A Holocene palaeomagnetic record and a geomagnetic master curve from Ireland   总被引：1，自引：0，他引：1  

ROY THOMPSON  KEVIN J. EDWARDS 《Boreas: An International Journal of Quaternary Research》1982,11(4):335-349

Magnetic analyses have been carried out on sediments collected from Lough Catherine. Northern Ireland, as part of a wider environmental study. The sediments span the whole of the Holocene. Radiocarbon and pollen dating of the palaeomagnetic signature locked in the sediments form the basis of an Irish Holocene geomagnetic master curve. The mineral magnetic characteristics of the sediments correspond with environmental changes, such as eighteenth century landscaping and the elm decline as revealed by pollen analyses. Both marginal and central sediments have been analysed. The sediments can be correlated by using either magnetic, pollen, or 14 C measurements. These three independent core correlation methods all agree extremely well with each other. A mathematical method is described which can be used to calculate continuous accumulation rates and influxes.  相似文献   

THE MAGNETISM OF MIAMI: SEGMENTED PATHS IN CUBAN MIGRATION*     

KEVIN E. McHUGH  INES M. MIYARES  EMILY H. SKOP 《Geographical review》1997,87(4):504-519

ABSTRACT. Miami is the primate city in a system of urban settlements that make up a Cuban ethnic archipelago in the United States. The city is also a national magnet, attracting Cuban migrants from metropolitan regions across the archipelago. Four large secondary cores of Cubans outside Florida serve as major “feeders” to the Miami enclave: northern New Jersey, New York City, Los Angeles, and Chicago. Currents of migration to Miami are especially strong among older, foreign-born, and disadvantaged Cubans, an indication of segmented paths in Cuban assimilation. Although concentration in Metropolitan Miami has been the Cuban story over the past three decades, processes of deconcentration now may well be under way.  相似文献   

PALEOENVIRONMENT AND “POCKET FEN” DEVELOPMENT ON THE WESTERN GREAT PLAINS*     

KEVIN P. GILMORE  DONALD G. SULLIVAN 《Geographical review》2010,100(3):413-429

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Climate change in the Arctic: current and future vulnerability in two Inuit communities in Canada   总被引：7，自引：0，他引：7  

JAMES D FORD  BARRY SMIT†  JOHANNA WANDEL†  MISHAK ALLURUT‡  KIK SHAPPA‡  HARRY ITTUSARJUAT§  KEVIN QRUNNUT§ 《The Geographical journal》2008,174(1):45-62

Climate change is already occurring in the Arctic and the Arctic Climate Impact Assessment recently concluded that future climate change could be devastating for Inuit. This paper characterises vulnerability to climate change in two Inuit communities in the Canadian territory of Nunavut, focusing on the resource harvesting sector. In both communities, Inuit have demonstrated significant adaptability in the face of current changes in climatic conditions. This adaptability is facilitated by traditional Inuit knowledge, strong social networks, flexibility in resource use, and institutional support. Changing Inuit livelihoods, however, have undermined certain aspects of adaptive capacity and have resulted in emerging vulnerabilities. Global and regional climate projections indicate that climatic conditions which currently pose risks are expected to be negatively affected by future climate change. These projections are not without precedent and analysis of current vulnerability and identification of adaptation constraints by Inuit in the two communities indicate the continued importance of traditional coping mechanisms. The ability to draw on these coping mechanisms in light of future climate change, however, will be unequal and the research indicates that young Inuit and those without access to economic resources, in particular, are vulnerable.  相似文献   

The destruction of Iapetus and Tornquist's Oceans     

KEVIN T. PICKERING 《Geology Today》1989,5(5):160-166

The Cambro-Ordovician Iapetus and Tornquist's Oceans formed a Pacific-type ocean basin rimmed by volcanic island arcs and marginal basins. By the latest Ordovician to earliest Silurian this ocean basin was beginning to close, to become a Mediterranean-type ocean basin. This was caused by the collision between a microcontinent (comprising England, Wales, much of Ireland and parts of north-west Europe), called Eastern Avalonia, and the North American super-continent, Laurentia, which resulted in no oceanic crust remaining in the region of present-day central Newfoundland. Marine basins, however, persisted into the Middle Silurian. Throughout the Silurian and early Devonian, some 40–45 million years, various terranes continued to collide with the North American margin, predominantly under major left-lateral strike-slip until the remaining seaways were eliminated in the early Middle Devonian, to be replaced by terrestrial environments of the Old Red Sandstone.  相似文献   

Quantitative study of the distributary braidplain of the Preboreal ice-contact Gardermoen delta complex, southeastern Norway     

KEVIN J. TUTTLE  SVElN ROAR ØOUSTMO  BJ ÖRN G. ANDERSEN 《Boreas: An International Journal of Quaternary Research》1997,26(2):141-156

This raised delta structure is an ice-contact deltaic complex with a volume of c. 4.4.10⁹ m³, deposited c . 9500 yr BP in a shallow wide 'fjord' during the retreat of the Scandinavian ice cap. The delta plain lies at an altitude of 200–223 m. It aggraded c . 20 m above the contemporaneous sea level during a regional marine regression. The braidplain palaeochannel characteristics indicate a peak meltwater discharge of 7–9 10³ m³/s. Calculations based on a glacial ablation model indicate a mid-summer discharge of c . 5.5 10³ m³/s. However, the fluvial topset of the delta has an erosive base whose altitude decreases upstream and indicates stream incision by more the 6 m below the contemporaneous sea level. The deep scour is ascribed to episodic floods over the relatively short delta plain, which exceeded direct ablation-associated discharges. The depositional time-span of the delta is assessed to have been 70 years, calculated from coastal gradient and shoreline displacement curves. The average sedimentation rate of the delta is thereby inferred to have been extremely high, c . 6. 10⁷ m³/yr. The sedimentation is thought to reflect 'extreme' ice-margin conditions, where the sediment and water discharge was maximized by full-scale ablation, with simultaneous subglacial, englacial and supraglacial sediment and water supply. These conditions might further coincide with an abundant rainfall in the catchment area or the drainage of dammed waters, initiating episodic floods which eroded deep beneath sea level. As a whole, the study illustrates the hydrological conditions of proglacial sedimentation at the front of the rapidly retreating last Scandinavian ice cap.  相似文献   

Physical initialization for numerical weather prediction over the tropics     

T. N. KRISHNAMURTI  JISHAN XUE  H. S. BEDI  KEVIN INGLES  D. OOSTERHOF 《地球，A辑:动力气象学与海洋学》1991,43(4):53-81

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Lower stratosphere waves during 1986–89 Southern Springs     

JULIA NOGUÉS-PAEGLE  KINGTSE C. MO  KEVIN P. CALLAHAN 《Tellus. Series B, Chemical and physical meteorology》1992,44(4):390-408

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The effect of hygroscopicity on cloud droplet formation     

MARKKU KULMALA  PEKKA KORHONEN  TIMO VESALA  HANS-CHRISTEN HANSSON  KEVIN NOONE  BIRGITTA SVENNINGSSON 《Tellus. Series B, Chemical and physical meteorology》1996,48(3):347-360

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Soil carbon storage in plantation forests and pastures: land-use change implications   总被引：14，自引：0，他引：14  

NEAL A. SCOTT  KEVIN R. TATE  JUSTIN FORD-ROBERTSON  DAVID J. GILTRAP  C. TATTERSALL SMITH 《Tellus. Series B, Chemical and physical meteorology》1999,51(2):326-335

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