Of ice and elephants

Article Abstract:

An improved method of uranium-thorium dating has been used to establish that the midpoint of the end of the second-to-last ice age was 135,000 plus or minus 2,000 years ago. This research can be seen as a significant improvement in the absolute dating of the oxygen isotope record. The researchers claim that the new date is consistent with deglaciation driven by orbital variations in solar irradiance, either in the tropics or in the Southern Hemisphere but not in the Northern Hemisphere. They therefore raise doubts about the Northern Hemisphere connection between orbital variations and climate.

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Possible displacement of the climate signal in ancient ice by premelting and anomalous diffusion

Article Abstract:

Research examining interpretations of high-resolution records illustrating climate changes which are derived from ice cores is presented. Particular attention is given to demonstrating that compositional diffusion is determined by pre-melting and causes advection of anomalies toward warmer areas.

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Iron uncertainty

Article Abstract:

Issues concerning the influence of iron availability during glacial periods on levels of carbon dioxide are discussed. More iron is thought to have been available to phytoplankton whose growth reduced carbon dioxide levels.

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