Geological Survey Map Research Articles

Average uranium bedrock concentration in Swedish municipalities predicts male lung cancer incidence rate when adjusted for smoking prevalence: Indication of a cumulative radon induced detriment

Bedrock U has been used as a proxy for local indoor radon exposure. A preliminary assessment of cancer incidence rate in a cohort of 809,939 adult males living in 9 different Swedish counties in 1986 has been used to correlate the cumulative lung cancer and total cancer (excluding lung) incidence rates between 1986 and 2020, respectively with the municipality average value of bedrock U concentration obtained from Swedish geological Survey (SGU). To control for regional difference in tobacco smoking, data on county average smoking prevalence, obtained from a survey conducted by the Public Health Agency of Sweden from 2001 to 2004, was used. Regression analysis shows that there is a significant positive correlation between smoking prevalence adjusted lung cancer incidence rate in males and the municipality bedrock U concentration (R2 = 0.273 with a slope 5.0 ± 0.87·10−3 ppm−1). The correlation is even more significant (R2 = 0.759 with a slope = 4.8 ± 0.25·10−3 ppm−1) when assessed on population weighted cancer incidence data binned in nine intervals of municipality average bedrock U concentration (ranging from 0.97 to 4.9 ppm). When assessing the corresponding correlations for total cancer incidence rate (excluding cancer of the lung) with adjustment for smoking prevalence, there appears to be no or little correlation with bedrock U concentration (R2 = 0.031). We conclude that an expanded future study needs age-standardized cancer incidence data to obtain a more consistent exposure-response model. Such model could be used to predict future lung cancer cases based on geological survey maps of bedrock U as an alternative to laborious indoor radon measurements, and to discern what future lung cancer rates can be expected for a population nearing zero smoking prevalence, with and without radon prevention.

Assessing the Impact of Land Use and Land Cover Data Representation on Weather Forecast Quality: A Case Study in Central Mexico

In atmospheric modeling, an accurate representation of land cover is required because such information impacts water and energy budgets and, consequently, the performance of models in simulating regional climate. This study analyzes the impact of the land cover data on an operational weather forecasting system using the Weather Research and Forecasting (WRF) model for central Mexico, with the aim of improving the quality of the operative forecast. Two experiments were conducted using different land cover datasets: a United States Geological Survey (USGS) map and an updated North American Land Change Monitoring System (NALCMS) map. The experiments were conducted as a daily 120 h forecast for each day of January, April, July, and September of 2012, and the near-surface temperature, wind speed, and hourly precipitation were analyzed. Both experiments were compared with observations from meteorological stations. The statistical analysis of this study showed that wind speed and near-surface temperature prediction may be further improved with the updated and more accurate NALCMS dataset, particularly in the forecast covering 48 to 72 h. The Root Mean Square Error (RMSE) of the average wind speed reached a maximum reduction of up to 1.2 m s−1, whereas for the near-surface temperature there was a reduction of up to 0.6 °C. The RMSE of the average hourly precipitation was very similar between both experiments, however the location of precipitation was modified.

Cancer Alley: Istrouma to the Gulf of Mexico

This photo-collage essay travels from Istrouma (Baton Rouge) to the Gulf of Mexico, illuminating seen and unseen realities along the banks of the Mississippi River, in a territory of south Louisiana known as “Cancer Alley.” Layers of evidence found in the public record, ranging from colonial renderings to US Geological Survey maps, in addition to photographic documentation, genealogical ties, and historical facts, are used to illustrate how colonial foundations have set a precedence for multinational corporations to perpetuate a legacy of extractive and shortsighted land and water use practices. Indigenous names and histories of a time prior to colonization help to redefine the remembrance of sites and strategic locations, contrasting past and present with the natural and industrial manmade manipulations that have complicated the Mississippi River Delta’s landscape and legacy.

