14.22 Determining Organic and Carbonate Content in Sediments

2013 ◽  
pp. 262-273 ◽  
Author(s):  
D.M. Kennedy ◽  
J.L.D. Woods
Keyword(s):  
Carbonate Content

scholarly journals Opto‐electrochemical Dissolution Reveals Coccolith Calcium Carbonate Content

2021 ◽  
Author(s):  
Minjun Yang ◽  
Christopher Batchelor-McAuley ◽  
Samuel Barton ◽  
Rosalind E.M. Rickaby ◽  
Heather A. Bouman ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Carbonate Content ◽  
Electrochemical Dissolution ◽  
Calcium Carbonate Content

scholarly journals A Novel Resorbable Composite Material Containing Poly(ester-co-urethane) and Precipitated Calcium Carbonate Spherulites for Bone Augmentation—Development and Preclinical Pilot Trials

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 102
Author(s):  
Claudia Rode ◽  
Ralf Wyrwa ◽  
Juergen Weisser ◽  
Matthias Schnabelrauch ◽  
Marijan Vučak ◽  
...  
Keyword(s):  
Composite Material ◽  
Calcium Carbonate ◽  
Bone Substitute ◽  
Pilot Trial ◽  
Carbonate Content ◽  
Precipitated Calcium Carbonate ◽  
Degradation Behaviour ◽  
Biodegradable Composite ◽  
Loss Of Mass

Polyurethanes have the potential to impart cell-relevant properties like excellent biocompatibility, high and interconnecting porosity and controlled degradability into biomaterials in a relatively simple way. In this context, a biodegradable composite material made of an isocyanate-terminated co-oligoester prepolymer and precipitated calcium carbonated spherulites (up to 60% w/w) was synthesized and investigated with regard to an application as bone substitute in dental and orthodontic application. After foaming the composite material, a predominantly interconnecting porous structure is obtained, which can be easily machined. The compressive strength of the foamed composites increases with raising calcium carbonate content and decreasing calcium carbonate particle size. When stored in an aqueous medium, there is a decrease in pressure stability of the composite, but this decrease is smaller the higher the proportion of the calcium carbonate component is. In vitro cytocompatibility studies of the foamed composites on MC3T3-E1 pre-osteoblasts revealed an excellent cytocompatibility. The in vitro degradation behaviour of foamed composite is characterised by a continuous loss of mass, which is slower with higher calcium carbonate contents. In a first pre-clinical pilot trial the foamed composite bone substitute material (fcm) was successfully evaluated in a model of vertical augmentation in an established animal model on the calvaria and on the lateral mandible of pigs.

scholarly journals Sinking rates and ballast composition of particles in the Atlantic Ocean: implications for the organic carbon fluxes to the deep ocean

2009 ◽  
Vol 6 (1) ◽  
pp. 85-102 ◽  
Author(s):  
G. Fischer ◽  
G. Karakaş
Keyword(s):  
Organic Carbon ◽  
Atlantic Ocean ◽  
Sediment Trap ◽  
Carbon Flux ◽  
Coastal Upwelling ◽  
Production Systems ◽  
Deep Ocean ◽  
Biogeochemical Model ◽  
Carbonate Content ◽  
Organic Carbon Flux

