Shaking and splashing—A case study of far-field effects of the Mjølnir asteroid impact on depositional environments in the Barents Sea

The Mjølnir impact crater in the Norwegian Barents Sea features among the 20 largest impact craters listed in the Earth Impact Database. The impact is dated to 142 ± 2.6 Ma, corresponding closely to the Jurassic/Cretaceous boundary in the Boreal stratigraphy. Multidisciplinary studies carried out over the last three decades have suggested that the up to 40 km wide crater was created by a 1–3 km diameter impactor colliding with a shallow epicontinental sea, causing regional havoc and a regional ecological crisis that followed in its wake. Only minor evidence for the consequences of the impact for the surrounding depositional basins has been documented so far. This study describes a large submarine slump penetrated by hydrocarbon exploration well 7121/9-1, located in the southern Hammerfest Basin and approximately 350 km away from the impact site. The slump is dated by a black shale drape, which contains characteristic impact-related biotic assemblages and potential ejecta material. This precise dating enables us to associate the slump with large-scale fault movements and footwall collapse along the basin-bounding Troms-Finnmark Fault Complex, which we conclude were caused by shock waves from the Mjølnir impact and the passage of associated tsunami trains. The draping black shale is interpreted to represent significant reworking of material from the contemporary seabed by tsunamis and currents set up by the impact.     

How effective are GIS in practice? A case study of British local government

Abstract

GIS have received increasing attention in recent years, particularly in local government. Despite the claims in the literature about the potential of the technology, to date there is still little information on the impact GIS applications are having on the organizations in which they are being implemented. With these considerations in mind this paper presents an evaluation of the findings of twelve case studies which were undertaken in a variety of British local government contexts during 1991 and 1992.

The evaluation of the findings of the case studies is divided into two parts. The first part indicates the limited impact GIS has had on the local authorities investigated even after at least two years experience. Given these findings the second part seeks to identify the issues which appear to be responsible for inhibiting the effective implementation of GIS in British local government. Overall it is suggested that some organizational cultures are inherently receptive and able to sustain the development of innovations such as GIS. However, whilst very few organizations are inherently innovative it was possible to identify four factors which appeared to enhance the chances of success. These are simple applications producing information which is fundamental to the work of potential users, user directed implementation involving the participation of all the stakeholders in the project, an awareness of the limitations of the organization with respect to the range of available resources, and a high degree of stability with respect to the general organizational environment, or alternatively an ability to cope with change. As a result the evaluation indicates that if GIS are to be effectively implemented much greater consideration must be given to the impact of organizational issues.     

Effects of rural–urban migration on vegetation greenness in fragile areas: A case study of Inner Mongolia in China

Different government departments and researchers have paid considerable attention at various levels to improving the eco-environment in ecologically fragile areas. Over the past decade, large numbers of people have emigrated from rural areas as a result of the rapid urbanization in Chinese society. The question then remains: to what extent does this migration affect the regional vegetation greenness in the areas that people have moved from? Based on normalized difference vegetation index (NDVI) data with a resolution of 1 km, as well as meteorological data and socio-economic data from 2000 to 2010 in Inner Mongolia, the spatio-temporal variation of vegetation greenness in the study area was analyzed via trend analysis and significance test methods. The contributions of human activities and natural factors to the variation of vegetation conditions during this period were also quantitatively tested and verified, using a multi-regression analysis method. We found that: (1) the vegetation greenness of the study area increased by 10.1% during 2000-2010. More than 28% of the vegetation greenness increased significantly, and only about 2% decreased evidently during the study period. (2) The area with significant degradation showed a banded distribution at the northern edge of the agro-pastoral ecotone in central Inner Mongolia. This indicates that the eco-environment is still fragile in this area, which should be paid close attention. The area where vegetation greenness significantly improved showed a concentrated distribution in the southeast and west of Inner Mongolia. (3) The effect of agricultural labor on vegetation greenness exceeded those due to natural factors (i.e. precipitation and temperature). The emigration of agricultural labor improved the regional vegetation greenness significantly.     

