Is the HP–UHP Hong’an–Dabie–Sulu orogen a piercing point for offset on the Tan–Lu fault?

The Tan–Lu fault is a major strike-slip fault in eastern China that appears to offset the high-grade rocks of the Hong’an–Dabie–Sulu orogen left-laterally ∼540 km. We evaluate models for the collision between the South and North China blocks, published radiometric dates recording HP–UHP metamorphism and exhumation in the Hong’an–Dabie and Sulu terranes, and the timing of sinistral motion on the Tan–Lu fault to evaluate whether UHP rocks provide a piercing point for offset on the Tan–Lu fault. UHP metamorphism in Hong’an–Dabie was concurrent with Sulu based on U–Pb dating of coesite-bearing domains of zircon at 244 ± 5–226 ± 2 Ma for Hong’an–Dabie and 243 ± 4–225 ± 2 Ma for Sulu. Retrograde metamorphism began c. 220 Ma for both Hong’an–Dabie and Sulu, but retrograde zircon growth ended c. 214 Ma in Hong’an–Dabie and continued until c. 202 Ma in Sulu based on U–Pb dating of zircon domains external to coesite-bearing domains. Structures in Sulu are rotated 25° counter-clockwise from, but are broadly similar to, Hong’an–Dabie suggesting the two areas have a common Triassic orogenic history that pre-dates motion on the Tan–Lu fault, and that is consistent with paleomagnetic studies. We constructed a pre-Cretaceous restoration of the Hong’an–Dabie–Sulu belt that moves the Sulu terrane south, aligning the suture and the eclogite-facies isograd, and rotates Sulu c. 25° clockwise to re-align structures with Hong’an–Dabie. Our restoration is supported by published data and shows that the Hong’an–Dabie–Sulu orogen is a piercing point for post-collisional offset on the Tan–Lu fault and that these regions shared a common subduction–exhumation history. The Tan–Lu fault did not play a significant role in the Hong’an–Dabie–Sulu collision and likely developed later, in the Early Cretaceous.     

Regional aeromagnetic and stratigraphic correlations of the Kalahari Copperbelt in Namibia and Botswana

The late Mesoproterozoic to Neoproterozoic Kalahari Copperbelt (KCB) in Namibia and Botswana is widely covered by Kalahari sand, which precludes direct correlations between known stratabound sediment-hosted Cu–Ag districts. We use a combination of review of literature data, and newly processed and interpreted high-resolution aeromagnetic maps in both countries to provide a new correlative cross-border interpretation. Lithostratigraphic control on the aeromagnetic response allows detailed indirect mapping of the Kalahari Copperbelt lithotectonic domains below the sand cover. This enabled us to redefine the width and lateral extent of the KCB as two continuous magnetic domains (the Rehoboth and Ghanzi–Chobe domains) extending from central Namibia to northern Botswana, and helped in resolving problems of stratigraphic correlations across the international border.The Rehoboth magnetic domain, in the western part of the KCB in Namibia, records continental arc magmatism at ~ 1200 Ma during orogenic events along the northwestern edge of the Kalahari Craton. This was followed at 1110–1090 Ma by widespread magmatism, identified within the entire KCB, and related to the 1112–1106 Ma Umkondo Large Igneous Province. The basal parts of the Tsumis Group in Namibia and Ghanzi Group in Botswana were deposited in shallow-water environments after a period of erosion and peneplanation. Subsequently, and prior to the Sturtian glaciation, the host-rocks of the Cu–Ag deposits formed by the deposition of chemically reduced shales and siltstones that formed in deeper water and overlie chemically oxidised shallow-water sandstones. This regional interface, which is both a permeability barrier and redox boundary, played a critical role in the formation of the stratabound sediment-hosted Cu–Ag deposits of the Kalahari Copperbelt, and the interface, with its strong magnetic contrast, can be followed through the entire Ghanzi–Chobe magnetic domain of the copperbelt. The whole KCB was affected by the Damara Orogeny during early Cambrian times, which resulted in the formation of a NE–SW trending ~ 250 km-wide fold-and-thrust belt.     

