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Late Glacial (late + glacial)
Selected AbstractsPast distribution and ecology of the cork oak (Quercus suber) in the Iberian Peninsula: a pollen-analytical approachDIVERSITY AND DISTRIBUTIONS, Issue 1 2000J. S. Carrión Abstract., This study presents pollen-analytical data from continental and offshore Iberian Peninsula sites that include pollen curves of Quercus suber, to provide information on the past distribution and ecology of the cork oak (Q. suber). Results centre on a new pollen record of Navarrés (Valencia, eastern Spain), which shows that the cork oak survived regionally during the Upper Pleistocene and was important during a mid-Holocene replacement of a local pine forest by Quercus -dominated communities. This phenomenon appears linked to the recurrence of fire and reinforces the value of the cork oak for reforestation programmes in fire-prone areas. In addition to Navarrés, other Late Quaternary pollen sequences (Sobrestany, Casablanca-Almenara, Padul, SU 8103, SU8113, 8057B) suggest last glacial survival of the cork oak in southern and coastal areas of the Peninsula and North Africa. Important developments also occur from the Late Glacial to the middle Holocene, not only in the west but also in the eastern Peninsula. It is suggested that, in the absence of human influence, Q. suber would develop in non-monospecific forests, sharing the arboreal stratum both with other sclerophyllous and deciduous Quercus and Pinus species. [source] Geoarchaeology and late glacial landscapes in the western lake superior region, Central North AmericaGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 1 2007Christopher L. Hill The transition from full glacial to interglacial conditions along the southern margin of the Laurentide ice sheet resulted in dramatic changes in landscapes and biotic habitats. Strata and landforms resulting from the Wisconsin Episode of glaciation in the area directly west of Lake Superior indicate a context for late Pleistocene biota (including human populations) connected to ice margins, proglacial lakes, and postglacial drainage systems. Late Glacial landscape features that have the potential for revealing the presence of Paleoindian artifacts include abandoned shorelines of proglacial lakes in the Superior and Agassiz basins and interior drainages on deglaciated terrains. The linkage between Late Pleistocene human populations and Rancholabrean fauna has yet to be demonstrated in the western Lake Superior region, although isolated remains of mammoth ( Mammuthus) have been documented, as well as fluted points assigned to Clovis, Folsom, and Holcombe-like artifact forms. Agate Basin and Hell Gap (Plano-type) artifacts also imply the presence of human groups in Late Glacial landscapes associated with the Agassiz and Superior basins. İ 2007 Wiley Periodicals, Inc. [source] Fossil evidence and phylogeography of temperate species: ,glacial refugia' and post-glacial recolonizationJOURNAL OF BIOGEOGRAPHY, Issue 11 2009Robert S. Sommer Abstract We present a short synthesis of the Pleistocene distribution dynamics and phylogeographic recolonization hypotheses for two temperate European mammal species, the red deer (Cervus elaphus) and the roe deer (Capreolus capreolus), for which high-resolution patterns of fossil evidence and genetic data sets are available. Such data are critical to an understanding of the role of hypothesized glacial refugia. Both species show a similar pattern: a relatively wide distribution in the southern part of Central Europe 60,000,25,000 years ago, and a strong restriction to areas in southern Europe for nearly 10,000 years during the Last Glacial Maximum (LGM) and the early Late Glacial (25,000,14,700 years ago). With the beginning of Greenland Interstadial 1 (Bĝlling/Allerĝd warming, c. 14,700,11,600 years ago) a sudden range expansion into Central Europe is visible, but the colonization of most of Central Europe, including the northern European Lowlands, only began in the early Holocene. In a European context, regions where the species were distributed during the LGM and early Late Glacial are most relevant as potential origins of recolonization processes, because during these c. 10,000 years distribution ranges were smaller than at any other time in the Late Quaternary. As far as the present distribution of temperate species and their genetic lineages is concerned, so-called ,cryptic refugia' are important only if the species are actually confirmed there during the LGM, as otherwise they could not possibly have contributed to the recolonization that eventually resulted in the present distribution ranges. [source] Distribution and genesis of Fahlerden (Albeluvisols) in GermanyJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2006Peter