ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
  • 1
    Electronic Resource
    Electronic Resource
    A simple, inexpensive piston corer for collecting undisturbed sediment/water interface profiles (1992)
    Springer
    Journal of paleolimnology 7 (1992), S. 157-161 
    Details
    ISSN: 1573-0417
    Keywords: coring device ; paleolimnology ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196870
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Low-background gamma counting: applications for210Pb dating of sediments (1994)
    Springer
    Journal of paleolimnology 10 (1994), S. 115-128 
    Details
    ISSN: 1573-0417
    Keywords: radiometric ; chronology ; 210Pb ; 226Ra ; 137Cs ; Lake ; paleolimnology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Sediment cores from three lakes were dated with210Pb using a constant rate of supply (CRS) model. We used low-background gamma counting to measure naturally occurring levels of210Pb,226Ra, and137Cs in sediment samples because sample preparation is simple and non-destructive,226Ra activity provides a direct measure of supported210Pb activity for each sample analyzed, and137Cs activity may provide an independent age marker for the 1962–1963 peak in atmospheric fallout of this radionuclide. In one core supported210Pb activity was estimated equally well from226Ra activity of each sampling interval or from the mean total210Pb activity of constant activity samples at depth. Supported210Pb activity was constant with depth in this core. In a short freeze core, determining226Ra activity of every sample proved advantageous in estimating supported210Pb activity because supported210Pb activity could be estimated from210Pb measurements only at the deepest sampling interval. Supported210Pb activity estimated from226Ra activity also yielded more precise estimates of highly variable sedimentation rates. In the third core226Ra activity exceeded210Pb activity at the top of the core and varied 20 fold with depth. This high input of226Ra in disequilibrium with210Pb is attributed to recent erosion of radium-bearing materials in the drainage basin. These data invalidate the assumption that supported210Pb activity is constant in sediment cores and can be estimated from the mean total210Pb activity at depths where210Pb activity is constant. We recommend using gamma counting or another independent assay of226Ra to validate the assumption of constant supported210Pb activity in sediment cores if there is reason to expect that226Ra activity varies with depth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00682508
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Recent sedimentary histories of shallow lakes in the guatemalan savannas (1990)
    Springer
    Journal of paleolimnology 4 (1990), S. 239-252 
    Details
    ISSN: 1573-0417
    Keywords: Guatemala ; paleolimnology ; pollen ; 210Pb ; savannas ; sediment geochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Shallow basins in the savannas of Peten, Guatemala filled with water after 305±55 BP (calibrated age+1430–1660 AD). Aguadas Chimaj and Chilonche possess dilute waters and iron-rich, clayey sediments that are poor in Ca and Mg, reflecting the highly weathered nature of riparian soils. Low 210Pb flux rates to Chimaj (0.085 pCi cm-2 yr-1) and Chilonche (0.134 pCi cm-2 yr-1) are attributed to low 222Rn emission rates from the nearby Caribbean Sea. Mean sediment accumulation rates in Chimaj and Chilonche for the past 150 years are 0.015 g cm-2 yr-1 and 0.047 g cm-2 yr-1 respectively. Forest expansion after 305 BP is documented in pollen profiles from the small aguadas and larger Lake Oquevix. Regional reforestation postdates the 9th century Classic Maya collapse and coincides with indigenous depopulation that was a consequence of European intrusion that began in the early 1500s. The timing of forest regrowth indicates the importance of historical anthropogenic factors in controlling Peten's vegetation. Nevertheless, other sedimentological lines of evidence (e.g. lithology, algal remains and charcoal particles) suggest that changing climate and/or local hydrology may have played a role in the reforestation process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239697
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Paleolimnology of Qilu Hu, Yunnan Province, China (1991)
    Springer
    Hydrobiologia 214 (1991), S. 333-340 
    Details
    ISSN: 1573-5117
    Keywords: China ; limnology ; paleolimnology ; Pleistocene ; sediment geochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Qilu Hu is a large (A = 36.9 km2), shallow (zmax = 6.8 m) lake that lies at an elevation of 1797 m above msl on the Yunnan Plateau, southern China. Lake waters are hard (Mg = 3.2m eq L−1, Ca = 1.3 meq L−1 ), fresh (conductivity = 380 μS cm −1), and productive (Secchi 〈 40 cm). An 11-m sediment core has a basal 14C age of 30960 ± 860 B.P. Sediments between 11 m and 6 m are high in % dry weight, rich in clay components Al2O3, Fe2O3, K2O, MgO, and low in organic C (≤6.1%), carbonate-C (〈1.0%), total N (〈3.2 mg g−1), and total S (〈-1.7 mg g−1). Diatoms and pollen indicate open-water conditions between 9.0 m and 6.0 m (1342011790 B.P.). Above 6.0 m, CaCO3 and organic matter concentrations increase relative to clastics. The transition marks a change to shallow-water conditions as inferred from diatoms and pollen, and probably reflects a shift to drier climate. Uppermost (80-0 cm) red clays were deposited rapidly, probably as a consequence of recent (decades to centuries) riparian disturbances (e.g. agriculture, lake-bottom reclamation, urban development). Dates assigned to events in the Qilu Hu profile are tentative because of potential hard-water-lake error.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00050968
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...