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SUMMARY:The Mechara caves and speleothems\, Southeastern Ethiopia: high-re
 solution palaeoclimate archives - Asfawossen Asrat (School of Earth Scienc
 es\, Addis Ababa University)
DTSTART:20170206T160000Z
DTEND:20170206T173000Z
UID:TALK70692@talks.cam.ac.uk
CONTACT:Geography/SPRI Webmaster
DESCRIPTION:Among the various climate proxies in speleothems (δ18O\, δ13
 C\, growth rate\, trace elements\, lipids) calcite δ18O is routinely used
  as rainfall proxy. However\, many studies including some from Ethiopia in
 dicated that a variety of climatic\, environmental and hydrologic paramete
 rs influence the geochemical and physical properties of speleothems\, and 
 multi-proxy approach is crucial as the various proxies respond to single c
 limate forcing in different manners. Calcite δ18O records from U-Th dated
 \, Holocene and late Pleistocene speleothems from Ethiopia are discussed i
 n this context. Since 2004\, we have been conducting multi-stalagmite\, mu
 lti-proxy analysis of speleothems from the Mechara karst system in the sou
 theastern Ethiopian highlands and have derived high-resolution paleoclimat
 e parameters such as precipitation. Both δ18O and growth rate parameters 
 of Holocene speleothems indicate marked decadal scale rainfall variability
  in this climatically sensitive region\, implying persistent decadal-scale
  variability for the large-scale atmospheric and oceanic driving factors t
 hroughout the Holocene. On the other hand\, the same two proxies from late
  Pleistocene speleothems from the same region respond non-linearly. In con
 clusion\, calcite δ18O could be a robust rainfall proxy\; however\, coupl
 ing it with other proxies (such as growth rate parameters) is crucial\, as
  any single proxy analysis could lead to an over-simplified interpretation
  of past climatic / environmental change.
LOCATION:Small Lecture Theatre\, Department of Geography
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