Abstract. The flux of materials to the deep sea is dominated by larger, organic-rich particles with sinking rates varying between a few meters and several hundred meters per day. Mineral ballast may regulate the transfer of organic matter and other components by determining the sinking rates, e.g. via particle density. We calculated particle sinking rates from mass flux patterns and alkenone measurements applying the results of sediment trap experiments from the Atlantic Ocean. We have indication for higher particle sinking rates in carbonate-dominated production systems when considering both regional and seasonal data. During a summer coccolithophorid bloom in the Cape Blanc coastal upwelling off Mauritania, particle sinking rates reached almost 570 m per day, most probably due the fast sedimentation of densely packed zooplankton fecal pellets, which transport high amounts of organic carbon associated with coccoliths to the deep ocean despite rather low production. During the recurring winter-spring blooms off NW Africa and in opal-rich production systems of the Southern Ocean, sinking rates of larger particles, most probably diatom aggregates, showed a tendency to lower values. However, there is no straightforward relationship between carbonate content and particle sinking rates. This could be due to the unknown composition of carbonate and/or the influence of particle size and shape on sinking rates. It also remains noticeable that the highest sinking rates occurred in dust-rich ocean regions off NW Africa, but this issue deserves further detailed field and laboratory investigations. We obtained increasing sinking rates with depth. By using a seven-compartment biogeochemical model, it was shown that the deep ocean organic carbon flux at a mesotrophic sediment trap site off Cape Blanc can be captured fairly well using seasonal variable particle sinking rates. Our model provides a total organic carbon flux of 0.29 Tg per year down to 3000 m off the NW African upwelling region between 5 and 35° N. Simple parameterisations of remineralisation and sinking rates in such models, however, limit their capability in reproducing the flux variation in the water column.

Pleistocene stratigraphy of the Saskatoon area, Saskatchewan, Canada: an update

1992 ◽  
Vol 29 (8) ◽  
pp. 1767-1778 ◽  
Author(s):  
E. A. Christiansen
Keyword(s):  
Ice Sheet ◽  
Carbonate Content ◽  
Stratigraphic Position

Pleistocene deposits in the Saskatoon area are divided into the Sutherland and Saskatoon groups. The Sutherland Group is divided into the Mennon, Dundurn, and Warman formations, and the Saskatoon Group is divided into the Floral and Battleford formations. The Floral Formation is subdivided into the lower till, the Riddell Member, and the upper till. Each formation is composed of a sequence of deposits, including basal proglacial sediment, till, upper proglacial sediment, and nonglacial sediment. Each formation is defined primarily on the basis of carbonate content and stratigraphic position of its till, and commonly it is bounded by weathered zones and (or) nonglacial sediments. The Sutherland Group is pre-Illinoian in age, and the lower till of the Floral Formation is Illinoian in age. The Riddell Member, between the lower and upper tills of the Floral Formation, is late Rancholabrean, probably Sangamon, in age. Radiocarbon ages of sediments lying between the upper till of the Floral Formation (Early Wisconsin) and the Battleford Formation (Late Wisconsin) range from more than 38 000 to 18 000 BP. The dissipating ice sheet margin stood in the vicinity of Saskatoon about 12 000 BP.

scholarly journals Landslides in weakly cemented glaciolacustrine sediments, Morkill River valley, British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 889-900 ◽  
Author(s):  
Corey R Froese ◽  
David M Cruden
Keyword(s):  
British Columbia ◽  
River Valley ◽  
Carbonate Content ◽  
Canadian Rocky Mountains ◽  
Density Profiles ◽  
Frost Action ◽  
Dominant Component ◽  
Freeze And Thaw ◽  
Calcite Cement ◽  
The Relationship

Slopes in weakly cemented glaciolacustrine sediments in the Morkill River valley in the Canadian Rocky Mountains stand at up to 70°. Based on field and laboratory observations it appears that a contributing factor to instability is the softening of the soils by frost action and the leaching of calcite cement. Field density profiles demonstrated increased density and carbonate content with an increase in depth. Laboratory tests of carbonate content indicated a positive correlation between calcium carbonate and density in the glaciolacustrine sediments. The relationship was strongest in sands, in which leaching and dissolution were important components of softening. In clays, frost action was the dominant component of softening. Freeze-thaw tests showed a 50% decrease in strength after one cycle of freeze and thaw in the silts and clays.Key words: landslide, cemented, glaciolacustrine sediments, British Columbia.

scholarly journals Carbonate Content Reduction in Zinc Ore Concentrate

2012 ◽  
Vol 1 (1) ◽  
pp. 27-30
Author(s):  
Lemyr Martins ◽  
Antonio Peres ◽  
Roberto Galéry ◽  
Carlos Pereira
Keyword(s):  
Carbonate Content

