Hydrothermal dolomitization,mixing corrosion and deep burial porosity formation: numerical results from 1‐D reactive transport models

Major corrosion has been found at depth in carbonate hydrocarbon reservoirs from different geologic provinces. Fluid inclusion microthermometry and stable isotopic compositions of carbonate cements, predating major corrosion, constrain the interpretation of the evolution of parental fluids during progressive burial and prior to the major corrosion event. Post‐major corrosion mineral paragenesis includes pyrite (‐marcasite), anhydrite, kaolinite (dickite) and fluorite. Although the post‐corrosion mineral paragenesis represents minor volumes of rock, it may provide valuable insights into the post‐corrosion brine chemistry. Using reactive transport numerical models, the roles of cooling and/or mixing of brines on corrosion have been evaluated as controls for dolomitization, deep burial corrosion and precipitation of the post‐corrosion mineral paragenesis. Modelling results show that cooling of deep‐seated fluids moving upward along a fracture may cause minor calcite dissolution and porosity generation. Significant dolomitization along a fracture zone and nearby host‐rock only occurs when deep‐seated fluids have high salinities (4 mol Cl kg^?1 of solution) and Darcian flow rates are relatively high (1 m³ m^?2 year^?1). Only minor volumes of quartz and fluorite precipitate in the newly formed porosity. Moreover, modelling results cannot reproduce the authigenic precipitation of kaolinite (dickite at high temperatures) by cooling. As an alternative to cooling as a cause of corrosion, mixing between two brines of different compositions and salinities is represented by two main cases. One case consists of the flow up along a fracture of deep‐seated fluids with higher salinities than the fluid in the wall rock. Dolomite does not precipitate at a fracture zone. Nevertheless, minor volumes of dolomite are formed away from the fracture. The post‐corrosion mineral paragenesis can be partly reproduced, and the results are comparable to those obtained from cooling calculations. Minor volumes of quartz and fluorite are formed, and kaolinite‐dickite does not precipitate. The major outputs of this scenario are calcite dissolution and slight net increase in porosity. A second case corresponds to the mixing of low salinity deep‐seated fluids, flowing up along fractures, with high salinity brines within the wall rock. Calculations predict major dissolution of calcite and precipitation of dolomite. The post‐corrosion mineral paragenesis can be reproduced. High volumes of quartz, fluorite and kaolinite‐dickite precipitate and may even completely occlude newly formed porosity.     

试论夏商城市水利设施及其功能

本文就考古所见夏商城址内的水利遗存进行了分析,对夏商城市水利设施的种类、功能、渊源等相关问题进行了初步探讨。     

In situ Measurements of Oxygen Dynamics in Unsaturated Archaeological Deposits

Oxygen is a key parameter in the degradation of archaeological material, but little is known of its dynamics in situ. In this study, 10 optical oxygen sensors placed in a 2 m deep test pit in the cultural deposits at Bryggen in Bergen have monitored oxygen concentrations every half hour for more than a year. It is shown that there is a significant spatial and temporal variation in the oxygen concentration, which is correlated to measured soil characteristics, precipitation, soil water content and degradation of organic material. In these deposits oxygen typically occurs when the air content of the soil exceeds 10–15% vol, while oxygen dissolved in infiltrating rainwater is of less importance for the supply of oxygen in the unsaturated zone.     

The Waikato River: Changing Properties of a Living Māori Ancestor

In Māori cosmology, rivers and other waterways are conceptualised as living ancestors, who have their own life force and spiritual strength. The special status of rivers in Māori society also explains why they are sometimes separated from other Māori claims to natural resources of which they were dispossessed in the 19th century. Until recently, Māori were often eager to contend that ownership of rivers is not their prime interest, but instead, they argued that they feel obliged and responsible to keep rivers fresh, clean, and flowing. This perspective, however, changed under the impact of a new government policy of selling shares in energy corporations that use freshwater and geothermal resources for energy production. In this paper, I provide an ethnohistorical account of the Waikato River and show how conceptions of this ‘ancestral river’ changed in the course of colonial and postcolonial history, more specifically in response to a recent shift in government policy. In 2008, a joint management agreement was signed between the government and Waikato Māori for a ‘clean and healthy river’, leaving the issue of ‘ownership’ undecided. Only two years later, however, Māori felt forced to claim ownership when the government moved to sell shares of power‐generating energy companies located along the river, which effectively transformed their ‘ancestor’ into a property object.     

Tracing Process to Performance of Collaborative Governance: A Comparative Case Study of Federal Hydropower Licensing

Despite collaborative governance's popularity, whether collaboration improves policy performance remains uncertain. This study assesses the link between collaborative decision making and licensed environmental management protocols in the Federal Energy Regulatory Commission's (FERC's) process for licensing hydropower facilities in the United States. Using results from a previous study of FERC relicensing (Ulibarri, forthcoming), one high‐, one medium‐, and one low‐collaboration case were selected. Using documents including meeting minutes, public comments, and issued licenses, I assessed collaboration and license outputs, then conducted process tracing to examine whether and how differences in collaboration produced differences in license quality. High collaboration resulted in jointly developed and highly implementable operating regimes designed to improve numerous resources, while low collaboration resulted in operating requirements that ignored environmental concerns raised by stakeholders and lacked implementation provisions. These results support the hypothesis that collaboration can improve environmental outcomes, revealing the pragmatic value of collaboration. [Correction added on 13 January 2015, after first online publication: the occurrences of ‘0’ in the abstract were erroneous and have now been corrected.]     

