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Michael J. Steventon Christopher A.‐L. Jackson David M. Hodgson Howard D. Johnson 《Basin Research》2019,31(3):600-620
Strain style, magnitude and distribution within mass‐transport complexes (MTCs) are important for understanding the process evolution of submarine mass flows and for estimating their runout distances. Structural restoration and quantification of strain in gravitationally driven passive margins have been shown to approximately balance between updip extensional and downdip contractional domains; such an exercise has not yet been attempted for MTCs. We here interpret and structurally restore a shallowly buried (c. 1,500 mbsf) and well‐imaged MTC, offshore Uruguay using a high‐resolution (12.5 m vertical and 15 × 12.5 m horizontal resolution) three‐dimensional seismic‐reflection survey. This allows us to characterise and quantify vertical and lateral strain distribution within the deposit. Detailed seismic mapping and attribute analysis shows that the MTC is characterised by a complicated array of kinematic indicators, which vary spatially in style and concentration. Seismic‐attribute extractions reveal several previously undocumented fabrics preserved in the MTC, including internal shearing in the form of sub‐orthogonal shear zones, and fold‐thrust systems within the basal shear zone beneath rafted‐blocks. These features suggest multiple transport directions and phases of flow during emplacement. The MTC is characterised by a broadly tripartite strain distribution, with extensional (e.g. normal faults), translational and contractional (e.g. folds and thrusts) domains, along with a radial frontally emergent zone. We also show how strain is preferentially concentrated around intra‐MTC rafted‐blocks due to their kinematic interactions with the underlying basal shear zone. Overall, and even when volume loss within the frontally emergent zone is included, a strain difference between extension (1.6–1.9 km) and contraction (6.7–7.3 km) is calculated. We attribute this to a combination of distributed, sub‐seismic, ‘cryptic’ strain, likely related to de‐watering, grain‐scale deformation and related changes in bulk sediment volume. This work has implications for assessing MTCs strain distribution and provides a practical approach for evaluating structural interpretations within such deposits. 相似文献
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《Marine Policy》2015
Recent changes in marine policy in Panama are closely related to sustained expansion of the Panamanian economy in the past ten years. Important drivers of economic growth such as the Panama Canal expansion, tourism, and real estate development directly involve marine and coastal areas. Therefore, maintaining the quality of these environments, as well as the sustainability of the human communities that depend on them, calls for the implementation of adequate management and planning policies. In light of a complex history of marine and coastal policy in Panama, current institutional restructuring processes, and a growing recognition of the importance of marine and coastal geographies, the authors aim to document the current status of, and community response to, marine and coastal policy in Panama, analyzed in terms of three important cross-cutting sectors: tourism, fishing, and conservation. To do so, the authors introduce two case studies: one in the Pearl Islands Archipelago and one in Bocas del Toro, each with varying degrees of participation or involvement in each sector, to illustrate the range of adaptations to change occurring in coastal communities. Based on an in-depth policy analysis and the case studies, the authors suggest that there are important administrative and structural gaps in the legislation and institutions that enforce them, as well as a lack of integration across institutions. In particular, the authors highlight the lack of clear marine and coastal property regimes as an obstacle to the implementation of integrative marine policies in Panama. 相似文献
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The purpose of this article is to examine how the geography of Brazil’s financial centers changed since 2000 in terms of financial center hierarchy, specialization, and spatial concentration. To address these questions, we use data on employment and mergers and acquisitions in financial and business services, complemented with data on remuneration and bank assets. Our results show that São Paulo has consolidated its dominance as Brazil’s primary financial center, with market for corporate control as an important channel of this process. Rio’s decline as a financial center, which started more than fifty years ago, has continued into this century. At the same time, Brasília has emerged as the third most important financial center of Brazil. We document the recent dynamic of this territorial division of labor, with Rio’s specialization in insurance and Brasília’s dependence on government-owned banks. Finally, we show signs that Brazil’s financial center activities might be following an inverse U-shaped pattern whereby increasing geographical concentration is followed by its slow decline. Key Words: Brazil, concentration, financial centers, São Paulo, territorial division of labor. 相似文献
