29 research outputs found
The acheulean handaxe : More like a bird's song than a beatles' tune?
© 2016 Wiley Periodicals, Inc. KV is supported by the Netherlands Organization for Scientific Research. MC is supported by the Canada Research Chairs Program, the Social Sciences and Humanities Research of Canada, the Canada Foundation for Innovation, the British Columbia Knowledge Development Fund, and Simon Fraser UniversityPeer reviewedPublisher PD
What do dust sinks tell us about their sources and past environmental dynamics? A case study for oxygen isotope stages 3â2 in the Middle Rhine Valley, Germany
The study of geological archives of dust is of great relevance as they are
directly linked to past atmospheric circulation and bear the potential to
reconstruct dust provenance and flux relative to climate changes. Among the
dust sinks, loessâpalaeosol sequences (LPSs) represent the only continental
and non-aquatic archives that are predominantly built up by dust deposits
close to source areas, providing detailed information on Quaternary climatic
and terrestrial environmental changes. Upper Pleistocene LPSs of western
central Europe have been investigated in great detail showing their linkage
to millennial-scale northern hemispheric climate oscillations, but
comprehensive data on dust composition and potential sourceâsink
relationships as well as inferred past atmospheric circulation patterns for
this region are still fragmentary.
Here, we present an integrative approach that systematically combines
sedimentological, rock magnetic, and bulk geochemical data, as well as information
on Sr and Nd isotope composition, enabling a synthetic interpretation of LPS formation. We focus on the Schwalbenberg RP1 profile in the Middle Rhine
Valley in Germany and integrate our data into a robust age model that has
recently been established based on high-resolution radiocarbon dating of
earthworm calcite granules. We show that Schwalbenberg RP1 is subdivided
into a lower section corresponding to late oxygen isotope stage 3 (OIS; âŒâ40â30âka)
and an upper section dating into the Last Glacial Maximum (LGM; âŒâ24â22âka),
separated by a major stratigraphic unconformity. Sedimentological proxies of
wind dynamics (UÂ ratio) and pedogenesis (finest clay) of the lower section
attest to comparable and largely synchronous patterns of northern
hemispheric climatic changes supporting the overall synchronicity of
climatic changes in and around the North Atlantic region. The anisotropy of
magnetic susceptibility (AMS) reveals a clear correlation between finer
grain size and increasing AMS foliation within interstadials, possibly owing
to continuous accumulation of dust during pedogenic phases. Such a clear
negative correlation has so far not been described for any LPS on
stadialâinterstadial scales.
Distinct shifts in several proxy data supported by changes in isotope
composition (87Sr/86Sr and ΔNd) within the lower
section are interpreted as changes in provenance and decreasing weathering
simultaneously with an overall cooling and aridification towards the end of
OIS 3 (after âŒâ35âka) and enhanced wind activity with
significant input of coarse-grained material recycled from local sources
related to increased landscape instability (after âŒâ31.5âka).
We find that environmental conditions within the upper section, most likely
dominated by local to regional environmental signals, significantly differ
from those in the lower section. In addition, AMS-based reconstructions of
near-surface wind trends may indicate the influence of north-easterly winds
beside the overall dominance of westerlies. The integrative approach
contributes to a more comprehensive understanding of LPS formation including
changes in dust composition and associated circulation patterns during
Quaternary climate changes.</p
Natur oder Kultur? Zur Frage ÀltestpalÀolithischer Artefaktensembles aus Haupterrassenschottern in Deutschland
Natur oder Kultur? Zur Frage ÀltestpalÀolithischer Artefaktensembles aus Haupterrassenschottern in Deutschland
Wetensch. publicatieFaculty of Archeolog
Evidence for Neanderthal hand preferences from the Late Middle Palaeolithic site of Buhlen, Germany: insights into Neanderthal learning behaviour
Bifacially backed knives (âKeilmesserâ) are known from different European Middle Palaeolithic contexts. However, this specific tool type is both so characteristic of and so frequent within Central and Eastern European late Middle Palaeolithic bifacial assemblages which are generally classed together as âMicoquianâ that they should more appropriately be described by the term âKeilmessergruppenâ (KMG). The KMG sites of Central Europe date into late OIS 5 until mid-OIS 3
Millennial-scale Land-surface Temperature and Soil Moisture Reconstruction Derived From Last Glacial European Loess Sequences
The warm and relatively stable Holocene climate was preceded by a pronounced event of abrupt warming in the Northern Hemisphere, the termination of the Younger Dryas cold period1,2. While this transition has been intensively studied, its imprint on low latitude ocean temperature is still controversial and its effects on sub-annual to decadal climate variability remain poorly understood1,3,4. We applied the extraordinary resolution provided by mass spectrometry imaging of long-chain alkenones5,6 to sediments from the tropical Cariaco Basin7, and reveal that the seasonal amplitude of reconstructed sea surface temperature increased more than twofold during the transition into the Holocene, while average temperature was not altered. We further observe modulations in interannual sea surface temperature variability that we attribute to a muting of the El Niño-Southern Oscillation at the end of the Younger Dryas, and a subsequent intensification during the early Holocene. These dynamics are consistent with the modeled interplay of meltwater and ice sheet forcing and suggest that climate recovery in the Pacific preceded the North Atlantic Younger Dryas-Holocene transition. Our results demonstrate that the abrupt changes that completed the most recent glacial to interglacial transition had pronounced effects on sub-and interannual climate variability in the Tropical North AtlanticThis preprint is Under Review at Nature Portfolio
The catastrophic final flooding of Doggerland by the Storegga Slide Tsunami.
Around 8200 calBP, large parts of the now submerged North Sea continental shelf (âDoggerlandâ) were catastrophically flooded by the Storegga Slide tsunami, one of the largest tsunamis known for the Holocene, which was generated on the Norwegian coastal margin by a submarine landslide. In the present paper, we derive a precise calendric date for the Storegga Slide tsunami, use this date for reconstruction of contemporary coastlines in the North Sea in relation to rapidly rising sea-levels, and discuss the potential effects of the tsunami on the contemporaneous Mesolithic population. One main result of this study is an unexpectedly high tsunami impact assigned to the western regions of Jutland