thorium sedimentation

thorium sedimentation

Thorium and Uranium Isotopes in Arctic Sediments ...

Abstract. Knowledge of accumulation rates of Arctic sediments is essential to the understanding of ice dynamics and sedimentation (Herman, 1974; Herman and Osmond, 1984; Markussen, Zahn, and Thiede, 1985) as well as to the paleoclimates and paleoceanography of the region (Herman, 1974).

(PDF) Natural Thorium Isotopes in Marine Sediment Core

The range of apparent sedimentation rates determined by this approach for these stations is 0.04–0.44 cm/year, after approximately 1000 m depth, sedimentation becomes

Thorium content in soil, water and sediment samples and ...

2019-10-2 · Thorium is a radioactive metal that is present in the environment in different species. 232 Th is the most abundant natural isotope (Holden 1990; Aggarwal 2016).High Th levels in the environment, derived from either natural or anthropogenic sources, increase exposure to other hazardous radioelements as a result of the corresponding decay series (Kritsananuwat et al. 2015; Danyłec et al.

Thorium-to-Uranium Ratios as Indicators of Sedimentary ...

The thorium-to-uranium ratios in sedimentary rocks range from less than 0.02 to more than 21. Ratios in many oxidized continental deposits are above 7, whereas most marine deposits have ratios much below 7. Thus, the thorium-to-uranium ratio varies with sedimentary processing and depositional environment.

Glacial episodes of a freshwater Arctic Ocean covered by a ...

2021-2-3 · Our approach explains the unexpected minima in Arctic thorium-230 records 9 that have led to divergent interpretations of sedimentation rates 10,11 and hampered their use for dating purposes ...

33. URANIUM AND THORIUM ISOTOPES: DEEP SEA

2007-6-5 · 1) To attempt to delineate sedimentation rates from the amount of the excess Th230 (i.e., uranium-unsupported) present in these sediments; 2) To detect from the ratios Th230/U234 and U234/U238 if any post-depositional migration of uranium and thorium isotopes had occurred, as samples from great depths, because of their ages, would be expected ...

Fe-Th (Iron-Thorium)

The obtained results allowed the choice of the condition of iron-thorium cake sedimentation from solutions from the perovskite processing (CaO concentration in lime milk, method of addition of ...

Discussion on the applicability of Th/U ratio for evaluating

2021-10-28 · obvious enrichment of thorium (Th) in sediments because of parent rock undergoing strong weathering and relative fast sedimentation rate influences the accuracy of Th/U ratio for evaluating the paleoredox conditions. Additionally, the different initial Th and ...

Improved determination of marine sedimentation rates

‘XSage’ can determine variations in sedimentation rate between stratigraphic horizons of known age and thus produce high-resolution age models. Using a Monte Carlo approach, the program calculates uncertainties for these age models and on the durations of intervals between tie-points.

Ocean Sediment - an overview | ScienceDirect Topics

III.E Biogenous Sedimentation. Ocean sediments consist of biogenic silica (global average of 14%), calcite (48%), and aluminosilicate dust (abyssal clay derived from the weathering of continents) (38%). The silicic acid [Si (OH)4] and calcium bicarbonate [Ca (HCO 3) 2] introduced into the oceans from rivers are removed by biogenous sedimentation.

marine sedimentation rate calculation using 232Thorium ...

From a high sedimentation rate core, obtained from the Yermak slope (Arctic Ocean), we deduced short-term climatic fluctuations of the last deglaciation lasting from 17,000 to 9,000 years BP.

Natural thorium isotopes in marine sediment core off ...

2014-2-12 · Abstract. Sediment core was collected from Labuan port and analyzed to determine the radioactivity of thorium (Th) isotopes. The objectives of this study are to determine the possible sources of Th isotopes at Labuan port and estimates the sedimentation rate based on {sup 228}Th/ {sup 232}Th model. The results suggest the {sup 230}Th and {sup ...

Thorium content in soil, water and sediment samples and ...

2019-10-2 · Thorium is a radioactive metal that is present in the environment in different species. 232 Th is the most abundant natural isotope (Holden 1990; Aggarwal 2016).High Th levels in the environment, derived from either natural or anthropogenic sources, increase exposure to other hazardous radioelements as a result of the corresponding decay series (Kritsananuwat et al. 2015; Danyłec et al.

Ratio of Thorium-230 to Thorium-232 in Deep-Sea

The ionium-thorium method for age determination in deep-sea sediments is critically reviewed, and its shortcomings are discussed. A method that allows an estimate of the rate of sedimentation in the superficial layer of the sediment is presented.

Thorium-to-Uranium Ratios as Indicators of Sedimentary ...

The thorium-to-uranium ratios in sedimentary rocks range from less than 0.02 to more than 21. Ratios in many oxidized continental deposits are above 7, whereas most marine deposits have ratios much below 7. Thus, the thorium-to-uranium ratio varies with sedimentary processing and depositional environment.

Retention of rare earth elements, thorium and uranium in ...

