Abstract
The ion microprobe is a highly versatile analytical instrument capable of a wide variety of in situ isotopic and trace element studies of solid materials, with a spatial resolution of 15 to 25 mm, consuming only 2 to 5 ng of sample per determination. In a study combining uranium-lead isotope dating, rare earth element fingerprinting, a sulfur plus lead isotope tracing, it has been possible to address critical questions concerning the timing of, sources of materials for, and processes involved in diamond formation in African kimberlites. The zircon uranium-lead data indicate that kimberlites may host two generations of minerals: one crystallizing at the time of kimberlite emplacement and the other significantly older, perhaps relict from a previous kimberlite magma-generating event. The data from this study can be reconciled with a single model in which introduction of crustal material into the mantle triggers both generation of the kimberlite and diamond growth. This makes plate tectonics of paramount importance in locating economic reserves of diamonds. -from Authors
Original language | English |
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Pages (from-to) | 271-280 |
Number of pages | 10 |
Journal | Economic Geology |
Volume | 90 |
Issue number | 2 |
Publication status | Published - 1995 |