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  • Cambridge University Press (CUP)  (5)
  • 1
    Online Resource
    Online Resource
    A new approach to detecting vegetation and land-use Change using high-resolution lipid biomarker records in stalagmites
    Cambridge University Press (CUP) ; 2007
    In:  Quaternary Research Vol. 68, No. 3 ( 2007-11), p. 314-324
    Details
    In: Quaternary Research, Cambridge University Press (CUP), Vol. 68, No. 3 ( 2007-11), p. 314-324
    Abstract: A hundred-year stalagmite lipid biomarker record from Mechara, southeastern Ethiopia, is presented. The record has been recovered at a 10-yr temporal resolution, marking the first time this has been achieved in stalagmite biomarker work and providing the first opportunity to investigate the relationship between stalagmite lipid records and hydrological transport lags, a vital issue in interpreting palaeoenvironmental signals. Preserved plant-derived n -alkanes and n -alkanols show clear changes in composition over time, relating to known land-use changes in the area, particularly the expansion of agriculture in the early twentieth century. The level of environmental detail provided by this technique, combined with the long-term chronological framework offered by stalagmites, holds significant promise for the investigation of early human environments and their associated climatic and anthropogenic controls.
    Type of Medium: Online Resource
    ISSN: 0033-5894 , 1096-0287
    URL: Article
    DOI: 10.1016/j.yqres.2007.08.002
    RVK:
    RA 1000
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2007
    detail.hit.zdb_id: 1471589-2
    detail.hit.zdb_id: 205711-6
    SSG: 13
    SSG: 14
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  • 2
    Online Resource
    Online Resource
    Letter to the Editor: Comment on “a test of annual resolution in stalagmites using tree rings”
    Cambridge University Press (CUP) ; 2003
    In:  Quaternary Research Vol. 59, No. 3 ( 2003-05), p. 476-478
    Details
    In: Quaternary Research, Cambridge University Press (CUP), Vol. 59, No. 3 ( 2003-05), p. 476-478
    Type of Medium: Online Resource
    ISSN: 0033-5894 , 1096-0287
    URL: Article
    DOI: 10.1016/S0033-5894(03)00038-3
    RVK:
    RA 1000
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2003
    detail.hit.zdb_id: 1471589-2
    detail.hit.zdb_id: 205711-6
    SSG: 13
    SSG: 14
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  • 3
    Online Resource
    Online Resource
    Bomb 14 C Recorded in Laminated Speleothems: Calculation of Dead Carbon Proportion
    Cambridge University Press (CUP) ; 1997
    In:  Radiocarbon Vol. 39, No. 1 ( 1997), p. 33-48
    Details
    In: Radiocarbon, Cambridge University Press (CUP), Vol. 39, No. 1 ( 1997), p. 33-48
    Abstract: We performed radiocarbon measurements using accelerator mass spectrometry (AMS) on 6 stalagmites 3 stalactites and 7 seepage waters from four different caves in Southwest France and Belgium in order to calculate the dead carbon proportion (dcp). All the speleothems studied are modern and annually laminated, which offers the advantage of an accurate chronology, with better than one-year resolution. Coupled with the fact that very little calcite is necessary for an AMS measurement (between 1.5 and 7 yr of calcite deposit), we obtained dead carbon values within an uncertainty limit of ± 1.5%. Results show that the dead carbon proportion varies from 9.2% to 21.9% for calcite deposits and from 3.6% to 21.9% for water. In each sampling site, the dcp is homogeneous. Although the inter-site dcp varies by 〉 11%, its average value of 15.5% ± 4.4 still lies within the uncertainty range of the accepted value of 15% ± 5 (dilution factor of 0.85 ± 0.5). We compare the average dcp of each site with the local geology, vegetation and climate. Given similar geology and temperature the highest dcp values are found under forest cover; dcp difference is up to 9%. However, the Belgian site, which is also under a forest shows a dcp very close to the dcp found under grassland sites of Southwest France, which proves that other unknown factors may play an important role in dissolution processes. Secondary calcite deposition and redissolution in the soil zone or more likely in the fracture system before reaching the cave itself could also explain the inter-site differences. The IAEA isotopic model (Pearson model adapted for open systems) is in good agreement with the measured activities.
