北极阿拉斯加北坡盆地天然气水合物成矿规律与资源潜力

北极阿拉斯加北坡盆地是全球开展天然气水合物的调查研究最早的地区之一,对全球天然气水合物的研究具有示范作用。在大量文献资料综合分析的基础上,本文系统归纳了阿拉斯加北坡地区天然气水合物的成矿地质条件和成矿规律。认为阿拉斯加北坡的天然气水合物成矿系统是下伏下白垩第三系含油气系统在浅部的衍生,是由下伏气源、断裂、岩性、北极的特殊环境(永久冻土、地层温压场)等多种因素共同作用的结果。通过模拟计算和分析,将阿拉斯加北坡地区划分了3级远景资源区,估算出整个阿拉斯加地区的天然气水合物资源为6.0×10^12 m^3标准天然气,其中I级远景区主要分布于阿拉斯加北坡的滨岸冻土区和陆架区,资源量为2.83×10^12 m^3标准天然气。     

EFFECTS OF DISTANCE INTERNAL TO THE FARM: A CHALLENGING SUBJECT FOR NORTH AMERICAN GEOGRAPHERS*

The effects of intra-farm distance on farm income have not been previously tested in North America. European studies are inconclusive as they use data taken from bookkeeping accounts for the farm as a whole. This paper calls for field-to-field farm analyses that combine internal movement costs with costs of production, yields, and farm-gate prices. In a study applying this method to Manitoba grain farms, it was found that adjustments in the organization and intensity of farming offset the effects of distance on net income.     

北冰洋海冰和海水变异对海洋生态系统的潜在影响

最近30年来,北冰洋海冰和海水发生了急剧变化:海冰覆盖面积减少、冰层变薄、水温升高、淡水输入增加、污染加剧,正威胁着现有与海冰关系密切的生态系统。预期随着变化的持续,与海冰相关的食物链将在部分海域消失并被较低纬度的海洋物种所取代、总初级生产力有望增加并为人类带来更多的渔获量、而北极熊和海象等以海冰作为栖息和捕食场所的大型哺乳动物的生存前景堪忧。今后人类将更为重视对北冰洋生态环境变化规律的认识并加以运用、关注北冰洋特有物种的命运并加以力所能及的保护、评估北冰洋生态系统的变化对人类社会经济的影响以期及早采取应对措施。数据积累是目前制约北极研究的最大障碍,但随着 SEARCH 等大型国际研究计划的实施,对北冰洋生态系统的监测和研究将更为系统和全面。     

OUTREACH TO PRECOLLEGIATE AMERICAN HISTORY TEACHERS: THE UTILITY OF HISTORICAL GEOGRAPHY THEMES *

The utility of introducing historical geography topics into pre-college American history courses is explored through surveys of social studies teachers in New England and at a meeting of the National Council for Geographic Education (NCGE). Many history teachers claim to use geography in their courses, but use mostly map skills, place locations, and determinism. History teachers are interested in materials and workshops on historical geography themes, however, and sample, materials were well received by teachers in attendance at a national and a regional conference.     

THE AMERICAN CHALLENGE TO BRITISH HEGEMONY, 1861–1947*

ABSTRACT. In The Shaping of America Donald Meinig describes a United States averse to challenging Britain geostrategically but emerging as a powerhouse economy by the late 1890s. But America embarked on a sustained economic struggle with Britain in 1861 by embracing protectionism; America's Civil War ironclads were as much to resist Britain as fight the Confederacy; and in 1866 uss Miantonomoh helped persuade Britain to reconsider, then pay, the Alabama Claims. Britain never retaliated in the economic struggle by moving to protectionism and in the late 1800s began to appease America in geostrategic terms. This struggle intensified in the 1920s and 1930s as America and Britain competed for control of international transportation, international communication, and the global oil supply, but by the mid‐1940s American hegemony was clear. This article traces the course of the complex economic and political struggle for hegemony in the light of recent models of transitions in the world economy.     

