BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Monogenetic Volcanism: A Window into Mantle Heterogeneity and Magm
 atic Processes - Ninad Bondre (Nature Geoscience\, London)
DTSTART:20081021T153000Z
DTEND:20081021T163000Z
UID:TALK14279@talks.cam.ac.uk
CONTACT:Francis Rowland
DESCRIPTION:Monogenetic volcano-fields - fields containing small\, predomi
 nantly-basaltic volcanoes - occur either in intraplate settings or in asso
 ciation with larger\, polygenetic volcanoes. Recent work has revealed that
  chemical and isotopic diversity within the products of single monogenetic
  volcanoes may be the rule\, rather than the exception. Such volcanoes for
 m during single\, relatively short-lived (months to years) eruptions\; com
 positional variability therefore raises several questions regarding their 
 sources and plumbing systems. Whether the geochemical diversity reflects s
 mall-scale heterogeneity in the mantle source and inefficient mixing of sm
 all magma batches\, or relatively rapid and somewhat erratic differentiati
 on\, is yet to be satisfactorily resolved by geochemical studies. Resolvin
 g this will likely require tapping into the rich information provided by f
 ield relationships and focusing on compositional variations between\, as w
 ell as within\, monogenetic volcanoes. This talk will address key question
 s pertaining to monogenetic volcanism by considering the Jordan Valley Vol
 canic Field in southeastern Oregon as an example. The integration of field
 \, geochemical and geochronologic data for this field hints at small-scale
  mantle heterogeneity and suggests that monogenetic volcanoes may provide 
 important constraints on the evolution and transport of basaltic magma in 
 continental settings.\n\n*Key References*:\n\nKogiso\, T.\, M. M. Hirschma
 nn\, and P. W. Reiners (2004)\, Length scales of mantle heterogeneities an
 d their relationship to ocean island basalt geochemistry\, Geochim. Cosmoc
 him. Acta.\, 68\, 345-360.\n\nMcKenzie D\, Stracke A\, Blichert-Toft J\, A
 lbarede F\, Gronvold K\, O'Nions R. K (2004)\, Source enrichment processes
  responsible for isotopic anomalies in oceanic island basalts\, Geochim. C
 osmochim. Acta.\, 68\, 2699-2724.\n\nNature Geoscience editorial (2008)\, 
 The mantle's fabric\, Nature Geosci.\, 1(4)\, p. 205.\n\nRamos\, F. C.\, a
 nd M. R. Reid (2005)\, Distinguishing between melting of heterogeneous man
 tle sources from crustal contamination: insights from Sr isotopes at the p
 henocryst scale\, Pisgah Crater\, California\, J. Petrol.\, 46\, 999-1012.
 \n\nStrong. M.\, and J. Wolff (2003)\, Compositional variations within sco
 ria cones\, Geology\, 31\, 143-146.
LOCATION:Tilley Lecture Theatre\, Department of Earth Sciences
END:VEVENT
END:VCALENDAR