Pour la reconstitution des paléoenvironnements, quelques exemples montrent l'intérêt d'une étude des micro et macrofossiles en complément avec l'analyse pollinique.
Late Wisconsin macrofossil records of desert vegetation in the American Southwest
Domaine aride ; Etats-Unis ; Géographie de l'Amérique ; Macrofossile ; Paléobiogéographie ; Paléoflore ; Pléistocène supérieur ; Quaternaire zones moyennes ; Southwestern United States ; Wisconsinien supérieur
Recent discovery of macrofossil assemblages in the Mojave Desert extends the record of desert vegetation back to 14,800 yr ago and to altitudes as high as 910 m. Although xerophytic conifer woodland was widespread in current desert habitats during
A l'aide de macrofossiles ligneux récoltés dans les fens, situés de part et d'autre de la limite moderne des forêts, nous avons reconstitué les déplacements de la limite des forêts au cours de l'Holocène, dans la région de Rivière aux Feuilles
. Cette reconstitution est basée sur une récolte exhaustive de plus de 700 macrofossiles ligneux, dont 67 spécimens sont datés (C).
Revised age of deglaciation of Lake Emma based on new radiocarbon and macrofossil analyses
In this study, a section of Lake Emma basal sediments was sampled at three horizons for insect and plant macrofossils. Paleoecological analyses suggesting climatic conditions warmer than present and subsequent accelerator radiocarbon dates on wood
Implications for the dating of Wisconsinan (Weichselian) Late-Glacial events of systematic radiocarbon age differences between terrestrial plant macrofossils from a site in SW Ireland
This paper presents radiocarbon dates from a Weichselian Lateglacial site in SW Ireland that show a systematic age difference between 2 types of terrestrial plant macrofossils. There is also a difference between the dates from the macrofossils
Pollen and macrofossils from Wisconsinan interstadial sediments in Northeastern Georgia
This paper presents results of pollen, plant macrofossil, and dating studies (TAMS and conventional) from a new site in the Piedmont region of northeastern Georgia. This study contributes information on vegetation of the region between 26,000
and 22,000 yr B.P., and provides a basis for reescamining interpretations from other southeastern sites. The AA. also use their data to address key problems of Pinus species identification from pollen and macrofossils and age-model uncertainties resulting
California ; Domaine aride ; Etats-Unis ; Géographie de l'Amérique ; Macrofossile ; Paléobiogéographie ; Paléoclimatologie ; Paléoflore ; Pléistocène supérieur ; Quaternaire zones moyennes ; Sierra Nevada
Macrofossils from six late Pleistocene packrat midden samples record a mixed coniferous forest dominated by the xerophytic conifers Juniperus occidentalis, Pinus cf. ponderosa, and P. monophylla. The pollen spectra of these Pleistocene middens
are dominated by Pinus sp., TaxodiaceaeCupressaceaeTaxaceae (TCT), and Artemisia sp. Mesophytic conifers are represented by low macrofossil concentrations. Sequoiadendron giganteum is represented by a few pollen grains in the full glacial. Edaphic control
and snow dispersal are the most likely causes of these mixed assemblages. The dominant macrofossils record a more xeric plant community than those that now occur on similar substrates at higher elevations or latitudes in the Sierra Nevada. These assemblages
Analyse macrofossile et pollinique de paléosols de dunes en Hudsonie, Québec nordique
Burton lac ; Canada ; Diagramme pollinique ; Forêt ; Géographie des régions polaires ; Holocène ; Hudson Bay ; Incendie de forêt ; Macrofossile ; Palynologie ; Paléosol ; Poste-de-la-Baleine ; Quaternaire zones froides ; Québec ; Toundra
Les analyses macrofossile et pollinique de paléosols de dunes ont permis de reconstituer l'histoire de la végétation dans trois stations d'Hudsonie. Dans les sites étudiés (lac Burton, grande rivière de la Baleine et Poste-de-la-Baleine), les
Division de la Chine en trois régions biogéographiques : le Sud, le Centre et le Nord. Sur la base de macrofossiles du Permo-carbonifère, correspondance avec des zones paléoclimatiques.
Pollen, plant macrofossils, and insects from fossil woodrat (Neotoma cinerea) middens in British Columbia
Résultats de l'étude du pollen, des macrofossiles de végétaux et des restes d'insectes recueillis dans les matières fécales de rats (Neotoma cinerea) dans deux sites du centre de la Colombie-Britannique. Discussion sur les nouvelles possibilités
Reconstitution paléo-écologique d'une tourbière littorale de l'estuaire du Saint-Laurent : analyse macrofossile et sporopollinique in 25 anniversaire du Centre d'Etudes Nordiques.
L'analyse sporollinique et macrofossile d'une carotte provenant d'une tourbière en marge d'un schorre à spartines permet de reconstituer le milieu littoral. L'analyse microstratigraphique en lames minces et une série de datations 14C fixe la
The objective of this study is to document the pattern of postglacial spread of larch along the east-west gradient toward Hudson Bay. The combination of pollen and macrofossil analyses is particularly relevant here because Larix is a poor pollen
producer. The AA. have examined both the macrofossil and pollen records of radiocarbon-dated peat deposits, and the population structure of the disjunct, extant populations for evidence of past and recent presence of larch in this area.
Late-glacial to early Holocene climate changes from a central Appalachian pollen and macrofossil record
A late-glacial to early Holocene record of pollen, plant macrofossils, and charcoal has been obtained from 2 cores from browns Pond in the central Appalachians of Virginia. An AMS radiocarbon chronology defines the timing of moist and cold
Analyse en composantes principales ; Analyse factorielle ; Analyse statistique ; California ; Domaine aride ; Dynamique de la végétation ; Etats-Unis ; Géographie de l'Amérique ; Holocène supérieur ; Limite altitudinale ; Macrofossile ; Mojave
of Coleogyne ramosissima (blackbrush), macrofossils of this shrub are only present in samples younger than 270 yr B.P. In order to measure changes more subtle than presence vs absence, macrofossil concentrations were quantified, and principal components