GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Document type
Publisher
Years
  • 1
    facet.materialart.
    Unknown
    Geochemical evidence of the 8.2 ka event and other Holocene environmental changes recorded in paleolagoon sediments, southeastern Brazil (2011)
    Cambridge University Press
    Details
    Publication Date: 2011-11-23
    Description: Publication year: 2011 Source: Quaternary Research, Available online 21 November 2011 Alethéa E.M. Sallun, William Sallun Filho, Kenitiro Suguio, Marly Babinski, Simone M.C.L. Gioia, ... The paleoclimatic record of Juréia Paleolagoon, coastal southeastern Brazil, includes cyclic and gradual changes with different intensities and frequencies through geological time, and it is controlled by astronomical, geophysical, and geological phenomena. These variations are not due to one single cause, but they result from the interaction of several factors, which act at different temporal and spatial scales. Here, we describe paleoenvironmental evidence regarding climatic and sea level changes from the last 9400 cal yr BP at the Juréia Paleolagoon — one of the main groups of protected South Atlantic ecosystems. Geochemical evidences were used to identify anomalies from multi-proxy analyses of a paleolagoon sediment core. The anomalies of centennial scale were correlated to climate and transgression–regression cycles from the Holocene period. Decadal scale anomalous oscillations in the Quaternary paleolagoon sediments occur between 9400 and 7500 cal yr BP, correlated with long- and short-term natural events, which generated high sedimentation rates, mainly between 8385 and 8375 cal yr BP (10 cm/yr). Our results suggest that a modern-day short-duration North Atlantic climatic event, such as the 8.2 ka event, could affect the environmental equilibrium in South America and intensify the South American Summer Monsoon.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Impact of fire on long-term vegetation dynamics of ombrotrophic peatlands in northwestern Québec, Canada (2011)
    Cambridge University Press
    Details
    Publication Date: 2011-11-22
    Description: Publication year: 2011 Source: Quaternary Research, Available online 20 November 2011 Gabriel Magnan, Martin Lavoie, Serge Payette A 7000-year record of local fire history was reconstructed from three ombrotrophic peatlands in the James Bay lowlands (northwestern Québec, Canada) using a high-resolution analysis of macroscopic charcoal (long axis ≥ 0.5 mm). The impact of fire on vegetation changes was evaluated using detailed analysis of plant macrofossils. Compared to upland boreal forest, fire incidence in theseSphagnum-dominated bogs is rather low. Past fire occurrence seems to have been controlled primarily by internal processes associated with local hydroseral succession. Size of the peatland basin and distance from the well-drained forest soils also appear to be factors controlling fire occurrence. The impact of peatland fires on long-term vegetation succession appears negligible except in a forested bog, where it initiated the replacement ofSphagnumby mosses. In some circumstances, fire caused marked changes in the bryophyte assemblages over many decades. However, ombrotrophic peatland vegetation is generally resilient to surface fire.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Mid-Holocene climate change and its effect on prehistoric cultural evolution in eastern Qinghai Province, China (2011)
    Cambridge University Press
    Details
    Publication Date: 2011-11-18
    Description: Publication year: 2011 Source: Quaternary Research, Available online 17 November 2011 Guanghui Dong, Xin Jia, Chengbang An, Fahu Chen, Yan Zhao, ... We studied the mid-Holocene climate change in eastern Qinghai Province, China and its impact on the evolution of Majiayao (3980–2050 BC) and Qijia (2183–1635 BC) cultures, near the important Neolithic site of Changning. The investigation focused on analyses of grain size, magnetic susceptibility, ratios of elemental contents, and pollen assemblage from a loess–paleosol sequence. The results indicate that the climate was wet during 5830–4900 cal yr BP, which promoted the development of early-mid Majiayao culture in eastern Qinghai Province. However, 4900–4700 cal yr BP were drought years in the region, responsible for the decline and eastward movement of prehistoric culture during the period of transition from early-mid to late Majiayao culture. The climate turned wet again during 4700–3940 cal yr BP, which accelerated the spread of Qijia culture to the middle reaches of the Huangshui River, including the Changning site.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Marine radiocarbon reservoir corrections (∆R) for Chesapeake Bay and the Middle Atlantic Coast of North America (2011)
    Cambridge University Press
    Details
    Publication Date: 2011-12-04