Geochemistry and petrogenesis of the Gallego Volcanic Field,Solomon Islands,SW Pacific and geotectonic implications

The Upper Miocene to present day Gallego Volcanic Field (GVF) is located in northwest Guadalcanal, Solomon Islands, SW Pacific, and potentially includes the offshore Savo volcano. The GVF is a multi-centred complex covering an area of ~ 800 km² on Guadalcanal and a further ~ 30 km² on the island of Savo, north of west Guadalcanal. GVF volcanism is characterised by effusive eruptions of lava, intrusion of sub-volcanic plutons, as well as pyroclastic flow and fall deposits dominated by block and ash flow deposits. Geochemical analysis of a representative suite of samples from the GVF demonstrates that the GVF comprise largely a ‘main suite’ of basalts to andesites and minor trachyandesites. The predominant mineralogy of the GVF comprises plagioclase, amphibole, clinopyroxene and magnetite-ilmenite. Associated with the ‘main suite’ are cognate nodules composed of hornblendite, gabbros, and clinopyroxenite. Interpretation of major and trace element geochemistry and petrographic studies suggests that fractionation was dominated by early clinopyroxene, and later amphibole + clinopyroxene + minor plagioclase. Geochemical features such as the incompatibility of Sr suggest that plagioclase largely crystallised en-masse late in the fractionation sequence. The presence of amphibole and late fractionation of plagioclase is suggestive of derivation from initially water-rich magmas. The region is characterised by strong geographically-related geochemical variations as evidenced by the Woodlark (and Manus) basins: basalts become more arc-like within the ocean basins with decreasing distance to the subducting trench. The GVF-Savo volcanoes are spatially and geochemically affected by deep N-S fractures that show some evidence of sympathetic geochemical variations with distance from the trench (e.g. Sr/Y ratios). Comparison with a range of international data for Th/Nb vs Pb/Nb and Dy/Yb vs SiO₂ indicate that: amphibole was indeed a strong controlling phase on magmatic evolution; garnet had no obvious role; there was little sediment input into the source region; that relative Pb/Nb enrichments may be linked to similar enrichments within the subducting Woodlark basin (and by analogy with the Manus basin and its abundant hydrothermal Pb-rich sulphide deposits); and the predominant influence on the source region for GVF-Savo was from metasomatic fluids and/or melts from the slab subducting at the southern trench.     

Mimicking state diplomacy: The legitimizing strategies of unofficial diplomacies

Diplomacy and recognition play central roles in the conventional conferral of state legitimacy and functioning of the inter-state system. In broadening the diplomatic frame by stepping outside the conventional state-system, this paper brings a poststructuralist and performative toolkit to mimetic diplomatic practices. Adapting Bhabha’s notion of mimicry to diplomatic discourse, it demonstrates how non-state diplomacies draw on, mimic and intervene in the realm of formal political action in ways which both promote ‘official’ state diplomacy as an ideal and dilute its distinction from other, ‘unofficial’ diplomacies. In thereby examining the enactment of international diplomacy in unexpected spaces, this paper brings together three empirical studies: a Government-in-Exile, a religious community and micropatrias (self-declared parodic nations). In each of these cases, attention focuses on: discourses of recognition; sovereignty and legitimacy; the diplomatic relationships fostered and institutions of diplomacy constructed; and the strategic position of such diplomacy vis-à-vis the conventional state-system. Unpacking the relationship between legitimacy, recognition and diplomacy and exploring the tension between state-centric and non-state diplomatic practices, this paper foregrounds the points of connection between the official and the unofficial. As a result, this paper expands the analytical gaze of diplomacy studies while incorporating lessons from the margins into our understandings of legitimacy, recognition, statecraft and sovereignty.     

