Thorium dating marine sediments

thorium dating marine sediments

Can we measure thorium isotopes in seawater?

Since the Atlantic work of Moore and Sackett includes the only non-coastal measurements of thorium in seawater, it was felt important to extend such measurements into the Pacific. Further, additional analyses on sediment samples appeared warranted to attempt to understand the most curious behavior of thorium isotopes in the major sedimentary cycle.

Are Ocean thorium concentrations similar in the Atlantic and Pacific Ocean?

Thorium concentrations in three open Pacific Ocean water samples had values of n × 10−10grams/liter, concentrations similar to those previously measured in the Atlantic.

What is the residence time of seawater thorium?

The sediments in the area in which the seawater thorium was determined accumulate at a rate around 5 mm per thousand years (table 2) and have densities of about 2 g/cm3 with a water content of 50%o. A residence time of 60 years is calculated with such figures.

What is the concentration of thorium in the ocean?

The absolute thorium concentrations in open ocean Pacific waters, 2 to 6.5 x 10-10 g/liter, are in accord with the Atlantic values of Moore and Sackett (1) who found between 3.6 and 4.5 x 10-10 g/liter.

What is the mass of a mole of thorium?

It has a mass of 231.0363043 grams/mole. 232Th is the only primordial nuclide of thorium and makes up effectively all of natural thorium, with other isotopes of thorium appearing only in trace amounts as relatively short-lived decay products of uranium and thorium.

What is the half life of Thor thorium?

Thorium has a characteristic terrestrial isotopic composition and thus a standard atomic weight can be given. Thirty-one radioisotopes have been characterized, with the most stable being 232 Th, 230 Th with a half-life of 75,380 years, 229 Th with a half-life of 7,917 years, and 228 Th with a half-life of 1.92 years.

Related posts: