Structure of the Inner Bristol Channel and Severn Estuary borderlands, UK: regional mapping and seismic interpretation yield a refined model for mountain front deformation and inversion.

<p>Decades of work has been completed on Variscan geology of the inner Bristol Channel and Severn Estuary, yet there are few structural models that correctly portray their regional framework. Many published charts loosely depict the positions, strikes and nature of the Variscan deformation front and its geometry across SE Wales. Thus, we correlate seismic data with coastal outcrop at appropriate scales and detail, to present a refined model for the front.</p><p>Coastal outcrops, in conjunction with known crustal-scale seismic data: BIRPS, SWAT and LISPB, are combined with archives of intermediate scale: wide-angle reflection, seismic refraction and reflection records. They justify a reinterpretation of the front and may explain the geometry and kinematics of its foreland. Using these data, we draw new sections from north Devon to South Wales showing the position of structural units, both Palaeozoic and Mesozoic, affected either directly by thrusts, folds and disturbances or indirectly through structural inheritance during reactivation.</p><p>We correlate extracts from SWAT lines 2 and 3, a reinterpretation of LISPB data and the new fine-scale sections, S-N across the inner channel and W-E across the estuary. They enable the synopsis of crustal-scale data and regional maps. We find from measurement of several hundred lineaments and planes along the borderlands that the predominant orientation is ENE-WSW, unlike the central Bristol Channel which is WNW-ESE. All these, plus outcrop scale geometries and striation analyses, support the new tectonic partition of SE Wales and west of England.</p><p>Much information on the partition boundaries can be gathered from the marine geography of the estuary using Admiralty charts that yield accurate soundings. Seabed profiles across the estuary illustrate the positions of bedrock. Many align with onshore structure both locally and on the grander scale and through 3D reconstruction, we find that a crucial confluence of three discrete trends of lineament converge near Flat Holm and Steep Holm and may represent the pristine Variscan WNW, the Caledonoid NE and pervasive NNW trends. These islands in the estuary are sentinels at a boundary to the hybrid terrane that underlies SE Wales.</p><p>Mesozoic strata of marginal to distal facies, preserved close to negatively inverted faults with partial growth, mark the reactivated stems of Variscan ramps and NE disturbances with significant thrust displacements. We note two phases of negative inversion require restoration in order to reconstruct the orientations within the Variscan basement. In addition, close examination of late (Tertiary) fault history of the estuary is required to adjust basement trends and displacements to get a better sense of rotation within the Palaeozoic foreland.</p><p>Through restoration the new hybrid sub terrane preserves characteristics of Variscan and Caledonoid trending faults and we deduce that a rotation in major thrust trajectory occurred contemporaneously with reactivation of deeper lineaments. This was followed by a structural decapitation as shallow-level thrusts encroached SE Wales, during late stages of the Variscan Orogeny. Finally, the detached stems were incorporated into an imbricate fan which was significantly affected by post-Carboniferous inversion.   </p><p> </p><p> </p>