How Topographic Maps Affect: Experiencing Washington, DC through the Maps of the “Other”

Does the type of map we use affect how we engage with a place in situ? This paper describes a creative activity that aimed to explore how the use of different topographic maps affects our engagement with an urban environment. Three groups of participants explored the neighbourhood surrounding the Gelman Library at George Washington University, each using an extract from a different map (all with street-level detail of the area) as a guide: (1) a contemporary selection from OpenStreetMap; (2) a United States Geological Survey (USGS) map from 1965; and (3) a Soviet military plan from 1975. The 32 participants recorded their experiences by taking photographs and uploading them to a shared online bulletin board (Padlet). After gaining feedback via group discussion, the resulting 108 images were classified, interpreted and mapped. The findings indicate that the groups’ engagement with their environment varied with the specific map used, and was possibly influenced by their interpretation of its function, although differences in individual perceptions and responses were more pronounced than between-map differences. The activity provides a starting point for understanding the role topographic maps play in the relationship between emotions and environment and offers some avenues for further research.

The Colorado and Virgin Rivers before Lake Mead

ABSTRACTIn 1936, the completion of Hoover Dam on the Colorado River in Nevada and Arizona created Lake Mead, the largest reservoir in the United States. When the lake reached capacity in 1941 several canyons and valleys were flooded, along with two towns, several mines, farm fields, and roads. The area had not been surveyed archaeologically and little detailed information exists about the vegetation and geology of this region. The map reconstructions the geography of the area in 1930 before Lake Mead was constructed, showing roads, towns, mines, physical features, and private property, and was created using a range of historical United States Geological Survey (USGS) maps, a digital elevation model (DEM) providing underwater elevations, and other historical sources. The map includes portions of southern Nevada and northwest Arizona, United States, and is at a scale of 1:210,000. It is hoped that the map may draw attention to the lost geographies of other localities across the United States due to the more than 84,000 dams and reservoirs in the country.

Assessment of the fuzzy ARTMAP neural network method performance in geological mapping using satellite images and Boolean logic

Currently, in executive comparative studies and even in the research studies of natural resources, the use of maps produced by the geological survey forms the basis of geological studies. However, in recent years, remote sensing technology has been introduced as a new and efficient tool for geological studies which in addition to the accuracy has other benefits such as access to the arduous mountainous areas or inaccessible that can help us to prepare geological maps with more accuracy. The purpose of this study is to compare geological survey geological maps with a scale of 1: 100,000, and produced and modified by Google Earth maps by using fuzzy ARTMAP artificial neural network method. For this purpose, the geological map of a part of Yazd-Shirkooh watershed prepared by using Landsat 7 image by fuzzy ARTMAP artificial neural network method with Kappa coefficient of 89%. Also, geological survey and Google Earth map prepared. Graphic map obtained from the visual interpretation of Google Earth images with the ground control was considered as the base map and comparing it with other maps evaluated by using Boolean logic. By using the sampling network created 100 points which 62 points were in the study area and 56 cases in the fuzzy ARTMAP map and 52 cases in the geological survey map were consistent with the base map. Due to reduced cost and time and no limits of time and space, fuzzy ARTMAP is a suitable method for the preparation of geological maps.

Victorian geological survey maps of Britain and Ireland

In a farsighted development, the British Geological Survey has brought a new lease of life to its historic material by putting its water-coloured map sheets online. This new digital archive (http://www.bgs.ac.uk/data/maps/home.html), with introductory notes and downloads, features mainly one inch to the mile 1 : 63 360 geological maps and their related cross-sections drawn up along the lines that were neatly etched across the sheets, which became increasingly detailed over the decades. Once a map sheet or section is selected online it could not be easier to enlarge it and swiftly pan around, looking at the meticulously engraved topographic base map and the often brightly coloured overlying geology, occasionally annotated, including coastal sheets with descriptive notes. Furthermore, it is then possible to order very high quality reprints to study an area in even more detail or simply put one of the more attractive sheets on the wall, as there are some real gems to choose from. This feature provides a guide to some of its more important maps.

Structural and lithostratigraphic controls of earth-flow evolution, Montaguto earth flow, Southern Italy

This paper aims to define the control exerted by geological setting on the evolution and segmentation of the Montaguto earth flow in Southern Italy. A detailed geological survey and multi-temporal maps were used to reconstruct the geological model of La Montagna Mt. and to quantify the evolution of the flow in terms of sediment pulse formation, movement direction and spatial change in earth-flow area. The spatial distribution of structural fabric of the mountainside was compared with (1) planar geometry of earth-flow source area, (2) orientation of strike-slip faults bounding the earth-flow moving core (i.e. movement direction) and (3) kinematic-zone position and extent. We infer that the evolution of the earth flow is controlled by geological structures and lithology. Moreover, the entire basal-slip surface is composed of newly formed basal-slip surface in the source area, and corresponds to pre-earth-flow topography downslope from the neck. Implications of our work are that (1) a detailed geological model of an unstable mountainside, combined with information about earth-flow spatial evolution, might be considered as a tool that allows the localization of areas of possible earth-flow enlargement and (2) geological structures constrain earth-flow movement, inducing a predictable seasonal behaviour in terms of movement direction.

