北黄海盆地构造运动学解析

以最新的地质 地球物理资料和北黄海盆地构造几何学特征为基础,采用盆地反演模拟与宏观分析相结合的方法,系统解析了北黄海盆地的构造运动学特征。研究表明,北黄海盆地在中、新生代时期经历了水平伸展、水平挤压、相对平移(走滑)以及垂直差异升降等几种运动型式,其中,水平伸展运动和垂直差异升降运动是北黄海盆地构造运动及形成演化的主体。水平伸展运动可以划分为J3-K1、E2和E3三个主要“伸展事件”,并控制着盆地的成盆演化,其南北向伸展强度均东强西弱,东西向最大伸展强度自中生代到新生代由东向西迁移。水平挤压运动主要有晚白垩世和渐新世末-中新世初期两期。相对平移(走滑)运动伴随水平伸展运动和水平挤压运动发生,使多数NNE向、NW向断裂具有相对压扭或张扭平移(走滑)性质,其中尤以NNE向断裂更为明显。垂直差异升降运动具有“幕式”渐进之特点,晚侏罗世、早白垩世、始新世、渐新世以及中新世中晚期以来为沉降期,其中尤以始新世的沉降速率最大,晚白垩世、古新世、中新世早期为抬升剥蚀期;盆地的中、新生代沉降作用具有明显的自东向西迁移规律:东部坳陷以中生代沉降作用最为显著,中部坳陷主沉降期为始新世,而西部坳陷的快速沉降主要发生在始新世,并一直持续到渐新世。     

智能潜器控制系统的实航验证

本文介绍了某智能潜器的系统概要及其使命规划系统和使命控制系统的结构,并通过对其实航试验结果的分析,证明了本系统能够实现自主导航、自主避障等功能。特别是,本系统对潜器的位置和艏向具有优良的控制特性,达到了预定的研究目标。     

新疆特克斯县阔拉萨依铁锌矿成矿特征分析

阔拉萨依铁锌矿位于新疆西天山伊犁金铜成矿带—伊什基里克成矿亚带,矿床类型属于火山岩型。文章在对阔拉萨依铁锌矿的成矿地质背景及矿区地质特征进行了系统研究的基础上,对矿区的矿床成因及控矿因素进行了分析,从而推断该区具有良好的铁锌找矿前景。     

Something in the Air: Civic science and contentious environmental politics in post-apartheid South Africa

The emergence of an environmental movement in post-apartheid South Africa has involved the reframing of the environment as a ‘brown’ issue, articulating the discourse of social and environmental justice and a rights-based notion of democracy. Environmental movements have pursued a dual strategy of deliberation and activist opposition. Environmental movements have deployed science to pursue the strategic task of democratic opposition and have established networks of environmental knowledge and expertise. Ecological modernization is the dominant approach to environmental governance and adopts a science-based policy approach. In this context the regulation and management of the environment is premised on the need for science, which provides the authoritative basis for a regulatory response. In local environmental movements, there exists a fundamental tension between a cumulative history of lay knowledge about pollution and the lack of official acknowledgement of qualitative narratives. This is accompanied by a lack and suspicion of reliable official data. Environmental movements have thus employed ‘civic science’ strategically to place the issue of air pollution on the political agenda. This paper uses the case of environmental politics in Durban to reflect on the ways in which civic science and lay knowledge, together constituting community hybrid knowledge, are produced and disseminated in order to pressure the state and capital. The three ways in which knowledge is deployed are: to frame environmental problems, in strategies of oppositional advocacy, and in deliberative policy forums. Empirical analysis shows that civic science is produced through knowledge networks, and both lay knowledge and civic science are opportunistically used by environmental movements to engage both inside and outside formal policy making arenas. This deployment of hybrid knowledge by environmental movements represents a broader challenge to the power of science and technology based on increasing evidence of the hazards and risks facing ordinary people in their daily lives.     

Mesozoic and Cenozoic vertical movements in the Atlas system (Algeria, Morocco, Tunisia): An overview

