Uranium thorium dating on corals

Uranium — Thorium dating is a way of determining the age of a rock by the amount of radioactive Thorium it contains. This method can be used to determine the age of calcium carbonate materials, such as coral . Scientists can measure the amount of Thorium -230 in a sample of rock, if the rock contained Uranium originally. Uranium is often found in trace amounts in certain types of rock and is radioactive. It has a half-life (the amount of time it takes for the elements radioactivity to decrease by half) of about 245,000 years. At this point it undergoes alpha decay (it releases an alpha particle, w

Uranium – thorium dating , also called thorium -230 dating , uranium -series disequilibrium dating or uranium -series dating , is a radiometric dating technique established in the 1960s which has been used since the 1970s to determine the age of calcium carbonate materials such as speleothem or coral . Unlike other commonly used radiometric dating techniques such as rubidium–strontium or uranium –lead dating , the uranium — thorium technique does not measure accumulation of a stable end-member decay product

Uranium — Thorium dating is based on the detection by mass spectrometry of both the parent (234U) and daughter (230Th) products of decay, through the emission of an alpha particle. The decay of Uranium 234 to Thorium 230 is part of the much longer decay series begining in 238U and ending in 206Pb. For Uranium — Thorium dating , the initial ratio of 230Th/234U at the time of sample formation must be known or calculated. With time, Thorium 230 accumulates in the sample through radiometric decay. U-Th ages obtained by mass spectrometry in corals from Barbados: sea level during the past 130,000 years. Nature 346: 456-458. Bard, E., Hamelin, B., Fairbanks, R.G. and Zindler, A. 1990.

@article{Chen2020UraniumthoriumDO, title={ Uranium — thorium dating of coral mortality and community shift in a highly disturbed inshore reef (Weizhou Island, northern South China Sea).}, author={Tianran Chen and Shu Li and Jian-xin Zhao and Yue-xing 俸月星 Feng}, journal={The Science of the total environment}, year={2020}, volume={752}. Inshore coral habitats are at high risk of loss due to a combination of climate warming and regional-scale human impacts. As a result, they have undergone significant declines. Direct evidence of acute and chronic disturbance on most inshore coral assemblages is limited. Long-term, periodical surveys and historical baseline data essential for effective management are lacking.

Uranium — Thorium analysis can provide information on the approximate date of cave art paintings by dating the thin calcite layers formed along the top of the artwork. In doing so, this analysis can provide a minimum age, also known as the terminus ante quem. Furthermore, in cases where the supporting calcite layer underlying the painting is accessible, a maximum age (terminus post quem) can also be established (Pons-Branchu et al. U-Th dating reveals regional-scale decline of branching Acropora corals on the Great Barrier Reef over the past century. Proceedings of the National Academy of Sciences, 114(39), pp.10350-10355. DOI: 10.1073/pnas.1705351114. DeCarlo, T.M., Gaetani, G.A., Cohen, A.L., Foster, G.L., Alpert, A.E. and Stewart, J.A., (2016).

Uranium – thorium dating is commonly used to determine the age of calcium carbonate materials such as speleothem or coral , because uranium is more soluble in water than thorium and protactinium, which are selectively precipitated into ocean-floor sediments, where their ratios are measured. The scheme has a range of several hundred thousand years.[2][3]. " Uranium – thorium dating has an upper age limit of somewhat over 500,000 years, defined by the half-life of thorium -230, the precision with which one can measure the thorium -230/ uranium -234 ratio in a sample, and the accuracy to which one know the

Uranium -series dating . Corals used in this study were cleaned mechanically, washed in dis-. tilled waterand X-rayed for aragonite purity. This dataset is a comprehensive, global compilation of published uranium – thorium (U-series) dated fossil coral records from ∼ 150 000–110 000 years ago, as well as associated elevation measurements and sample metadata. In total, 1312 U-series measurements from 994 unique coral colonies are included in the current version of the dataset, all of which have been normalized and recalculated using the same decay constant values.

Timing and duration of growth hiatuses in mid Holocene massive Porites corals from the northern South China Sea. Journal of Quaternary Science ◽. 10.1002/jqs.1410 ◽.

In sum, uranium -series dating of corals and other marine carbonates have demonstrated that sea level responds directly to changes in insolation resulting from changes in orbital geometry. There is also strong evidence that sea level responds to other processes, such as those responsible for millennial-scale climate change, changes in atmospheric CO2 levels, and/or insolation forcing modulated in some fashion.

Уран -ториевое датирование , также называемое датирование торием-230 , неравновесное датирование по урановым сериям или датирование по урановым сериям — это метод радиометрического датирования , созданный в 1960-х годах, который используется с 1970-х годов для определения возраст материалов карбоната кальция , таких как speleothem или коралл . В отличие от других широко используемых методов радиометрического датирования , таких как рубидий-стронциевый или уран -свинцовый метод датирования, уран -ториевый