Landform signature of the Laurentide and Cordilleran ice sheets across Alberta during the last glaciation

Government geological survey maps and research publications have portrayed the distribution of glacial landforms associated with the advance and retreat of the Laurentide and Cordilleran ice sheets across Alberta at a local, regional, and continental scale. To date, this information has not been systematically synthesized into a single compilation at a consistent scale. Although this original work provided valuable information to constrain reconstructions of former ice sheet extent, configuration, and flow geometry, its derivation primarily from the interpretation of aerial photographs and the Shuttle Radar Topography Mission 90 m digital elevation model (DEM) may result in methodological inconsistencies and spatial biases. These biases, together with challenges associated with geomorphic mapping in densely forested areas of western and northern Alberta limit the usefulness of previous mapping when applied to inversion-based ice sheet reconstructions, which have specific input data demands. Recently, light detection and ranging (LiDAR) DEMs have become increasingly available throughout Alberta. Hill-shaded imagery of these data provides unprecedented geomorphic detail beneath the forest cover and reveals that that the glacial geomorphology of northern and western Alberta is more complex than previously recognized. In this paper, we describe the methodology and geomorphic criteria used to produce a glacial landform map of Alberta using previously published data, supplemented by comprehensive new analysis of high-resolution (2–25 m) DEMs. These include 306 624 km2 of LiDAR imagery, with which it is now possible to verify and where necessary augment previous mapping, particularly across areas with a dense forest cover.

Glacier Retreat in Doda Valley, Zanskar Basin, Jammu & Kashmir, India

Glacier monitoring is important to provide estimates of freshwater storage in Himalayan region. Therefore, understanding the spatio-temporal glacier retreat is important for utilization of the Himalayan water resource. The study area covers Dodavalley, Zanskar basin in Jammu & Kashmir. An attempt is also made here to analyze the glacier retreat and morphometric parameters like, length, width, area, area accumulation ratio (AAR), specific mass balance etc., of the glaciers using multi-temporal satellite data of IRS-1C LISS III of August 2001, Landsat of 1975, 1992 and 2002and in conjunction with Survey of India (SOI) topographical map of 1962 and United State of Geological Survey (USGS) map of 1925. In this study, it was found that, total glacier area loss from 1962 to 2001 is 18.16%. Though in the years 1975 and 1992, there is positive specific mass balance but in the year 2001, specific mass balance of all glaciers was negative.

Suhard Massif. A geomorphological study

Suhard Mts., part of the Northern Carpathians, stretch over an area of 323 sq km, in the shape of a northwest-oriented ridge. This massif is composed of crystalline schists (meso- and epimetamorphic), as well as sedimentary rocks pertaining to the trans-Carpathian flysch deposits (i.e. various types of sandstone, conglomerates and marls) in the southwestern sector. Whereas this region is characterized by the occurrence of a wide range of carbonate rocks, we noted the scarcity of karst forms. Geological survey maps of the area indicate the occurrence of few folded structures; moreover, the massif is mostly part of an ample anticline whereby the axis underlies the valley of Bistrita Aurie river, accompanied by a large syncline underlying Cosna river valley (tributary of Dorna river). The prevalence of crystalline rocks within this anticlinorium results in the overall massif shape of these mountains (hence, the name), which is the foundation for the detail structural and lithological relief forms. The array of structural relief forms includes structural plateaus on sedimentary and crystalline carbonate rocks, and steep slopes in the form of both hogbacks and overthrust scarps. The lithological relief occurs primarily as a result of the contrasting chemical composition of various crystalline rocks, whereas sedimentary rocks seldom generate such forms and solely when favored by the structure, as well. Consequently, carbonate rocks are rather discrete and only stand out in the form of clints (lapies) and gorges, or hums. As regards the matter of denudation surfaces, which has proved rather difficult to solve, we were able to determine the presence of an erosion surface ranging from 1200-1300 m to 1500-1600 m, wherein neotectonics played a significant role by fragmenting the original surface, particularly in the northwestern sector, where its fragments descend in the shape of consecutive steps towards Rotunda saddle. Periglacial modeling of the relief resulted in a variety of forms of both erosion (scarps, ridges, hums) and accumulation (scree) located in the highest areas, particularly along the main ridge (summit).