Rifting,subduction and collisional records from pluton petrogenesis and geochronology in the Hindu Kush,NW Pakistan

New U-(Th)/Pb geochronology and geochemical analyses of plutonic bodies in the Hindu Kush range, NW Pakistan, provide insight on the crustal growth and tectonic evolution of the southern Eurasian margin. These new data outline a protracted magmatic history that spans the Cambrian to the Neogene (ca. 538 to 23 Ma) and record a variety of petrogenetic associations variably influenced by within plate, volcanic arc, and collision tectonic environments. The Kafiristan pluton (538 ± 4 to 487 ± 3 Ma) yields geochemical signatures consistent with extensional plutonism and rifting of the Hindu Kush terrane from Gondwana. The Tirich Mir (127 ± 1 to 123 ± 1 Ma) and Buni-Zom (110 ± 1 to 104 ± 1 Ma) plutons have geochemical signatures that can be attributed to a subduction related continental volcanic arc system that developed along the southern margin of Eurasia in the Mesozoic. The Garam Chasma pluton, the youngest body in the study area (27.3 ± 0.5 to 22.8 ± 0.4 Ma), yields a geochemical signature consistent with widespread anatexis during crustal thickening related to the development of the Himalaya. The present geochemical and geochronological analysis from the Hindu Kush have produced important new constraints on the timing of tectonic events and variable tectonic settings along the south Eurasian margin before and after the continued India–Asia collision.     

Crustal structure in the Tengchong volcanic area and position of the magma chambers

In this paper, we extract 1500 P receiver functions in the Tengchong volcanic area from 211 teleseismic events recorded at nine digital seismic stations. A common conversion point stacking technique is used to improve the signal-to-noise ratio and to get the time delays of the Ps, PpPs, PsPs + PpSs phases within grids of 10 km × 10 km. Finally, the crustal thickness and Poisson’s ratio are calculated. The results show that the crustal thickness ranges from 28 to 40 km and the Poisson’s ratio ranges from 0.28 to 0.36. There exist two mantle-uplifting sites each with a horizontal scale of about 30 km × 30 km, one in Mazhan–Tengchong–Maanshan and the other in Wuhe–Longjiang–Tuantian. The high Poisson’s ratio is consistently located within these two sites. Recorded shocks with Ms > 2.0 reveal that most of the shocks are distributed around the two sites and few are located at the centers. The shocks, the geothermal distribution, and the crustal structure suggest that the magma is still active, and the two mantle-uplifting sites detected may be the positions of two magma chambers in the crust.     

Temporary skilled international migration of young professional cricketers: ‘Going Down-Under’ to move-up the career path

Recent theories of temporary skilled international migration tend to be predicated on intra-company overseas transfers and secondments. In this paper we present original findings from a study of cricket migrants to highlight another important form of temporary international movements that enable upskilling from strategic, channelled placements into a foreign club, to propel the careers of young professionals on return migration to their respective home club. Drawing upon interviews with 35 early-career English cricketers, we reveal that moving to Australia for 3–6 months during the English domestic off-season is an increasingly common practice to extend the number of months playing the sport in both distinctive work and climatic conditions. Encountering different overseas sporting cultures and environments is becoming a normative part of formative training and development of young professional cricketers to make the ‘‘unfamiliar’ more ‘familiar’’ and enhance skills and competencies. We argue that these flows of international migrants have been facilitated by the post-2001 professionalization of cricket, and the institutionalisation of global networks between cricket organisations and key actors in the sport. We suggest that there are parallels between cricket placements and other sports and occupational sectors, such as temporary overseas moves linked to loans (e.g. football), visiting fellowships, internships and secondments, in ever-competitive global professional labour markets.     

Ultrahigh-temperature mafic granulites from Panrimalai,south India: Constraints from phase equilibria and thermobarometry

