Linking the NE Anatolian and Lesser Caucasus ophiolites: evidence for large-scale obduction of oceanic crust and implications for the formation of the Lesser Caucasus-Pontides Arc     

Marc Hässig  Yann Rolland  Marc Sosson  Ghazar Galoyan  Lilit Sahakyan  Gültekin Topuz 《Geodinamica Acta》2013,26(3-4):311-330

In the Lesser Caucasus and NE Anatolia, three domains are distinguished from south to north: (1) Gondwanian-derived continental terranes represented by the South Armenian Block (SAB) and the Tauride–Anatolide Platform (TAP), (2) scattered outcrops of Mesozoic ophiolites, obducted during the Upper Cretaceous times, marking the northern Neotethys suture, and (3) the Eurasian plate, represented by the Eastern Pontides and the Somkheto-Karabagh Arc. At several locations along the northern Neotethyan suture, slivers of preserved unmetamorphozed relics of now-disappeared Northern Neotethys oceanic domain (ophiolite bodies) are obducted over the northern edge of the passive SAB and TAP margins to the south. There is evidence for thrusting of the suture zone ophiolites towards the north; however, we ascribe this to retro-thrusting and accretion onto the active Eurasian margin during the latter stages of obduction. Geodynamic reconstructions of the Lesser Caucasus feature two north dipping subduction zones: (1) one under the Eurasian margin and (2) farther south, an intra-oceanic subduction leading to ophiolite emplacement above the northern margin of SAB. We extend our model for the Lesser Caucasus to NE Anatolia by proposing that the ophiolites of these zones originate from the same oceanic domain, emplaced during a common obduction event. This would correspond to the obduction of non-metamorphic oceanic domain along a lateral distance of more than 500?km and overthrust up to 80?km of passive continental margin. We infer that the missing volcanic arc, formed above the intra-oceanic subduction, was dragged under the obducting ophiolite through scaling by faulting and tectonic erosion. In this scenario part of the blueschists of Stepanavan, the garnet amphibolites of Amasia and the metamorphic arc complex of Erzincan correspond to this missing volcanic arc. Distal outcrops of this exceptional object were preserved from latter collision, concentrated along the suture zones.  相似文献   

Pliocene to Quaternary deformation in the Var Basin (Nice, SE France) and its interpretation in terms of “slow-active” faulting     

Victorien Bauve  Yann Rolland  Guillaume Sanchez  Gérard Giannerini  Dimitri Schreiber  Michel Corsini  Jean-Louis Perez  Adrien Romagny 《Swiss Journal of Geoscience》2012,105(3):361-376

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晋冀豫交界地区地壳三维速度结构与地震分布特征          下载免费PDF全文

刘巧霞  徐志萍  邱勇  段永红  姜磊  莘海亮  赵延娜  贾宇鹏  张丹 《地震工程学报》2021,43(6):1251-1262,1279

利用区域双差层析成像方法,基于2008年10月—2018年6月近震资料,对晋冀豫交界地区记录到的地震事件进行震源位置与P波、S波三维速度结构的联合反演。重新定位后,地震空间位置得到明显改善,浅部的速度结构与地形及沉积层厚度对应较好,研究区内控制性断裂和地震多分布在太行山隆起区的高、低速变化梯级带上。对比分析研究区内不同构造单元及同一构造单元不同深度的P、S波速度异常特征及其与中小地震和历史强震的分布关系,结合研究区内历史强震和现今中、小震分析发震构造及深部孕震环境,为该区未来强震危险区判定提供科学依据。  相似文献   

Steady-state vertical distribution of cohesive sediments in a flow   总被引：1，自引：0，他引：1  

Martin Sánchez  Patricia Grimigni  Yann Delanoë 《Comptes Rendus Geoscience》2005,337(3):357-365

Settling velocity of diluted suspended aggregates is examined under steady-state conditions. It is shown that if the local settling velocity of the suspended mass of sediments at the bottom is gamma distributed, then, the vertical variation of the local mean settling velocity $\overline{W}$ is proportional to a power $1/r$ of the local concentration C, where r is the gamma distribution parameter. That is a consequence of the suspended-sediment sorting produced by the vertical dynamics. The parameter r characterizes the range of settling velocity values for all the aggregates simultaneously in suspension. To cite this article: M. Sánchez et al., C. R. Geoscience 337 (2005).  相似文献   

A composition-independent quantitative determination of the water content in silicate glasses and silicate melt inclusions by confocal Raman spectroscopy   总被引：2，自引：0，他引：2  

Zoltán Zajacz  Werner Halter  Wim J. Malfait  Olivier Bachmann  Robert J. Bodnar  Marc M. Hirschmann  Charles W. Mandeville  Yann Morizet  Othmar Müntener  Peter Ulmer  James D. Webster 《Contributions to Mineralogy and Petrology》2005,150(6):631-642

