Stability Zone of Natural Gas Hydrates in a Permafrost-Bearing Region of the Beaufort—Mackenzie Basin: Study of a Feasible Energy Source1 (Geological Survey of Canada Contribution No.1999275)

Analysis of geological and geophysical data from 150 wells in the Beaufort—Mackenzie region(study area between 68°30–70°00N and 131°–39°W) led to reinterpretation of the depth ofmethane hydrate stability and construction of the first contour maps displaying thickness of hydratestability zones as well as hydrate stability zone thicknesses below permafrost. Calculations werebased on construction of temperature-depth profiles incorporating regional heat-flow values, temperatureat the base of ice-bearing permafrost, and models relating thermal conductivity with depth.Data analysis indicates the presence and extent of the methane hydrate stability zone is relatedmainly to the history of permafrost development and less so by the relatively small regionalvariations of temperature gradients. Analysis of well logs and other indicators in conjunction withknowledge of the hydrate stability zone allows reevaluation of the location of possible gas hydrateoccurrences. Log analysis indicates that in the onshore and shallow sea area of theBeaufort—Mackenzie Basin, methane hydrate occurs in 27 wells. Fifteen of these locations coincides withunderlying conventional hydrocarbon occurrences. Previous analyses place some of the hydrateoccurrences at greater depths than proposed for the methane hydrate stability zone described inthis study. Interpretation of geological cross sections reveals that hydratesare related mainly to sandy deltaic and delta-plain deposits in Iperk, Kugmallit, and Reindeer sequences althoughadditional hydrate picks have been inferred in other sequences, such as Richards. Overlyingpermafrost may act as seal for hydrate accumulations; however, the thickness of permafrost andits related hydrate stability zone fluctuated during geological time. It is interpreted that only inthe last tens of thousand of years (i.e., Sangamonian to Holocene), conditions for hydrates changedfrom nonstable to stable. During Early and Late Wisconsinan and Holocene time, conditions werefavorable for generation and trapping of hydrates. However, previously during Sangamonian time,less favorable conditions existed for hydrate stability. Gas release from hydrates may have occurredduring times when hydrate stability was nonexistent because of permafrost melting episodes. It isinterpreted that entrapment of gas in hydrate molecular structures is related to the existence ofconventional structural traps as well as less permeable sediments such as the Mackenzie BayFormation, which act as seal.     

Assessment of Thermal Maturity,Source Rock Potential and Paleodepositional Environment of the Paleogene Lignites in Barsingsar,Bikaner–Nagaur Basin,Western Rajasthan,India

Natural Resources Research - Investigations on the Paleogene lignites were carried out through geochemical, mineralogical and petrographic analyses to assess their paleodepositional environment,...     

A Study in Historico-Geography—The Establishing of the Ohio-Michigan Boundary Line

Abstract

Geography is a part of scientific knowledge devoted to the study of two fundamental relations of human life: relations with the natural world and relations across space. These relations do not exist in isolation but are merely aspects of life as a whole. They must be understood and taught as parts of a total theory of human existence. Marxism is such an attempt to holistically understand the world. It is also, however, an attempt to change the world. Although Marxists recognize that capitalism has yielded enormous technical and material benefits for a minority of the world's people, we now find other competing purposes rising to primary positions in the list of urgent societal tasks. These purposes include equalizing living standards, finding jobs for the present doomed generation of children, removing the economic and social tensions underlying dangerous military antagonisms, and achieving a stable, managed relation with the natural environment. For purposes like these, Marxists consider capitalism outdated as a form of social and economic organization. Most Western Marxists are also critical of the centralized socialism of the Soviet Union. Socialism in the Soviet Union has achieved a modest standard of living for its working class. But the Soviet Union has yet to begin an approach towards a true model of socialism in the sense of decentralizing economic and political power directly to the mass of the people. Because we live in capitalist countries however, the focus of this critique is capitalist, rather than Soviet-style socialist society.     

Experimental Analysis of the Dynamic Effects of Coal–Gas Outburst and a Protean Contraction and Expansion Flow Model

Natural Resources Research - As one of the most serious dynamic disasters in underground coal mining, coal–gas outburst (CGO) leads to very high casualties and economic losses. To research...     

