福建晋江中-基性岩墙群的锆石SHRIMP U-Pb定年和岩石地球化学

Methods recently advanced for discrimination on the genesis of metamorphic zircon, such as analysis of mineral inclusions and trace elements, provide us powerful means to distinguish zircon overgrowth during high-pressure metamorphism. No inherited core was identified in the analyzed zircons by means of cathodoluminescence images. The occurrence of high-pressure metamorphic mineral inclusions in zircon, such as garnet, omphacite, rutile, and the flat HREE pattern in zircon indicate that the zircon formed at high-pressure metamorphic conditions.

Therefore, a weighted average U-Pb age of This is a preview of subscription content, log in to check access. Gebauer, D.

This method has potential for dating sedimentary sequences of all ages but should be especially valuable for refining the Precambrian time scale. View Full Text.

Such a sophisticated ion probe, which can attain a high sensitivity at a high mass resolution, based on a double focusing high mass-resolution spectrometer, designed by Matsuda , was constructed at the Australian National University. Since its installation, our focus has been on the in-situ U—Pb dating of the mineral apatite, as well as zircon, which is a more common U-bearing mineral.

In this paper, we review the methodology associated with in-situ apatite dating and our contribution to Earth and Planetary Science over the past 16 years. Since the monumental studies reported in , 1 an enormous amount of work related to the Pb—Pb dating of meteorites has been reported via the use of TIMS Thermal Ionization Mass Spectrometry.

After this, following cleaning with ethanol, to minimize surface contaminating Pb, the thin section was gold-coated to prevent a charge from developing on the sample surface during SHRIMP analyses. The positive secondary ions were thereby extracted and detected on a single electron multiplier by peak switching. A similar equation also describes the U—Pb secondary ion emission data from other minerals such as monazite, titanite, baddeleyite, rutile.

In the case of ion microprobe U—Pb zircon dating , the expected initial lead based on the U—Pb evolution model is subtracted from the observed lead signals.