    Description: Publication year: 2011 Source: Quaternary Research, Available online 2 December 2011 Torben C. Rick, Gregory A. Henkes, Darrin L. Lowery, Steven M. Colman, Brendan J. Culleton Radiocarbon dates from known age, pre-bomb eastern oyster (Crassostrea virginica) shells provide local marine reservoir corrections (∆R) for Chesapeake Bay and the Middle Atlantic coastal area of eastern North America. These data suggest subregional variability in ∆R, ranging from 148 ± 46C yr on the Potomac River to − 109 ± 38C yr at Swan Point, Maryland. The ∆Rweighted mean for the Chesapeake's Western Shore (129 ± 22C yr) is substantially higher than the Eastern Shore (− 88 ± 23C yr), with outer Atlantic Coast samples falling between these values (106 ± 46 and 2 ± 46C yr). These differences may result from a combination of factors, includingC-depleted freshwater that enters the bay from some if its drainages,C-depleted seawater that enters the bay at its mouth, and/or biological carbon recycling. We advocate using different subregional ∆Rcorrections when calibratingC dates on aquatic specimens from the Chesapeake Bay and coastal Middle Atlantic region of North America.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Cool, wet conditions late in the Younger Dryas in semi-arid New Mexico (2011)
    Cambridge University Press
    Details
    Publication Date: 2011-12-05
    Description: Publication year: 2011 Source: Quaternary Research, Available online 3 December 2011 Stephen A. Hall, William L. Penner, Manuel R. Palacios-Fest, Artie L. Metcalf, Susan J. Smith A thick alluvial sequence in central New Mexico contains the Scholle wet meadow deposit that traces upstream to a paleospring. The wet meadow sediments contain an abundant fauna of twenty-one species of freshwater and terrestrial mollusks and ten species of ostracodes. The mollusks and ostracodes are indicative of a local high alluvial water table with spring-supported perennial flow but without standing water. Pollen analysis documents shrub grassland vegetation with sedges, willow, and alder in a riparian community. Stable carbon isotopes from the wet meadow sediments have δC values ranging from − 22.8 to − 23.3‰, indicating that 80% of the organic carbon in the sediment is derived from C3species. The wet meadow deposit is AMS dated 10,400 to 9700 C yr BP, corresponding to 12,300 to 11,100 cal yr BP and overlapping in time with the Younger Dryas event (YD). The wet meadow became active about 500 yr after the beginning of the YD and persisted 400 yr after the YD ended. The Scholle wet meadow is the only record of perennial flow and high water table conditions in the Abo Arroyo drainage basin during the past 13 ka.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Frequency and intensity of high-altitude floods over the last 3.5 ka in northwestern French Alps (Lake Anterne) (2011)
    Cambridge University Press
    Details
    Publication Date: 2011-12-05
    Description: Publication year: 2011 Source: Quaternary Research, Available online 3 December 2011 Charline Giguet-Covex, Fabien Arnaud, Dirk Enters, Jérôme Poulenard, Laurent Millet, ... In central Western Europe, several studies have shown that colder Holocene periods, such as the Little Ice Age, also correspond to wet periods. However, in mountain areas which are highly sensitive to erosion processes and where precipitation events can be localized, past evolution of hydrological activity might be more complicated. To assess these past hydrological changes, a paleolimnological approach was applied on a 13.4-m-long sediment core taken in alpine Lake Anterne (2063 m asl) and representing the last 3.5 ka. Lake sedimentation is mainly composed of flood deposits triggered by precipitation events. Sedimentological and geochemical analyses show that floods were more frequent during cold periods while high-intensity flood events occurred preferentially during warmer periods. In mild temperature conditions, both flood patterns are present. This underlines the complex relationship between flood hazards and climatic change in mountain areas. During the warmer and/or dryer times of the end of Iron Age and the Roman Period, both the frequency and intensity of floods increased. This is interpreted as an effect of human-induced clearing for grazing activities and reveals that anthropogenic interferences must be taken into account when reconstructing climatic signals from natural archives.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Burning peat and reworking loess contribute to the formation and evolution of a large Carolina-bay basin (2011)
    Cambridge University Press
    Details
    Publication Date: 2011-12-05
    Description: Publication year: 2011 Source: Quaternary Research, Available online 3 December 2011 Antonio B. Rodriguez, Matthew N. Waters, Michael F. Piehler Carolina bays are nearly ubiquitous along ~ 1300 km of the North American Atlantic Coastal Plain, but relatively few bays have been examined in detail, making their formation and evolution a topic of controversy. The Lake Mattamuskeet basin, eastern North Carolina, USA, is a conglomeration of multiple Carolina bays that form a 〉 162 kmlake. The eastern shoreline of the lake is made up of a 2.9-km-wide plain of parabolic ridges that recorded rapid shoreface progradation. The lower shoreface deposit contains abundant charcoal beds and laminae dated 6465–6863 cal yr BP, corresponding with initiation of a lacustrine environment in the eastern part of the lake. A core from the western part of the lake sampled a 1541–1633 cal yr BP charcoal bed at the base of the lacustrine unit, indicating formation of this part of the basin postdates the eastern basin. Lake Mattamuskeet has no relationship to the Younger Dryas or a linked impact event because rim accretion significantly postdates 12,000 cal yr BP. The shoreline progradation, and association of charcoal beds with the oldest lake sediment in both main parts of the basin, suggest that fire and subsequent hydrodynamic processes were associated with initial formation of these Carolina bays.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Provenance and climate change inferred from Sr–Nd–Pb isotopes of late Quaternary sediments in the Huanghe (Yellow River) Delta, China (2012)