Temporal change and suitability assessment of cropland in the Yellow River Basin during 1990–2005

Rapid landscape pattern change has taken place in many arid and semi-arid regions of China such as Yellow River Basin over the past decade. In this article, the physical suitability of cropland and its change were evaluated and analyzed by the combined use of satellite remote sensing, geographical information system, and landscape modeling technologies. The aim was to improve our understanding of cropland change so that sustainable cropland utilization could be established. First, the spatial pattern change of cropland was analyzed using the 1-km² area percentage model; second, the numerical model for cropland suitability assessment was explored and developed using analytical hierarchy process analysis method. Using this model, cropland suitability index was computed for the whole of the basin from 1990 to 2005. The cropland suitability index was classified into five levels: better, good, middle, bad, and worse, following the natural breaks classification. The spatial distribution of cropland suitability level and its changes over the 15 years from 1990 to 2005 were analyzed and the driving factors of cropland change were investigated. The results showed that the cropland suitability in the study area was at good level, and the cropland quality had been gradually improved on the whole. However, the cropland quality had become worse over the 15 years in some regions. In the study area, governmental policies for eco-environmental protection and population growth were found to be the major factors that caused the cropland change over the past 15 years.     

Does Social Learning Lead to Better Natural Resource Management? A Case Study of the Modern Farming Community of Practice in Sweden

This study investigates whether social learning among large-scale farmers in central Sweden leads to better natural resource management in the agricultural landscape. Three different frames of social learning are first identified: social learning as a fundamental social phenomenon, social learning as collaborative learning, and social learning as deeper learning. This article investigates the role of social learning and other factors through semistructured in-depth interviews. Results show that learning among farmers is inherently social, but that this learning does not necessarily improve natural resource management or lead to better environmental governance. The article discusses when social learning can be expected to influence natural resources management, and finds that without the presence of policy, individual leadership, or facilitation, it is not an important factor. Furthermore, the call for social learning based on results from successful instrumental application risks obscuring findings indicating that both social learning and better natural resource management are conditioned on the same external factors.     

Comparative Analysis of Gas–Solid–Liquid Coupling Behavior in Front of the Working Face Before and After Water Injection During Coal Mining

Natural Resources Research - Coal seam water injection is a critical measure for the prevention of coal-and-gas outbursts. However, the gas–solid–liquid coupling effect in front of the...     

Mapping Human Terrain in the Joint Army–Navy Intelligence Study of Korea (1945)

The concept of human terrain has become a prominent element of U.S. military strategy. It is a means to capture the cultural–geographical qualities of an enemy or target population. An early effort to map human terrain is found in the Joint Army–Navy Intelligence Study (JANIS) of Korea (1945). We argue that the JANIS report on Korea was paradigmatic for the U.S. military's contemporary geographical work and offers insights into the cultural politics of human terrain mapping. This explains why the JANIS text is cited by the National Geospatial-Intelligence College (NGC) today as an historical model. This article not only offers a window into the history of geography counterinsurgent but also shows that geography has been entwined with empire.     

Drivers of Change and Sustainability in Linked Social–Ecological Systems: An Analysis in the Volta River Basin of Ghana,West Africa

Understanding the nature and relative importance of various drivers of change is crucial for sustainable management of natural resources and in prioritizing management efforts, allocating limited resources, and understanding cumulative effects. For this article, we employed structured an expert judgments approach to identify, characterize, and assess the relative importance of the key biophysical and socioeconomic drivers of change within the Volta River Basin, West Africa. Precipitation variability, water availability, land use change, drought events, and population growth were perceived as most important, while biodiversity loss, social conflicts, pest and disease occurrence, urbanization, and pollution were viewed as less critical. A majority of these drivers were characterized as “slow” acting processes as compared to rapidly changing drivers. Intra- and interexpert groups agreement were found to be significant and convergent, indicating the reliability of the results. The implications of these results for sustainable water resources management and agricultural production are discussed.     

Geological Characterization of the Miocene–Pliocene Succession in the Semliki Basin,Uganda: Implications for Hydrocarbon Exploration and Drilling in the East African Rift System

Natural Resources Research - The Albertine Graben, an active sedimentary petroliferous basin, has gained global attention as the unexplored areas are recently being targeted for hydrocarbon...     

Governance,Gender and the Appropriation of Natural Resources: A Case Study of ‘Left-Behind’ Women’s Collective Action in China

China’s rapid urbanization has created large scale of population migration, resulting in many villages being dominated by “left-behind” women, and weak governance of those collectively owned resources. The situation has required these women to take up the functions of decision-making and governance as a remedial mechanism as well as a new path. Based on a case study in a typical hollowing-out village in central China, this paper explores an example of left-behind women’s collective action to prevent the over-exploitation of community and resources. It finds out that although traditionally excluded from public activities and marginalized, the “left-behind” women were able to mobilize and enhance collective action. When empowered, they are growing fast with endurance and courage, and as capable as anyone of defending the common-pool resources. It suggests that the left-behind women offer a new governance option for those population hollowing out rural areas.     

