The use of X-ray radiographic methods in studying sedimentary properties and rates of sediment accumulation

Axelsson, Valter

doi:10.1007/bf00028429

Cited by 38 publications

(9 citation statements)

References 2 publications

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“…Accordingly, the density of the coarser-grained layers is slightly higher, leading to less darkening of the X-ray film (Axelsson, 1983). Therefore, Xradiographs have been successfully used for varve counting on sediment cores PS1599, PS1789, and PS1791 (Weber et al, 2010).…”

Section: Varvesmentioning

confidence: 99%

Seasonal changes in glacial polynya activity inferred from Weddell Sea varves

et al. 2014

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Abstract. The Weddell Sea and the associated FilchnerRønne Ice Shelf constitute key regions for global bottomwater production today. However, little is known about bottom-water production under different climate and icesheet conditions. Therefore, we studied core PS1795, which consists primarily of fine-grained siliciclastic varves that were deposited on contourite ridges in the southeastern Weddell Sea during the Last Glacial Maximum (LGM). We conducted high-resolution X-ray fluorescence (XRF) analysis and grain-size measurements with the RADIUS tool (Seelos and Sirocko, 2005) using thin sections to characterize the two seasonal components of the varves at sub-mm resolution to distinguish the seasonal components of the varves.Bright layers contain coarser grains that can mainly be identified as quartz in the medium-to-coarse silt grain size. They also contain higher amounts of Si, Zr, Ca, and Sr, as well as more ice-rafted debris (IRD). Dark layers, on the other hand, contain finer particles such as mica and clay minerals from the chlorite and illite groups. In addition, Fe, Ti, Rb, and K are elevated. Based on these findings as well as on previous analyses on neighbouring cores, we propose a model of enhanced thermohaline convection in front of a grounded ice sheet that is supported by seasonally variable coastal polynya activity during the LGM. Accordingly, katabatic (i.e. offshore blowing) winds removed sea ice from the ice edge, leading to coastal polynya formation. We suggest that glacial processes were similar to today with stronger katabatic winds and enhanced coastal polynya activity during the winter season. Under these conditions, lighter coarser-grained layers are likely glacial winter deposits, when brine rejection was increased, leading to enhanced bottom-water formation and increased sediment transport. Vice versa, darker finer-grained layers were then deposited during less windier season, mainly during summer, when coastal polynya activity was likely reduced.

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Section: Varvesmentioning

confidence: 99%

Seasonal changes in glacial polynya activity inferred from Weddell Sea varves

et al. 2014

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“…In this study, four plastic electrical installation liners (1.5 )/5)/49 cm) were used in subsampling for stereo X-ray imaging of the cores (e.g. Axelsson 1983). The subsamples were X-rayed with a Philip constant potential MG 102 L X-ray machine and the developed pictures were scanned with 400 and 600 pixel (dpi) resolution.…”

Section: Methodsmentioning

confidence: 99%

Dating early Holocene palaeoseismic event(s) in the Gulf of Bothnia, Baltic Sea

Hutri¹,

Heinsalu²,

Kotilainen³

et al. 2007

SBOR

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Deformation structures in submarine Holocene sediments caused by palaeoseismicity have recently been found in the Olkiluoto area, Gulf of Bothnia, Baltic Sea, within old fracture zones of bedrock. In this study, the palaeoseismic event(s) was dated and the palaeoenvironment was characterized using palaeomagnetic, biostratigraphical and lithostratigraphical methods, thereby enhancing the reliability of the chronology. The variations in the inclination and declination of the Olkiluoto sediment core showed very good correlation with the palaeosecular variations recorded in the annually laminated long lake sediment record from Lake Nautajärvi in central Finland. Combined litho-, bio-and palaeomagnetic stratigraphy revealed an age estimation of 10 650 to 10 200 cal. yr BP for the palaeoseismic event(s), which coincides with postglacial bedrock faulting in northern Fennoscandia.

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“…It enables the documentation of ne-scale variations in the sediment structure (e.g. Koivisto & Saarnisto 1978;Axelsson 1983;Saarinen & Saarnisto 1998). As expressed by Axelsson (1983), the method is 'a fast, non-destructive scanning and recording technique, which may reveal sediment structures that are not revealed by other methods of analysis'.…”

Section: X-ray Densitometrymentioning

confidence: 99%

“…Koivisto & Saarnisto 1978;Axelsson 1983;Saarinen & Saarnisto 1998). As expressed by Axelsson (1983), the method is 'a fast, non-destructive scanning and recording technique, which may reveal sediment structures that are not revealed by other methods of analysis'. Later on, Saarnisto (1986) recommended the systematic use of this method in the study of nely laminated sediments.…”

Section: X-ray Densitometrymentioning

confidence: 99%

“…Schaaf & Thurow 1994), and obtaining very high-resolution measurements previously dif cult to obtain, such as annual grain size (Francus 1998). The purpose of this study is to compare measurements obtained using X-ray densitometry techniques (Axelsson 1983;Tiljander et al in press) and image analysis of Backscattered Scanning Electron microscope Images (BSEI) of thin sections (Francus 1998).…”

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confidence: 99%

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Comparing X-ray densitometry and BSE-image analysis of thin section in varved sediments

Ojala¹,

Francus²

2002

Boreas

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Francus, P. 2002 (March): Comparing X-ray densitometr y and BSE-image analysis of thin section in varved sediments. Boreas, Vol. 31, pp. 57-64. Oslo. ISSN 0300-9483 .A 10-cm long section from varved sequence of Lake Nautajärvi, Finland, has been analysed using both X-ray densitometr y and image analysis of Backscattered Scanning Electron microscope Images (BSEI) of thin sections. Lake Nautajärvi's clastic-organi c varves appear in X-ray images as a successio n of dark and pale stripes, pale ones being the spring detrital minerogeni c layers and dark ones organic matter laid down during the time of summer, autumn and winter ice cover. Owing to the sharp contrast of the minerogeni c spring layer, a semiautomatic tree-ring width and density measurement DendroScan system was applied to obtain seasonal /annual data of relative X-ray density. Mean density of BSEI was also acquired . Then BSEI were processe d to produce black and white images, where white pixels represent the clay-rich sedimentar y matrix and black pixels the particles in the matrix: silt-or sand-sized , terrigenou s grains, authigenic particles and diatoms. Measurements of the size of the detrital particles forming the varves were obtained. For each varve, mean grey-level values in BSEI correlate d well with the mean grey-level values of X-ray images, but grain size obtained on BSEI did not correlate with any parameters computed from X-ray radiography .

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The use of X-ray radiographic methods in studying sedimentary properties and rates of sediment accumulation

Cited by 38 publications

References 2 publications

Seasonal changes in glacial polynya activity inferred from Weddell Sea varves

Seasonal changes in glacial polynya activity inferred from Weddell Sea varves

Dating early Holocene palaeoseismic event(s) in the Gulf of Bothnia, Baltic Sea

Comparing X-ray densitometry and BSE-image analysis of thin section in varved sediments

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