A Queer Country? A case study of the politics of gay/lesbian belonging in an Australian country town

The present paper examines the complex politics of gay/lesbian belonging through a case study of Daylesford, Victoria, an Australian country town. It contributes to two research bodies: gay/lesbian rural geographies and the politics of belonging. Daylesford hosts ChillOut, Australia's largest rural gay/lesbian festival, which provides a telling context for investigating gay/lesbian belonging in rural Australia. We use qualitative data from the 2006 ChillOut Festival, including interviews with local residents, newspaper commentaries, and visitors’ surveys, to explore how Daylesford has been constructed, imagined, and experienced as a ‘unique’ site of gay/lesbian belonging in rural Australia. We find that ChillOut crucially contributes to its wider reputation as a gay-friendly country town, but also, we argue, to the contested nature of gay/lesbian belonging. This was most powerfully demonstrated by the local council's refusal to fly the gay-identified rainbow flag on the Town Hall during the 2006 Festival and its subsequent banning of the display of all festival flags from that key public building. Because ChillOut was the catalyst for this protocol, the resolution was viewed as homophobic. Indeed, the homophobic and heterosexist rhetoric that ensued in the Letters to the Editor section of the local newspaper revealed some residents’ underlying antagonism towards ChillOut and the local gay/lesbian community. Moreover, appealing to a shared ‘Australian identity’ and associated normative ‘family values’, these letter writers deployed a multi-scalar politics of belonging, where a sense of gay/lesbian belonging to Daylesford at the local scale was contested by the assertion of a ‘more meaningful’ national scale of allegiance fashioned by heteronormativity.     

Can designation without regulation preserve land in the face of urbanization? A case study of ZNIEFFs in the Paris region

Preservation through legal protection of natural areas is costly and limited in its extent. A much cheaper strategy to preserve natural areas could be to simply identify areas of ecological interest and let it be known. A survey was launched in France to identify such areas (called ZNIEFF) in the early 1980s. Since then, municipalities have had to account for ZNIEFFs in their formal land planning schemes, though they are not under any obligation to protect them. In this study, we tested the effectiveness of ZNIEFFs as a conservation tool in an area of high growth near Paris. Using GAM modeling, we compared the rate of urbanization inside and outside ZNIEFFs in the 17 years following designation, accounting for the share of farmland, the overall rate of urbanization and ZNIEFF proportion in the municipalities, and also accounting for demography and physical constraints (hydromorphy and slope). Overall, there was less urbanization inside ZNIEFFs, but this varied depending on the context. Surprisingly, they were better preserved in areas of more intense urbanization. This effect was increased if farmland area was already reduced (<30% of the municipality area). In contrast, when farmland was still predominant and urbanization rates were lower, ZNIEFFs tended to be more urbanized than the areas outside. This shows that the value of remnant natural areas varies considerably, perhaps as a function of the value attributed to farmland.     

Impact of radiations on the long-range correlation of soil moisture: A case study of the A’rou superstation in the Heihe River Basin

Journal of Geographical Sciences - Analyses of the soil moisture evolution trend and the influence of different types of radiation on soil moisture are of great significance to the simulation and...     

The impacts of climate change on hydrology in a typical glacier region—A case study in Hailuo Creek watershed of Mt. Gongga in China

The glaciers of the Hengduan Mountains play an important role in the hydrology processes of this region. In this study, the HBV Light model, which relies on a degree-day model to simulate glacier melting, was employed to simulate both glacier runoff and total runoff. The daily temperature and precipitation at the Hailuo Creek No. 1 Glacier from 1952 to 2009 were obtained from daily meteorological observed data at the glacier and from six national meteorological stations near the Hailuo Creek Basin. The daily air temperature, precipitation, runoff depth, and monthly potential evaporation in 1995, 1996, and 2002 were used to obtain a set of optimal parameters, and the annual total runoff and glacier runoff of the Hailuo Creek Glacier(1952–2009) were calculated using the HBV Light model. Results showed the average annual runoff in the Hailuo Creek Basin was 2,114 mm from 1952 to 2009, of which glacial melting accounted for about 1,078 mm. The river runoff in the Hailuo Creek catchment increased as a result of increased glacier runoff. Glacier runoff accounted for 51.1% of the Hailuo Creek stream flow in 1994 and increased to 72.6% in 2006. About 95% of the increased stream flow derived from the increased glacier runoff.     

