The late-Holocene tufa decline in Europe: Myth or reality?

Dabkowski, Julie

doi:10.1016/j.quascirev.2019.106141

Cited by 28 publications

(26 citation statements)

References 82 publications

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“…Additionally, tufa may erode, incorporate some allochthonous terrestrial material and "dead" carbonate, and experience recrystallization [9][10][11]. Reliable dating of tufa enables interpretation of the physico-chemical proxies and can provide many answers on Holocene and Pleistocene palaeoclimate [1,4,6,7,[12][13][14][15][16][17][18][19][20][21][22][23][24][25]. It is essential that the results obtained by different analyses can be put into a correct time frame.…”

Section: Introductionmentioning

confidence: 99%

The Potential of Tufa as a Tool for Paleoenvironmental Research—A Study of Tufa from the Zrmanja River Canyon, Croatia

et al. 2021

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Tufa is a fresh-water surface calcium carbonate deposit precipitated at or near ambient temperature, and commonly contains the remains of macro- and microphytes. Many Holocene tufas are found along the Zrmanja River, Dalmatian karst, Croatia. In this work we present radiocarbon dating results of older tufa that was found for the first time at the Zrmanja River near the Village of Sanaderi. Tufa outcrops were observed at different levels, between the river bed and up to 26 m above its present level. Radiocarbon dating of the carbonate fraction revealed ages from modern, at the river bed, up to 40 kBP ~20 m above its present level. These ages fit well with the hypothesis that the Zrmanja River had a previous surface connection with the Krka River, and changed its flow direction toward the Novigrad Sea approximately 40 kBP (Marine Isotope Stage 3). Radiocarbon AMS dating of tufa organic residue yielded a maximum conventional age of 17 kBP for the highest outcrop position indicating probable penetration of younger organic material to hollow tufa structures, as confirmed by radiocarbon analyses of humin extracted from the samples. Stable carbon isotope composition (δ13C) of the carbonate fraction of (−10.4 ± 0.6)‰ and (−9.7 ± 0.8)‰ for the Holocene and the older samples, respectively, indicate the autochthonous origin of the carbonate. The δ13C values of (−30.5 ± 0.3)‰ and (−29.6 ± 0.6)‰ for organic residue, having ages <500 BP and >5000 BP, respectively, suggest a unique carbon source for photosynthesis, mainly atmospheric CO2, with an indication of the Suess effect in δ13C during last centuries. The oxygen isotopic composition (δ18O) agrees well with deposition of tufa samples in two stages, the Holocene (−8.02 ± 0.72‰) and “old” (mainly MIS 3 and the beginning of MIS 2) (−6.89 ± 0.34‰), suggesting a ~4 °C lower temperature in MIS 3 compared to the current one.

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Section: Introductionmentioning

confidence: 99%

The Potential of Tufa as a Tool for Paleoenvironmental Research—A Study of Tufa from the Zrmanja River Canyon, Croatia

et al. 2021

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“…Für die zielorientierte hydrogeologische und hydrogeochemische Standortuntersuchung betrachten wir eine feinsedimentäre Talfüllung, wie sie typisch ist für viele Regio-nen Mitteleuropas (Hagedorn und Rother 1992;Collins et al 2006;Dabkowski 2020). Das ca.…”

Section: Standortbeschreibungunclassified

Kombination geophysikalischer und hydrogeologischer Methoden zur gezielten Erkundung feinkörniger Talfüllungen

Klingler

Martin

Cirpka

et al. 2021

Grundwasser - Zeitschrift der Fachsektion Hydrogeologie

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KurzfassungSedimentäre Strukturen können die Fließ- und Stofftransportpfade in feinkörnigen Talfüllungen stark beeinflussen. Diese Strukturen müssen gezielt auf ihre Ausdehnung und Eigenschaften untersucht werden, um Verweilzeiten, Fließpfade und das Abbaupotenzial eingetragener Schadstoffe zu bestimmen. In der quartären Talfüllung der Ammeraue bei Tübingen wurden beispielhaft Torflagen und eine Kiesrinne untersucht, um ihre Einflüsse auf die regionale Hydrogeologie und Hydrochemie zu bewerten. Dafür wurden geophysikalische und hydrogeologische Erkundungsmethoden ausgewählt und kombiniert. Mit geoelektrischen Oberflächenmessungen konnte die Ausdehnung der betrachteten Strukturen erkundet werden. Unterschiedliche Direct-Push-Sondierungen, darunter eine In-situ-Bestimmung der Sedimentfarbe, und bohrlochgeophysikalische Messungen erfassten ihre Geometrie und interne Heterogenität. Die hydraulischen und biogeochemischen Eigenschaften der Sedimente und des Grundwassers wurden anschließend durch gezielte Probennahmen und hydraulische Tests an repräsentativen Ansatzpunkten bestimmt. Die dargestellte Methodenkombination zur Abgrenzung relevanter Teilgebiete mit anschließender hochauflösender Untersuchung lässt sich auch auf die Untersuchung großflächiger Täler übertragen.