The Panrimalai area constitutes part of the granulite-facies rocks of the Madurai block in the Southern Granulite Terrain (SGT), India. Garnet-bearing mafic granulites in Panrimalai occur as small enclaves within charnockite. The common stable assemblage during peak metamorphism contains hornblende, garnet, orthopyroxene, clinopyroxene, quartz and plagioclase. The resorption of garnet in various reaction textures and the development of spectacular orthopyroxene–plagioclase and hornblende–plagioclase symplectites characterize the subsequent stages of metamorphism. Application of multi-equilibrium calculation procedures for mineral core compositions of the early assemblage yields near peak conditions at  ≥ 900 °C at 9 kbar. These estimates are the highest yet reported in mafic granulites from the Madurai block. The post-peak P–T path is constructed for the mafic granulites based on observed microstructural relations and thermobarometric results is characterized by a steep clockwise decompressional P–T segment from  ≥ 9 to  < 4.5 kbar. Constraints from model Nd ages provide evidence for Paleoproterozoic magmatism restricted to the Madurai block in the Southern Granulite Terrain. The early part of the crustal evolution of the Panrimalai granulites could be coeval with the Paleoproterozoic event. Subsequent development of symplectitic assemblages via near-isothermal decompression can be ascribed to a distinctly later tectonic event. Available U–Pb and Sm–Nd mineral dates suggest a widespread Pan-African tectonothermal event in the SGT. Given the general recognition of ultrahigh-temperature (UHT) and isothermal decompression (ITD) in Pan-African age metamorphism in the East-African–Antarctic Orogen (EAAO) , the Panrimalai UHT history is considered to be part of this record.     

Relationship of antimony with gold mineralization in the ore districts of Eastern Kazakhstan

In Eastern Kazakhstan, Sb mineralization is the most widespread in the Irtysh and Bakyrchik ore districts of the West Kalba gold-bearing belt. It is spatially related to disseminated gold-sulfide ores at some deposits and is structurally and spatially isolated at others. Disseminated gold-sulfide mineralization is localized in Carboniferous carbonaceous-terrigenous carbonate rocks. It is marked off by zones of dynamic metamorphism and foliation and is characterized by the ribbon-like-lenticular morphology of ore deposits. Later Sb (predominantly, quartz-antimonite) mineralization is formed in an extension setting as brecciated/veined ores. In combination with gold-sulfide ores, Sb mineralization is more diverse. For example, microparageneses with berthierite, native Sb, aurostibite, ullmannite, jamesonite, and tetrahedrite coexist with pocket-vein quartz-carbonate-antimonite mineralization in the gold-sulfide ores of the Suzdal’skoe deposit. Also, Sb-containing minerals such as arsenopyrite and pyrite are observed. Two temperature regimes of mineralization are established here: 418-300 °C for gold-polysulfide mineralization and 280-200 °C for later Sb mineralization. The isotopic composition of antimonite sulfur at the Suzdal’skoe, Zherek, Zhanan, Bakyrchik, and Dal’ny I deposits shows close values within the interval 5³⁴S of -3.8 to 2.5%c, suggesting its great-depth origin. No visible gold is found in the antimonite of the quartz-antimonite veins, but atomic-absorption analysis reveals few ppm or more gold. Point X-ray analysis indicates the possible presence of the so-called “invisible” gold. Microstructural observations, temporal relationships of the parageneses, and studies of gas-liquid inclusions at the Suzdal’skoe deposit permit assigning Sb mineralization to the second productive gold-polysulfide stage of the ore deposition. The late antimonite stage of mineralization is separated from the gold-polysulfide stage by 7 Myr long intramineralization tectonic shifts. Gold-polysulfide mineralization (248.3 ± 3.4 Ma) was synchronous with Triassic tectonomagmatic activity.     

A new approach for reconstructing glacier variability based on lake sediments recording input from more than one glacier

We explore the possibility of building a continuous glacier reconstruction by analyzing the integrated sedimentary response of a large (440 km²) glacierized catchment in western Norway, as recorded in the downstream lake Nerfloen (N61°56’, E6°52’). A multi-proxy numerical analysis demonstrates that it is possible to distinguish a glacier component in the ~ 8000-yr-long record, based on distinct changes in grain size, geochemistry, and magnetic composition. Principal Component Analysis (PCA) reveals a strong common signal in the 15 investigated sedimentary parameters, with the first principal component explaining 77% of the total variability. This signal is interpreted to reflect glacier activity in the upstream catchment, an interpretation that is independently tested through a mineral magnetic provenance analysis of catchment samples. Minimum glacier input is indicated between 6700–5700 cal yr BP, probably reflecting a situation when most glaciers in the catchment had melted away, whereas the highest glacier activity is observed around 600 and 200 cal yr BP. During the local Neoglacial interval (~ 4200 cal yr BP until present), five individual periods of significantly reduced glacier extent are identified at ~ 3400, 3000–2700, 2100–2000, 1700–1500, and ~ 900 cal yr BP.     

