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SUMMARY:Late Quaternary tephrostratigraphies from East African lakes - Chr
 istine Lane\, Department of Geography\, University of Cambridge
DTSTART:20170126T173000Z
DTEND:20170126T183000Z
UID:TALK69457@talks.cam.ac.uk
CONTACT:Dr Rachael Rhodes
DESCRIPTION:This talk is part of the Quaternary Discussion Group (QDG)\n\n
 Understanding the spatial and temporal variability of climate forcing and 
 palaeoenvironmental response across a continent as climatically diverse as
  Africa relies upon comparison of data from widespread palaeoenvironmental
  archives. Accurate\, precise and independent chronologies for such record
 s are essential\; however this remains a challenge in many environments an
 d often prevents the valid comparison of detailed palaeo-proxy records. Ma
 ny studies have now shown that volcanic ash (tephra) can be detected in te
 rrestrial and marine sediments thousands of kilometres from their source\,
  often as microscopic or “cryptic” layers. As well as offering opportu
 nities for both direct (e.g. by 40Ar/39Ar methods) and indirect (e.g. by a
 ssociated 14C dates) dating of the sediment sequence\, tephra layers can p
 rovide stratigraphic tie-lines between archives\, facilitating precise cor
 relations at single moments in time. Furthermore\, where two or more tephr
 a layers are co-located in multiple records\, rates of change can be compa
 red within a period of equivalent duration\, even in the absence of absolu
 te age estimates.  \nInvestigations into the presence of visible and non-v
 isible (crypto-) tephra layers within lacustrine palaeoenvironmental recor
 ds of the last ~150 ka BP from across East Africa are revealing the potent
 ial for this approach to (i) correlate palaeoclimate archives from across 
 and beyond tropical Africa within a regional tephrostratigraphic framework
 \; (ii) provide age constraints for individual core chronologies\, in part
 icular beyond the limits of radiocarbon dating\; and (iii) increase our kn
 owledge of the history of Late Quaternary explosive volcanism in East Afri
 ca. \n
LOCATION:Latimer Room (Old Court)\, Clare College\, Trinity Lane
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