terra Cotta Siltstone, New Mountain Sandstone and Altar Mountain formations based on the lithology of sandstones and their ichnology. A northward onlap during the Early Devonian is indicated.

Sign in / Sign up

Export Citation Format

Share Document