Late Pleistocene and Holocene glaciation of the Fish Lake valley,northeastern Alaska Range,Alaska     

Nicolás E. Young  Jason P. Briner  Darrell S. Kaufman 《第四纪科学杂志》2009,24(7):677-689

We reconstructed a chronology of glaciation spanning from the Late Pleistocene through the late Holocene for Fish Lake valley in the north‐eastern Alaska Range using ¹⁰Be surface exposure dating and lichenometry. After it attained its maximum late Wisconsin extent, the Fish Lake valley glacier began to retreat ca. 16.5 ka, and then experienced a readvance or standstill at 11.6 ± 0.3 ka. Evidence of the earliest Holocene glacial activity in the valley is a moraine immediately in front of Little Ice Age (LIA) moraines and is dated to 3.3–3.0 ka. A subsequent advance culminated at ca. AD 610–900 and several LIA moraine crests date to AD 1290, 1640, 1860 and 1910. Our results indicate that ¹⁰Be dating from high‐elevation sites can be used to help constrain late Holocene glacial histories in Alaska, even when other dating techniques are unavailable. Close agreement between ¹⁰Be and lichenometric ages reveal that ¹⁰Be ages on late Holocene moraines may be as accurate as other dating methods. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Use of LSPIV in assessing urban flash flood vulnerability     

Nicolás Federico Guillén  Antoine Patalano  Carlos Marcelo García  Juan Carlos Bertoni 《Natural Hazards》2017,87(1):383-394

The probability of the occurrence of urban flash floods has increased appreciably in recent years. Scientists have published various articles related to the estimation of the vulnerability of people and vehicles in urban areas resulting from flash floods. However, most published works are based on research performed using numerical models and laboratory experiments. This paper presents a novel approach that combines the implementation of image velocimetry technique (large-scale particle image velocimetry—LSPIV) using a flash flood video recorded by the public locally and the estimation of the vulnerability of people and vehicles to high water velocities in urban areas. A numerical one‐dimensional hydrodynamic model has also been used in this approach for water velocity characterization. The results presented in this paper correspond to a flash flood resulting on November 29, 2012, in the city of Asunción in Paraguay. During this flash flood, people and vehicles were observed being carried away because of high water velocities. Various sequences of the recorded flash flood video were characterized using LSPIV. The results obtained in this work validate the existing vulnerability criterion based on the effect of the flash flood and resulting high water velocities on people and vehicles.  相似文献   

An overview of the geology and major ore deposits of Central Africa: Explanatory note for the 1:4,000,000 map “Geology and major ore deposits of Central Africa”     

J.P. Milesi  S.F. Toteu  Y. Deschamps  J.L. Feybesse  C. Lerouge  A. Cocherie  J. Penaye  R. Tchameni  G. Moloto-A-Kenguemba  H.A.B. Kampunzu  N. Nicol  E. Duguey  J.M. Leistel  M. Saint-Martin  F. Ralay  C. Heinry  V. Bouchot  J.C. Doumnang Mbaigane  V. Kanda Kula  F. Chene  J. Monthel  P. Boutin  J. Cailteux 《Journal of African Earth Sciences》2006,44(4-5):571

This paper is prepared within the frameworks of IGCP Project 470 and the associated BRGM scientific project “Africa 1999–2004” to accompany the 1:4,000,000 scale map “Geology and major ore deposits of Central Africa, presented at the 20th Colloquium of African Geology in Orleans in June 2004. It incorporates geological and metallogenic data from eight countries in Central Africa (Angola, Cameroon, Chad, Central African Republic, Congo Brazzaville, Democratic Republic of Congo (DRC), Equatorial Guinea and Zambia). The map is a harmonised and geo-referenced preliminary map, based on a GIS at 1:2,000,000 scale, and focusses on the spatial and temporal distribution of selected major deposits.  相似文献   

A combined methodology to assess the intrinsic vulnerability of aquifers to pollution from agrochemicals     

Vassilis G. Aschonitis  Giuseppe Castaldelli  Nicolò Colombani  Micòl Mastrocicco 《Arabian Journal of Geosciences》2016,9(7):503

The groundwater vulnerability indices are valuable tools for the development of agrochemicals management strategies based on environmental/agricultural policies. The groundwater vulnerability methods of LOS, SINTACS, DRASTIC, Pesticide DRASTIC, GOD and AVI were applied for the agricultural fields of Sarigkiol basin (Northern Greece). The results of the aforementioned methods were examined and discussed in order to show how the dissimilarities in the vulnerability assessment approaches may become an advantage. The results of the methods were used to propose a combined conceptual approach which adds another two dimensions (depth and time) in the current two-dimensional vulnerability mapping (longitude, latitude) procedures. The LOS method provided information about the intrinsic vulnerability of the topsoil (30 cm) to water (+conservative pollutants) and nitrogen losses, and the AVI method described the vulnerability of the unsaturated zone to allow pollutants to reach the aquifer while the aquifer vulnerability was analysed using SINTACS, DRASTIC, Pesticide DRASTIC and GOD. In this study, the results of the SINTACS method were found more accurate to describe the local aquifer conditions. The final conceptual approach provided a stratified vulnerability (dimension of depth) of the overall hydrogeologic system using LOS for the topsoil, AVI for unsaturated zone and SINTACS for the aquifer. The dimension of time was introduced by the LOS and AVI methods, which provide quantitative results in time. The use of LOS method also highlighted the basic limitation of the other methods to describe the potential contribution to pollution of areas (especially upland areas) which are out of the aquifer boundaries.  相似文献   

Assessing rheological properties of fluid mud samples through tuning fork data     

Fonseca  Diego Luiz  Marroig  Patrícia Cunha  Carneiro  Juliane Castro  Gallo  Marcos Nicolás  Vinzón  Susana Beatriz 《Ocean Dynamics》2019,69(1):51-57

Ocean Dynamics - At the nautical bottom approach, part of the fluid mud layers can be included in the available depth if they present favorable rheology. As it is difficult to perform in situ...  相似文献   

Induced earthquakes and house prices: the role of spatiotemporal and global effects     

Durán  Nicolás  Elhorst  J. Paul 《Journal of Geographical Systems》2023,25(2):157-183

Journal of Geographical Systems - This paper contributes to the existing literature on the explanation of housing prices. First, our proposed methodology accounts for cross-sectional dependence,...  相似文献