The altitudinal climatic effect on the stable isotope compositions of Agave and Opuntia in arid environments – A case study at the Big Bend National Park,Texas, USA

Several environmental factors potentially influence the stable isotope compositions of plants, depending on species and local environment. Although several studies have discussed these aspects in C₃ and C₄ plants, only a few have attempted to identify the major drivers of δ¹³C, δ¹⁸O, and δ¹⁵N in CAM plants. In this study, stable isotopic ratios of CAM plants collected along an altitudinal transect in the Chisos Mountains/USA during two growth seasons, are used to understand major factors governing isotopic variability. A strong and significant relationship between δ¹³C and altitude, positive for agave at <1700 m and negative for both agave and cacti at >1500 m, suggests variable carbon isotope fractionation at different altitudes, which may be unique to CAM plants. Our data suggest that temperature primarily governs δ¹³C of the studied plants. The significant negative correlations observed between the δ¹⁸O of agaves and the recorded air temperature (0.59‰/°C) are similar to the δ¹⁸O of precipitation vs. temperature variability in global data. The δ¹⁵N variations suggest a similar N-source for both agaves and cacti, and reflect progressive changes in the dominant N-source across desert–grassland–woodland zones. We conclude that the stable carbon and oxygen isotope composition of agave reflects the climatic conditions along the elevation transect.     

Microfirms in peripheral areas: How can evolutionary economic geography contribute in studies of diversification? A case study from Norway

The article discusses whether and how the emerging approach of evolutionary economic geography is fruitful when researching diversification among microfirms in peripheral regions. The author argues that such microfirms represent a source of heterogeneity that potentially could enrich our understanding of economic evolution. The sources of variation and mechanisms of selection operating among diversifying farmers in Norway are examined and diversifying farms are identified as both microfirms and households. The findings indicate that motivation at household level is the key to successful diversification. Further, the findings confirm that microfirms are not only able to influence their own destiny, but also institutional progress at regional level. The author concludes that the role of microfirms as actors and the possibility for the study of the agency of such actors are the major reasons why evolutionary economic geography is a fruitful approach in researching microfirms in peripheral areas.     

How do Ghana’s landfills affect residential property values? A case study of two sites in Accra

Like many countries in sub-Saharan Africa, Ghana lacks well-engineered sanitary landfill sites. Increased urbanization and concomitant real estate growth lead landfills to compete with residential land use, resulting in closer proximity between landfill sites and residential neighborhoods. The effects of landfills on the property values of nearby residential communities have been the subject of much debate in the developed world, where state-of-the-art and environmentally well-engineered landfills are common. However, academic and other research is inconclusive on the effects of landfills on property values in the developed countries. This paper addresses this knowledge gap by exploring the effects of landfills on residential property values in Ghana, using the Oblogo and Mallam landfills in Accra as a case study. Our analysis indicates that while landfills do depress nearby residential property values, the effects are contingent on property location relative to the level of urbanization in a community, and year of completion and total costs of property development.     

Spatial-temporal differences in in-stream flow requirement based on GIS： A case study of Yan＇an region,northern Shaanxi

Although water has the central function of the bloodstream in the biosphere especially in arid or semi-arid regions such as Yah＇an region in northwestern China, yet the very limited attention is paid to the role of the water-related processes in ecosystem. In this research, based on continuous nearly 50-year data including runoff volume, sediment discharge as well as sediment accretion from hydrographic stations, and 10-year information of water quality from pollution monitoring stations, the method for measuring in-stream flow requirement has been put forward supported by experiential models and GIS spatial analysis. Additionally, the changes of in-stream flow requirement for environment and economic development have been addressed from spatial-temporal dimensions. The results show that： （1） According to the central streams in Yan＇an region, mean annual in-stream flow requirement reaches 1.0619 billion m^3, and the surface water for economic exploitation is 0.2445 billion m3 （2） Mean annual in-stream flow requirement for sediment transfers in flood period occupies over 80% of the integrated volume in a year. （3） From the 1950s to 1970s, in-stream flow requirement for sediment transfers is comparatively higher, while from the 1980s to 1990s, this requirement presents a decreasing tendency.     