SNOWSHED CONTRIBUTIONS TO THE NOOKSACK RIVER WATERSHED,NORTH CASCADES RANGE,WASHINGTON*

ABSTRACT. Meltwater contributes to watershed hydrology by increasing summer discharge, delaying the peak spring runoff, and decreasing variability in runoff. High‐elevation snowshed meltwater, including glacier‐derived input, provides an estimated 26.9 percent of summer streamflow (ranging annually from 16 to 40 percent) in the Nooksack River Basin above the town of Deming, Washington, in the North Cascades Range. The Nooksack is a major spawning river for salmon and once was important for commercial, recreational, and tribal fishing, and in the past its flow met the demands of both human and aquatic ecosystems. But the river is already legally overallocated, and demand is rising in response to the rapidly growing human population. Variability in snowshed contributions to the watershed is considerable but has increased from an average of 25.2 percent in the 1940s to an average of 30.8 percent in the 1990s. Overall stream discharge shows no significant increase, suggesting that the glaciers are melting, and/or precipitation levels (or other hydrologic factors) are decreasing at about the same rate. If glaciers continue to recede, they may disappear permanently from the Cascades. If that occurs, their summer contribution to surface‐water supplies will cease, and water‐management policies will need drastic revision.     

THE PARLOR IN THE WILDERNESS: DOMESTICATING AN ICONIC AMERICAN LANDSCAPE*

ABSTRACT. Thirty years ago D. W. Meinig argued that certain landscapes “are part of the iconography of nationhood.” From the earliest European settlement, the North American “wilderness” forged the crucible that shaped U.S. culture. By the early nineteenth century romantic aesthetic theories and nationalistic patriotism influenced American perspectives on the emerging cultural landscape. Artists, writers, and travelers sought out places for their healthful and scenic qualities as well as for moral instruction from nature. The locus of this confluence of politics, philosophy, and art was the Hudson River Valley of New York State. Guesthouses and hotels, especially in and around the Catskill Mountains, accommodated these travelers. This article examines the cultural basis of the mountain resort in its appropriation and marketing of a regional landscape and its incorporation as a national icon, with a specific history of the development of Mohonk Mountain House by the Smiley family from 1869 to 2008.     

THE U.S. MILITARY AS GEOGRAPHICAL AGENT: THE CASE OF COLD WAR ALASKA*

ABSTRACT. Alaska was strategically key to the U.S. defense plan during the cold war (1946–1989). As such, it was the scene of an enormous and sustained military investment, the effect of which was amplified by Alaska's undiversified economy, sparse development, small resident population, and marginalized political status at the beginning of the era. The strong military presence affected Alaskan demographics, economic development, and infrastructure and figured prominently in the admission of Alaska to the union in 1959. The high profile and long‐term presence of the U.S. military had such a dramatic affect on the course of Alaska that the result was tantamount to a “militarized landscape.”     

HOLOCENE CARBONATE PRECIPITATES ON PRECAMBRIAN BEDROCK IN THE HIGH ARCTIC: AGE AND POTENTIAL FOR PALAEOCLIMATIC INFORMATION

ABSTRACT. Crusts of white carbonate precipitate occur commonly on the upper surfaces of glacially sculptured Precambrian granites and gneisses in east-central Ellesmere Island. Radiocarbon dating of 21 such carbonate precipitates, from elevations between 50 m and 1050 m a.s.l., has yielded only Holocene ages. Two samples from Ellesmere Island, plus one from Inglefield Land, Greenland, have calibrated ages over 5000 years, the rest are younger. The formation of these deposits, mainly calcite and characterized by unusually heavy δ¹³C ratios (+3.36 to +15.18‰), has apparently been aided in some cases by the presence of bacteria, and some crusts seem to have developed where Ca-bearing minerals are more prevalent. In the case of Bache Peninsula and Cape Herschel, where the carbonate crusts are particularly abundant, the presence of calcareous till may have played a role as well. The carbonate crusts may be related to the presence of small, thin carapace ice caps, when such features formed at lower elevations than those at which they exist today. The more extensive cover of ice and snow is postulated to have existed during the latter, cooler part of the Holocene, especially during the period from 2500 to 100 years ago, deduced as a period of low melt from ice core studies on the Agassiz Ice Cap, 200 km to the north. The existence of carapace ice caps at lower elevations also agrees with the radiocarbon evidence for outlet glacier advances during the last 2000 years on both east and west margins of the Prince of Wales Icefield. Alternatively, the white carbonate crusts may be, to a large degree, the result of weathering processes. In either case they provide minimum ages for the exposed, ice-sculptured rock surfaces on which they occur.     

