Radioisotopic dating method currently used
Some laboratories retain all smears that have been reviewed by a laboratory hematologist or pathologist; this can create a storage problem, and it is likely that, increasingly, digital images of important abnormal smears will be stored.
The continuing importance of the blood smear is highlighted by the recent introduction of photographs of blood smears as a regular feature in both the journal Blood and the British Journal of Haematology, by ongoing efforts to develop image-recognition technology for the automated examination of blood smears, and by the development of telehematology to permit the remote interpretation or second opinions of blood smears.
For the reader who is unfamiliar with geologic terms, a glossary is presented at the end of the article.
Terms listed in the glossary are italicized on their first use in the text. Carbon is widely dissolved in the earth’s silicate minerals at part-per-million levels and lower.
Diamonds are stable under the high pressure and temperature conditions that are only met at great depth in the earth’s mantle.
This phase diagram depicts the stability fields of graphite and diamond in relation to the convecting mantle (asthenosphere) and the lithospheric mantle.
Recent work of the research community (summarized in Pearson and Shirey, 1999; Cartigny, 2005; Harlow and Davies, 2005; Stachel et al., 2005, 2009; Stachel and Harris, 2008, 2009; Gurney et al., 2010; Shirey et al., 2013) has been of considerable interest to economic geologists searching for natural diamonds, guiding their models of how to explore for new occurrences.
The experimentally determined pressure-temperature conditions where diamond is stable (figure 3) dictate formation pressures higher than 40 thousand atmospheres (4 GPa) and temperatures of 950–1400ºC.
While these pressure-temperature conditions seem extreme, for a large rocky planet such as ours, they are not.
Diamond provides the perfect container for mantle minerals, isolating them from the high pressure and temperature reactions within the earth for geologic time scales.
Even low elemental concentrations and minute features in diamond can now be analyzed using instruments with higher sensitivity and resolution.