TY - JOUR
T1 - Shrimp zircon ages and petrology of lower crustal granulite xenoliths from the letseng-la-terae kimberlite, lesotho
T2 - Further evidence for a namaqua-natal connection
AU - Sommer, H.
AU - Wan, Y.
AU - Kröner, A.
AU - Xie, H.
AU - Jacob, D. E.
PY - 2013/12
Y1 - 2013/12
N2 - Recrystallized zircons extracted from intermediate granulites of the Letseng-la-Terae Diamond Mine in northeastern Lesotho provide evidence that the Tugela Terrane of the Mesoproterozoic high-grade Namaqua-Natal mobile belt may extend -200 km farther west than previously thought. The rock-forming minerals in the investigated lower crustal granulites contain garnet, clinopyroxene, plagioclase and quartz or garnet, wollastonite, plagioclase and quartz. Calculated values for peak granulite-facies metamorphism are ∼13 kbar and ∼850°C. Thermal overprint and therein granulite-facies metamorphism occurred during the late Mesoproterozoic and is documented by SHRIMP metamorphic zircon ages of 1018 ± 18, 1126 ± 10 and 1127 ± 6 Ma. These ages are in good agreement with the timing of other events in the Namaqua-Natal belt. High-grade metamorphism was probably caused by crustal thickening resulting from continent-arc collision, followed by underplating of hot mantle melts.
AB - Recrystallized zircons extracted from intermediate granulites of the Letseng-la-Terae Diamond Mine in northeastern Lesotho provide evidence that the Tugela Terrane of the Mesoproterozoic high-grade Namaqua-Natal mobile belt may extend -200 km farther west than previously thought. The rock-forming minerals in the investigated lower crustal granulites contain garnet, clinopyroxene, plagioclase and quartz or garnet, wollastonite, plagioclase and quartz. Calculated values for peak granulite-facies metamorphism are ∼13 kbar and ∼850°C. Thermal overprint and therein granulite-facies metamorphism occurred during the late Mesoproterozoic and is documented by SHRIMP metamorphic zircon ages of 1018 ± 18, 1126 ± 10 and 1127 ± 6 Ma. These ages are in good agreement with the timing of other events in the Namaqua-Natal belt. High-grade metamorphism was probably caused by crustal thickening resulting from continent-arc collision, followed by underplating of hot mantle melts.
UR - http://www.scopus.com/inward/record.url?scp=84901440283&partnerID=8YFLogxK
U2 - 10.2113/gssajg.116.2.183
DO - 10.2113/gssajg.116.2.183
M3 - Article
SN - 1012-0750
VL - 116
SP - 183
EP - 198
JO - South African Journal of Geology
JF - South African Journal of Geology
IS - 2
ER -