THE POTENTIAL OF MAIL SURVEYS IN GEOGRAPHY: SOME EMPIRICAL EVIDENCE*

Faced with soaring survey costs, geographers may increasingly consider mail or telephone surveys as alternatives to in-person interviews. This study goes beyond comparisons of response rates to analyze possible biases of administration methods in geographic studies. An empirical comparison between an in-person interview survey and two mail surveys of recent home buyers’ housing preferences revealed that the mail surveys provided better representation of this population, as they had a higher completion rate (though lower response rate). While respondent attributes differed across administration modes, no direct effects of administration method on responses were found. Mail surveys appear to be a viable alternative to personal interviews in a wider set of cases than geographers usually assume, though more empirical work is needed to determine the extent of such cases.     

THE INTERNATIONAL MOBILITY OF LABOR: NORTH AFRICAN MIGRANT WORKERS IN FRANCE*

Since World War II, migrant labor has contributed significantly to Western Europe's economic growth. Initially, industries recruited and hired migrant workers to overcome labor shortages and downward demographic trends within the domestic work force. Since the recession of the mid-1970s, however, migrant labor has faced increasing job loss and restricted entry to many Western European countries. Throughout the postwar period, state immigration policy has supported industry, initially by assisting in the recruitment, and more recently, facilitating the repatriation of migrant workers. Economic and social disparities between developed core and underdeveloped peripheral countries are linked to international labor mobility. Certain sectors in the core benefit from the reserve labor force while emigration from peripheral countries partially contributes to these countries' economic problems. These issues are explored through a case study of the employment of North Africans in the French automobile industry.     

TRACEABILITY: TRACKING AND PRIVACY IN THE FOOD SYSTEM*

ABSTRACT. Lapses in food safety have spurred development of governmental traceability systems to track every stage of food production as part of a standardized information base. These systems form part of national and international government efforts to reduce food‐security risks and control food‐related disease outbreaks. The European Union, the United States, Japan, and Canada have traceability requirements now in various stages of implementation, as does the Codex Alimentarius. Traceability regulations require that, from farm (plant or animal) to fork, foods have a clear, verifiable record that tracks through all stages of cultivation, production, supplying, transporting, processing, and distribution. Traceability implies complete information control over the geography of one of life's most essential acts, eating. The apparent object of traceability is food, which seems to imply that human tracking is not part of the process, but food does not move on its own. Those people responsible at each stage for food transfers and transactions may go into the traceability database, making their locations part of the record and supporting precise monitoring of labor performance, consumer buying patterns, and ownership and management strategies. Given these capabilities, the development of public‐sector traceability systems demands careful consideration. Owners, especially large exporters and importers, are likely to see their needs and fears shape the system. The food workforce may well bear tracking's brunt. Consumers, the presumed beneficiaries of the systems, will probably resist direct incorporation (and full benefit), favoring their privacy over their safety.     

THE NON‐PENNSYLVANIA TOWN: DIFFUSION OF URBAN PLAN FORMS IN THE AMERICAN WEST*

ABSTRACT. Wilbur Zelinsky's classic 1977 account of the Pennsylvania town as a cultural place type–the urban component of the nationally influential Pennsylvanian culture region–acknowledged that it was not exported intact across the successive western frontiers of the United States. But, aside from Edward Price's specialized study of courthouse squares, we know little that is systematic about how town‐planning ideas diffused across the continent. This investigation offers evidence from the Willamette Valley in Oregon of the eventual variety and geographical distribution of town‐platting conventions that developed in this Pacific Coast “destination’ setting and the possible provenance in the Ohio Valley of certain early Oregonian town‐plan features. The evidence raises questions about the resilience of town‐planning conventions in light of the distance carried, cultural time lags, and changing ideas about best practice and local suitability.     

MOSCOW ON THE RISE: FROM PRIMATE CITY TO MEGAREGION*

In this article I examine Moscow's role in the political‐economic space of the Russian Federation. A broad range of data supports the thesis that the capital has become a primate city, one that serves no longer as the command center of a closed system but as the primary node of interconnection between Russia and the rest of the world. The effort to create a larger, polycentric “New Moscow” next to the ancient capital is marked by a tightening of central control, in contrast to governance regimes of European megaregions. Nevertheless, expansion of the capital region very likely will further boost Moscow's dominance over the country.