    Cambridge University Press
    Details
    Publication Date: 2012-08-27
    Description: Publication year: 2012 Source: Quaternary Research Bangqi Hu, Guogang Li, Jun Li, Jianqiang Bi, Jingtao Zhao, Ruyuan Bu We present a provenance study of core ZK2 from the Huanghe (Yellow River) Delta in order to assess the impacts of climate change on the sediment supplies during the last glacial–interglacial cycle. Facies analysis and sequence stratigraphy methods are used to construct the age model. Sr isotopic compositions of ZK2 range from 0.716389 to 0.723884, with 87 Sr/ 86 Sr increased with decreasing grain size. Nd and Pb isotopic compositions display two large major excursions during Marine Oxygen Isotope stages (MIS) 2 and 4, with less radiogenic εNd and lower 208 Pb/ 204 Pb, 207 Pb/ 204 Pb, and 206 Pb/ 204 Pb values during these periods. These excursions have been explained in terms of changes in the mixing proportion of sediments from the Loess Plateau and Ordos Plateau, resulting from East Asian monsoon intensity variations. The weak summer monsoon precipitation resulted in decreased erosion of Loess Plateau during MIS 2, 4 and the middle of MIS 3. Meanwhile, both the intensified East Asian winter monsoon and the southward expansions of Mu Us desert significantly enhanced the eolian sand entering the Huanghe. Therefore, our results highlight the impact of monsoon variability on erosion patterns in the Huanghe basin.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Woody vegetation, fuel and fire track the melting of the Scandinavian ice-sheet before 9500calyrBP (2012)
    Cambridge University Press
    Details
    Publication Date: 2012-08-28
    Description: Publication year: 2012 Source: Quaternary Research Christopher Carcaillet, Greger Hörnberg, Olle Zackrisson New studies indicate the presence of early Holocene ice-free areas far north in Scandinavia. Post-glacial fire and vegetation were investigated based on sedimentary charcoal and pollen from two small lakes in northern Sweden. Accumulation of organic sediment started around 10,900 and 9200 cal yr BP, showing that both lake valleys were ice-free extremely early given their northerly location. Fire events started after 9600 cal yr BP and became less common around the ‘8.2-ka event’. Woody vegetation provided fuel that contributed to fires. The first vegetation in our pollen record consisted of Hippophae , Dryas , grasses and sedges. Subsequently broadleaved trees ( Betula , Salix ) increased in abundance and later Pinus , Alnus , ferns and Lycopodium characterized the vegetation. Pollen from Larix , Picea and Malus were also found. The change in vegetation composition was synchronous with the decrease in lake-water pH in the region, indicating ecosystem-scale processes; this occurred during a period of net global and regional warming. The changes in fire frequency and vegetation appear independent of regional trends in precipitation. The reconstructed fire history and vegetation support the scenario of early ice-free areas far north in Scandinavia during early Holocene warming, creating favorable conditions for woody plants and wildfires.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    A 14,000year vegetation history of a hypermaritime island on the outer Pacific coast of Canada based on fossil pollen, spores and conifer stomata (2012)
    Cambridge University Press
    Details
    Publication Date: 2012-09-25
    Description: Publication year: 2012 Source: Quaternary Research Terri Lacourse, J. Michelle Delepine, Elizabeth H. Hoffman, Rolf W. Mathewes Pollen and conifer stomata analyses of lake sediments from Hippa Island on the north coast of British Columbia were used to reconstruct the vegetation history of this small hypermaritime island. Between 14,000 and 13,230 cal yr BP, the island supported diverse herb–shrub communities dominated by Cyperaceae, Artemisia and Salix . Pinus contorta and Picea sitchensis stomata indicate that these conifers were present among the herb–shrub communities, likely as scattered individuals. Transition to open P. contorta woodland by 13,000 cal yr BP was followed by increases in Alnus viridis , Alnus rubra and P. sitchensis . After 12,000 cal yr BP, Pinus -dominated communities were replaced by dense P. sitchensis and Tsuga heterophylla forest with Lysichiton americanus and fern understory. Thuja plicata stomata indicate that this species was present by 8700 cal yr BP, but the pollen record suggests that its populations did not expand to dominate regional rainforests, along with Tsuga and Picea , until after 6600 cal yr BP. Conifer stomata indicate that species may be locally present for hundreds to thousands of years before pollen exceed thresholds routinely used to infer local species arrival. When combined, pollen and conifer stomata can provide a more accurate record of paleovegetation than either when used alone.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Published by Cambridge University Press
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...