Normalizing XRF-scanner data: A cautionary note on the interpretation of high-resolution records from organic-rich lakes

Löwemark, Ludvig; Chen, H. F; Yang, Tsung-Yeh; Kylander, Malin E.; Yu, Ein-Fen; Hsu, Yung-Chang; Lee, T. Q; Song, Sheng-Rong; Jarvis, Stuart

doi:10.1016/j.jseaes.2010.06.002

Cited by 235 publications

(144 citation statements)

References 27 publications

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“…The organic-rich intercalations (E1-E6) can clearly be seen on the PC 3 /PC 1 profile. This observation supports the results obtained by Löwemark et al (2011), who noted that Al-normalized Ti and Fe profiles correlate with the organic matter content of sediments. It should be noted that PC 3 represents Mg and Al ( Figure 5E); however Mg and Al data measured by ITRAX with Mo tube is not reliable, because Mg is out of the detection range and Al data generally have very low signal-to-noise ratio.…”

Section: Identification Of Sedimentary Events and Chronologysupporting

confidence: 92%

Seismically-triggered organic-rich layers in recent sediments from Göllüköy Lake (North Anatolian Fault, Turkey)

Avşar

Hubert‐Ferrari

Batist

et al. 2014

Quaternary Science Reviews

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Multi-proxy analyses on the sedimentary sequence of Göllüköy Lake, which is located on the eastern North Anatolian Fault (NAF), reveals a complete and high-resolution paleoseismic record for the last 650 years. Six sedimentary events are detected in a 3.1 m-long piston core. They form distinct organic-rich intercalations within the background sedimentation, which are characterized by strong anomalies on the loss-on-ignition (LOI) and total organic carbon (TOC) profiles, as well as by lighter colours on the X-ray radiographic images. Itrax micro-XRF core scanner data are also used to contribute to the detection and characterization of the event deposits. After the detection of the sedimentary events, their temporal correlation with the earthquakes in the historical seismicity catalogue of the NAF is tested. The youngest event is dated to 1940s by using 210 Pb and 137 Cs profiles in sediment, which coincides with the 1939 earthquake (M s = 7.7) on the NAF. The ages of the older five events are determined based on radiocarbon dating and regional time-stratigraphic correlation. Radiocarbon dating on the bulk sediment samples does not provide reliable results due to hard-water effect. On the other hand, dating on charcoals, Ephippia of Daphnia and phragmite remains significantly improves the results and implies a mean sedimentation rate of 0.28 cm/yr. Based on this preliminary sedimentation rate, we show that organic matter content variations through our record correlates with the varve-based δ 18 O record of Nar Lake, which is located 350 km southwest of Göllüköy Lake. Accordingly, high-precipitation/low-evaporation climatic episodes detected in Nar Lake are represented by higher organic matter content in Göllüköy sediments. Fine-tuning the Göllüköy LOI record to the Nar δ 18 O record reveals that the ages of the sedimentary events in Göllüköy match with well-known historical earthquakes that occurred around the lake. Finally, the origin of the organic-rich intercalations is discussed based on macroscopic observations and organic geochemistry. The events are attributed to reworked organic matter eroded from the lake's littoral zone by seismically-induced water oscillations (seiche), and their subsequent deposition at the middle parts of the lake. These seismically-induced events are atypical compared to the classic earthquake-triggered sedimentary processes in lacustrine environments, which are shortly reviewed in order to emphasize the unusual Göllüköy Lake record.

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Section: Identification Of Sedimentary Events and Chronologysupporting

confidence: 92%

Seismically-triggered organic-rich layers in recent sediments from Göllüköy Lake (North Anatolian Fault, Turkey)

Avşar

Hubert‐Ferrari

Batist

et al. 2014

Quaternary Science Reviews

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“…XRF-scan data of water-rich core sections, in particular, should be routinely compared to Cl intensities in a way comparable to checking the core surface for any disturbances, such as unevenness and presence of cracks or gaps (Löwemark et al 2011). If enhanced Cl levels correspond to simultaneous dips in the light elements (those with atom numbers from Al to Fe; see Table 1), then enhanced caution is needed.…”

Section: Comments and Recommendationsmentioning

confidence: 99%

X‐ray fluorescence core scanning of wet marine sediments: methods to improve quality and reproducibility of high‐resolution paleoenvironmental records