The Neogene and Quaternary of England: landscape evolution,tectonics, climate change and their expression in the geological record

During the Neogene and Quaternary, tectonic and climatic processes have had a profound impact upon landscape evolution in England and, perhaps as far back as 0.9 Ma, patterns of early human occupation. Until the Late Miocene, large-scale plate tectonic processes were the principal drivers of landscape evolution causing localised basin inversion and widespread exhumation. This drove, in places, the erosion of several kilometres of Mesozoic cover rocks and the development of a regional unconformity across England and the North Sea Basin. By the Pliocene, the relative influence of tectonics on landscape evolution waned as the background tectonic stress regime evolved and climatic influences became more prominent. Global-scale climate-forcing increased step-wise during the Plio-Pleistocene amplifying erosional and depositional processes that operated within the landscape. These processes caused differential unloading (uplift) and loading (subsidence) of the crust (‘denudational isostasy’) in areas undergoing net erosion (upland areas and slopes) and deposition (basins). Denudational isostasy amplified during the Mid-Pleistocene Transition (c.0.9 Ma) as landscapes become progressively synchronised to large-scale 100 ka ‘eccentricity’ climate forcing. Over the past 0.5 Ma, this has led to the establishment of a robust climate record of individual glacial/interglacial cycles enabling comparison to other regional and global records. During the Last Glacial-Interglacial Transition and early Holocene (c.16–7 ka), evidence for more abrupt (millennial/centennial) scale climatic events has been discovered. This indicates that superimposed upon the longer-term pattern of landscape evolution is a more dynamic response of the landscape to local and regional drivers.     

Crustal thickness and velocity structure beneath Singapore’s seismic network

We estimated the crustal thickness and velocity structure beneath the five stations comprising the Republic of Singapore’s seismic network. Our data set was composed of 697 teleseismic receiver functions and 7 months of broad-band data that was cross-correlated to produce inter-station Green’s functions. Surface wave group velocities were extracted from the Green’s functions to obtain dispersion data for a path from central Sumatra to Singapore in order to provide a complimentary data set to the receiver functions. Crustal thickness was estimated via an H − k stacking technique, and high-resolution 1D P-wave velocity profiles were generated beneath each station by jointly inverting receiver function stacks and the group velocity data using a linearised time-domain inversion scheme. Crustal thickness beneath four stations was found to be between 28.0 km and 32.0 km, while one station in the northeast of Singapore indicates 24.0 km thick crust. This implies a significant crustal thinning beneath Singapore over the lateral extent of 50.0 km. Inversion results exhibit several crustal features that are observable in the derived models at all five stations, indicating that they exist across Singapore as a whole. There appears to be an upper-crustal high-velocity zone beneath Singapore, underlain by a velocity inversion. Station NTU shows slower near-surface velocities than the other stations, consistent with its situation above the sedimentary Jurong formation. These results expand the available global velocity data set, as well as being useful for assessing the seismic hazard in Singapore.     

Assimilation of sulfate and carbonaceous rocks: Experimental study,thermodynamic modeling and application to the Noril’sk-Talnakh region (Russia)