A Review of: “Pittsburgh and the Appalachians: Cultural and Natural Resources in a Postindustrial Age”

Abstract

Geography is one of the subjects offered toward a diploma of the International Baccalaureate Organization. Like the others, its syllabus is regularly reviewed and revised to remain current. The advent of a revised syllabus brings overlap that can be challenging for teachers. The syllabus that is now coming to an end was described in 107(4–5) of the Journal of Geography. The present article compares that syllabus with the new one and, particularly, the demands the new syllabus will place on teachers and students alike.     

Transmutation of ancient settlements and environmental changes between 6000–2000 aBP in the Chaohu Lake Basin,East China

Based on the temporal-spatial distribution features of ancient settlement sites from the middle and late Neolithic Age to the Han dynasty in the Chaohu Lake Basin of Anhui Province, East China, using the methods of GIS combined with the reconstructed paleoenvironment by the records of lake sediment since Holocene, the transmutation of ancient settlements with response to environmental changes in this area has been discussed. Studies show that the main feature of transmutation of ancient settlements from the middle and late Neolithic Age to the Han Dynasty was that the distribution of settlements in this area changed from high altitudes to low ones and kept approaching the Chaohu Lake with the passage of time. These could be the response to the climate change from warm-moist to a relatively warm-dry condition during the middle Holocene, leading to the lake level fluctuations. The large area of exposed land provided enough space for human activities. These indicate that the above changes in geomorphologic evolution and hydrology influenced by climate conditions affected the transmutation of ancient settlements greatly. The distribution pattern of settlement sites was that the number of sites in the west was more than in the east. This pattern may be related to the geomorphologic conditions such as frequent channel shifting of the Yangtze River as well as flood disasters during the Holocene optimum. Therefore, climate change was the inducement of the transmutation of ancient settlements in the Chaohu Lake Basin, which exerted great influence on the distribution, expansion and development of the ancient settlements.     

Spatiotemporal variations of maximum seasonal freeze depth in 1950s–2007 over the Heihe River Basin, Northwest China

Investigation on spatiotemporal variations of maximum seasonal freeze depth （MSFD） over the Heihe River Basin is of great importance for systematic understanding of regional climate and environmental change, ecological-hydrological processes, water resources assessment, construction and resource development. Based on soil and air temperatures at the meteorological stations of the China Meteorological Administration （CMA） over the Heihe River Basin, MSFDs time series are structured into a composite time series over the 1960-2007 period. Evaluating the averaged MSFD time series for 1960 2007 reveals a statistically significant trend of 4.0 cm/decade or a net change of-19.2 cm for the 48-year period over the basin. The MSFD had significantly negative correlation with mean annual air temperature （MAAT）, winter air temperature, mean annual ground surface temperature （MAGST）, degree days of thawing for the air （DDTa） as well as for the surface （DDTs）, and degree days of freezing for the surface （DDFs）. While there was significantly positive correlation between DDF,. and MSFD time series, MSFD was deeper and changed greatly in the Heihe River source area. It was shallower in the east-central basin and gradually deepened in other sections of the basin. The MSFD distribution pattern in 2003-2005 is consistent with that of averaged degree days of freezing for air （DDFa） in 1960-2007. However, the maximum of MSFD may not be accurate, because there is no long term observation data in the deep seasonally frozen ground regions near the lower boundary of permafrost. With increasing elevation, averaged DDFa increased at a rate of 51.6 ℃-day/100m, therefore, the MSFG and the date reaching MSFG became deeper and later, respectively.     

Impacts of water conservancy and soil conservation measures on annual runoff in the Chaohe River Basin during 1961–2005

