New Zealand and UK Holocene flooding demonstrates interhemispheric climate asynchrony
Mark G. Macklin et al., Institute of Geography and Earth Sciences, Aberystwyth University, Ceredigion SY23 3DB, UK. Posted online 29 June 2012; doi: 10.1130/G33364.1.
More than 1,000 radiocarbon ages sourced from floodplains in the UK and New Zealand have been used to detect the timing of large-scale flooding during the past ~10,000 years in these temperate maritime regions of the Northern and Southern Hemispheres. Probability and statistical analyses of these datasets shows that flood-rich centuries in New Zealand and the UK were largely asynchronous during this time period. Since these major periods of flooding, or "wet centuries," are controlled by large-scale shifts in atmospheric circulation, these findings demonstrate that short-term climate change was out of phase in the temperate maritime regions of the Northern and Southern Hemispheres. This supports recent research that has suggested that Holocene climate changes may have been antiphased between the polar regions, possibly related to variation in the strength of deep water formation. Reconstructing and interrogating flood histories in the UK and New Zealand provides a novel means of addressing one of the grand challenges in Holocene paleoclimate research, namely establishing whether centennial-scale climate change between the Hemispheres has been synchronous. These data strongly suggest climatic asynchrony.
Oxidation state of subarc mantle
K.A. Evans et al., School of Applied Geology, Curtin University, GPO Box 1987, WA 6845, Australia. Posted online 29 June 2012; doi: 10.1130/G33037.1.
Ocean crust forms from mantle-derived magmas at mid-ocean ridges, travels across the ocean floor as Earth's tectonic plates move, and descends down subduction zones to be recycled into the Earth. This
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