Bedded jaspers of the Ordovician Løkken ophiolite,Norway: seafloor deposition and diagenetic maturation of hydrothermal plume-derived silica-iron gels

Sedimentary beds of jasper (red hematitic chert) in the Ordovician Løkken ophiolite of Norway are closely associated with volcanogenic massive sulphide (VMS) deposits. The jaspers occur in the immediate hangingwall and laterally peripheral to the large Løkken (25–30 Mt) and small Høydal (0.1 Mt) VMS deposits, and are exposed discontinuously for several kilometres along strike. Massive or laminated types predominate; jasper-sulphide debris-flow deposits are also abundant near VMS deposits. The jaspers contain hematite-rich laminae showing soft-sediment deformation structures and microtextural evidence that record the presence of a colloidal precursor and an origin as gels. Early textures include: (1) straight or curved chains of hematitic filaments 3–10 µm in diameter and 20–100 µm long; (2) branching networks of 15–25 µm-thick, tubular structures surrounded by cryptocrystalline hematite and filled with quartz and euhedral hematite; (3) small (up to 10 µm) spherules composed of cryptocrystalline hematite and silica; and (4) up to 50 µm silica spherules with hematitic cores. The small filaments seem to have been deposited in varying proportions in the primary laminae, possibly together with hematitic and siliceous microspheroids. Diagenetic changes are represented by polygonal syneresis cracks, and the presence of cryptocrystalline (originally opaline) silica, chalcedony, quartz, carbonate and cryptocrystalline hematite and/or goethite forming botryoidal masses and spheroids <10 µm to 5 mm in diameter. Coarser euhedral grains of quartz, carbonate, and hematite are integral parts of these textures. Bleached, silica-rich jaspers preserve only small relics of fine-grained hematite-rich domains, and locally contain sparse pockets composed of coarse euhedral hematite±epidote. The jaspers are interpreted to record colloidal fallout from one or more hydrothermal plumes, followed by maturation (ageing) of an Si-Fe-oxyhydroxide gel, on and beneath the Ordovician sea floor. Small hematitic filaments in the jaspers reflect bacteria-catalysed oxidation of Fe ²⁺ within the plume. The larger tubular filaments resulted from either microbial activity or inorganic self-organized mineral growth of Fe-oxyhydroxide within the Si-Fe-oxyhydroxide gel after deposition on the sea floor, prior to more advanced maturation of the gel as represented by the spheroidal and botryoidal silica-hematite textures. Bleaching and hematite±epidote growth are interpreted to reflect heat and fluids generated during deposition of basaltic sheet flows on top of the gels.     

INTERMODAL TRANSPORTATION IN NORTH AMERICA AND THE DEVELOPMENT OF INLAND LOAD CENTERS*

This paper analyzes the changes that are transforming intermodal transportation in the United States and Canada. Traffic is being concentrated at a relatively small number of inland load centers that serve as regional truck distribution points, and are linked by high volume dedicated train services. Both theoretical and practical implications of the changes are examined, and a range of research questions are presented.     

Fifty years of organisational change in container shipping: regional shift and the role of family firms

Spectacular growth has marked the industry initiated by Malcolm McLean with the sailing of the Ideal-X in 1956. While the growth of container shipping has been typically seen in terms of technological advances, increasing vessel capacity, traffic growth, financial performance and competitiveness, it has been shaped also by organisational transformations. This paper provides an overview of the major companies that make up the container shipping industry, tracing the rapid adoption of containerisation by American carriers to its diffusion to Europe and then Asia. While several carriers belong to business conglomerates, the most dynamic in recent years have been those that are those that possess a family structure. About 12 of the present top 20 carriers are largely family controlled, including 4 out of the top 5. Unlike other capital intensive industries, where the power has shifted towards corporate governance, the container shipping industry retains a strong individualistic entrepreneurial character. At a time when North American ownership in container shipping is no more, the spirit of innovation began 50 years ago by an American visionary is still evident in the entrepreneurial dynamism of many of the industry leaders.     

Natech or natural? An analysis of hazard perceptions,institutional trust,and future storm worry following Hurricane Harvey

Natural Hazards - Researchers have traditionally conceptualized hazards that give rise to disasters as “natural” or “technological.” An extensive literature has documented...     