Atlas of the potential vegetation of Ethiopia

Floras and vegetation maps are the basis of understanding the ecology and botany of every country. Engler published the first map of the vegetation of Africa in 1882, defining the separation of African vegetation into firstly the forest regions, and secondly grasslands and wooded grasslands, a basic distinction that not surprisingly has remained intact. He refined his concepts over the years, putting the work into an evolutionary and phytogeographical context with his field research, particularly in East Africa, publishing a particularly important paper in Annals of Botany (Engler, 1904). Over the last century, floras for both African regions and individual countries have been published, with the Flora of Ethiopia and Eritrea, published over the period 1980 to 2009 by Swedish Science Press, including an up-to-date and thoroughly revised treatment of the diverse species that occur in these tropical but topographically diverse countries. With the increasing linkage of taxonomy with biogeography and ecology, it has now become common that vegetation maps are produced along with floras. This new comprehensive and well-researched volume by Friis et al. fills the need for a high-quality (1 : 2 000 000 or 5 cm : 100 km, with 90 × 90 m resolution) vegetation map of Ethiopia for land-use planning, natural resource management, agricultural development and conservation. Sadly, an important group of uses will also be to track the destruction of vegetation, areas where the ‘potential’ vegetation of the title is no longer present, and the effects of change in climate, and for this the Atlas sets an essential reference point. As with any field project, geographical information systems (GIS) and digital mapping have revolutionized the production of works such as this, particularly in large countries such as Ethiopia where the vegetation zones may be relatively small and with complex boundaries. In this case, much of the country is covered by the Ethiopian highlands, which lie mostly between 1300 and 2000 m, rising to over 4500 m. At lower elevations, the country includes the northern end of the Great Rift Valley, part of one of the major ecosystems of Africa. The first section of the book gives a 13-page review of details of the geography, geology and climate of the country, and this is followed by accounts of the methods used, the history of the vegetation and its study. These do provide an outstanding introduction to the country and I would recommend reading them to anyone visiting Ethiopia with interests in the natural environment. In the second section of the book there are formalized and detailed, but admirably concise and readable, descriptions of the 12 major vegetation types that are recognized, along with their sub-types. The authors nicely balance the distinction of indicator species between constancy and fidelity, with an appendix detailing occurrence of woody species in each recognized vegetation type. Conservation and erosion issues are discussed within the vegetation sections, although from my own interests I would have liked to see a little more about the crops that are characteristic of each zone and perhaps the invasive species. The final section of the book includes the maps themselves. These, with a scale of 1 : 2 000 000, are appropriately detailed with respect to the vegetation types. I am sure it will be no difficulty for the specialist who will mostly make use of the Atlas, but as a recent casual visitor to the country, I would have found it useful to have had coordinates along the axes to avoid juggling of road maps too! The volume is very nicely produced, with well over 100 colour illustrations, mostly filling a half-page, which give an immediate impression of the nature and structure of each of the vegetation types. Apart from the vegetation maps, it also has about 20 maps of various environmental and geographical features, and reproductions of earlier vegetation maps. A minor criticism of many maps is that the shades of colours are very hard to correlate with the legends, and quite impossible to follow in a dark hotel room. Maybe consideration should be given to combining the shades with a numeric key, as is done in the British Geological Survey maps. While most book reviews require some consideration of the readership, I expect this book has a well-defined audience: any organization involved in land-use, development, agriculture, tourism as well as plant taxonomy should have a copy available. It is a very high-quality study of the vegetation of Ethiopia, filling a significant gap. As such the volume should find a place in all libraries that cover the geography and land use of the continent, as well as herbaria with East African collections. I certainly found it an invaluable reference while driving and flying around parts of the country.