The E-W trending Atlas System of Maghreb consists of weakly shortened, intra-continental fold belts associated with plateau areas (“Mesetas”), extending between the south-westernmost branch of the Mediterranean Alpine Belt (Rif-Tell) and the Sahara Platform. Although the Atlas system has been erected contemporaneously from Morocco to Algeria and Tunisia during the Middle Eocene to Recent, it displays a conspicuous longitudinal asymmetry, with i) Paleozoic outcrops restricted to its western part; ii) highest elevation occurring in the west, both in the Atlas System and its foreland (Anti-Atlas); iii) low elevation corridors (e.g. Hodna) and depressed foreland (Tunisian Chotts and Sahel area) in the east. We analyse the origin of these striking contrasts in relation with i) the Variscan heritage; ii) crustal vertical movements during the Mesozoic; iii) crustal shortening during the Cenozoic and finally, iv) the occurrence of a Miocene-Quaternary hot mantle anomaly in the west. The Maghreb lithosphere was affected by the Variscan orogeny, and thus thickened only in its western part. During the Late Permian-Triassic, a paleo-high formed in the west between the Central Atlantic and Alpine Tethys rift systems, giving birth to the emergent/poorly subsident West Moroccan Arch. During the late Middle Jurassic-Early Cretaceous, Morocco and western Algeria were dominantly emergent whereas rifting lasted on in eastern Algeria and Tunisia. We ascribe the uplift of the western regions to thermal doming, consistent with the Late Jurassic and Barremian gabbroic magmatism observed there. After the widespread transgression of the high stand Cenomanian-Turonian seas, the inversion of the Atlas System began during the Senonian as a consequence of the Africa-Eurasia convergence. Erosion affected three ENE-trending uplifted areas of NW Africa, which we consider as lithospheric anticlines related to the incipient Africa-Europe convergence. In contrast, in eastern Algeria and Tunisia a NW-trending rift system developed contemporaneously (Sirt rifting), normal to the general trend of the Atlas System. The general inversion and orogenesis of the Atlas System occurred during two distinct episodes, Middle-Late Eocene-Oligocene and Late Miocene-Pliocene, respectively, whereas during the intervening period, the Africa-Europe convergence was mainly accommodated in the Rif-Tell system. Inversion tectonics and crustal thickening may account for the moderate uplift of the eastern Atlas System, not for the high elevation of the western mountain ranges (Middle Atlas, High Atlas, Anti-Atlas). In line with previous authors, we ascribe part of the recent uplift of the latter regions to the occurrence of a NE-trending, high-temperature mantle anomaly, here labelled the Moroccan Hot Line (MHL), which is also marked by a strip of late Miocene-Quaternary alkaline magmatism and significant seismicity.     

Sediment supply from the Betic-Rif orogen to basins through Neogene

We present a quantification of total and partial (divided by time slices) sedimentary volumes in the Neogene basins of the Betic-Rif orogen. These basins include the Alboran Sea, the intramontane basins, the Guadalquivir and Rharb foreland basins and the Atlantic Margin of the Gibraltar Arc. The total volume of Neogene sediments deposited in these basins is ~ 209,000 km³ and is equally distributed between the internal (Alboran Basin and intramontane basins) and the external basins (foreland basins and Atlantic Margin). The largest volumes are recorded by the Alboran Basin (89,600 km³) and the Atlantic Margin (81,600 km³). The Guadalquivir and Rharb basins amount 14,000 km³ and 14,550 km³, respectively whereas the intramontane basins record 9235 km³. Calculated mean sediment accumulation rates for the early-middle Miocene show an outstanding asymmetry between the Alboran basin (0.24 mm/yr) and the foreland basins (0.06-0.07 mm/yr) and the Atlantic Margin (0.03 mm/yr). During the late Miocene, sedimentation rates range between 0.17 and 0.18 mm/yr recorded in the Alboran Basin and 0.04 mm/yr in the intramontane basins. In the Pliocene-Quaternary, the highest sedimentation rates are recorded in the Atlantic Margin reaching 0.22 mm/yr. Sedimentary contribution shows similar values for the inner and outer basins with a generalized increase from late Miocene to present (from 3500 to 6500 km³/My). Interestingly, the Alboran Basin records the maximum sedimentary contribution during the late Miocene (5500 km³/My), whereas the Atlantic Margin does during the Pliocene-Quaternary (6600 km³/My). The spatial and time variability of the sediment supply from the Betic-Rif orogen to basins is closely related to the morphotectonic evolution of the region. The high sedimentation rates obtained in the Alboran Basin during the early-middle Miocene are related to active extensional tectonics, which produced narrow and deep basins in its western domain. The highest sedimentary contribution in this basin, as well as in the foreland and intramontane basins, is recorded during the late Miocene due to the uplift of wide areas of the Betics and Rif chains. The analysis of the sedimentary supply also evidences strong relationships with the post-Tortonian crustal thickening and coeval topographic amplification that occurred in the central Betics and Rif with the concomitant evolution of the drainage network showing the fluvial capture of some internal basins by rivers draining to the Atlantic Ocean (the ancestral Guadalquivir).     

