Search results for "last glacial maximum"
showing 10 items of 61 documents
Phylogeographic patterns of decapod crustaceans at the Atlantic-Mediterranean transition.
2012
9 páginas, 4 figuras, 3 tablas.
Palaeogeographical evolution of the Egadi Islands (western Sicily, Italy). Implications for late Pleistocene and early Holocene sea crossings by huma…
2019
Abstract The continental shelf morphology offshore of western Sicily suggests that during the Last Glacial Maximum (LGM, 20 ka cal BP), two of the Egadi Islands, Favignana and Levanzo, were connected to Sicily by a wide emerged plain, while Marettimo was only separated from the other islands by a narrow channel. We studied the relative sea-level variation from the LGM until today, focussing on two important time slices: the Mesolithic (9.5–13 ka cal BP) and the Neolithic (6.5–7.5 ka cal BP). In this research, we discuss a sea-level rise model by means of geomorphological, archaeological and geophysical observations and new radiocarbon dating of marine and terrestrial fossil fauna. The resul…
Environmental changes during the Upper Pleistocene–Holocene in Mediterranean NE Spain as recorded by the mineralogy and geochemistry of alluvial reco…
2013
Abstract Landscape evolution and environmental conditions from Last Glacial Maximum (LGM) to Late Holocene times were reconstructed from the mineralogical and geochemical characteristics of the alluvial morphochronostratigraphy, recorded in Bardenas Reales Natural Park (Ebro Basin, NE Spain). Alluvial architecture includes a LGM-Holocene gravelly unit (≈22–9 ka BP), a Lower Holocene silty–muddy unit (≈9–7 ka BP), and an Upper Holocene sandy unit (≈5–0.1 ka BP). Increases in illite–smectite mixed layers, kaolinite, chlorite and modified Chemical Index of Alteration (CIA*), as well as the decrease in illite FWHM(E), are indicators of minor increases in the chemical weathering of the alluvial …
The arid–humid transition in the Sahara and the Sahel during the last deglaciation
1990
At the time of the Last Glacial Maximum, the Sahara and Sahel regions of North Africa were extremely dry. New records of rainfall show that during the subsequent deglaciation, the transition from arid to humid conditions in these regions occurred synchronously in two main steps. Comparison with other records of palaeoclimate in Europe and the North Atlantic Ocean shows that certain common factors controlled changes in ocean and atmosphere dynamics during the deglaciation.
Neoendemic ground beetles and private tree haplotypes: two independent proxies attest a moderate last glacial maximum summer temperature depression o…
2011
Abstract Previous findings regarding the Last Glacial Maximum LGM summer temperature depression (maxΔT in July) on the Tibetan Plateau varied over a large range (between 0 and 9 °C). Geologic proxies usually provided higher values than palynological data. Because of this wide temperature range, it was hitherto impossible to reconstruct the glacial environment of the Tibetan Plateau. Here, we present for the first time data indicating that local neoendemics of modern species groups are promising proxies for assessing the LGM temperature depression in Tibet. We used biogeographical and phylogenetic data from small, wingless edaphous ground beetles of the genus Trechus , and from private junip…
Phylogeographic analysis of the red seaweed Palmaria palmata reveals a Pleistocene marine glacial refugium in the English Channel
2005
Phylogeography has provided a new approach to the analysis of the postglacial history of a wide range of taxa but, to date, little is known about the effect of glacial periods on the marine biota of Europe. We have utilized a combination of nuclear, plastid and mitochondrial genetic markers to study the biogeographic history of the red seaweed Palmaria palmata in the North Atlantic. Analysis of the nuclear rDNA operon (ITS1-5.8S-ITS2), the plastid 16S-trnI-trnA-23S-5S, rbcL-rbcS and rpl12-rps31-rpl9 regions and the mitochondrial cox2-3 spacer has revealed the existence of a previously unidentified marine refugium in the English Channel, along with possible secondary refugia off the southwes…
The Carpathians as a Major Diversity Hotspot in Europe
2011
The Carpathians are one of the major mountain ranges of Europe, but still one of its least studied regions. It is increasingly recognized that they played a major role in the formation and Pleistocene survival of numerous continental, arctic, and arctic–alpine taxa. Many endemic taxa have been described from these mountains. The number of phylogeographic/phylogenetic studies covering at least partially the Carpathians is also increasing. These studies reveal unevenly distributed genetic and taxonomic diversity. In this work, we analyse population genetic structures in the Carpathians revealed by case studies on aquatic insects, comparing them to existing literature data on plants, butterfli…
Eolian sedimentation in central European Auel dry maar from 60 to 13 ka
2021
AbstractThe climate in central Europe during the last 60 ka is characterized by rapid temperature and moisture changes and strong cold periods (Heinrich events). All these variations are preserved in sediments of marine and also some terrestrial archives. Here we present a continuous, terrestrial sediment record with almost all Greenland stadials and Heinrich events between 60 and 13 ka visible from carbonate roundness of the Eifel Laminated Sediment Archive Dust Stack-20 and CaCO3 data for central Europe. The carbonate roundness data show almost all stadials between 60 and 13 ka. CaCO3 data show a general transport system change with the beginning of Heinrich event 3. Since there are no ca…
Sea-level changes during the last 41,000 years in the outer shelf of the southern Tyrrhenian Sea: Evidence from benthic foraminifera and seismostrati…
2011
Abstract An integrated high resolution study based both on a seismostratigraphic approach and on a sedimentary core (VIB 10), collected in the outer shelf (127 m depth) from the southern Tyrrhenian Sea (Gulf of Termini, Sicily), provides new data about climatic, eustatic and paleoenvironmental changes during the last ∼41,000 years. The results based on the interpretation of a seismic profile, on benthic foraminifera assemblages and on δ18O records, allowed recognition of two drastic sea-level falls during the Last Glacial Maximum (LGM) and the Younger Dryas (YD). The short deglacial event, between LGM and YD, known as Bolling/Allerod, played an important role in the sea-level rise that prod…
Regional climate model simulations for Europe at 6 and 0.2 k BP: sensitivity to changes in anthropogenic deforestation
2014
International audience; This study aims to evaluate the direct effects of anthropogenic deforestation on simulated climate at two contrasting periods in the Holocene, ∼ 6 and ∼ 0.2 k BP in Eu-rope. We apply the Rossby Centre regional climate model RCA3, a regional climate model with 50 km spatial resolution, for both time periods, considering three alternative descriptions of the past vegetation: (i) potential natural vegetation (V) simulated by the dynamic vegetation model LPJ-GUESS, (ii) potential vegetation with anthro-pogenic land use (deforestation) from the HYDE3.1 (History Database of the Global Environment) scenario (V + H3.1), and (iii) potential vegetation with anthropogenic land …