Timing of vegetation changes at the end of the Holocene Humid Period in desert areas at the northern edge of the Atlantic and Indian monsoon systems   总被引：1，自引：0，他引：1  

Anne-Marie Lézine 《Comptes Rendus Geoscience》2009,341(8-9):750-759

This article aims at discussing the ecological response of the terrestrial and fresh water dependant environments to the installation of arid conditions at the end of the Holocene Humid Period in the Atlantic and Indian monsoon domains. It is mainly focused on dry environments from Chad, Oman and Pakistan where new, high-resolution pollen sequences have been provided. Pollen data show that local hydrological conditions have played a major role in the destruction or survival of tropical tree populations at the end of the Holocene Humid Period, as well as partly explaining the asynchronous pattern of recorded environmental changes in most tropical regions. In desert areas, the response of the fresh water dependant systems to the shift from humid to arid climate conditions appears to have followed a threshold-like pattern. In contrast, terrestrial ecosystems have gradually adapted to increased drought, as shown by the progressive decrease of tropical tree species at Yoa or the gradual expansion in dry plant types in Oman and Pakistan from 6000 cal yrs BP to the present. A remarkable synchroneity in environmental change is recorded at the northern edge of the Atlantic and Indian monsoon systems, with the extreme end of the Holocene Humid Period corresponding to the last occurrence of tropical trees in the desert and the last record of prolonged SW monsoon rainfall over north-western Asia around 4700–4500 cal yrs BP.  相似文献   

The Qijurittuq site (IbGk-3), Eastern Hudson Bay: An IPY Interdisciplinary Study     

Pierre M. Desrosiers  Susan Lofthouse  Najat Bhiry  Anne-Marie Lemieux  Hervé Monchot  Daniel Gendron 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(2):227-243

Geografisk Tidsskrift—Danish Journal of Geography 110(2):227–243, 2010

An interdisciplinary study was conducted at Qijurittuq (IbGk-3), an archaeological site located on Drayton Island along the eastern shore of Hudson Bay, Nunavik. Local Inuit made important contributions to the research. High school students participated in the field school, and elders shared their traditional knowledge. The elders expressed an interest in the source of the wood used to construct Qijurittuq's semi-subterranean dwellings, and this inspired us to expand our research in that direction. This interdisciplinary study included a reconstruction of the geomorphological and environmental history of Drayton Island, wood provenance and dendrochronology studies, research on house architecture and settlement patterns, and a zooarchaeological analysis. This paper synthesizes the preliminary results of this interdisciplinary investigation within the context of climate change. We discuss the persistence of semi-subterranean dwellings in eastern Hudson Bay long after they had been abandoned elsewhere. At Qijurittuq, their abandonment corresponds with the end of Little Ice Age. However, at the same time, the development of more permanent contact with Euro-Canadians was having a strong impact upon Inuit culture.  相似文献   

Constructing Alterity in Ile De France?     

Anne-Marie d'Hauteserre 《Urban geography》2013,34(6):864-886

Abstract

The aim of the article is to determine whether the Walt Disney Company has manufactured a landscape “other” to French culture around its parks in the Eastern Paris Basin. Val d'Europe is contentiously constructed by three main groups, not just one enterprise: the French state, the Walt Disney Company and local and regional governments, as well as by present and future residents, within the constraints of a contract based on French laws. The Company's investment has been a tremendous boost to the French state's project but did not lead to Disneyfication of the Briard landscape of agricultural lands in the Eastern Paris basin. In Val d'Europe the French state did not abdicate its authority in favor of commoditization of Paris as a global metropolis. The French state and French culture were never “weak” and overwhelmed.  相似文献   

Temporal relationship between Holocene human occupation and vegetation change along the northwestern margin of the Central African rainforest     

Anne-Marie Lézine  Augustin F.-C. Holl  Judicaël Lebamba  Annie Vincens  Chimène Assi-Khaudjis  Louis Février  Émmanuelle Sultan 《Comptes Rendus Geoscience》2013,345(7-8):327-335

This paper discusses the relationship between patterns of human settlements and environmental change during the Holocene along the northwestern margins of the equatorial rain forest of central Africa. Palaeoenvironmental data from high-resolution sediment cores from lacustrine deposits, plant macro-remains from forest soils, and archaeological data are harnessed to discuss the differential impact of climate and/or humans on the central African rain forest. It is shown that climate change impacted the rain forest well before the widespread expansion of human settlements all over the study area.  相似文献   

Influence of instruments on the H/V spectral ratios of ambient vibrations   总被引：3，自引：3，他引：0  

Bertrand Guillier  Kuvvet Atakan  Jean-Luc Chatelain  Jens Havskov  Matthias Ohrnberger  Fabrizio Cara  Anne-Marie Duval  Stratos Zacharopoulos  Paula Teves-Costa  The SESAME Team 《Bulletin of Earthquake Engineering》2008,6(1):3-31