    Type of Medium: Online Resource
    ISSN: 0033-8222 , 1945-5755
    URL: Article
    DOI: 10.1017/S0033822200040881
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 1997
    detail.hit.zdb_id: 2028560-7
    SSG: 11
    SSG: 13
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  • 4
    Online Resource
    Online Resource
    Calculation of Past Dead Carbon Proportion and Variability by the Comparison of AMS 14 C and Tims U/TH Ages on Two Holocene Stalagmites
    Cambridge University Press (CUP) ; 1999
    In:  Radiocarbon Vol. 41, No. 3 ( 1999), p. 251-270
    Details
    In: Radiocarbon, Cambridge University Press (CUP), Vol. 41, No. 3 ( 1999), p. 251-270
    Abstract: Twenty-two radiocarbon activity measurements were made by accelerator mass spectrometry (AMS) on 2 Holocene stalagmites from Belgium (Han-stm1b) and from southwest France (Vil-stm1b). Sixteen thermal ionization mass spectrometric (TIMS) U/Th measurements were performed parallel to AMS analyses. The past dead carbon proportion (dcp) due to limestone dissolution and old soil organic matter (SOM) degradation is calculated with U/Th ages, measured calcite 14 C activity and atmospheric 14 C activity from the dendrochronological calibration curves. Results show that the dcp is different for the 2 stalagmites: between 10,800 and 4780 yr from present dcp=17.5% (σ=2.4; n=10) for Han-stm1b and dcp=9.4% (σ=1.6; n=6) between 3070 and 520 yr for Vil-stm1b. Despite a broad stability of the dcp during the time ranges covered by each sample, a slight dcp increase of about 5.0% is observed in the Han-stm1b sample between 8500 and 5200 yr. This change is synchronous with a calcite δ 13 C increase, which could be due to variation in limestone dissolution processes possibly linked with a vegetation change. The dcp and δ 13 C of the 2 studied samples are compared with 5 other modern stalagmites from Europe. Results show that several factors intervene, among them: the vegetation type, and the soil saturation leading to variable dissolution process systems (open/closed). The good correlation (R 2 =0.98) between the U/Th ages and the calibrated 14 C ages corrected with a constant dcp validates the 14 C method. However, the dcp error leads to large 14 C age errors (i.e. 250–500 yr for the period studied), which is an obstacle for both a high-resolution chronology and the improvement of the 14 C calibration curves, at least for the Holocene.
    Type of Medium: Online Resource
    ISSN: 0033-8222 , 1945-5755
    URL: Article
    DOI: 10.1017/S003382220005712X
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 1999
    detail.hit.zdb_id: 2028560-7
    SSG: 11
    SSG: 13
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  • 5
    Online Resource
    Online Resource
    Non-Destructive Portable Analytical Techniques for Carbon In Situ Screening Before Sampling for Dating Prehistoric Rock Paintings
    Cambridge University Press (CUP) ; 2013
    In:  Radiocarbon Vol. 55, No. 2 ( 2013), p. 436-444
    Details
    In: Radiocarbon, Cambridge University Press (CUP), Vol. 55, No. 2 ( 2013), p. 436-444
    Abstract: Direct dating of prehistoric paintings is playing a major role in Paleolithic art studies. Very few figures can be directly dated since the necessary condition is that they contain organic carbon-based material. Thus, it is very important to check the presence of organic carbon-based material in situ before sampling in order to protect the visual integrity of the paintings or drawings. We have tested and compared 3 different portable analytical systems that can be used in cave environments for detecting carbon in prehistoric paintings: (1) a very compact X-ray fluorescence (XRF) system in Villars Cave (Dordogne, France); (2) a portable micro-Raman spectrometer in Rouffignac Cave (Dordogne, France); and (3) an infrared reflectography camera in both caves. These techniques have been chosen for their non-destructiveness: no sample has to be taken from the rock surface and no contact is made between the probes and the paintings or drawings. The analyses have shown that all the animal figures have been drawn with manganese oxides and cannot be directly dated by radiocarbon. However, carbon has been detected in several spots such as black dots and lines and torch marks. 14 C results were obtained from 5 torch marks selected in Villars Cave, with ages between 17.1–18.0 ka cal BP. Three methods were used to identify carbon in black pigments or to confirm the presence of torch marks by carbon detection. Thanks to these new analytical developments, it will be now possible to select more accurately the samples to be taken for 14 C dating prehistoric paintings and drawings.
    Type of Medium: Online Resource
    ISSN: 0033-8222 , 1945-5755
    URL: Article
    DOI: 10.1017/S003382220005757X
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2013
    detail.hit.zdb_id: 2028560-7
    SSG: 11
    SSG: 13
    Location Call Number Limitation Availability
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