Hegemony and resistance: Disturbing patterns and hopeful signs in the impact of neoliberal policies on small-scale fisheries around the world

This paper reviews the major themes and contributions of this Special Issue in light of a broader social science literature on how to conceptualize small-scale fisheries, the role of the state in facilitating or limiting neoliberalism, and the failure of neoliberal policies to improve conservation. It concludes with a look at ways in which neoliberalism is being undermined by emerging alternatives.     

Governmentality and security in the US President’s Emergency Plan for AIDS Relief (PEPFAR)

This article offers a critical theoretical exploration of the US President’s Emergency Plan for AIDS Relief (PEPFAR). The article examines the background to PEPFAR and its reauthorization in Washington DC in 2008 through the conceptual lens of governmentality. Building on existing work, it interprets PEPFAR as a programme for securing the welfare of populations. It also qualifies and extends this work in the following ways. Rather than representing a break with the history of geopolitics, it argues that PEPFAR emerged out of accommodations between geopolitics and governmentality. This point is developed through two takes on geopolitics, first in terms of the projection of sovereign power, and second in terms of articulations between PEPFAR and geopolitical economies of global health. The article suggests, first, that the geopolitics of sovereign power shaped the timing, scale and form of PEPFAR, and second, that PEPFAR articulated with geopolitical economies of global health through its mobilization of US-based corporations, non-governmental and faith-based organizations. The article extends existing work by examining the role of critical mobilizations in shaping PEPFAR, both in relation to questions of political economy and the contentious politics of life. Reflecting on the politics of global health, it considers the prospects for using ideas of security and the international response to HIV/AIDS as stepping stones towards the development of broad-based health systems.     

The role of strong earthquakes and tsunami in the Late Holocene evolution of the Fortore River coastal plain (Apulia, Italy): A synthesis

Morphological analysis of the Fortore River coastal plain and the Lesina Lake coastal barrier integrated with radiocarbon age data indicates that the evolution of the coastal landscape has been strongly affected by a number of strong earthquakes and related tsunamis which occurred during the last 3000 years. The first seismic event struck this coastal area in the V century BC. It produced strong erosion of the Fortore River coastal plain and significant emersion of Punta delle Pietre Nere, as well as the large tsunami responsible for the development of the Sant'Andrea washover fan. The second event occurred in 493 AD; it induced severe erosion of the Fortore River coastal plain and triggered the large tsunami that hit the Lesina Lake coastal barrier, producing the Foce Cauto washover fan. Then later in 1627, an earthquake was responsible for the further coseismic uplift of Punta delle Pietre Nere, the subsidence of Lesina village area and the development of a tsunami which produced two washover fans.Morphological analysis points out that seismic events strong enough to control the morphological evolution of local coastal landscapes show a statistical return period of about 1000 years. These major events produced important coseismic vertical movements and large tsunamis. However, the correct identification of the tectonic structure responsible for the generation of these strong earthquakes is still an unsolved problem.     

The liquid limit of peat and its application to the understanding of Irish blanket bog failures

Catastrophic failures of blanket bogs, involving the escape and outflow of large volumes of semi-liquid basal peat, are well-known phenomena in Ireland but have only very rarely been reported from elsewhere in the world. Their precise causes and mechanisms are as yet unclear. The liquid limit (w _L) was identified as a potentially useful indicator of the susceptibility of peat to such failure because peat has extremely high natural water contents and, as an index property, w _L takes no account of the properties or structures of highly heterogeneous intact peat. However, the usual procedure for determining the w _L of peat is not fully standardised. Prepared samples will normally include potentially highly reactive particles of disrupted fibres and wood fragments that would not be present in such freshly disintegrated form in the field. This paper presents results from w _L determinations of peat obtained from the scar margins of three bog failures in northwest Ireland, using four different test procedures including a method involving wet-sieving of the peat to separate the humified <425-μm fraction for testing without incorporating artificially fragmented particles of fibres. The sampled peat was classified as H₈–H₁₀ according to the von Post humification scale. The fibre contents varied between the sites, but the ash contents were <3% in all but one test sample, and bulk densities (dry and field-wet) of the peat from all three sites were almost identical. w _L results from the wet-sieving method were 708–785%, compared with 633–980% from the standard method. The highest measured field water contents exceeded the wet-sieved w _L for all three of the field sites. Tests of cone penetration into intact peat cores demonstrated the influence of the reinforcing effect of in situ fibres. The results strongly suggest the need to adopt a fully standardised procedure for determining the w _L of peat. Additional shear vane measurements of intact and remoulded peat from a bog failure in Northern Ireland indicated a very high ‘strength sensitivity’. This leads to the suggestion that a slight disturbance of basal peat can lead to a loss of strength that rapidly propagates as local stresses change and cause further remoulding as water contents exceed w _L.