Most of the intrusions in the Noril’sk-Talnakh region (Siberia) are hosted in thick sedimentary sequences including abundant evaporitic and terrigenous sedimentary rocks. Three mafic-ultramafic intrusions in this region contain unusually thick massive sulfide deposits, which represent one of the world’s largest economic concentrations of Ni, Cu and PGE. The interaction of Siberian magmas with sulfate and organic matter-rich sedimentary rocks has been proposed as a possible mechanism for the origin of these exceptional sulfide deposits but the interaction process and the reaction paths have never been fully investigated. Here we clarify, by both experimental petrology and thermodynamic modeling, how sulfate and organic matter assimilation occur in mafic-ultramafic magmas, affecting magma composition, crystallization and sulfide saturation.Interaction experiments were conducted at conditions relevant to the emplacement of Noril’sk type intrusions (1200 °C, ∼80 MPa) to simulate the assimilation of sulfate and/or organic compounds by ultramafic magmas. We used a picrite from Noril’sk1 intrusion, and coal and anhydrite from the area as starting materials. The experimental results show that the incorporation of anhydrite into the magma occurs by chemical dissolution in the melt, which increases the magma’s sulfur content, but suppresses sulfide saturation and reduces olivine crystallization. Extreme assimilation leads to sulfate saturation in the magma and high dissolved sulfur contents of 0.9 ± 0.1 wt% S. Conversely, coal assimilation promotes sulfide segregation and magma crystallization, while decreasing the dissolved H₂O content of the melt and increasing the amount of coexisting fluid phase.We also employed gas-melt thermodynamic calculations to quantify the effect of these assimilations on the redox conditions and the S content of the magma, and investigate the role of temperature, pressure, and initial gas content of the magma in the assimilation process. We quantify how sulfate assimilation strongly oxidizes the magma and increases its S content; both effects are intensified by increasing pressure (from 50 to 100 MPa in this study), decreasing temperature (from 1350 to 1200 °C in this study), and decreasing amounts of fluid phase initially coexisting with the magma (from 2 to 0 wt%). The interaction with organic matter (CH in this study) induces a strong reduction of the magma, even for extremely low degrees of assimilation (few tenths of wt%), and the dehydration of the melt.We therefore suggest that in the Noril’sk-Talnakh district (1) additional S was supplied to mantle derived magmas by the assimilation of evaporitic rocks, and was transported during magma ascent in the form of dissolved, oxidized S; (2) a substantial reduction of the magma inducing sulfide segregation and important crystallization then occurred due to the interaction with carbonaceous sediments. This mechanism can potentially produce massive sulfide deposits by important sulfate assimilation (locally higher than 3 wt% CaSO₄) and minor organic matter assimilation (few tenths of wt% CH); however, if one of the two steps does not occur, or the assimilation in (1) is not large enough, disseminated sub economic or no sulfide deposits are produced. We conclude that exceptional conditions favoring substantial assimilation of sediments are needed to generate exceptional ore deposits like those of the Noril’sk-Talnakh district.     

The neoliberalization of Contemporary Christian Music’s new Social Gospel

This paper explores how Contemporary Christian Music (CCM) forges neoliberal subjectivities. CCM, popular music featuring evangelical Christian lyrics, is one of the most widely consumed forms of commercial entertainment for America’s 70–80 million white evangelical Christians. I argue that by synthesizing evangelical individualism and an insular community ethos, the everyday practices of CCM help constitute particularly neoliberal senses of self and power relations with others. These ostensibly apolitical subjectivities sustain neoliberal ventures such as the reinvention of the Social Gospel through Christian non-governmental organizations (NGOs). As well as demonstrating the role of religious and musical practices in cultivating neoliberal subjectivities, CCM helps illuminate neoliberalism’s fractures, dynamism, and multiplicities.     

The relationship between shrink–swell occurrence and climate in south-east England

Climate change is one of the biggest environmental problems that the UK faces. Increased understanding of the impacts is vital to enable adaption to, and mitigation of, the consequences. This analysis and modelling of the relationship between climate and shrink–swell behaviour has been carried out to increase understanding of the potential consequences of changes in precipitation and temperature on ground movement in the south-east of England during the coming century.Analysis of historical climate data and comparison with subsidence claims data demonstrated the relatively close relationship of subsidence with two years’ previous precipitation. Boundaries are identified, with precipitation above 394 mm for the previous two years, leading to a lower level subsidence claims, and below 350 mm leading to a higher incidence. Combined with this inverse relationship, a direct relationship with temperature is identified, with a rise above 22.6 °C in the mean maximum temperature for an accounting quarter leading to a peak in claims.To model a projection for susceptibility of south-east England to future climate change, UKCIP02 forecast climate data were used, and combined with the British Geological Survey national shrink–swell GeoSure geohazard dataset. Preliminary results demonstrate the most noticeable increases in subsidence susceptibility are within the areas underlain by the London Clay Formations, with other clay-rich formations also being identified, including glacial till.Despite this being a preliminary model, with large amounts of future work identified, these results are significant, providing an insight into areas of higher susceptibility and the potential for changes in ground movement for the coming century.     

