Shrimp dating zircon intimidating team names
Experimental studies have shown that zircon solubility is mainly governed by temperature and melt composition, and for typical peraluminous melts zircon solubility ranges from ~100 ppm dissolved at 750 °C to 1300 ppm at 1020 °C (Boehnke et al. Although zircon is most widely used to constrain crystallisation ages of granites, monazite geochronology has been employed sporadically to date the crystallisation age of granites (e.g., Grosse et al. However, there has been little attempt to systematically evaluate the suitability of monazite for geochronology of leucocratic granite types even though monazite appears to be common in a range of granites (Bea ).
The crystallisation ages of several leucocratic granites are not well defined by U–Pb zircon geochronology, which has created uncertainty about the duration and distribution of some of the granite supersuites and related orogenic events in the province.
Leucocratic granite samples analysed previously using U–Pb zircon geochronology were re-analysed in this study using U–Th–Pb monazite geochronology.
Presented below are the original zircon geochronology results for selected peraluminous, leucocratic samples from three generations of Proterozoic magmatism (Table a).
euhedral-subhedral one with striped absorption and round one with obvious oscillatory zoning rims.
The cathodoluminescence (CL) images of the zircons indicate that they can be divided into two major types, i.e.Early indications were that the granites belonged to the Paleoproterozoic Durlacher Supersuite (Culver ).This appeared to be consistent with the fact that the leucocratic granites and pegmatites do not intrude Mesoproterozoic sedimentary rocks of the Bangemall Supergroup within the Ti Tree Shear Zone (Fig.In this paper we use SHRIMP U–Th–Pb monazite geochronology to re-evaluate the emplacement ages of these granites in order to obtain reliable igneous crystallisation ages consistent with the existing geological framework.In turn, this provides better constraints on the duration of granitic magmatism and magma production rates and allows for a more complete magmatic and tectonothermal history of the orogen to be established.).