Quaternary dating

Molodkov (2001) used ESR to date eight terrestrial shell samples from Treugolnaya (Triangular) Cave (Northern Caucasus), ages ranging from 583,000 to 393,000Y old.

Shigueo et al., (2003) dated a calcite formation found on a rock wall painting at Toca da Bastiana, rock shelter in Serra da Capivara National Park, Piaui, Brazil, obtaining an age of 35,000 to 43,000Y, indicating that humans lived there before 35,000 years ago (this being the date for the first humans to arrive in Brazil).

ESR has been used with tooth enamel for determining the age of Palaeolithic archaeological sites, mainly because tooth enamel is ubiquitous in these contexts and because it allows dating beyond the [sup.14]C dating time range (40-45 Ka max.).

It is thus also very useful in important sites regarding human evolution studies, sites having palaeontological interest within a quaternary time frame and because many sites lack the volcanic materials needed for K--Ar and [sup.40]Ar/[sup.39]Ar dating (Rink 1997). A]) to which a sample has been exposed whilst being buried; the exposure time is then determined by comparing DA to the average dose rate over such period: T = [

This is because it is a good compromise between sensitivity, sample size and water content effects; v [approximately equal to] 9.8 GHz and H [approximately equal to] 350 m T for the X band.

ESR dating and dosimetry are based on the fact that ionising radiation produces paramagnetic centres having long lifetimes in a number of materials. O., Baffa O., (2001): ESR dosimetry of 89Sr- and 153Sm-in bone.

ESR allows some materials to be dated because free radical concentration is a measurement of the total radiation dose absorbed by the sample during the time it was exposed to radiation and hence their burial time (Jonas 1977). T., (1994): Cosmic ray contributions to dose-rates for luminescense and ESR dating: large depths and long-term time variations.

Materials and Methods The dentine was initially removed from teeth using a dental drill and water cooling. IAEA Report., (2002): Use of electron paramagnetic resonance dosimetry with tooth enamel for retrospective dose assessment.

Unpaired electrons from free radicals have spin equal to V.

There are two magnetic levels ( 1/2 and -1/2) in a magnetic field, both having different energy (Figure 2); the transition between these two levels is possible in the following resonance condition: hv = g[beta]H (1) where v is resonance frequency, h is Plank's constant, g is the g-factor (which is a constant = 2 for 1/2 spin), [beta] is the Bohr magneton which is an electron magnetic dipole moment and H is the magnetic field.

After irradiation, the ESR signal was measured with a Bruker ESP300 X-band spectrometer.

The parallel signals' peak to peak height was used for calculating amplitude.

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Materials and Methods The dentine was initially removed from teeth using a dental drill and water cooling. IAEA Report., (2002): Use of electron paramagnetic resonance dosimetry with tooth enamel for retrospective dose assessment. Unpaired electrons from free radicals have spin equal to V. There are two magnetic levels ( 1/2 and -1/2) in a magnetic field, both having different energy (Figure 2); the transition between these two levels is possible in the following resonance condition: hv = g[beta]H (1) where v is resonance frequency, h is Plank's constant, g is the g-factor (which is a constant = 2 for 1/2 spin), [beta] is the Bohr magneton which is an electron magnetic dipole moment and H is the magnetic field. After irradiation, the ESR signal was measured with a Bruker ESP300 X-band spectrometer. The perpendicular to and parallel signals' peak to peak height was used for calculating amplitude.

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