Polyphasic hydrothermal and meteoric fluid regimes during the growth of a segmented fault involving crystalline and carbonate rocks (Barcelona Plain,NE Spain)

A polyphasic tectonic‐fluid system of a fault that involves crystalline and carbonate rocks (Hospital fault, Barcelona Plain) has been inferred from regional to thin section scale observations combined with geochemical analyses. Cathodoluminescence, microprobe analyses and stable isotopy in fracture‐related cements record the circulation of successive alternations of hydrothermal and low‐temperature meteoric fluids linked with three main regional tectonic events. The first event corresponds to the Mesozoic extension, which had two rifting stages, and it is characterized by the independent tectonic activity of two fault segments, namely southern and northern Hospital fault segments. During the Late Permian‐Middle Jurassic rifting, these segments controlled the thickness and distribution of the Triassic sediments. Also, dolomitization was produced in an early stage by Triassic seawater at shallow conditions. During increasing burial, formation of fractures and their dolomite‐related cements took place. Fault activity during the Middle Jurassic–Late Cretaceous rifting was localized in the southern segment, and it was characterized by hydrothermal brines, with temperatures over 180°C, which ascended through this fault segment precipitating quartz, chlorite, and calcite. The second event corresponds to the Paleogene compression (Chattian), which produced exhumation, folding and erosion, favouring the percolation of low‐temperature meteoric fluids which produced the calcitization of the dolostones and of the dolomite cements. The third event is linked with the Neogene extension, where three stages have been identified. During the syn‐rift stage, the southern segment of the Hospital fault grew by tip propagation. In the relay zone, hydrothermal brines with temperature around 140°C upflowed. During the late postrift, the Hospital fault acted as a unique segment and deformation occurred at shallow conditions and under a low‐temperature meteoric regime. Finally, and possibly during the Messinian compression, NW‐SE strike‐slip faults offset the Hospital fault to its current configuration.     

Role of compressive tectonics on gas charging into the Ordovician sandstone reservoirs in the Sbaa Basin,Algeria: constrained by fluid inclusions and mineralogical data

Structure‐ and tectonic‐related gas migration into Ordovician sandstone reservoirs and its impact on diagenesis history were reconstructed in two gas fields in the Sbaa Basin, in SW Algeria. This was accomplished by petrographical observations, fluid inclusion microthermometry and stable isotope geochemistry on quartz, dickite and carbonate cements and veins. Two successive phases of quartz cementation (CQ1 and CQ2) occurred in the reservoirs. Two phase aqueous inclusions show an increase in temperatures and salinities from the first CQ1 diagenetic phase toward CQ2 in both fields. Microthermometric data on gas inclusions in quartz veins reveal the presence of an average of 92 ± 5 mole% of CH₄ considering a CH₄‐CO₂ system, which is similar to the present‐day gas composition in the reservoirs. The presence of primary methane inclusions in early quartz overgrowths and in quartz and calcite veins suggests that hydrocarbon migration into the reservoir occurred synchronically with early quartz cementation in the sandstones located near the contact with the Silurian gas source rock at 100–140°C during the Late Carboniferous period and the late Hercynian episode fracturing at temperatures between 117 and 185°C, which increased in the NW‐direction of the basin. During the fracture filling, three main types of fluids were identified with different salinities and formation temperatures. A supplementary phase of higher fluid temperature (up to 226°C) recorded in late quartz, and calcite veins is related to a Jurassic thermal event. The occurrence of dickite cements close to the Silurian base near the main fault areas in both fields is mainly correlated with the sandstones where the early gas was charged. It implies that dickite precipitation is related to acidic influx. Late carbonate cements and veins (calcite – siderite – ankerite and strontianite) occurred at the same depths resulting from the same groundwater precipitation. The absence of methane inclusions in calcite cements result from methane flushing by saline waters.     

Asylum and the Post‐Political: Domopolitics,Depoliticisation and Acts of Citizenship

This paper explores the ways in which practices of asylum governance serve to depoliticise those seeking asylum in the UK. In critiquing claims over the “post‐political” nature of contemporary governance, the paper proposes a focus upon situated practices of depoliticisation which displace those seeking asylum through the production of specific sites of accommodation and specific discourses of risk, security and moralised concern. The paper questions the tendency within “post‐political” thought to strip the potential of modes of informal citizenship through arguing that minor acts of resistance are ineffectual and illusory. In response, the paper explores irregular migrant's “acts of citizenship”, and suggests that such prosaic acts can be powerful forms of political interruption through which new ways of seeing asylum are constructed. The paper concludes by suggesting that an incremental politics orientated around such acts of interruption is essential to challenge the material, affective and discursive closures of asylum domopolitics.     

Middle Bronze Age II Battleaxes from Rishon LeZion,Israel: Archaeology and Metallurgy

Thirteen bronze battleaxes from Middle Bronze Age II graves at Rishon LeZion, Israel were analysed by ED XRF at multiple surface locations in order to determine their metallurgical composition. Six of these were further subjected to neutron diffraction using an ENGIN‐X diffractometer in order to determine bulk phase composition. The results indicate that the previously established geographical and chronological variability in Sn–Cu (with occasional Pb) and As–Cu alloys found using the former method may be an artefact of preservation and conservation. In addition, the varying homogeneity determined by the latter reflects special treatment for improving on the metal cast.     

