Fig4OmanComp.png

Hemispherically in-phase precipitation variability over the last 1700 years in a Madagascar speleothem record

http://dx.doi.org/10.1016/j.quascirev.2017.03.017

Nick Scroxton, Stephen J. Burns, David McGee, Ben Hardt, Laurie R. Godfrey, Lovasoa Ranivoharimanana, Peterson Faina

Our new 1,700 stalagmite record from Anjohibe cave in northwestern Madagascar, looking at the history of the Madagascan monsoon and how it relates to the Oman monsoon in the northern hemisphere and rainfall in tropical east-Africa.

Published in Quaternary Science Reviews

Data stored at: tba

1-s2.0-S0031018215005921-gr6.jpg

Natural attrition and growth frequency variations of stalagmites in southwest Sulawesi over the past 530,000 years

http://dx.doi.org/10.1016/j.palaeo.2015.10.030

Nick Scroxton, Michael K. Gagan, Gavin B. Dunbar, Linda K. Ayliffe, Wahyoe S. Hantoro, Chuan-Chou Shen, John C. Hellstrom, Jian-xin Zhao, Hai Cheng, R. Lawrence Edwards

We investigated the distribution of stalagmite basal ages back through time, and discovered a remarkable exponential relationship. This relationship suggests that older stalagmites become harder and harder to find because they get destroyed (natural attrition) at an approximately constant rate. This means that random sampling of stalagmites will not generate long term records without huge amounts of waste and destruction to the cave. Therefore paleoclimate scientists should be dating stalagmites before removing them, in order to preserve the cave environment. By accounting for this 1st order relationship we can then use the residual frequency distribution as a proxy for changes in stalagmite growth initiation, which can be used as a paleoclimate proxy.

Published in Palaeogeography, Palaeoclimatology, Palaeoecology

All data presented in paper

palo1722-fig-0003.png

Persistent El Niño–Southern Oscillation variation during the Pliocene Epoch

http://dx.doi.org/10.1029/2010PA002097

N. Scroxton, S. G. Bonham, R. E. M. Rickaby, S. H. F. Lawrence, M. Hermoso, A. M. Haywood

During the Pliocene, the Pacific Ocean is said to have been in a Permanent El Niño state with important climatic implications for global climate. But since previous studies which only looked at the average state of the climate over many years, it was unclear as to whether this meant that the average state was similar to a modern El Niño, with inter-annual variability around it, or whether the climate was stuck in a permanent El Niño. We used individual foraminifera analysis, combined with the HadCM3 model, to show that despite the El Niño-like mean state, ENSO like variability still existed, with the thermocline fluctuating through the photic zone on inter-annual timescales.

Published in Paleoceanography

Data stored at Pangaea: doi:10.1594/PANGAEA.744735