For an optimal analysis of the H/V curve, it appears necessary to check the instrument signal to noise ratio in the studied frequency band, to ensure that the signal from the ground noise is well above the internal noise. We assess the reliability and accuracy of various digitizers, sensors and/or digitizer-sensor couples. Although this study is of general interest for any kind of seismological study, we emphasize the influence of equipment on H/V analysis results. To display the impact of the instrumental part on the H/V behavior, some series of tests have been carried out following a step-by-step procedure: first, the digitizers have been tested in the lab (sensitivity, internal noise...), then the three components sensors, still in the lab, and finally the usual user digitizers-sensors couple in lab and outdoors. In general, the digitizer characteristics, verified during this test, correspond well to the manufacturer specifications, however, depending on the digitizer, the quality of the digitized waveform can be very good to very poor, with variation from a channel to another channel (gain, time difference etc.). It appears very clearly that digitizers need a warming up time before the recording to avoid problems in the low-frequency range. Regarding the sensors, we recommend strongly to avoid the use of “classical” accelerometers (i.e., usual force balance technology). The majority of tested seismometers (broadband and short period, even 4.5 Hz) can be used without problems from 0.4 to 25 Hz. In all cases, the instrumentation should be checked first to verify that it works well for the defined study aim, but also to define its limit of use (frequency, sensitivity...).  相似文献   

The paleolimnology of a small waterbody in the Pocono Mountains of Pennsylvania,USA: reconstructing 19th–20th century specific conductivity trends in relation to changing land use     

Anne-Marie Lott  Peter A. Siver  Laurence J. Marsicano  Kenneth P. Kodama  Robert E. Moeller 《Journal of Paleolimnology》1994,12(2):75-86

Remains of scaled chrysophytes, magnetic minerals and pollen were used to analyze the recent paleolimnological history of a small lake, Lake Waynewood, in the Pocono Mountains of Pennsylvania. Important shifts in all three variables were observed over the 133 years represented by the core. The most significant changes occurred near the turn of the century when the watershed was heavily logged. Before the logging event, species such asSynura sphagnicola, S. spinosa, Mallomonas galeiformis andM. duerrschmidtiae were co-dominant members of the flora. Subsequent to the deforestation of the watershed other taxa, includingM. crassisquama, M. caudata andS. petersenii, increased in relative importance. Concurrent with changes in the scaled chrysophytes was a six-fold increase in the concentrations of magnetic material, presumably the result of increased erosion caused by the logging. Changes in pollen grains also correlate well with the onset of the deforestation event. The scaled chrysophyte inferred specific conductivity of the lake has more than tripled, with the primary increase occurring concurrent with the commencement of logging and the increase in magnetic mineral material. The effects of other human-related disturbances are also discussed.  相似文献   

[Without Title]     

Anne-Marie de Grosbois 《Environmental Geology》2006,50(8):1265-1269

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Effects of food particle size on Perca fluviatilis larval growth     

Lakhdar Tamazouzt  Claude Leray  Anne-Marie Escaffre  Denis Terver 《Aquatic Sciences - Research Across Boundaries》1998,60(2):89-98

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Towards a microzonation of the Greater Beirut area: an instrumental approach combining earthquake and ambient vibration recordings     

Marleine Brax  Pierre-Yves Bard  Anne-Marie Duval  Etienne Bertrand  Muhsin-Elie Rahhal  Rachid Jomaa  Cécile Cornou  Christophe Voisin  Alexandre Sursock 《Bulletin of Earthquake Engineering》2018,16(12):5735-5767

Lebanon is situated on the 1000 km long Levant transform fault that separates the Arabic from the African tectonic plates. In Lebanon, the Levant fault splits up into a set of ramifications that had, in the past, generated major destructive earthquakes causing a lot of destruction and thousands of casualties. The most devastating one was the 551 A.D. offshore earthquake that destroyed Beirut, the capital of Lebanon. This paper presents a site effect study in Beirut, aimed at proposing a framework for future microzonation works in the city. It includes two complementary parts. A 6-month, temporary seismological experiment was first conducted to estimate the site response at 10 sites sampling the main geological units of Beirut on the basis of local and regional earthquake recordings. This spatially sparse information was then complemented by a large number (615) of microtremor measurements covering the Beirut municipality and part of its suburbs with a 400 m dense grid. The recordings were analysed with the standard site-to-reference and horizontal-to-vertical spectral ratio methods for earthquake recordings, and the horizontal-to-vertical ratio for ambient noise recordings. Significant ground motion amplification effects (up to a factor of 8) are found in a few areas corresponding to recent deposits. The consistency between results from earthquake and microtremor recordings allows proposing a map of the resonance frequencies within the city and its suburbs, with frequencies ranging from 0.5 to 5 Hz for the deepest deposits, and 5–10 Hz for shallow areas. Finally, the results are discussed and a way to combine the results obtained from the temporary stations to the great number of recordings coming from the permanent Lebanese network is proposed.  相似文献   

Reviews on books, internet and scientific media     

Grosbois de Anne-Marie  J. Rasanen  F. A. Assaad  P. E. LaMoreaux 《Environmental Geology》2007,51(6):1089-1091

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