TY - JOUR
T1 - Kimberlites from the Wawa area, Ontario
AU - Kaminsky, Felix V.
AU - Sablukov, Sergei M.
AU - Sablukova, Ludmila I.
AU - Shchukin, Vladimir S.
AU - Canil, Dante
PY - 2002/12
Y1 - 2002/12
N2 - Two newly discovered kimberlites from the Wawa area, Ontario, are Group-1 kimberlites in their petrographic, mineralogical, geochemical, and isotopic features. They contain mantle minerals and xenoliths of the Fe-Ti-association (magnesian ilmenite, iron-rich olivine, orange Ti-pyrope garnet, augite, and ferroan enstatite) and of the Cr-association (chromian spinel, forsteritic olivine, purple Cr-pyrope garnets, chromian diopside, and enstatite); minerals of Fe-Ti-association are much more abundant. Minerals of eclogitic association are absent. Both G-10 pyrope garnets and high Cr spinels typically associated with diamond are represented in the Cr-association. The average age of the kimberlites is 1097 ± 7 Ma; i.e., contemporaneous with other alkaline igneous rocks in the Wawa area. Equilibration pressures and temperatures of mantle xenoliths plot close to a 40-45 mW m-2 geotherm. On the basis of the Ni-in-garnet geothermometer, garnets from the Wawa kimberlites equilibrated at 800-1350°C, and at least in part within the diamond stability field. It is likely that kimberlitic magma was derived from light rare earth-element-enriched asthenospheric mantle.
AB - Two newly discovered kimberlites from the Wawa area, Ontario, are Group-1 kimberlites in their petrographic, mineralogical, geochemical, and isotopic features. They contain mantle minerals and xenoliths of the Fe-Ti-association (magnesian ilmenite, iron-rich olivine, orange Ti-pyrope garnet, augite, and ferroan enstatite) and of the Cr-association (chromian spinel, forsteritic olivine, purple Cr-pyrope garnets, chromian diopside, and enstatite); minerals of Fe-Ti-association are much more abundant. Minerals of eclogitic association are absent. Both G-10 pyrope garnets and high Cr spinels typically associated with diamond are represented in the Cr-association. The average age of the kimberlites is 1097 ± 7 Ma; i.e., contemporaneous with other alkaline igneous rocks in the Wawa area. Equilibration pressures and temperatures of mantle xenoliths plot close to a 40-45 mW m-2 geotherm. On the basis of the Ni-in-garnet geothermometer, garnets from the Wawa kimberlites equilibrated at 800-1350°C, and at least in part within the diamond stability field. It is likely that kimberlitic magma was derived from light rare earth-element-enriched asthenospheric mantle.
UR - http://www.scopus.com/inward/record.url?scp=0036999164&partnerID=8YFLogxK
U2 - 10.1139/e02-089
DO - 10.1139/e02-089
M3 - Review article
AN - SCOPUS:0036999164
SN - 0008-4077
VL - 39
SP - 1819
EP - 1838
JO - Canadian Journal of Earth Sciences
JF - Canadian Journal of Earth Sciences
IS - 12
ER -