On the Origin of the Green Colour of Archaeological Bone Artefacts of the Gallo‐Roman Period

Recent findings in the city of Reims have lead to the discovery of manufactured bone objects coloured in green throughout their entire volume. In order to discover the intentional nature of the colouration and to propose a colouration mechanism, modern ox bones have been coloured in the laboratory. Bones with a hue similar to that of the archaeological artefacts have been obtained by boiling in an acidic brine in a copper vessel. A combination of infrared spectroscopy, X‐ray diffraction and transmission electron microscope observations did not reveal the speciation of copper, but allowed us to validate the colouration process and to discuss the intentional origin of the colouration.     

Rehydroxylation of Fired‐Clay Ceramics: Factors Affecting Early‐Stage Mass Gain in Dating Experiments

To obtain accurate results in the RHX dating of ceramics, it is essential that the RHX measurements are continued until the rate of mass gain is constant with (time)^1/4. In this paper, we discuss how the initial stages of mass gain are affected by the specific surface area (SSA) of the ceramic material. The paper provides guidance on experimental protocols to avoid dating results being distorted by relatively early‐time mass gain data.     

THE VERTIGO OF HISTORICAL ANALYSES IN A GLOBALIZING WORLD

In this anthology, Joan Scott reconfigures her understanding of feminist history and thus contributes to a long overdue theoretical discussion on how we can write feminist history in a globalizing world. She traces both the history of gender history and the history of feminist movements. Scott's main source of inspiration is the French version of psychoanalysis following Lacan. In a further development of her pioneering 1986 article, “Gender: A Useful Category of Historical Analysis,” she points out that gender is neither a mere social construction nor a somehow biological referent (such as “sex”). Integrating the constructive criticism of her approach elaborated prominently by Judith Butler during the 1990s, Scott argues instead that gender is a historically and culturally specific attempt to resolve the dilemma of sexual difference. Sexual difference, for its part, is also far from referring simply to physically different male/female bodies. Sexual difference is, for Scott, a permanent quandary for modern subjects, a puzzle to which every society or culture finds specific answers. My reading of her book concentrates on two main questions that run like a thread through her considerations: First, how can we bridge the gap between a subject and a group? Second, how can we overcome binary oppositions and/or fixed categories and entities—a challenge that becomes even more important every day in a rapidly globalizing world. I broadly discuss the benefits and shortcomings of the pivotal role Scott ascribes to fantasy. Although the concept of fantasy is powerful and striking, particularly with reference to the concepts of “imagined communities” and “invented traditions,” coined by Eric Hobsbawm and Benedict Anderson, I find the Lacanian tone to be less convincing.     

“FUTURE PAST”: TIME AND TELEOLOGY IN (ANCIENT) HISTORIOGRAPHY

The historian's account of the past is strongly shaped by the future of the events narrated. The telos, that is, the vantage point from which the past is envisaged, influences the selection of the material as well as its arrangement. Although the telos is past for historians and readers, it is future for historical agents. The term “future past,” coined by Reinhart Koselleck to highlight the fact that the future was seen differently before the Sattelzeit, also lends itself to capturing this asymmetry and elucidating its ramifications for the writing of history. The first part of the essay elaborates on the notion of “future past”: besides considering its significance and pitfalls, I offset it against the perspectivity of historical knowledge and the concept of narrative “closure” (I). Then the works of two ancient historians, Polybius and Sallust, serve as test cases that illustrate the intricacies of “future past.” Neither has received much credit for intellectual sophistication in scholarship, and yet the different narrative strategies Polybius and Sallust deploy reveal profound reflections on the temporal dynamics of writing history (II). Although the issue of “future past” is particularly pertinent to the strongly narrative historiography of antiquity, the controversy about the end of the Roman Republic demonstrates that it also applies to the works of modern historians (III). Finally, I will argue that “future past” alerts us to an aspect of how we relate to the past that is in danger of being obliterated in the current debate on “presence” and history. The past is present in customs, relics, and rituals, but the historiographical construction of the past is predicated on a complex hermeneutical operation that involves the choice of a telos. The concept of “future past” also differs from post‐structuralist theories through its emphasis on time. Retrospect calms the flow of time, but is unable to arrest it fully, as the openness of the past survives in the form of “future past” (IV).     

IS COMPARATIVE HISTORY POSSIBLE?

In recent years the trend toward comparative histories, frequently read in terms of transnational studies, has produced some remarkably exciting work. The prospect of the comparative is gaining broader appeal, a development we should applaud but at the same time begin to examine in a critical fashion. This essay lays out some of the problems involved in comparative work and suggests ways in which we might profitably utilize these potential snares in productive ways. Comparative history has the potential to operate as a “bridge‐builder,” encouraging inventive thinking that moves scholars beyond the familiar terrain of their training. In this respect, it encourages original and innovative ways of approaching historical work. But there are lessons to be learned and problems to be faced in managing a complex scholarly enterprise of this kind. Comparative work runs the risk of reproducing and consolidating older models of universalist history that assume universal standards. It further runs the risk of assuming rather than historicizing the idea of the nation as a fixed point of historical reference rather than seeing the nation itself as a site for historical scrutiny. In this paper, my goal is to lay out these problems alongside the palpable rewards of comparative work, and then to suggest how we might turn such problems to our advantage.