Estuarine and Coastal Habitat Use of Gulf Sturgeon (<Emphasis Type="Italic">Acipenser oxyrinchus desotoi</Emphasis>) in the North-Central Gulf of Mexico

Gulf sturgeon are anadromous, spawning in freshwater and returning to the marine environment to feed. Herein, we document the marine distribution and timing of movement in and out of the marine environment of Gulf sturgeon natal to the Pascagoula and Pearl rivers (MS and LA). From 1999 to 2004, we attached sonic transmitters to 194 fish averaging 151 (MS) to 160 (LA) cm in fork length. We located 56 different Gulf sturgeon in the estuarine or marine environments, some multiple times. Fish were distributed nonrandomly, being found primarily in shallow water (mean = 3.9 m) in barrier island passes. Benthic samples taken at Gulf sturgeon telemetry location sites were dominated by Florida lancelets, sand dollars, annelids, haustoriid amphipods, and mollusks—all documented prey of Gulf sturgeon. Movement into salt water consistently occurred in October and November; movement back into rivers or low salinity estuaries was complete by the end of March.     

Ionospheric Tomography Network of Egypt: A New Receiver Network in Support of the International Heliophysical Year

The International Heliophysical Year (IHY) 2007 is an international scientific program designed to coordinate observations of the heliosphere, the region of space from the solar surface through the solar wind and various planetary magnetospheres to the planetary upper atmospheres. A particular emphasis is given to the development of long-term international collaborations that will study the external drivers to the space environment and climate. The Ionospheric Tomography Network of Egypt (ITNE) is one such collaboration. It is a new chain of ionospheric tomography receivers that will be deployed to investigate the equatorial regions of the Earth’s ionosphere. The distribution of plasma density within 20° of the magnetic equator is highly sensitive to forcing from the solar wind through a process known as the equatorial fountain. ITNE will provide new observations of the density structures associated with the equatorial fountain.     

Across the pond: container shipping on the North Atlantic in the era of globalisation

This paper describes the development of containerisation in one of the most important theatres of maritime trade, the North Atlantic. As the original hearth of containerisation, it has been an area of experimentation and evolution for a technology that has burst around the world. Although over the last decade the Atlantic has been superceded by the Pacific Ocean as the major market focus for containers, it still is an important market arena. The emergence of global shipping networks is tending to favour the Atlantic once again. The paper provides an analysis of these recent developments. This revised version was published online in July 2006 with corrections to the Cover Date.     

Electrokinetic control of nitrate movement in soil

Nitrate contamination of surface and groundwater has become a serious concern in many agricultural areas throughout the world. Nitrate fertilization is widely used to increase crop yields and quality, but nitrates are highly soluble in water with low retention by soils. Appropriate nitrate application practices can minimize losses, but untimely rainfall can foil management intent. A small dc electrical input has previously been reported to influence nitrate movement in wet soil. Two sets of lysimeter experiments were conducted to evaluate the effect of parallel electrodes on pH and nitrate distribution in field soils subjected to an electrical input. In one experiment, drip irrigation with injected nitrate application was used to grow Sudan grass; in the other, nitrate distribution in wet soil was observed after application of varying levels of electrical current. Increased nitrate concentration, reduced sodium and calcium concentration and lower pH values near the anode, the expected results, were not attained consistently in the test soils with an electrical input of 100–700 mA. The evaluation is being continued with simpler, more controlled conditions in soil column laboratory experiments.     

The challenge of peripheral ports: an Asian perspective

The growth of ports peripheral to the dominant container hubs has been well documented in North America and Europe, and has led to the elaboration of several theoretical models. This paper applies these models to the situation in South East Asia where much of the growth in containerisation is taking place. While confirming the emergence of several peripheral ports that are mounting challenges to the major hubs, we demonstrate that the factors behind the challenges are different to those postulated in the literature. Issues of governance arising out of the complex restructuring of the global ports industry are singled out. We suggest that a new geography of container terminals based on management and operational strategies of private and public bodies involved in the port industry needs to be fashioned.