Empowering the empowered? Slum tourism and the depoliticization of poverty

Mumbai’s Dharavi slum occupies a plot half the size of Central Park. It is home to one million people, with almost half of residents living in spaces under 10 m², making it over six times as dense as daytime Manhattan. Using ethnographic fieldwork and online analysis, this article examines slum tourism and the perceptions and experiences of western visitors. Local tour operators emphasize the productivity of the slum, with its annual turnover of $665 million generated from its hutment industries. Its poor sanitation, lack of clean water, squalid conditions and overcrowding are ignored and replaced by a vision of resourcefulness, hard work and diligence. This presentation of the slum as a hive of industry is so successful that visitors overlook, or even deny, its obvious poverty. Dharavi is instead perceived as a manufacturing hub and retail experience; and in some cases even romanticized as a model of contentment and neighbourliness, with western visitors transformed by ‘life-changing’, ‘eye-opening’ and ‘mind-blowing’ experiences. This article concludes that the potential of slum tours as a form of international development is limited, as they enable wealthy middle-class westerners to feel ‘inspired’, ‘uplifted’ and ‘enriched’, but with little understanding of the need for change.     

Modelling and in-situ measurements of intense currents during a winter storm in the Gulf of Aigues-Mortes (NW Mediterranean Sea)

While oceanic circulation in the Gulf of Lion (GoL) has often been studied in calm weather or with northerly winds (Tramontane or Mistral) through observations and numerical circulation models, few studies have focused on southeasterly storm events. Yet, correct representation of the circulation during storms is crucial if the suspension of sediments is to be correctly modelled throughout the Gulf. The purpose of this paper is to describe the hydrodynamics in the Gulf of Aigues-Mortes (NW of the GoL) during the storm of 18 February 2007 by using a set of data from an ADCP station placed at a depth of 65 m on the sea bed off the coast at Sète, supplemented by the ocean circulation model SYMPHONIE. This storm was characterized by a moderate south-easterly wind (15 m . s^?1) and waves of up to 5 m of significant height at its apex. At the ADCP, strong currents of up to 0.8 m . s^?1 near the surface and 0.5 m . s^?1 near the bottom were recorded, parallel to the coast, flowing towards the south-west. The simulated currents were widely underestimated, even taking the effect of waves into account in the model. It was suspected that the representation of the wind in the atmospheric model was an underestimation. A new simulation was therefore run with an arbitrarily chosen stronger wind and its results were in much better agreement with the measurements. A simplified theoretical analysis successfully isolated the wind-induced processes, responsible for the strong currents measured during the apex and the strong vertical shear that occurred at the beginning of the storm. These processes were: 1/ the barotropic geostrophic current induced by a wind parallel to the coast and 2/ the Ekman spiral. The duration of the storm (about 36 h at the apex) explains the continuous increase of the current as predicted by the theory. The frictionally induced Ekman transport explains the current shear in the surface layer in the rising stage of the storm, and the addition of high waves and strong wind at the apex is more in favour of strong vertical mixing in the surface layer.     

Crustal and lithospheric thinning beneath the seismogenic Kachchh rift zone,Gujarat (India): Its implications toward the generation of the 2001 Bhuj earthquake sequence