Seismic Hazard Mapping of California considering Site Effects

In this paper, we have combined the U.S. Geological Survey's National Seismic Hazard Maps model with the California geologic map showing 17 generalized geologic units that can be defined by their VS30. We regrouped these units into seven VS30values and calculated a probabilistic seismic hazard map for the entire state for each VS30value. By merging seismic hazard maps based on the seven different VS30values, a suite of seismic hazard maps was computed for 0.2 and 1.0 s spectral ordinates at 2% probability of exceedance (PE) in 50 years. The improved hazards maps explicitly incorporate the site effects and their spatial variability on ground motion estimates. The spectral acceleration (SA) at 1.0 s map of seismic shaking potential for California has now been published as California Geological Survey Map Sheet 48.

The geology and mineralisation of the Carina Iron Deposit, central Yilgarn Craton, Western Australia

The Carina iron ore deposit is 105 km northeast of Southern Cross, WA. The area designated the Yilgarn Iron Ore Project (YIOP) comprises five prospects along an east–southeast trending greenstone belt that extends from the Helena-Aurora Ranges in the northwest to the Yendilberrin Hills in the southeast, over a strike length of approximately 40 km. The YIOP project encompasses the previously identified iron deposits of Bungalbin, Bungalbin East and Mt Walton. The Carina deposit was discovered in May 2007. The Carina deposit is located within and parallel to the structurally complex northwest trending Mount Dimer Shear Zone. The volcano-sedimentary Archaean greenstone sequence consists of ultramafic and mafic lavas and flows with interbedded sedimentary rocks dominated by chert and banded iron formation (BIF). Supergene enrichment processes formed a goethite ore body replacement of BIF sequences within a doubly plunging synclinal fold structure. Mineralised outcrops dominated by goethite form a low ridge 1500 m long, up to 90 m wide and drilled to over 200 m in depth. In the vicinity of the Carina deposit, iron occurrences have been identified over at least a 12 km strike length. The current exploration in the area began in 2006. Target generation in the area used existing state geological survey maps and regional magnetic survey data to focus on BIF occurrences associated with major structures. Early field investigations resulted in the identification of a large outcrop of predominantly goethite mineralisation at Carina. Detailed geological and structural mapping was completed, followed by close-spaced reverse circulation and diamond drilling. The mineralisation is predominantly goethite with specular and coarse platy hematite localised along structures that cut the goethite mineralisation. Mineralised zones are moderately vuggy and larger cavities occur in proximity to fault zones that transect the ore body. There is a capping by a thin veneer of canga or ferricrete up to 9 m thick. By July 2010, 184 reverse circulation and 11 diamond drill holes (seven surface holes, four tails) were completed. The current JORCcompliant resource estimate is based on assays from 170 RC and 11 diamond drill holes and using a 55% Fe cut-off is quoted as an Inferred Resource of 26·7 Mt at 58·9% Fe, 1·2% Al2 O3, 3·2% SiO2 , 0.11% P, 0·08% S, and 9·5 % LOI. Mining is planned to commence in early July 2011.

Performances of Different Global Positioning System Devices for Time-Location Tracking in Air Pollution Epidemiological Studies

Background:People’s time-location patterns are important in air pollution exposure assessment because pollution levels may vary considerably by location. A growing number of studies are using global positioning systems (GPS) to track people’s time-location patterns. Many portable GPS units that archive location are commercially available at a cost that makes their use feasible for epidemiological studies.Methods:We evaluated the performance of five portable GPS data loggers and two GPS cell phones by examining positional accuracy in typical locations (indoor, outdoor, in-vehicle) and factors that influence satellite reception (building material, building type), acquisition time (cold and warm start), battery life, and adequacy of memory for data storage. We examined stationary locations (eg, indoor, outdoor) and mobile environments (eg, walking, traveling by vehicle or bus) and compared GPS locations to highly-resolved US Geological Survey (USGS) and Digital Orthophoto Quarter Quadrangle (DOQQ) maps.Results:The battery life of our tested instruments ranged from <9 hours to 48 hours. The acquisition of location time after startup ranged from a few seconds to >20 minutes and varied significantly by building structure type and by cold or warm start. No GPS device was found to have consistently superior performance with regard to spatial accuracy and signal loss. At fixed outdoor locations, 65%–95% of GPS points fell within 20-m of the corresponding DOQQ locations for all the devices. At fixed indoor locations, 50%–80% of GPS points fell within 20-m of the corresponding DOQQ locations for all the devices except one. Most of the GPS devices performed well during commuting on a freeway, with >80% of points within 10-m of the DOQQ route, but the performance was significantly impacted by surrounding structures on surface streets in highly urbanized areas.Conclusions:All the tested GPS devices had limitations, but we identified several devices which showed promising performance for tracking subjects’ time location patterns in epidemiological studies.

