The SAGE handbook of economic geography edited by A. Leyshon,R. Lee,L. McDowell and P. Sunley (eds), Sage,London, 2012. 411 pp. ISBN 978‐1‐84860‐114‐7.     

Etienne Nel 《New Zealand geographer》2014,70(2):150-151

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Liquidus surfaces of ultracalcic primitive melts: formation conditions and sources   总被引：4，自引：1，他引：3  

Etienne?MédardEmail author  Max?W.?Schmidt  Pierre?Schiano 《Contributions to Mineralogy and Petrology》2004,148(2):201-215

CaO-rich, Al₂O₃-poor ultracalcic primitive melts occur at mid-ocean-ridges, back-arc basins, ocean islands and volcanic arcs. They are subdivided into a nepheline-normative alkaline-rich, silica-poor group uniquely found in arcs and in hypersthene-normative fairly refractory melts which occur in all of the above environments. The high CaO contents (to 19.0 wt%) and CaO/Al₂O₃ ratios (to 1.8) exclude an origin from fertile lherzolites at volatile-absent conditions. Experimental investigation of the liquidus of a hypersthene-normative and a nepheline-normative ultracalcic melt results in quite distinct pressure-temperature conditions of multiple saturation: whereas the hypersthene-normative liquid saturates in olivine + clinopyroxene at 1.2 GPa and 1,410°C, this occurs at 0.2 GPa and 1,220°C for the nepheline-normative ultracalcic liquid. Our results in combination with melting experiments from the literature suggest that hypersthene-normative melts result from melting of a refractory olivine + clinopyroxene ± orthopyroxene source at elevated mantle temperatures. Contrasting, nepheline-normative ultracalcic melts form from wehrlitic cumulates in the arc crust; to account for the high alkaline and low silica contents, and the relatively low temperatures, source wehrlites must have contained amphibole.  相似文献   

Petrology,U/Pb dating and (C-O) stable isotope constraints on the source and evolution of the adakite-related Mezcala Fe-Au skarn district,Guerrero, Mexico     

Gilles?LevresseEmail author  Eduardo?González-Partida  Alejandro?Carrillo-Chavez  Jordi?Tritlla  Antoni?Camprubí  Alain?Cheilletz  Dominique?Gasquet  Etienne?Deloule 《Mineralium Deposita》2004,39(3):301-312

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Behaviour of Li and its isotopes during metasomatism of French Massif Central lherzolites     

Christiane Wagner  Etienne Deloule 《Geochimica et cosmochimica acta》2007,71(17):4279-4296

Li behaviour and distribution in the mantle were investigated by ion microprobe in situ measurements on co-existing olivine (ol), orthopyroxene (opx), clinopyroxene (cpx) and amphibole (amp) in xenoliths from the French Massif Central. The fertile spinel lherzolites of this study record increasing degrees of mantle metasomatism, from unmetasomatised anhydrous samples through cryptically metasomatised samples to highly metasomatised amphibole-rich samples. In anhydrous lherzolites, Li is preferentially incorporated into olivine (1.1-1.4 ppm, average values) compared to pyroxenes (0.2-0.9 ppm). The hydrous samples clearly show enrichment of Li in ol (1.5-5.0 ppm), opx (1.1-2.4 ppm) and cpx (2.4-5.4 ppm), while amphibole incorporates less Li than the co-existing phases (0.8-1.3 ppm). Average δ⁷Li values range from +7.6 to +14.5‰ in ol, from 5.1 to +13.7‰ in opx and from 8.8 to +10.3‰ in cpx from the anhydrous lherzolites. A layered peridotite sample (Sdi) shows higher Li content in all phases, with lighter isotopic composition in opx and cpx (−0.6 and −2‰ average δ⁷Li values, respectively). In the hydrous lherzolites average δ⁷Li values both overlap and extend beyond these ranges in ol (up to 17.5 ‰) and in opx (up to 22.9‰), and vary widely in cpx (−2.7 to +9.7‰). Low δ⁷Li values are observed in some opx (−10.4‰) and cpx (−13‰) from sample Sdi, and in cpx from three hydrous samples (from −9.7 to −5.3‰). The different anhydrous phases from the hydrous samples show large intra-grain variations in Li isotopic ratios (e.g., up to 18‰) compared to the same phases from the anhydrous samples (mostly less than 6‰), excepting sample Sdi which has up to 20.4‰ variation in cpx. Similar to the anhydrous silicates, amphiboles show a wide variation of δ⁷Li values on the intra-grain scale (2-27‰). These variations are interpreted to result from fractionation processes during metasomatism by a silicate melt undergoing compositional changes as it percolates through and reacts with the peridotite phases. Thus Li abundances and isotopic in situ measurements are useful for tracing metasomatic processes but the heterogeneities observed in the samples preclude any identification of a specific mantle source by its Li signature.  相似文献   

Corrigendum to “Revision of the Upper Cretaceous Rudists from Northwestern Peru” [South American Earth Science 17 (2004) 39–48]     

Jean Philip  Etienne Jaillard   《Journal of South American Earth Sciences》2005,19(4)

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变质锆石拉曼光谱研究--以大别造山带为例   总被引：5，自引：0，他引：5  

