Nano sized clay detected on chalk particle surfaces

Skovbjerg, L.L.; Hassenkam, Tue; Makovicky, Emil; Hem, C. P.; Yang, Mingjun; Bovet, N.; Stipp, S. L. S.

doi:10.1016/j.gca.2012.05.037

Cited by 41 publications

(56 citation statements)

References 54 publications

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“…In both heterococcoliths, Ti nodules are not correlated with Ca-rich spots but rather located at the junction between CaCO 3 crystals. Ti nodules could possibly be nanoscale Ti-rich clay particles, which size (down to 100 nm) is consistent with the clay particles observed by Skovbjerg et al (2012). However, these Ti-rich clay nodules are different from the central area clay, highlighting at least two sources of contamination in our results.…”

Section: Clay Contaminationsupporting

confidence: 87%

“…broken pieces of shells and tests), siliciclastic particles (e.g. Ti nodules could possibly be nanoscale Ti-rich clay particles, which size (down to 100 nm) is consistent with the clay particles observed by Skovbjerg et al (2012). In both heterococcoliths Wbrit1 and Wbrit2, the centre of the heterococcoliths is contaminated.…”

Section: Clay Contaminationsupporting

confidence: 78%

“…Clays are generally composed of Si, Al, Fe, Mg, Ca, Na and K as major ele- ments and contain traces of Ti, Cr, Cu, Zn, Rb and Sr (K€ oster, 1996); they are typically depleted in Ca and Sr in comparison with heterococcoliths (Stoll & Ziveri, 2004). High Fe/Ca was already proposed as a way to identify clay contamination in heterococcolith geochemistry studies (Halloran et al, 2009); with clay contamination being later confirmed by atomic force microscopy observations of submicron clay particles covering heterococcoliths (Skovbjerg et al, 2012) and secondary ion mass spectrometry (Prentice et al, 2014). In this study, Ti is particularly concentrated in small nodules with size ranging from 100 to 500 nm.…”

Section: Clay Contaminationmentioning

confidence: 96%

“…In sedimentary carbonate deposits, contaminants could be either carbonate from the matrix (e.g. High Fe/Ca was already proposed as a way to identify clay contamination in heterococcolith geochemistry studies (Halloran et al, 2009); with clay contamination being later confirmed by atomic force microscopy observations of submicron clay particles covering heterococcoliths (Skovbjerg et al, 2012) and secondary ion mass spectrometry (Prentice et al, 2014). clay and quartz) or organic matter (OM).…”

Section: Clay Contaminationmentioning

confidence: 99%

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Perspectives on heterococcolith geochemical proxies based on high‐resolution X‐ray fluorescence mapping

et al. 2016

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International audienceHeterococcoliths are micron-scale calcite platelets produced by coccolithophores. They have been the most abundant and continuous fossil record over the last 215 million years (Myr), offering great potential for geochemical studies, although the heterococcolith fossil record remains underutilised in this domain. We have mapped heterococcoliths' composition using X-ray fluorescence (XRF) with a 100-nm resolution beam to decipher element distributions in heterococcoliths and to investigate the potential development of geochemical proxies for palaeoceanography. The study presents two Middle Jurassic Watznaueria britannica heterococcoliths from Cabo Mondego, Portugal. XRF analysis was performed with a 17 keV incident energy beam at the European Synchrotron Radiation Facility ID22NI beamline to study elements from Sr down to S. Ca, Sr and Mn are distributed following the heterococcolith crystalline arrangement. Cl, Br and S display an homogeneous distribution, whereas K, Fe, Cu, Zn and Rb are concentrated at the edges and in the central area of the heterococcoliths. Distributions of K, Fe, Ti, Fe, Cu, Zn, Rb and to a lesser extent V and Cr are highly influenced by clay contamination and peripheral diagenetic overgrowth. Mn is related to diagenetic Mn-rich CaCO3 overgrowth on top of or between heterococcoliths shields. Cl and Br are likely to be present in heterococcoliths inside interstitial nano-domains. We assume that the cytoplasm [Cl−] and [Br−] are mediated and constant during heterococcolithogenesis. Assuming a linear correlation between cytoplasm [Cl−] and sea water [Cl−], heterococcolith Cl may have potential as a salinity proxy. As S is incorporated into heterococcoliths by sulphated polysaccharides, our study suggests a role for such polysaccharides in heterococcolithogenesis for at least 170 Myr. The low Sr/Ca in the W. britannica specimens studied here may either highlight an unusual cellular physiology of Mesozoic coccolithophores or result from low growth rates in oligotrophic environments