Hennekam

Lange

2012

Limnology & Ocean Methods

116

112

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X‐ray fluorescence (XRF) core‐scanning is a convenient non‐destructive tool to rapidly assess elemental variations in unprocessed sediments. However, substantial analytical deviations may occur in such data due to physical sedimentary properties. The consequences of these artifacts on element intensities are important for paleoclimatic studies, but as yet have not been adequately studied for high resolution (≤ 1‐cm interval) records. We have done a high resolution comparison between results from XRF scanning and from two more conventional methods: XRF with beads and inductively coupled plasma optical emission spectrometry (ICP‐OES), both on discrete samples. Our XRF scan data concord reasonably well with those from the conventional methods for most elements. In several discrete intervals large deviations occur that could have been attributed to major paleoceanographic events. However, these deviations appear to be mainly related to water content and distribution. We show that the variability in the water film thickness underneath the plastic foil is highly variable, causing significant apparent variability in all elements from Al to Fe. The unverified use of these elements in ratios can thus lead to deviations in the paleoenvironmental interpretation. Erroneous element (ratio) variability can, however, be recognized and corrected using conventional analytical data of a few discrete samples. The antipathetic behavior of Ca to K or Ti, and their similar behavior to water absorption, leaves their ratios relatively unaffected at variable water film thicknesses. Hence, Ca/K and Ca/Ti ratios are recommended for a preliminary down‐core overview of sedimentary variability and for stratigraphic correlations between unprocessed marine cores.

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“…X-ray fluorescence core scanning was done on an AVAAT-ECH instrument at the ETH Zurich and with a spatial resolution of 200 µm. XRF core scanning is a fast, non-destructive technique which provides information about elemental variations directly from untreated sediment and reflects proportions of different minerogenic components (Löwemark et al, 2011). Among the various elements tested , and considering the geological setting of the catchment, we provide the Ca / Si ratio to distinguish between authigenic carbonate sedimentation from glacial face leaching, mostly comprising siliceous stones transported by the glacial tongue in the valley.…”

Section: Core Sampling and Sedimentologymentioning

confidence: 99%

Climate and vegetation changes during the Lateglacial and early–middle Holocene at Lake Ledro (southern Alps, Italy)

et al. 2013

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Adding to the on-going debate regarding vegetation recolonisation (more particularly the timing) in Europe and climate change since the Lateglacial, this study investigates a long sediment core (LL081) from Lake Ledro (652 m a.s.l., southern Alps, Italy). Environmental changes were reconstructed using multiproxy analysis (pollen-based vegetation and climate reconstruction, lake levels, magnetic susceptibility and X-ray fluorescence (XRF) measurements) recorded climate and land-use changes during the Lateglacial and early–middle Holocene. The well-dated and high-resolution pollen record of Lake Ledro is compared with vegetation records from the southern and northern Alps to trace the history of tree species distribution. An altitude-dependent progressive time delay of the first continuous occurrence of Abies (fir) and of the Larix (larch) development has been observed since the Lateglacial in the southern Alps. This pattern suggests that the mid-altitude Lake Ledro area was not a refuge and that trees originated from lowlands or hilly areas (e.g. Euganean Hills) in northern Italy. Preboreal oscillations (ca. 11 000 cal BP), Boreal oscillations (ca. 10 200, 9300 cal BP) and the 8.2 kyr cold event suggest a centennial-scale climate forcing in the studied area. Picea (spruce) expansion occurred preferentially around 10 200 and 8200 cal BP in the south-eastern Alps, and therefore reflects the long-lasting cumulative effects of successive boreal and the 8.2 kyr cold event. The extension of Abies is contemporaneous with the 8.2 kyr event, but its development in the southern Alps benefits from the wettest interval 8200–7300 cal BP evidenced in high lake levels, flood activity and pollen-based climate reconstructions. Since ca. 7500 cal BP, a weak signal of pollen-based anthropogenic activities suggest weak human impact. The period between ca. 5700 and ca. 4100 cal BP is considered as a transition period to colder and wetter conditions (particularly during summers) that favoured a dense beech (Fagus) forest development which in return caused a distinctive yew (Taxus) decline. We conclude that climate was the dominant factor controlling vegetation changes and erosion processes during the early and middle Holocene (up to ca. 4100 cal BP)

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Normalizing XRF-scanner data: A cautionary note on the interpretation of high-resolution records from organic-rich lakes

Cited by 235 publications

References 27 publications

Seismically-triggered organic-rich layers in recent sediments from Göllüköy Lake (North Anatolian Fault, Turkey)

Seismically-triggered organic-rich layers in recent sediments from Göllüköy Lake (North Anatolian Fault, Turkey)

X‐ray fluorescence core scanning of wet marine sediments: methods to improve quality and reproducibility of high‐resolution paleoenvironmental records

Climate and vegetation changes during the Lateglacial and early–middle Holocene at Lake Ledro (southern Alps, Italy)

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