Characteristics of thawed interlayer and its effect on settlement beneath embankment in permafrost regions—A case study for the Qinghai-Tibet Highway

Based on ground temperatures and deformations monitored at the Xieshuihe site along the Qinghai-Tibet Highway(QTH)in permafrost regions from 2004 to 2015,variation of artificial permafrost table(APT),maximum frozen depth(MFD),thawed interlayer thickness(TIT)and ground temperature beneath embankment is analyzed,respectively.The results indicate that under the embankment,the change of APT occurred from October to December of that year and presented a deepening trend.The change of MFD occurred from April to June of that year with no obvious change trend,and TIT had an increasing trend year by year,which mainly resulted from the deepening artificial permafrost table.Mean annual ground temperature at 0.5 m depth was 3.91°C higher beneath the embankment center than that under the natural field.The rising ground temperature at shallow layer of embankment resulted in the development of thawed interlayer beneath the embankment and warming of underlying permafrost.Embankment settlement is closely associated with TIT.Greater settlement easily occurs when permafrost with higher ice content exists under the thawed interlayer,and in turn the settlement is smaller when permafrost with lower ice content exists under the thawed interlayer.     

Analysis on geo-effects of China’s overseas industrial parks: A case study of Cambodia Sihanoukville Special Economic Zone

China's overseas industrial parks contribute to political and economic cooperation,cultural exchange between home and host countries.Current studies mainly discuss the ef-fect of overseas industrial parks from the perspective of institutional and cultural difference,multi-scale coupling,as well as key partnerships,while little attention has been paid to the comprehensive analysis of overseas industrial parks.Based on a theoretical framework,this paper explores the overall effect of China's overseas industrial parks from the geo-effects perspective by using field interviews and a case study approach.The research shows that:(1)the geo-effects reveal the over effect of overseas industrial parks from the multiple and com-plementary dimensions of geopolitics,geo-economics,geo-society and geo-culture;(2)the Cambodia Sihanoukville Special Economic Zone,as a flagship BRI project,has produced the prominent and positive geo-effects;(3)the institutional-economic-cultural-environmental adaptability of overseas industrial parks is becoming important.Overseas industrial parks must be rooted in the politics,economy,society,and culture of host country;embedded in local social networks;balance the rights and interests of all stakeholders;and form the community of interests,community of destiny,and community of responsibility with political mutual trust,economic integration,cultural inclusiveness,and social harmony.The paper not only deepens the understanding about the overall effect of overseas industrial parks,but also provides decision support and theoretical reference for government policy makers and the overseas investment of enterprises.     

Do river deltas in east India retreat? A case of the Krishna Delta

The construction of multiple dams and barrages in many Indian River basins over the last few decades significantly reduced river flow to the sea and affected the sediment regime. More reservoir construction is planned through the proposed National River Linking Project (NRLP), which will transfer massive amounts of water from the North to the South of India. The impacts of these developments on fertile and ecologically sensitive deltaic environments are poorly understood and quantified at present. In this paper an attempt is made to identify, locate and quantify coastal erosion and deposition processes in one of the major river basins in India—the Krishna—using a time series of Landsat images for 1977, 1990 and 2001 with a spatial resolution ranging from 57.0 m to 28.5 m. The dynamics of these processes are analyzed together with the time series of river flow, sediment discharge and sediment storage in the basin. Comparisons are made with similar processes identified and quantified earlier in the delta of a neighboring similarly large river basin—the Godavari. The results suggest that coastal erosion in the Krishna Delta progressed over the last 25 years at the average rate of 77.6 ha yr^− 1, dominating the entire delta coastline and exceeding the deposition rate threefold. The retreat of the Krishna Delta may be explained primarily by the reduced river inflow to the delta (which is three times less at present than 50 years ago) and the associated reduction of sediment load. Both are invariably related to upstream reservoir storage development.     