Kühn Abstract Fahlerden dominate large areas of the young and old moraine landscapes of N and E Germany. Fahlerden (part of Fahlerden corresponds to Albeluvisols) and their transitional subtypes are supposed to have a higher intensity of clay illuviation than Parabraunerden (Luvisols). Besides this macroscopic feature reflecting periglacial influence, micromorphological features such as lenticular platy microstructure, vesicles, and fragments of clay coatings in Bt streaks document the initiation of Fahlerde genesis, which began in the Late Glacial. A model of Fahlerde genesis chronologically connects sedimentological and periglacial processes, vegetation development, and soil-forming processes like decalcification, clay illuviation, and humification. The classification criterion of larger differences in clay contents between E and Bt horizons to distinguish Fahlerden from Parabraunerden needs to be reconsidered, because most Fahlerden have developed in stratified parent material in periglacially influenced landscapes. The interpretation of a soil data base listing data of both soil types distributed in Brandenburg demonstrates that the difference in clay contents between E and Bt horizons may even be smaller in Fahlerden than in Parabraunerden. [source] THE TRAVERSETTE (ITALIA) ROCKFALL: GEOMORPHOLOGICAL INDICATOR OF THE HANNIBALIC INVASION ROUTE*ARCHAEOMETRY, Issue 1 2010W. C. MAHANEY Numerous small, low volume rockfalls around the crest of the Italian and French Alps, principally formed from calcareous mica schist and metabasalt, have impeded travel across the major cols for millennia. As documented by Polybius and Livy in the ancient literature, Hannibal's Army was blocked by a two-tier rockfall on the lee side of the Alps, a rubble sheet of considerable volume that delayed his exit into the upper Po River Country. An in-depth study of the possible cols reveals that the only such two-tier landform lies below the Col de la Traversette, at ,2600 m above sea level. In addition, it represents a problem in applied geomorphology, namely, to accurately determine the nature of the surface rubble sheet in Hannibal's time (218 bc). A reconstruction of the initial deposit, likely Late Glacial, following the retreat of the Po Glacier, is based upon an analysis of the source rock and geological setting. Further specifications on the geometry of the Neoglacial cover sediment are based on weathering characteristics, lichen cover and soil development. The ,myth' that Hannibal fired the rockfall to comminute boulders is plausible given the vegetation records which support tree growth nearby, but is unsubstantiated by the lack of any carbonized rock. [source] Putative glacial refugia of Cedrus atlantica deduced from Quaternary pollen records and modern genetic diversityJOURNAL OF BIOGEOGRAPHY, Issue 7 2009R. Cheddadi Abstract Aim, To investigate the impact of past environmental changes on Cedrus atlantica and its current genetic diversity, and to predict its future distribution. Location, Morocco, Algeria and Tunisia. Methods, Eleven fossil pollen records from these three countries were used to locate putative glacial refugia and to reconstruct past climate changes. A mechanistic vegetation distribution model was used to simulate the distribution of C. atlantica in the year 2100. In addition, a genetic survey was carried out on modern Moroccan C. atlantica. Results, Pollen records indicate that Cedrus was present during the last glacial period, probably in scattered refugia, in Tunisia, Algeria and Morocco. In the Tunisian and Algerian sites, cedar expanded during the late glacial and the early Holocene, then disappeared after c. 8000 yr bp. Reconstructed mean annual precipitation and January temperature show that the last glacial period in Morocco was cooler by 10,15°C and drier by c. 300,400 mm year,1 than the climate today. Modern chloroplast microsatellites of 15 C. atlantica populations in Morocco confirm the presence of multiple refugia and indicate that cedar recolonized the Moroccan mountains fairly recently. Model simulation indicates that by the year 2100 the potential distribution of C. atlantica will be much restricted with a potential survival area located in the High Atlas. Main conclusions, Environmental changes in northern Africa since the last glacial period have had an impact on the geographical distribution of C. atlantica and on its modern genetic diversity. It is possible that by the end of this century C. atlantica may be unable to survive in its present-day locations. To preserve the species, we suggest that seedlings from modern C. atlantica populations located in the High Atlas mountains, where a high genetic diversity is found, be transplanted into the western High Atlas. [source] | |||||||||||||