NOAA’s Certification program in Marine Cartography

<p><strong>Abstract.</strong> Since its establishment in 1807, the National Oceanic and Atmospheric Administration’s (NOAA) Office of Coast Survey has provided nautical charts to support safe shipping, national defence, and the delamination of maritime boundaries. The mission of the office is to provide navigation products and services that ensure safe and efficient maritime commerce on America’s oceans and coastal waters, and in the Great Lakes. The Office of Coast Survey employs cartographers, hydrographers, physical scientists, managers and administrative staff in order to fulfil its mission. Until recently, training in nautical cartography at the office of Coast Survey was conducted at the branch level and differed based on level of employee seniority (i.e., Entry, Intermediate and Advanced) and the processing branch of the employee. Over the past two years, NOAA has established a Coast Survey CAT B program that is intended to train and educate to up to 13 cartographers per year in nautical cartography, through a combination of lectures, hands-on chart production experience, details to various branches within the Coast Survey, and field trips to working hydrographic survey vessels through six training modules spread over a one-year period, spread over six courses that include:</p><ul><li><i>Refresher course</i> that provides a review of the basic math, computer and communication technology, marine geography, hydrography, and geodetic topics. The goal of this course is to ensure that students have a sufficient academic background to succeed in the subsequent CAT-B program courses and other activities.</li><li><i>Introduction to Cartography course</i> that reviews elements of cartography, specifically scale, design, and data manipulation techniques. Students will gain an appreciation for maps and map-making, including manual techniques. This introductory course will include hands-on use of computer graphics tools.</li><li><i>Map Design course</i> that reviews the various styles and techniques associated with cartographic design. The course will require the student to: 1) analyse chart design parameters, 2) compile thematic cartographic projects, and 3) experiment with map design.</li><li><i>GIS and Spatial Analysis course</i> that provides students with a comprehensive understanding of spatial analysis methods and they will learn practical skills in using GIS and spatial analysis. The class covers the methods of spatial analysis including measuring aspects of geometric features and identifying spatial patterns of geospatial objects that are represented as point, line, network, areal data, and 3-D surfaces.</li><li><i>GIS and Spatial Modelling course</i> that provides the students a foundation and understanding of various issues related to modelling and simulation in the GIS. It will address the concepts, tools, and techniques of GIS modelling (vector- and raster-based modelling). In addition, it will present modelling concepts and theory as well as provide opportunities for hands-on model design, construction, and application.</li><li><i>NOAA training project and internship program course</i> that includes: 1) a detailed review of many of the activities conducted by the branches in NOAA’s Marine Chart Division and 2) a training project that demonstrates the student’s ability to implement the knowledge gained during the certification.</li></ul><p>This paper presents a newly established CAT B certificate program in Standards of Competence for Nautical Cartographers that is conducted at NOAA’s main campus in Silver Spring, Maryland, USA. The CAT B certificate program provides NOAA a mechanism to both enhance building capacity within the organization and recognizing NOAA cartographers for their capabilities and efforts. In addition, such a program at NOAA can also be used to recruit new employees and help to build capacity in sister organizations.</p>

Coastal and Marine Geography

The 1990s witnessed a significant increase in popular interest in the US regarding the geography of the world’s coastal and marine spaces. Factors motivating this renewed interest included growing public environmental awareness, a decade of unusually severe coastal storms, more frequent reporting of marine pollution hazards, greater knowledge about (and technology for) depleting fishstocks, domestic legislation on coastal zone management and offshore fisheries policies, new opportunities for marine mineral extraction, heightened understanding of the role of marine life in maintaining the global ecosystem, new techniques for undertaking marine exploration, the 1994 activation of the United Nations Convention on the Law of the Sea, reauthorization of the US Coastal Zone Management Act in 1996, and designation of 1998 as the International Year of the Ocean. Responding to this situation, the breadth of perspectives from which coastal and marine issues are being encountered by geographers, the range of subjects investigated, and the number of geographers engaging in coastal-marine research have all increased during the 1990s. As West (1989a) reported in the original Geography in America, North American coastal-marine geography during the 1980s was focused toward fields such as coastal geomorphology, ports and shipping, coastal zone management, and tourism and recreation. Research in these areas has continued, but in the 1990s, with increased awareness of the importance of coastal and marine areas to physical and human systems, geographers from a range of subdisciplines beyond those usually associated with coastal-marine geography have begun turning to coastal and marine areas as fruitful sites for conducting their research. Climatologists are investigating the sea in order to understand processes such as El Niño, remote-sensing experts are studying how sonic imagery can be used for understanding species distribution in three-dimensional environments, political ecologists are investigating the ocean as a common property resource in which multiple users’ agendas portend conflict and cooperation, and cultural geographers are examining how the ocean is constructed as a distinct space with its own social meanings and “seascapes.” Despite (or perhaps because of ) this expansion in coastal-marine geography, the subdiscipline remains fragmented into what we here call “Coastal Physical Geography,” “Marine Physical Geography,” and “Coastal-Marine Human Geography.”