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Section: Clay Contaminationsupporting

confidence: 87%

Section: Clay Contaminationsupporting

confidence: 78%

Section: Clay Contaminationmentioning

confidence: 96%

Section: Clay Contaminationmentioning

confidence: 99%

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Perspectives on heterococcolith geochemical proxies based on high‐resolution X‐ray fluorescence mapping

et al. 2016

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“…With this technique, we have shown how wettability varies on pore surfaces in chalk (Hassenkam, Skovbjerg, and Stipp 2009, Skovbjerg et al 2012, Skovbjerg et al 2013) and in sandstone reservoirs (Hassenkam, Matthiesen, et al 2012). We have tested the low salinity effect using a tip functionalised with acidic compounds on preserved and solvent cleaned sandstone samples, to see if we could confirm the release mechanism proposed by Lager et al (Lager, Webb, Black, et al 2008) (Hassenkam et al 2011, Hassenkam, Matthiesen, et al 2012.…”

Section: Introductionmentioning

confidence: 78%

A Fast Alternative to Core Plug Tests for Optimising Injection Water Salinity for EOR

Hassenkam

Andersson

Hilner

et al. 2014

SPE Improved Oil Recovery Symposium

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Core tests have demonstrated that decreasing the salinity of injection water can increase oil recovery. Although recovery is enhanced by simply decreasing salt content, optimising injection water salinty would offer a clear economic advantage for several reasons. Too low salinity risks swelling of the clays which would lead to permanent reservoir damage but evidence of effectiveness at moderate salinity would offer the opportunity to dispose of produced water. The goal is to define boundary conditions so injection water salinity is high enough to prevent reservoir damage and low enough to induce the low salinity effect while keeping costs and operational requirements at a minimum. Traditional core plug testing for optimising conditions has some limitations. Each test requires a fresh sample, core testing requires sophisticated and expensive equipment, and reliable core test data requires several months because cores must be cleaned, restored and aged before the tests can begin. It is also difficult to compare data from one core with results from another because no two cores are identical, making it difficult to distinguish between effects resulting from different conditions and effects resulting from different cores. Gathering statistics is limited by the time required for each test and the fact that core material is in short supply. Thus, our aim was to explore the possibility of a cheaper, faster alternative. We developed a method that uses atomic force microscopy (AFM) to investigate the relationship between the wettability of pore surfaces and water salinity. We functionalise AFM tips with organic molecules and use them to represent tiny oil droplets of nonpolar or polar molecules and we use sand grains removed from core plugs to represent the pore walls in sandstone. We bring our "oil" close to the sand grain surface and measure the work of adhesion between the tip and the surface. Repeated "feeling" the surface with the tip produces data that can be converted to maps of adhesion and contact angle. Adhesion work is proportional to wettability and is directly correlated with the salinity of the fluid in contact with the tip and the particle surface. From our measurements, the threshold values for the onset of the low salinity response is 5,000 to 8,000 ppm, which benchmarks remarkably well with observations from core plug tests. Changing either the type of "oil" on our probe or the character of the grain surface both affect the adhesion response. From a mechanistic perspective, the correlation between salinity and adhesion provides evidence for the role of electrical double layer expansion in the low salinity response; expansion of the double layer decreases oil wettability. Because AFM experiments can be done relatively quickly on very little material, it gives the possibility of testing salinity response on samples from throughout a reservoir and for gathering statistics. Our approach provides a range of data that can be used to screen core plug testing conditions and to provide extra data that would be too...

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Importance of eDNA taphonomy and sediment provenance for robust ecological inference: Insights from interfacial geochemistry

Sand,

Jelavić,

Kjær

et al. 2024

Environmental DNA

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Retrieval of modern and ancient environmental DNA (eDNA) from sediments has revolutionized our ability to study past and present ecosystems. Little emphasis has been placed, however, on the fundamentals of the DNA–sediment associations in environmental settings. Consequently, our understanding of mineralogic controls and geochemical processes that take place on the DNA–sediment interface, and its implications for eDNA taphonomy and provenance, remain extremely limited. Here, we apply interfacial geochemical principles to elucidate how depositional processes and the stability of DNA–sediment associations in different environments can influence our interpretation and identify possible interpretational biases arising from neglecting mineral and geochemical controls on eDNA taphonomy. We use atomic force microscopy to show how interfacial geochemical interactions drive DNA adsorption behavior and we outline how to increase the scope and resolution of ecological interpretations from eDNA by combining mineralogic composition information with experimental adsorption data. We bring the concepts together and propose how to integrate sediment provenance as well as mineralogic and geochemical principles in eDNA taphonomy analysis for improved reconstruction of past ecosystems and monitoring of modern ecosystems from eDNA data. We provide a conceptual understanding of how eDNA taphonomy and sediment provenance can be addressed and further applied to enhance the scope, resolution, and accuracy of modern and past ecological reconstructions based on eDNA data.

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Nano sized clay detected on chalk particle surfaces

Cited by 41 publications

References 54 publications

Perspectives on heterococcolith geochemical proxies based on high‐resolution X‐ray fluorescence mapping

Perspectives on heterococcolith geochemical proxies based on high‐resolution X‐ray fluorescence mapping

A Fast Alternative to Core Plug Tests for Optimising Injection Water Salinity for EOR

Importance of eDNA taphonomy and sediment provenance for robust ecological inference: Insights from interfacial geochemistry

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