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“…We performed the direct‐push color logging fieldwork in unconsolidated Quaternary floodplain sediments in the Ammer valley near Tübingen, Germany. Previous floodplain‐wide distributed sediment coring indicated a sedimentary succession typical for European Pleistocene to Holocene floodplains (Dabkowski, 2020; Fuchs et al, 2011; Lespez et al, 2008; Newell et al, 2015; Žák et al, 2002): up to 10 m thick clay‐rich gravels at the bottom, overlain by a 1–3 m thick silty clay, up to 8 m thick calcareous tufa sediments with abundant vegetation and organic‐rich layers and an upper 2 m of silty clay alluvial cover (Martin et al, 2020). In many of these cores we found up to 1 m thick peat layers at different depths within the tufa sequence.…”

Section: Methodsmentioning

confidence: 99%

“…In many of these cores we found up to 1 m thick peat layers at different depths within the tufa sequence. Tufa sediments generally indicate a spatially very variable swampy depositional environment with ponding waters and patchy vegetation in warm climate (Dabkowski, 2020; Pedley, 1990). Therefore, we expected a high spatial variability of peat lenses with high organic carbon content.…”

Section: Methodsmentioning

confidence: 99%

Direct‐Push Color Logging Images Spatial Heterogeneity of Organic Carbon in Floodplain Sediments

et al. 2020

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In soils and sediments, large amounts of total organic carbon (TOC) mark reducing conditions. As dark sediment colors are good predictors for high-TOC zones, they indicate hot spots of biogeochemical turnover and microbial activity. Traditionally, obtaining the sediment color or TOC at depth requires costly core sampling, resulting in poor horizontal resolution and related uncertainty caused by interpolation. We suggest using a direct-push tool for optical screening of the sediment color to acquire multiple high-resolution vertical color profiles and demonstrate its applicability to a biogeochemical transition zone in floodplain sediments, dominated by tufa. We use Gaussian mixture models for a cluster analysis of 35 color logs in the International Commission on Illumination (CIE) L*a*b* color space to identify three colorfacies that differ in lithology and TOC content: a dark colorfacies that agrees well with peat layers, a gray colorfacies associated with clay, and a creamy-brown facies made of autochthonous carbonate precipitates. We test different approaches either to infer the TOC content from color metrics, namely, the lightness and chroma, across all facies, or to identify TOC ranges for each colorfacies. Given the high variability in TOC due to organic carbon specks in the tufa, the latter approach appears more realistic. In our application we map the 3-D distribution of organic matter in a floodplain in distinct facies over 20,000 m 2 down to 12 m depth. While we relate the sediment color only to the TOC content, direct-push color logging may also be used for in situ mapping of other biogeochemically relevant properties, such as the ferric-iron content or sedimentary structure. Plain Language Summary Geologists can say a lot about soils and loose materials in the ground by looking at their color. Dark materials normally contain dead plants, called organic carbon, which are food for bacteria and cause chemical reactions. To get the color of the soil, geologists normally need soil samples, but getting them from depth takes time and money. We test a method of pushing a camera into the ground and recording the color therein. From the recorded color we can say which type of geological material is at which depth and how much organic carbon is there without taking samples everywhere. This can be done very quickly, so that we can do it over a large area and down to the depth of the loose material in the ground, where most of the groundwater flows.

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The late-Holocene tufa decline in Europe: Myth or reality?

Cited by 28 publications

References 82 publications

The Potential of Tufa as a Tool for Paleoenvironmental Research—A Study of Tufa from the Zrmanja River Canyon, Croatia

The Potential of Tufa as a Tool for Paleoenvironmental Research—A Study of Tufa from the Zrmanja River Canyon, Croatia

Kombination geophysikalischer und hydrogeologischer Methoden zur gezielten Erkundung feinkörniger Talfüllungen

Direct‐Push Color Logging Images Spatial Heterogeneity of Organic Carbon in Floodplain Sediments

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