程昊  陈道公  Etienne Deloule  吴元保 《矿物学报》2002,22(4):353-358

对大别山的道士冲辉石岩、双河榴辉岩和碧溪岭石榴橄缆岩的锆石进行了激光拉曼探针，阴极发光（CL）观察和U、Th等微量元素的微区分析及U－Pb同位素测定，发现锆石拉曼光谱波数和半高宽都能指示其蜕晶化程度，但对于高度蜕晶化锆石，波数已经不再完全适用，而只能通过其特征谱峰半高宽来确定。碧溪岭石榴橄榄岩锆石微区微量元素和拉曼探针分析发现，半高宽和Th/U比正相关，这是由岩浆锆石在变质过程中不同程度的固态重结晶作用造成的，其可能曾经遭受过约220Ma的热事件扰动。双河榴辉岩锆石则可能遭受了流体参与下的变质重结晶作用的影响。锆石重结晶作用是变质岩中锆石年龄和化学组成变化的主要原因。  相似文献   

碧溪岭岩体中石榴橄榄岩的锆石显微结构及离子探针定年   总被引：7，自引：1，他引：7  

吴元保  陈道公  程昊  Etienne Deloule  夏群科 《高校地质学报》2001,7(3):356-362

对碧溪岭岩体中石榴橄榄岩的锆石进行了BSE和CL显微结构分析，并在此基础上用离子探针进行了锆石微区U－Pb定年。锆石CL图像显示其有明显的核边结构，核部具岩浆锆石，边部是变质增生锆石的特征。结合锆石的外形特征认为，边部的变质锆石是在超高压变质作用中重结晶形成的。离子探针分析结果在一致曲线图中构成不一致线，得到上下交点 年龄分别为824±39Ma和254±38Ma。结合CL图像认为上交点824±39Ma的年龄代表其原岩形成年龄，下交点254±38Ma为基超高压变质作用的年龄。另有少量较年龄的捕虏晶锆石，可能来自岩浆上升过程中同化混染的围岩。  相似文献   

The Origin and Significance of Debris-charged Ridges at the Surface of Storglaciären, Northern Sweden     

Neil F. Glasser  Michael J. Hambrey  James L. Etienne  Peter Jansson  Rickard Pettersson 《Geografiska Annaler: Series A, Physical Geography》2003,85(2):127-147

Storglaciären is a 3.2 km long polythermal valley glacier in northern Sweden. Since 1994 a number of small (1–2 m high) transverse debris‐charged ridges have emerged at the ice surface in the terminal zone of the glacier. This paper presents the results of a combined structural glaciological, isotopic, sedimentological and ground‐penetrating radar (GPR) study of the terminal area of the glacier with the aim of understanding the evolution of these debris‐charged ridges, features which are typical of many polythermal glaciers. The ridges originate from steeply dipping (50–70°) curvilinear fractures on the glacier surface. Here, the fractures contain bands of sediment‐rich ice between 0.2 and 0.4 m thick composed of sandy gravel and diamicton, interpreted as glaciofluvial and basal glacial material, respectively. Structural mapping of the glacier from aerial photography demonstrates that the curvilinear fractures cannot be traced up‐glacier into pre‐existing structures visible at the glacier surface such as crevasses or crevasse traces. These curvilinear fractures are therefore interpreted as new features formed near the glacier snout. Ice adjacent to these fractures shows complex folding, partly defined by variations in ice facies, and partly by disseminated sediment. The isotopic composition (δ¹⁸O) of both coarse‐clear and coarse‐bubbly glacier ice facies is similar to the isotopic composition of the interstitial ice in debris layers that forms the debris‐charged ridges, implying that none of these facies have undergone any significant isotopic fractionation by the incomplete freezing of available water. The GPR survey shows strong internal reflections within the ice beneath the debris‐charged ridges, interpreted as debris layers within the glacier. Overall, the morphology and distribution of the fractures indicate an origin by compressional glaciotectonics near the snout, either at the thermal boundary, where active temperate glacier ice is being thrust over cold stagnant ice near the snout, or as a result of large‐scale recumbent folding in the glacier. Further work is required to elucidate the precise role of each of these mechanisms in elevating the basal glacial and glaciofluvial material to the ice surface.  相似文献   

U–Pb zircon (TIMS and SIMS) and Sm–Nd whole-rock geochronology of the Gour Oumelalen granulitic basement, Hoggar massif, Tuareg shield, Algeria     

Jean Jacques Peucat  Amar Drareni  Louis Latouche  Etienne Deloule  Philippe Vidal 《Journal of African Earth Sciences》2003,37(3-4):229

Two major granulitic units are recognized in the Gour Oumelalen area. One of the units is composed partially of Archean gneisses (Red Gneiss complex) with U–Pb zircon SIMS and TIMS ages of approximately 2.7 Ga. Although they were formed from 3.0- to 3.2-Ga-old precursors, as indicated by Nd model ages, we find no evidence of any older history (≈3.5 Ga) as suggested by previous Pb–Pb ages. The other formation (Gour Oumelalen supergroup) is a metasedimentary sequence at least partly of Paleoproterozoic age, as indicated by zircon dates of a metavolcanic rock at approximately 2.2 Ga. A later magmatic event is recorded at approximately 1.9 Ga in both units and related to coeval granulite-facies metamorphism that affected both units. Nd model ages at approximately 2.0 Ga suggest an accretion of juvenile crust formation at that time. The existence of T_DM Nd model ages intermediate between 2.5 and 2.9 Ga could result from the mixing of 3.2 and 2.0-Ga-old material or may reflect separate events.  相似文献   

Andean geodynamics: main issues and contributions from the 4th ISAG, Göttingen     

Etienne Jaillard  Grard Hrail  Tony Monfret  Gerhard Wrner 《Tectonophysics》2002,345(1-4)

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