A high-resolution passive seismic experiment in the Kachchh rift zone of the western India has produced an excellent dataset of several thousands teleseismic events. From this network, 500 good teleseismic events recorded at 14 mobile broadband sites are used to estimate receiver functions (for the 30–310° back-azimuth ranges), which show a positive phase at 4.5–6.1 s delay time and a strong negative phase at 8.0–11.0 s. These phases have been modeled by a velocity increase at Moho (i.e. 34–43 km) and a velocity decrease at 62–92 km depth. The estimation of crustal and lithospheric thicknesses using the inversion of stacked radial receiver functions led to the delineation of a marked thinning of 3–7 km in crustal thickness and 6–14 km in lithospheric thickness beneath the central rift zone relative to the surrounding un-rifted parts of the Kachchh rift zone. On an average, the Kachchh region is characterized by a thin lithosphere of 75.9 ± 5.9 km. The marked velocity decrease associated with the lithosphere–asthenoshere boundary (LAB), observed over an area of 120 km × 80 km, and the isotropic study of xenoliths from Kachchh provides evidence for local asthenospheric updoming with pockets of partial melts of CO₂ rich lherzolite beneath the Kachchh seismic zone that might have caused by rifting episode (at 88 Ma) and the associated Deccan thermal-plume interaction (at 65 Ma) episodes. Thus, the coincidence of the area of the major aftershock activity and the Moho as well as asthenospheric upwarping beneath the central Kachchh rift zone suggests that these pockets of CO₂-rich lherzolite partial melts could perhaps provide a high input of volatiles containing CO₂ into the lower crust, which might contribute significantly in the seismo-genesis of continued aftershock activity in the region. It is also inferred that large stresses in the denser and stronger lower crust (at 14–34 km depths) induced by ongoing Banni upliftment, crustal intrusive, marked lateral variation in crustal thickness and related sub-crustal thermal anomaly play a key role in nucleating the lower crustal earthquakes beneath the Kachchh seismic zone.     

First rocks sampled in Antarctica (1840): Insights into the landing area and the Terre Adélie craton

In January 1840, Dumont d’Urville's expedition landed along the coast of “Terre Adélie” and took three rock specimens, the first ever sampled on the Antarctic continent. The petrological and geochemical study of these samples, stored at the “Muséum national d’histoire naturelle”, in Paris, characterizes them as migmatitic cordierite + microcline-bearing paragneiss and mesocratic quartz + biotite-bearing amphibolite. The paragneiss reached 670 °C at 3.2 kbar, suggesting an abnormal high-T gradient of ca. 60 °C/km during the regional metamorphism that affected the “Terre Adélie” craton 1.7 Ga ago. The studied samples are identical to the rocks observed at the “Rocher du Débarquement”, confirming that this was the actual landing place. On the other hand, quartz diorite and volcanic rocks reportedly sampled in Adélie Land during the same expedition and stored at Le Mans and Toulouse Museums do not originate from Antarctica. The examination of Dumont d’Urville's map suggests an icecap shrinking by 9 km in the landing area since 1840.     

Veracity of Neoproterozoic negative C-isotope values: The termination of the Shuram negative excursion

There is widespread interest in the Neoproterozoic period of the Earth's history (1000 to 542 Ma) because of unprecedented δ¹³C fluctuations to < − 10‰ PDB through thick (> 1000 m) succession of stratigraphically complex sedimentary rocks deposited during tens of millions of years. In contrast, Phanerozoic large negative C-isotope excursions have been interpreted as the result of diagenetic fluid mixing during carbonate stabilization and burial and are less enigmatic due to the excellent biostratigraphic control on their timing and duration.The Ediacaran Nafun Group of Oman (part of the Huqf Supergroup spanning the Cryogenian–Early Cambrian) contains a large δ¹³C negative excursion (the Shuram excursion) reaching values as negative as − 12‰ at the base of the Shuram Formation. A steady recovery to positive values occurs over the entire Shuram and half through the overlying Buah Formation, suggesting a duration on the order of tens of My. Based on trace metal, chemostratigraphic and sedimentological analyses, the carbon isotope record obtained from the Buah Formation of northern Oman indicates a systematic and reproducible shift of δ¹³C values from − 6‰ to + 1‰ in 1 — a demonstrably diagenetic altered carbonate-cemented siliciclastic facies, and 2 — a least diagenetically altered stromatolitic facies. The identical reproducible isotopic pattern in these time-equivalent sections combined to the presence of exceptionally preserved δ¹⁸O values around − 2 to + 1‰ associated with the most negative δ¹³C values rules out isotopic resetting by diagenetic fluids as a mechanism to explain these values.It is concluded that it is possible to retain depositional δ¹³C values in demonstrably diagenetically altered carbonates. This raises the issue of the ability to recognize diagenetic alteration of C-isotopic values in Neoproterozoic rocks where a robust time frame to support reproducibility is not available. The results of this study provide strong support to a non diagenetic origin of the negative Shuram C-isotope excursion, believed to be the most profound (in terms of amplitude and duration) in the Earth's history.