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José Carlos G. Aguiar 《Singapore journal of tropical geography》2012,33(2):171-183
The vision of a borderless world, of people, ideas and products freely circulating within a self‐regulating market, is one that clashes with the emerging legal regime based on the punitive force of the state. After a period of liberalization, seen in the opening of national economies and the promotion of regional trade projects and free‐trade zones, the ambivalence of neoliberalism is manifest in a borderless capitalism that ambiguously depends on the securitization of national borders. Such a changing regime of state intervention is clearly seen at the Iguazú triangle – the tri‐border urban conglomerate that straddles Brazil, Paraguay and Argentina – where the illegality of informal cross‐border trading has been tolerated for decades. Recently stepped up police raids and controls hinder the passage of people and goods, while a new fiscal regime introduced in 2009 in Brazil attempts to regularize cross‐border trafficking by turning petty smugglers into micro entrepreneurs. Petty smugglers – dubbed sacoleiros– can hardly be defined as entrepreneurs and do not constitute an identifiable category of entrepreneurship but, as typical in the informal sector, act on opportunity and need. Drawing on ethnographic research, this paper contextualizes the programmes for border controls and regularizing smuggling inspired by neoliberal ideology in South America. 相似文献
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《The Professional geographer》2012,64(1):131-138
This article argues for a more sustained use of courtroom ethnography by geographers as a means to research legal phenomena, especially in matters of court trials. To do this, I begin by referencing two main threads of courtroom ethnographies conducted in disciplines outside geography, specifically the spaces of the courthouse and courtrooms and the study of emotion and bodily performances by sociolegal and sociology scholars. To then underscore the ways in which a geographical perspective can enhance this existing research and point to topical and theoretical interventions that courtroom ethnography might offer geography, I draw on my experiences with courtroom ethnography on the criminal trial against former Enron chief executives Ken Lay and Jeffrey Skilling. This experience produced a nuanced and lively understanding of how law, justice, and space comingle through the court’s physical spaces and performative embodiments. My conclusions emphasize courtroom ethnographies’ scholarly opportunities for researchers who study the intersection of law and space, while also reflecting on its challenges. Key Words: corporation, courtroom, Enron, ethnography, legal geography. 相似文献
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Assessment of evaporation and water fluxes in a column of dry saline soil subject to different water table levels 总被引：1，自引：0，他引：1 
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下载免费PDF全文 María Fernanda Hernández‐López Jorge Gironás Isabelle Braud Francisco Suárez José Francisco Muñoz 《水文研究》2014,28(10):3655-3669
Dry saline soils are common in the arid and hyper‐arid basins located in the Chilean Altiplano, where evaporation from shallow groundwater is typically the major component of the water balance. Thus, a good understanding of evaporation processes is necessary for improving water resource planning and management in these regions. In this study, we conducted laboratory experiments with a natural saline soil column to estimate evaporation rates and assess the liquid and water vapor fluxes under different water table levels. Water content, electrical conductivity and temperature at different depths were utilized to assess the liquid and water vapor fluxes in the soil column. We observed movement of water that dissolves salts from the soil and transports them to areas in the column where they accumulate. Isothermal liquid flux was predominant, while thermal and isothermal liquid and thermal water vapor fluxes were negligible, except for deep water table levels where isothermal and thermal water vapor fluxes had similar magnitude but opposite directions. Differences observed in total fluxes for all water table levels were due to different upward and downward fluxes, which depend on changes in water content and temperature within the soil profile. Both the vapor flux magnitude and direction were found to be very sensitive to the choice of empirical parameters used in flux quantification, such as tortuosity and the enhancement factor for local temperature gradients in the air phase within the column. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Late Pleistocene–Holocene environments in Valle Carbajal, Tierra del Fuego, Argentina 总被引：1，自引：0，他引：1