Spatio-temporal differentiation of landscape ecological niche in western ecological frangible region： A case study of Yan＇an region in northwestern China

In this study, we attempt to put forward a conception of landscape ecological niche, enlightened by international scholars on extending the ecological niche theory from spatial niche to functional niche. That is helpful for comprehensively appraising landscape spatial patterns and ecological functions, also, presents a new method for analyzing landscape features from multidimensional aspects. The practice process is demonstrated by taking Yan＇an region in northwestern China as a case. Firstly, the indices system including spatial attribute and functional attribute is established for assessing landscape ecological niche. Additionally, two-dimensional figures are drawn for comparing the spatio-temporal features of landscape ecological niche in 1987 and 2000 among the 13 administrative counties. The results show that from 1987 to 2000, towards Yan＇an region, spatial attribute value of landscape ecological niche changes from 1.000 to 1.178 with an obvious increment, and functional attribute value changes from 0.989 to 1.069 with a little increment, both of which enhance the regional landscape ecological niche. Towards each county, spatial attribute value of landscape ecological niche increases to different extent while functional attribute value changes dissimilarly with an increment or a decrement.     

Effect of removing small (<150?μm) chironomids on inferring temperature in cold lakes

Sieving samples for chironomid analysis with a 150 μm mesh was shown to greatly reduce sample preparation time, and use of only larger specimens did not affect chironomid-inferred salinities in African lakes. Here, we tested if this method is suitable for temperature reconstruction in colder lakes at higher latitudes. Removal of specimens <150 μm in two training sets, one from Canada and one from Sweden, had little impact on the performance statistics of the calibration models. Chironomid abundance, however, decreased greatly because more than half of the head capsules in assemblages were <150 μm. This had major impacts on the temperature reconstructions. Inferences were on average 2°C warmer with the modified models (all specimens >150 μm) than those obtained with the full model (all specimens >100 μm). General patterns of temperature change were also altered. For Lake 7 on Southampton Island, Canada, a cooling trend was reconstructed with the full Canadian model while the modified Canadian model yielded a warming trend. When only specimens >150 μm were used, two to three times more wet sediment was needed to obtain a sufficient number of head capsules. These results indicate that, in cold lakes (mean July/August air temperature ≤11°C), large proportions of head capsules are <150 μm, and sieving the samples in a 150 μm mesh leads to altered temperature reconstructions.     

The impact of perceived urban human settlement quality on subjective well-being: A case study using urban health examination data in the Yangtze River Delta region北大核心CSCD

城市体检是促进中国城市人居环境高质量和提升城市居民幸福感的创新举措,但却很少有研究正面关注城市体检社会评价对居民福祉的影响。论文基于2021年住建部在长三角地区8个样本城市开展的大规模城市体检社会满意度调查数据,采用主成分分析和多元回归分析相结合方法,分别探讨了长三角地区居民的城市人居环境质量感知因子及其对居民幸福感的影响,并从以人为本视角提出长三角地区城市人居环境高质量发展策略。研究发现:(1)城市体检社会满意度评价指标共提取了7个城市人居环境感知评价主成分因子,分别命名为城市管理、城市活力、城市舒适、城市宜居、城市包容、城市安全和城市便利,累计贡献率达到66.767%。(2)城市人居环境感知评价因子均对长三角地区城市居民幸福感具有显著影响,但不同城市人居环境感知评价因子的影响方向却存在差异性。其中,城市管理、城市活力、城市舒适、城市宜居和城市包容等因子显著正向影响幸福感,城市安全和城市便利等因子显著负向影响幸福感。(3)不同城市规模居民幸福感的人居环境主导因子有所不同,同时不同户口和年龄居民幸福感的人居环境影响因素也有差异。研究结果对促进长三角地区城市居民幸福感提升和指导城市人居环境建设具有重要的决策参考作用。     