Recommended Tolerances for Magnetometer Orientation and Field Calibration Procedure

Magnetometers are increasingly being deployed for traffic detection in both fixed wired and wireless installations around the United States. Magnetometers respond to local magnetic field disturbances from the ambient magnetic field of the earth, and this response may be expected to depend on the relative orientation of the magnetometer axis and the direction of the earth's magnetic field lines at the point of deployment. As documented by U.S. Geological Survey (USGS) maps, the declination and inclination of the earth's magnetic field vary significantly over the continental United States, yet there is no traffic engineering design literature characterizing the effect of geographic magnetic field variation on magnetometer detection performance. This study briefly reviews the scientific theory, identifies the magnetometer installation parameters of most importance, and characterizes their impact on performance. In addition, recommendations are based on USGS data, which can be used to develop specifications for installation, testing, and acceptance of magnetometer-based detection technology. Finally, a simple procedure for field calibration of sensor orientation in a conduit to near-optimal rotation angle is presented.

A melilite-bearing high-temperature calcic skarn, Camasunary Bay, Isle of Skye

Synopsis The occurrence of high-temperature calcic skarns is relatively rare, with around 30 being reported worldwide. Here, we report on a newly discovered occurrence of a melilite-bearing high-temperature calcic skarn at Camasunary Bay, Isle of Skye. The contact metamorphism was caused by the intrusion of the Cuillin Hills gabbro and the later intrusion of the Coire Uaigneich granophyre. The calcic skarn consists of a high-temperature assemblage of wollastonite, åkermanite–gehlenite, vesuvianite, tilleyite, spurrite. andradite–grossular garnet, monticellite and perovskite. It also includes the very rare Zr-rich garnet kimzeyite and baghdadite (Ca 3 (Zr,Ti)Si 2 O 9 ), indicating transfer of Zr, Ti and other incompatible element-rich fluids derived from the hydrous Coire Uaigneich granophyre. The calcic skarn contains numerous cherty nodules and stringers, which bear a remarkable resemblance to the Cambrian–Ordovician dolostone exposures observed in other parts of Skye. suggesting that the protolith was originally an impure dolomite. The nature of the contact between the calcic skarn and surrounding Torridonian sedimentary rocks could not be directly observed, but elsewhere on Skye this contact is the Kishorn Thrust plane. This has implications for the simplified tectonic map accompanying the British Geological Survey map of Broadford (Sheet 71W), which now requires modification.

Colorado Front Range Rock Glaciers: Distribution and Topographic Characteristics

ABSTRACTIn the Colorado Front Range, rock glacier distribution has been noted on U.S. Geological Survey maps and in several publications; however, a comprehensive account of distribution is not available. When analyzed in a Geographic Information System (GIS), Digital Elevation Model variables (elevation, slope, or aspect) could reveal unique topographic characteristics of rock glaciers. The objectives of this study are to provide an accurate, complete account of rock glacier locations in a digital format, to compare topographic variables of rock glacier form and activity classes, and to evaluate glacier and rock glacier topographic information. Rock glacier locations were obtained from previous studies and were re-digitized on high-resolution digital orthophotos. Glacier distribution was determined through classification of a satellite image. Topographic information for rock glacier form and activity classes as well as for glaciers was obtained through zonal overlay in a GIS. Results indicate that tongue-shaped rock glaciers occur at higher elevations, have more northerly aspects, and have gentler slopes compared to lobate rock glaciers. Active, inactive, and fossil forms showed typical elevation and aspect gradients. Active rock glaciers are found at the highest elevations and most northern aspects. Inactive rock glaciers are found at lower elevations on all aspects with a tendency to face northeast, and fossil rock glaciers occur at the lowest elevations on all aspects. Topographic variables for all rock glaciers were statistically different compared to glacier locations; however, active tongue-shaped rock glaciers had similar topographic variables compared to glaciers, but lobate forms showed a significant difference. In the Front Range, active tongue-shaped rock glaciers are developed by glacial processes and active lobate forms are the product of periglacial processes.