Ana María Borromei Andrea Coronato Mirta Quattrocchio Jorge Rabassa Silvia Grill Claudio Roig 《Journal of South American Earth Sciences》2007,23(4):321-335
The authors discuss Late Pleistocene–Holocene depositional environments in one of the Fuegian Andes valleys on the basis of palynological, geomorphological, and sedimentological analyses from two sites located near the Beagle Channel. The results obtained at these localities reinforce and refine the Late Pleistocene–Holocene climatic pattern previously recorded there. A colder period, associated with the Younger Dryas stadial event, is suggested by low Nothofagus pollen frequency, and communities of grass, low scrub, and shrub heath expanded into the low/middle slopes (10,310 14C yr BP). By ca. 9500 14C yr BP, warmer and drier conditions occurred, as evidenced by the development of open-grown vegetation in the valley floors (pollen zone O-3), followed by the expansion of open Nothofagus woodland (pollen zone O-2) in the middle Holocene. The milder climate subsequently changed, as indicated by the spreading of the closed forest and mire (pollen zone O-1), to more humid and cooler conditions during the last ca. 5000 yr BP. 相似文献
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Four of the major plutons in the vicinity of the Candelaria mine (470 Mt at 0.95% Cu, 0.22 g/t Au, 3.1 g/t Ag) and a dike–sill system exposed in the Candelaria open pit have been dated with the U–Pb zircon method. The new geochronological data indicate that dacite magmatism around 123 Ma preceded the crystallization of hornblende diorite (Khd) at 118 ± 1 Ma, quartz–monzonite porphyry (Kqm) at 116.3 ± 0.4 Ma, monzodiorite (Kmd) at 115.5 ± 0.4 Ma, and tonalite (Kt) at 110.7 ± 0.4 Ma. The new ages of the plutons are consistent with field relationships regarding the relative timing of emplacement. Plutonism temporally overlaps with the iron oxide Cu–Au mineralization (Re–Os molybdenite ages at ∼115 Ma) and silicate alteration (ages mainly from 114 to 116 and 110 to 112 Ma) in the Candelaria–Punta del Cobre district. The dated dacite porphyry and hornblende diorite intrusions preceded the ore formation. A genetic link of the metallic mineralization with the quartz–monzonite porphyry and/or the monzodiorite is likely. Both of these metaluminous, shoshonitic (high-K) intrusions could have provided energy and contributed fluids, metals, and sulfur to the hydrothermal system that caused the iron oxide Cu–Au mineralization. The age of the tonalite at 110.7 Ma falls in the same range as the late alteration at 110 to 112 Ma. Tonalite emplacement may have sustained existing or driven newly developed hydrothermal cells that caused this late alteration or modified 40Ar/39Ar and K/Ar systematic in some areas. 相似文献
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The Molí del Baró-1 site (north-eastern Iberia) has yielded one of the richest fossil assemblages of the continental upper Maastrichtian from western Europe. It includes abundant plant (charophytes, sporomorphs, angiosperm leaves, seeds and logs), invertebrate (mollusc shells, partial insect exoskeletons and eggs) and vertebrate (teeth, bones, eggshells) fossils. The fossil assemblage is composed of both parautochthonous and allochthonous remains that mostly deposited in a pool formed at the edge of a meandering river. Plant megafossil evidence suggest that at least three angiosperm species (a willow-like dicot, palms and a likely typhacean monocot) formed the plant community growing in this fluvial environment. Tooth remains indicate that crocodylomorphs were diverse (including atoposaurids, ziphosuchians and eusuchians) which together with small theropod dinosaurs likely consumed prey carcasses or scavenged near the depositional setting. Prismatoolithid eggshells also suggest the presence of nearby nesting area of theropods. On the other hand, hadrosauroids apparently dominated phytophagous faunas including lambeosaurines as well as more basal forms. The taxonomic composition of the Molí del Baró-1 site matches the expected for the timespan and environment and represents a relevant locality to know the diversity of the latest Cretaceous terrestrial ecosystems in south western Europe. 相似文献