U pb isotope dating
In uranium–lead (U–Pb) dating of zircon, the zircon is found to exclude initial lead almost completely.
Minerals, too, are predictable chemical compounds that can be shown to form at...
This study presents new geochemical (major and trace element, Nd–Sr isotope) and U–Pb zircon, monazite, titanite and rutile data for various rock types (eclogite, high-pressure granulite, amphibolite, orthogneiss, leucosome) of the high-grade metamorphic Mariánské Lázně Complex in the western Bohemian Massif.
Concordant U–Pb zircon analyses from the mafic to intermediate samples disclose the Mariánské Lázně Complex as a mixture of .
540 Ma oceanic rocks juxtaposed at depth with lower-crustal rocks of the structurally overlying Teplá–Barrandian Unit.
This interpretation refutes earlier models in which the Mariánské Lázně Complex was interpreted as a dismembered Cambro-Ordovician ophiolite complex affected by Variscan subduction.
ion bombardement is significantly enhanced if the sample surface is saturated with regard to oxygen.
During zircon analysis, oxygen gas is leaked through a valve into the ims1270 sample chamber. Note: in order to open EP10, EP11 or to vent the door, the leak valve has to be closed (1.5 turns clockwise).
Pb have characteristic energy distributions (see Figure) and therefore optimizing intensities and finding a region in the energy distribution sufficiently stable to minimize interelement fractionation is a prerequisite for analysis.
The sequence is as follows: In order to stabilize the secondary ion signal and to remove surface contamination, the primary beam is focused on the sample surface for a certain time period prior to data acquisition.