Taking the Chaohe River Basin above the Miyun Reservoir in North China as a study area, the characteristics and variation trends of annual runoff and annual precipitation during 1961–2005 were analyzed applying Mann-Kendall test method on the basis of the hydrologic data of the major hydrological station (Xiahui Station) located at the outlet of the drainage basin and the meteorological data of 17 rainfall stations. Human activities including water conservancy projects construction and water diversion as well as implementation of soil and water conservation from 1961 to 2005 were carefully studied using time series contrasting method. The referenced period (1961–1980) that influenced slightly by human activities and the compared period (1981–2005) that influenced significantly by water conservancy and soil conservation measures were identified according to the runoff variation process analysis and abrupt change points detection during 1961–2005 applying double accumulative curve method, mean shift t-test method and Mann-Kendall mutation test technique. Based on the establishment of a rainfall-runoff empirical statistical model, impacts and the runoff-reducing effects of water conservancy and soil conservation measures on runoff reduction were evaluated quantitatively. The major results could be summarized as follows: (1) The annual precipitation in the drainage basin tends to decrease while the runoff has declined markedly since the 1960s, the average annual runoff from 1991 to 2000 was only 90.9% in proportion to that from 1961 to 1970. (2) The annual runoff variations in the drainage basin are significantly related to human activities. (3) During 1981–1990, 1991–2000, 2001–2005 and 1981–2005, the average annual runoff reduction amounts were 1.15×10⁸, 0.28×10⁸, 1.10×10⁸ and 0.79×10⁸ m³ respectively and the average annual runoff-reducing effects were 31.99%, 7.13%, 40.71% and 23.79% accordingly. Runoff-reducing effects by water conservancy and soil conservation measures are more prominent in the low water period.     

Soil carbon and nitrogen in a Great Basin pinyon–juniper woodland: Influence of vegetation,burning, and time

Much of the Great Basin, U.S. is currently dominated by sagebrush (Artemisia tridentate ssp. (Rydb.) Boivin) ecosystems. At intermediate elevations, sagebrush ecosystems are increasingly influenced by pinyon (Pinus monophylla Torr. & Frém.) and juniper (Juniperus osteosperma Torr.) expansion. Some scientists and policy makers believe that increasing woodland cover in the intermountain western US will create new carbon storage on the landscape; however, little is currently known about the distribution of carbon on these landscapes. This is especially true of below ground pools. Our objectives were to quantify the spatial distribution of soil carbon in expansion woodlands, and to determine prescribed fire's effect on soil C and N. We looked at two treatments (control and burn), three microsites (undertree, undershrub, and interspace), and four soil depths (0–8, 8–23, 23–38, and 38–52 cm). The study was conducted over a six year period with one year pre-fire and five years post-fire data. Results for both carbon and nitrogen were similar, indicating the close relationship between the two elements in this ecosystem. Undershrub microsites had higher soil C and N concentrations than interspace and undertree microsites; however, under tree microsites had higher C:N ratio than interspace and undershrub microsites. Carbon and nitrogen concentration tended to decrease with increasing depth at both control and burn sites. Prescribed burning caused immediate increases in surface soil C and N concentration, but over intermediate to longer periods of time no statistically detectable change in soil C or N content occurred from burning.     

Household Water Insecurity in the Global North: A Study of Rural and Periurban Settlements on the Texas–Mexico Border

This article examines household-level characteristics that predict water insecurity in low-income rural and periurban communities on the Texas–Mexico border. We employ two logistic regression models (binary and ordered) to identify household characteristics that are more likely to result in water insecurity. Our analyses yielded unexpected findings: Whereas socioeconomic factors are weak predictors, immigration status of household members is a significant variable that contributes to household water insecurity. Policymakers need to pay more attention to marginalized communities as “universal” water access still leaves populations without adequate, reliable, and affordable water in the Global North.     

A Retrospective of Oil and Gas Field Development in the U.S. Outer Continental Shelf Gulf of Mexico, 1947–2017

Natural Resources Research - The U.S. Gulf of Mexico is a world-class hydrocarbon basin and industry has an impressive track record of advancing its capabilities in the region. From 1947 to 2017,...     

Working in a Landscape of Recession and Expansion: Academic Jobs in Geography in the United States, 1990–2011

The recent economic recession brought much university hiring to a standstill in the United States. Geography, in spite of strong prerecession growth, was no exception. Without a sense of how the academic geography job market has changed over the past decades, however, it is difficult to assess any recession-related decline or the relative strength of any recovery. This article presents an analysis of academic job postings in the field of geography from 1990 through 2011. Using data aggregated from the AAG Newsletter, which acts as an informal clearinghouse for most academic openings for geographers at four-year colleges and universities in the United States, we assess changes in the overall magnitude in numbers of academic job openings, with the particular goal of placing the recession-based paucity of openings within its broader historical context. Our results indicate that, indeed, the recession led to a very sharp decline in advertisements, but compared to previous recessions, the recovery appears to have occurred very quickly. Open-rank and temporary/non-tenure-track positions appear to have been fairly robust to the poor economic conditions, whereas assistant professor openings were particularly hard hit.