Low resistivity zones at contacts of igneous intrusions emplaced in organic-rich formations and their implications on fluid flow and petroleum systems: A case study in the northern Neuquén Basin,Argentina

Igneous sills and laccoliths emplaced in sedimentary basins may significantly impact petroleum systems, both positively and negatively. Igneous intrusions provide heat to maturate regionally immature organic-rich host rocks, act as fractured reservoirs hosting commercial accumulations of hydrocarbons, and form structures affecting fluid flow and trapping at different scales. Nevertheless, the petrophysical implications of igneous intrusions on their host rock are poorly known. In this study, we analyse 200 wells in the Río Grande Valley oil field, Neuquén basin, Argentina, where the main reservoirs are in fractured igneous sills. This dataset represents a globally unique possibility to characterize the igneous–host rock interaction using both wireline logs and core material. We identify a systematic Contact Low Resistivity Zone (CLRsZ) at both the upper and lower contacts of the sills emplaced in the organic-rich Vaca Muerta and Agrio Formations. We characterize the nature of these CLRsZ and their petrophysical properties by integrating resistivity and gamma ray well logs, petrographic analyses, petrophysical tests and geochemical analyses. The low resistivity signal of the CLRsZ is dominantly carried by massive-sulphide deposits, mainly pyrite, observed both in the host rock and the chilled margin of the sills. Well log images and porosity-permeability analysis on core plugs show that both the sills and their associated CLRsZ can act as carrier for fluid flow and reservoir for hydrocarbons storage. The thickness of the upper and lower CLRsZ correlates linearly with the thickness of the sill, and the volume of both the upper and lower CLRsZ represents ca. 40% with respect to the volume of their associated sill. The thickness of the CLRsZ represents ca. 13% of the thickness of contact aureole induced by the sills. In the CLRsZ, a great proportion of kerogen was transformed to hydrocarbon, so that CLRsZ were restricted to the innermost contact aureole of the sills. Our results show that the CLRsZ can have major implications on fluid flow and should be considered in reservoir models in volcanic basins hosting sills emplaced in organic-rich formations.     

Do swarms of migrating barchan dunes record paleoenvironmental changes? — A case study spanning the middle to late Holocene in the Pampa de Jaguay, southern Peru

Swarms of barchan dunes are common in arid environments. Unlike immobile or slowly moving dunes whose stratigraphy can be used to reconstruct paleoenvironmental changes, the high migration rate of barchans seems to prohibit their use as geoarchives. In this paper, a possible use of barchan swarms for paleoenvironmental reconstructions is presented. The approach is based on dune migration. In a case study based on 500 dunes in the Pampa de Jaguay aeolian transport corridor in coastal southern Peru, middle to late Holocene changes in the supply of aeolian material are inferred from calculating the time of dune initiation at the coastline. Limitations posed by the assumptions underlying this approach are discussed.     

Has the oil boom generated new problems of housing affordability in resource-driven agglomerations in Canada? A case study of St. John’s,Saskatoon, Calgary,Edmonton, and Fort McMurray, 1991–2011

Recent studies focused on Canadian metropolitan areas suggest that growing income inequality underlies problems of housing affordability for low- and moderate-income earners. This article investigates how unprecedented commodity-led economic growth between 1991 and 2011 has impacted housing affordability in five resource-driven agglomerations in Canada. Housing affordability is analyzed across income quintiles, looking at income, housing costs, tenure, housing quality, and housing debt. Using Statistics Canada Census microdata, we find that low- to mid-income earners faced the fastest relative increase in housing costs between 1991 and 2011, combined with small income gains over that period. Homeowners in the lowest income quintiles seem particularly vulnerable when carrying a mortgage, with economic volatility engendering greater risks of housing market contractions or job loss over time. Whereas previous literature has emphasized housing vulnerability in large metropolitan areas, the results highlight new patterns of risk-laden housing-related vulnerability in resource-driven regions in Canada.