Invited comment on Wray & Gale's ‘The palaeoenvironment and stratigraphy of the Late Cretaceous Chalks’: Proceedings, Vol. 117, 2006, pp. 145–162

Despite the context of this reply we would wish to echo the tributes to Jake Hancock expressed elsewhere in this volume. His contribution in papers over many years (e.g. 1961, 1972, 1975, 1991, 2000) is considerable and, in many cases, still relevant. We would also like to thank Wray and Gale for demonstrating the breadth of research into the understanding of the Chalk and its environment of deposition. Our major concern is with the inaccuracy, incorrect assumptions and misrepresentations implied and stated by Wray & Gale (2006) in their discussion of the modern Chalk lithostratigraphical framework applied to British Geological Survey (BGS) maps and demonstrated in many published documents. This reply gives the BGS an opportunity to restate in brief the lithostratigraphical framework for the Chalk Group of England and to deal with specific points raised by Wray and Gale. Our reply is prompted in part by the implications in Wray & Gale that the geological mapping of the Chalk Group in England is carried out in a haphazard and uncontrolled manner without scientific rigour and is of ‘little value’. This implication is refuted absolutely. In fact, it is a test of the robustness of the framework that a large number of field geologists can apply the scheme across southern England and provide such a powerful predictive tool for the practical benefit of the nation. A further verification of the framework’s pertinence, over and above its application to pure scientific endeavours, is its widespread use in applied geological studies. For example, the framework provides the foundation for investigations into the structure of the Chalk, its engineering characteristics and hazards and, perhaps most importantly of all, provides the key and new impetus to studies, including predictive modelling, of the hydrogeology of the UK’s largest and most important aquifer. As stated by Wray & Gale, the development of the regional Chalk lithostratigraphies in the late 1970s to the mid-1980s (Wood & Smith 1978; Mortimore 1983, 1986; Jarvis & Woodroof 1984; Robinson 1986) made it apparent that the traditional tripartite scheme embodied by Jukes-Browne & Hill (1903, 1904) did not delineate fully the lithological variation in the Chalk. This inadequacy led to the development of a more detailed and broadly applicable framework by BGS. The modern lithostratigraphical framework builds upon the expertise of a large number of field geologists. It was presented in a model (Bristow et al. 1997) that was modified at a workshop of the UK’s Chalk experts in 1999. It belongs to all those who contributed and signed up to it, and is the ‘agreed lithostratigraphical framework’ (Rawson et al. 2001). The outline framework with minor additions at member level is given in Figure 1. The full framework report for the Chalk Group of the UK, approved by the Geological Society of London’s Stratigraphy Commission (GSLSC), appears in Hopson (2005) and is available (in pdf format) as a free download from the BGS website (http:// www.bgs.ac.uk) as a joint BGS/GSLSC publication.

Effects of uncertain geoacoustic parameters and coastal shipping densities on shipping noise directionality

The bearing-elevation directionality of low-frequency shipping noise is influenced both by the sediment geoacoustic parameters and by the coastal shipping density. This study examines the effects of geoacoustic parameter and shipping density uncertainties on noise directionality through simulations for a North Pacific site. The simulations are based in part on stochastic models of the spatial variations of geoacoustic parameters that incorporate: (1) conditional probability densities of the geoacoustic parameters given mean sediment grain size, derived from measurement compilations reported by Hamilton et al. [J. Acoust. Soc. Am. 72,1891], and (2) location-dependent probability densities of the mean grain size, derived from field measurements. [Carlson et al., U.S. Geological Survey Map MF 876]. The simulations also incorporate coastal shipping noise source uncertainties based on models of commercial fishing vessel locations and ship-radiated noise. [Wales and Heitmeyer, J. Acoust. Soc. Am. 111, 1211] The results quantify the effects of the geoacoustic and coastal shipping uncertainties on received low-frequency bearing-elevation noise directionality. Variances in the noise power at horizontal arrival due to geoacoustic uncertainties substantially exceed those associated with uncertainties in the shipping noise source distributions and levels. These results are interpreted in terms of down-slope propagation effects. [Work supported by ONR.]