The retention of rare earth elements (REE),thorium (Th),and uranium (U) in deep sedimentary formations of the Horonobe area, Hokkaido, Japan (the Koetoi and Wakkanai Formations) was investigated in the present investigation as a case study.

33. URANIUM AND THORIUM ISOTOPES: DEEP SEA

2007-6-5 · 1) To attempt to delineate sedimentation rates from the amount of the excess Th230 (i.e., uranium-unsupported) present in these sediments; 2) To detect from the ratios Th230/U234 and U234/U238 if any post-depositional migration of uranium and thorium isotopes had occurred, as samples from great depths, because of their ages, would be expected ...

Tracing dust input to the global ocean using thorium ...

2016-9-28 · The estimated fraction of dust-derived thorium that dissolves in seawater ranges from 1% to 20% [Hsieh et al., 2011; Hayes et al., 2013], and reabsorption of 232 Th diss onto sinking particulates could lead to biases in low sedimentation rate regimes such as ocean gyres.

Fe-Th (Iron-Thorium)

The obtained results allowed the choice of the condition of iron-thorium cake sedimentation from solutions from the perovskite processing (CaO concentration in lime milk, method of addition of ...

KGS--Geological Log Analysis--The Gamma Ray Log

The thorium, uranium, and potassium curves in Tracks 2 and 3 record the quantities of these elements, which can be used in a more systematic analysis. Spectral gamma-ray log analysis is commonly made on the basis of the thorium-to-potassium (Th/K) ratio;

marine sedimentation rate calculation using 232Thorium ...

From a high sedimentation rate core, obtained from the Yermak slope (Arctic Ocean), we deduced short-term climatic fluctuations of the last deglaciation lasting from 17,000 to 9,000 years BP.

Thorium-to-Uranium Ratios as Indicators of Sedimentary ...

The thorium-to-uranium ratios in sedimentary rocks range from less than 0.02 to more than 21. Ratios in many oxidized continental deposits are above 7, whereas most marine deposits have ratios much below 7. Thus, the thorium-to-uranium ratio varies with sedimentary processing and depositional environment.

Proceedings of the Ocean Drilling Program, Scientific ...

2006-7-27 · rium/uranium chronology and 180 stratigraphy indicate relatively constant sedimentation rates throughout the se­ quence. At Site 646, down Greenland slope, and at Site 645, in Baffin Bay, highly variable uranium and thorium con­ centrations and isotopic ratios were observed in relation to highly variable sedimentation rates. As a whole, the lower

33. URANIUM AND THORIUM ISOTOPES: DEEP SEA

2007-6-5 · 1) To attempt to delineate sedimentation rates from the amount of the excess Th230 (i.e., uranium-unsupported) present in these sediments; 2) To detect from the ratios Th230/U234 and U234/U238 if any post-depositional migration of uranium and thorium isotopes had occurred, as samples from great depths, because of their ages, would be expected ...

Fe-Th (Iron-Thorium)

The obtained results allowed the choice of the condition of iron-thorium cake sedimentation from solutions from the perovskite processing (CaO concentration in lime milk, method of addition of ...

Radioactivity in the Marine Environment: Uranium‐Thorium ...

2018-12-27 · The remaining lecture focuses on four case studies that cover a range of applications where uranium-thorium series radionuclides are used and includes: scavenging, air-sea gas exchange, tracing groundwater, and sedimentation/age dating. This lecture is the second of a four-part lecture series on radionuclides in the marine environment.

30. GEOCHEMISTRY OF SEDIMENTS FROM THE PERU

2006-9-20 · Thorium (ppm) 0 5 10 15 Bromine (ppm) 0 100 200 300 400 Thorium (ppm) 0 5 10 15 Bromine (ppm) 0 100 200 300 400 Figure 2. Downhole plots of TOC, opaline silica, thorium, and bromine for Site 680. Site 680 Site 680 (Fig. 1) is located in water 250 m deep in the center of a lens-shaped sediment accumulation of organic carbon-

GEOPHYSICAL METHODS IN EXPLORATION AND

2004-4-5 · Thorium content, like uranium content, tends to increase in felsic rocks and generally increases with alkalinity. Gamma-ray spectrometry, because it can provide direct quantitative measures of the natural radioelements, provides geoenvironmental information concerning radiation dose and radon potential. Because uranium and (or)

Ocean Sediment - an overview | ScienceDirect Topics

III.E Biogenous Sedimentation. Ocean sediments consist of biogenic silica (global average of 14%), calcite (48%), and aluminosilicate dust (abyssal clay derived from the weathering of continents) (38%). The silicic acid [Si (OH)4] and calcium bicarbonate [Ca (HCO 3) 2] introduced into the oceans from rivers are removed by biogenous sedimentation.

KGS--Geological Log Analysis--The Gamma Ray Log

The thorium, uranium, and potassium curves in Tracks 2 and 3 record the quantities of these elements, which can be used in a more systematic analysis. Spectral gamma-ray log analysis is commonly made on the basis of the thorium-to-potassium (Th/K) ratio;