A new approach was developed to measure the water content of silicate glasses using Raman spectroscopy, which is independent of the glass matrix composition and structure. Contrary to previous studies, the compositional range of our studied silicate glasses was not restricted to rhyolites, but included andesitic, basaltic and phonolitic glasses. We used 21 glasses with known water contents for calibration. To reduce the uncertainties caused by the baseline removal and correct for the influence of the glass composition on the spectra, we developed the following strategy: (1) application of a frequency-dependent intensity correction of the Raman spectra; (2) normalization of the water peak using the broad T–O and T–O–T vibration band at 850–1250 cm⁻¹ wavenumbers (instead of the low wavenumber T–O–T broad band, which appeared to be highly sensitive to the FeO content and the degree of polymerization of the melt); (3) normalization of the integrated Si-O band area by the total number of tetrahedral cations and the position of the band maximum. The calibration line shows a ±0.4 wt% uncertainty at one relative standard deviation in the range of 0.8–9.5 wt% water and a wide range of natural melt compositions. This method provides a simple, quick, broadly available and cost-effective way for a quantitative determination of the water content of silicate glasses. Application to silicate melt inclusions yielded data in good agreement with SIMS data.  相似文献   

Paleotectonic evolution of the Zürcher Weinland (northern Switzerland), based on 2D and 3D seismic data     

Robin Marchant  Yann Ringgenberg  Gérard Stampfli  Philip Birkh?user  Philippe Roth  Beat Meier 《Eclogae Geologicae Helvetiae》2005,98(3):345-362

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Ultraviolet Laser Sampling and High Resolution Inductively Coupled Plasma-Mass Spectrometry of NIST and BCR-2G Glass Reference Materials     

Yann Lahaye  David Lambert  Steve Walters 《Geostandards and Geoanalytical Research》1997,21(2):205-214

A Merchantek LUV266 ^TM petrographic ultraviolet (UV) laser microprobe has been used in conjunction with a Finnigan MAT ELEMENT ^TM high resolution ICP double-focusing mass spectrometer (HR-ICP-MS) for solid microsampling and geochemical analysis. This new configuration for laser ablation has the advantage of coupling the high sensitivity and fast scanning technology applied in the ELEMENT with the ablation efficiency of a UV laser. Optimisation of the configuration on the synthetic NIST SRM 612 glass standard reference material using Q-switched UV laser energy of 2 mJ and a 5 Hz repetition rate demonstrates: (1) a linear element response factor throughout the mass spectrum, suggesting limited fractionation during laser ablation; (2) a high sensitivity and very low background noise for most elements of interest; (3) limits of detection ranging from 3 ng g-1 for Sc to 300 pg g-1 for U; (4) a flat topped peak shape suitable for precise isotopic measurements; and (5) a flat bottomed crater geometry which permits progressive ablation for the analysis of thin sections. Average precision and accuracy estimates based on replicate analyses of synthetic NIST standard reference material and USGS BCR-2G glasses are below 10% for most elements.  相似文献   

Unprecedented risk of spring frost damage in Switzerland and Germany in 2017     

Yann Vitasse  Martine Rebetez 《Climatic change》2018,149(2):233-246

Spring frosts are feared by farmers, fruit growers, and wine growers as they can cause significant damage to crops when they occur during the development of the plants. In the second half of April 2017, following a very warm period that had caused premature vegetation growth, a cold air mass from the Arctic penetrated central and western Europe, causing severe damage to natural and cultivated vegetation over broad areas. Here, we analyze how exceptional this event was in Switzerland and Germany in relation to the accumulated growing degree days (GDD), used as a proxy for plant phenology advancement. Although this damaging frost was not the latest on record in terms of calendar days, our results show that it was, in some regions, unprecedented in relation to the accumulated warmth during the preceding period, at least since the beginning of instrumental temperature records (1864). Our results also highlight how global warming has considerably increased the number of days with mean temperature above 5 °C in late winter and early spring, especially since 1970 (+?16.8?±?4.7 °C days decade^?1). However, in spite of earlier spring phenology due to climate warming, our results suggest that the risk of damaging frost events to vegetation has remained unchanged over the last 150 years in lowlands of Switzerland and Germany, due to the concurring earlier occurrence of the last potentially damaging frosts (about ??20 days since 1864). Our analyses reveal therefore that the April 2017 damaging frost was a true outlier in terms of risk of frost damage to plants.  相似文献   

Shorter snow cover duration since 1970 in the Swiss Alps due to earlier snowmelt more than to later snow onset   总被引：1，自引：0，他引：1  

Geoffrey Klein  Yann Vitasse  Christian Rixen  Christoph Marty  Martine Rebetez 《Climatic change》2016,139(3-4):637-649

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Spatial stabilization and intensification of moistening and drying rate patterns under future climate change     

Yann Chavaillaz  Sylvie Joussaume  Sandrine Bony  Pascale Braconnot 《Climate Dynamics》2016,47(3-4):951-965

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