Search results for "Glacial period"
showing 10 items of 196 documents
Late Pleistocene to Early Holocene natural and human influenced sediment dynamics and soil formation in a 0-order catchment in SW-Germany (Palatinate…
2013
This paper presents the dynamics of sedimentation processes and soil development of a steeply sloping 0-order catchment in the sandy Lower Bunter of the south-western mid-range mountains in the Palatinate Forest (Germany) during the transition period from the Late Glacial to the Early Holocene. Field investigations, chemical, physical, micromorphological and anthracological analyses revealed a complex palaeosol-sediment sequence along the thalweg of a dry valley, where a significant amount of the sediment from the adjacent slopes had been captured. The deposition of aeolian sands in the lowermost sediment layer took place in the early Late Glacial. The subsequent sediments were deposited by…
The origin and glaciodynamic significance of sandstone ridge networks from the Hirnantian glaciation of the Djado Basin (Niger)
2007
The Djado Basin (Niger) was located beneath the inner part of the Late Ordovician ice sheet. The Felar-Felar Formation consists mainly of glaciomarine deposits, associated with the major ice sheet recession within the glaciation, and is bounded by two glacial unconformities. Structures corresponding to sandstone ridges are found within the Felar-Felar Formation. Sandstone ridges are several metres high, about 10 m wide and hundreds of metres long. These structures are organized in extensive anastomosed to subpolygonal networks. The association of sandstone ridge networks with the later glacial unconformity and with other glacial evidence suggests sub-glacial conditions for their origin. San…
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…
The palaeoecoloical potential of pollen records in caves: the case of Mediterranean Spain
1999
Abstract Important palynological sequences are reviewed from caves with archaeological interest in Mediterranean Spain. Upper Pleistocene sites include Abric Romani and Abric de l’Arbreda in NE Spain, and in SE Spain Cueva de la Carihuela, Cova Beneito, Cueva de Perneras, Cueva del Algarrobo and the Holocene Cova de l’Or and Cova de les Cendres. Carihuela has the longest sequence, starting in the last interglacial and covering most of the last glaciation. A pre-Wurm phase was followed by two glacial maxima separated by an interpleniglacial phase, and in the Lateglacial the Younger Dryas seems present. Whereas at Carihuela harsh pleniglacial conditions caused Mediterranean associations to di…
Palynology and lithostratigraphy of Late Elsterian to Early Saalian aquatic sediments in the Ziemupe–Jūrkalne area, western Latvia
2000
Abstract This study is based upon lithological and palynological investigation of test-drilling cores along the Baltic Sea coast. Three intertill units of basin sediments are underlain by a thin layer of Lētiža (Elsterian) till and overlain by glaciotectonically deformed Kurzeme (Saalian Complex) till. The Kurzeme till differs from the Lētiža till by higher contents of limestone clasts and rounded hornblende grains. The lowermost intertill unit consists of glaciolacustrine to glaciomarine laminated clay of the Sudrabi member, a late glacial deposit of the Lētiža glaciation. Treeless vegetation covered the adjoining land. Next is the marine to brackish Akme n rags formation, deposited during…
Late Quaternary vegetational history at Navarres, Eastern Spain. A two core approach
1996
summary Percentage and concentration pollen diagrams are presented for two cores (taken 5 m apart) at an upper Pleistocene and Holocene site at Navarres (Valencia, eastern Spain). Chronological information is provided by an internally consistent radiocarbon dating series that extends from c. 20700 to 3075 yr BP. The results highlight the dangers of relying on a single core in interpreting the patterns of variation of particular taxa. Significant palynological differences, seemingly locational, are described between the two cores. The upper Pleistocene records accords well with the widely recognized European sequence of (a) upper Pleniglacial, (b) Bolling-Allerod warm period, and (c) Younger…
A Cromerian Complex palaeolake sediment sequence from the Zidini site, south-eastern Latvia
2013
Abstract This study is based upon palaeobotanical reinvestigation of the Pleistocene deposit strata revealed by test drillings in the buried valley at the Zidini site, southeastern Latvia. Up to 100 m thick lake sediment strata covered by three different till layers have been found in three 120–171 m deep test drillings. New palynological and plant macroremain analysis for sediment samples from core No. 43 have been done. These results and data from the earlier investigations at Zidini were compared. Clearer insights into depositional environment and vegetation change during the accumulation of sediments in the palaeolake have been acquired. According to recent studies and correlation of ob…
27. A new holsteinian pollen record from the dry maar at Döttingen (Eifel)
2007
Abstract A new interglacial pollen sequence from the Dottingen dry maar in the Eifel region of the Rheinish Schield is presented. Palynology is used to correlate with several classical north German Holsteinian sites. The lake sediments reveal the complete interglacial and also 60 m of laminated sediments from the glacial preceding the Holsteinian. The interglacial section indicates limnic conditions in its lower part and telmatic conditions in its upper part with an intermediate episode of peat formation. Ash layers document intensive volcanism during the interglacial in the Eifel region. Some of the north German Holsteinian sites reveal spikes of high abundance of Pinus, Betula and Poaceae…
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…
Orbital variations in planktonic foraminifera assemblages from the Ionian Sea during the Middle Pleistocene Transition
2013
Abstract The Middle Pleistocene Transition (1.2–0.7 Ma) is the most recent re-organization of the global climate system which includes variations in the frequency and amplitude of glacial/interglacial cycles, increased ice sheet volume, sea surface temperature cooling and a significant drop in the CO 2 atmospheric levels. Here we present high-resolution planktonic foraminifera data (mean sampling resolution of about 780 years) from core LC10 recovered in the Ionian Sea (eastern Mediterranean), between 1.2 and 0.9 Ma. Selected taxa, among them G. ruber , T. quinqueloba and G. bulloides , show significant periodicities that can be associated to orbital cycles, mainly precession and obliquity.…