CARBONATE MINERALOGY OF LAKE SEDIMENTS AND SURROUNDING SOILS. 2. THE QU’APPELLE LAKES

1983 ◽  
Vol 63 (2) ◽  
pp. 259-269 ◽  
Author(s):  
K. GHEBRE-EGZIABHIER ◽  
R. J. ST. ARNAUD
Keyword(s):  
Lake Sediments ◽  
Particle Size Analysis ◽  
Parent Material ◽  
Size Analysis ◽  
Carbonate Content ◽  
Mineral Contents ◽  
Ionic Activity ◽  
South Central ◽  
Direct Precipitation ◽  
Lake Waters

The nature and distribution of carbonate minerals in the upper Qu’Appelle basin in south-central Saskatchewan were investigated. The equivalent carbonate content and calcite:dolomite ratios of the deposits reflect the mechanisms of glacial deposition and some differences in the sources of the original parent material. The particle size analysis shows that the Qu’Appelle Lake sediments are more clayey than the surrounding soils and till deposits. Mg-bearing calcites occur only in the fine-sized fraction of the carbonate accumulation horizons. However, most of the upper Qu’Appelle Lake sediments contain appreciable amounts of sand-sized Mg-bearing calcites. The marked increase in carbonate content of the sediments relative to the adjacent soils and deposits is partially due to direct precipitation of calcite from the supersaturated lake waters. In this respect, a good correlation exists between the lake water ionic activity products for CaCO3 and the relative equivalent carbonatic mineral contents of the sediments. Key words: Mg-bearing calcite, dolomite, IAP, erosion

A SIMPLE METHOD FOR MEASURING THE CARBONATE CONTENT OF SOILS

2005 ◽  
Vol 69 (4) ◽  
pp. 1066-1068 ◽  
Author(s):  
Balázs Horváth ◽  
Oliver Opara-Nadi ◽  
Friedrich Beese
Keyword(s):  
Carbonate Content ◽  
Simple Method

scholarly journals Radiocarbon Dating of Calcined Bones: Where Does the Carbon Come from?

Radiocarbon ◽  
2009 ◽  
Vol 51 (2) ◽  
pp. 601-611 ◽  
Author(s):  
A Zazzo ◽  
J-F Saliège ◽  
A Person ◽  
H Boucher
Keyword(s):  
Radiocarbon Dating ◽  
Tooth Enamel ◽  
Skeletal Remains ◽  
Archaeological Sites ◽  
Carbonate Content ◽  
The Past ◽  
Mineral Fraction ◽  
Different Temperatures ◽  
C Value ◽  
Paleodietary Reconstruction

Over the past decade, radiocarbon dating of the carbonate contained in the mineral fraction of calcined bones has emerged as a viable alternative to dating skeletal remains in situations where collagen is no longer present. However, anomalously low δ13C values have been reported for calcined bones, suggesting that the mineral fraction of bone is altered. Therefore, exchange with other sources of carbon during heating cannot be excluded. Here, we report new results from analyses on cremated bones found in archaeological sites in Africa and the Near East, as well as the results of several experiments aiming at improving our understanding of the fate of mineral and organic carbon of bone during heating. Heating of modern bone was carried out at different temperatures, for different durations, and under natural and controlled conditions, and the evolution of several parameters (weight, color, %C, %N, δ13C value, carbonate content, crystallinity indexes measured by XRD and FTIR) was monitored. Results from archaeological sites confirm that calcined bones are unreliable for paleoenvironmental and paleodietary reconstruction using stable isotopes. Experimental results suggest that the carbon remaining in bone after cremation likely comes from the original inorganic pool, highly fractionated due to rapid recrystallization. Therefore, its reliability for 14C dating should be seen as close to that of tooth enamel, due to crystallographic properties of calcined bones.

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