Water and power in South Arabia: the excavation of “Monumental Building 1” (MB1) at Sumhuram (Sultanate of Oman)

The ancient port city of Sumhuram (Dhofar Governorate, Sultanate of Oman) has been the focus of over 20 years of research by the Italian Mission to Oman (IMTO), University of Pisa, in collaboration with the Office of the Adviser to His Majesty the Sultan for Cultural Affairs (Muscat-Salalah, Sultanate of Oman). Excavation has revealed most of the town layout, leading to the identification of several buildings, alleyways, squares and workshops, among which two massive buildings stand out, significantly named by the excavators as “Monumental Building” 1 and 2 (MB1 and MB2). This paper presents the results of the excavation inside MB1, characterised by the presence of the only well discovered within the city walls, which was previously interpreted alternatively as a palace or as a temple. The architectural development of the building, its distinctive features, the archaeological material discovered inside it, and its chronology will be discussed. These results highlight the absence of fitting parallels from other ancient South Arabian towns. Overall, it is clear that access to, management of, and control over the water supply of the town represented a key asset which justified the huge investment in workforce and building materials that is reflected in the monumental architecture of this edifice.     

Global aspirations and local (dis-)connections: A critical comparative perspective on tramway projects in Casablanca and Jerusalem

This article puts emphasis on the political representation of tramway projects in Casablanca, Morocco, and Jerusalem, Israel/the Palestinian territories. In this paper, we discuss both tramway projects as flagships of national worlding strategies that try to promote the respective city on global markets of attention, competing for international investors and tourists. As such, they are majorly driven by national political interests, fostering the hegemonic position of the central state in cooperation with private actors. The tramways are aimed at portraying modernity as well as political and economic stability, while aspiring to a supposed international urban world-class. At the same time, governments frame tramways as tools to promote socio-urban integration and to improve local transport systems. However, the paper shows that although governments are eager to stress the integrative role of tramways, they continue with violent politics of urban exclusion at the same time. Thus, the integrative wording behind tramway planning has to be understood against political (and economic) pressures to regain political legitimacy in a moment of crisis - both domestically and internationally. Consequently, the paper uses interview data and applies methods of discourse analysis to shed light on the worlding of tramways and its ambivalent practices of symbolic inclusion and exclusion.     

基于电阻率成像法的莫高108窟墙体内水盐运移过程分析

非均质的砂砾石层是莫高窟壁画的主要墙体,但砂砾石层的非均质性如何在水盐运移过程中发挥作用却还不清楚。为此,通过在108窟西壁面上1 m×1 m和2 m×2 m范围的三维高密度电阻率成像监测,发现在这些区域上,墙体电阻率的空间分布都是非均匀的,低阻值区域在空间位置、大小和形状上都会随时间而变化。这明确说明在构成墙体的非均质砂砾石层内存在着重要的水分饱和与非饱和过程(再分配过程),正是这一不断重复的饱和与非饱和过程促进了墙体内水分的运移和盐分在一些特定区域的聚集。研究成果对全面认识莫高窟墙体内的水盐运移机理,减轻和防治壁画盐害都具有重要意义。     

Power and the material arrangements of a river basin management plan: the case of the Archipelago Sea

The drive towards collaborative governance has raised critical questions about the hidden forms of power practised in consensual planning processes. In the field of water governance, the issue has been analysed in terms that treat power as an intrinsic property of actors or planning settings. Alternatively power is located in the discursive means mobilized by the human participants. Drawing from actor-network theory, this paper calls attention to the material arrangements constitutive for the practicing of power in target-driven, consensus-seeking planning. It sets focus on the obligatory passage points and factual closures through which a planning task links, for example, to ecosystems, policy principles and trajectories of governance. In the meantime, some other entities and issues may lose their planning-steering potentiality. As shown by the analysis of a river-basin planning process, the arrangements that end up steering consensus-seeking cannot be treated as merely discursive outputs operating upon a passive non-human reality. Materialities and living processes contribute to the outcome. However, the link is not deterministic. With different means of arrangement, the planning reality can – and, in the studied case, could have – end up different.     

One for all,or all for oneself? Governance cultures in regional public transport planning

Due to the fragmented organizational landscape characterizing public transport, it is important to study and explore how regional governance of public transport adapts to national institutional reforms. By employing the term ‘governance cultures’ to a comparative case study of regional public transport planning in Sweden, we contribute to theories of governance by cultural sensitization. Combining governance theory with cultural analysis, we apply a cultural perspective to understand the two cases. We conclude that public transport planning in the Stockholm region is defined by ‘negotiations’ between stakeholders, whereas in the Västra Götaland region it is characterized by a governance culture of ‘collaboration’. The evidence from our case studies emphasizes the importance of understanding local governance practices as situated in cultural contexts as well as of viewing governance cultures as an important factor affecting the purpose, degree and outcomes of collaboration in planning practices.