Anczkiewicz, R. Lu-Hf geochronology and trace element distribution in garnet: Implications for uplift and exhumation of ultra-high pressure granulites in the Sudetes, SW Poland. Lithos , 95 pp. The surrounding rocks were metamorphosed at the same time as indicated by The second metamorphic episode, which affected most of the lower crust in the Orlica-Snieznik Massif OSM occurred at ca. Trace element distribution in garnets from the layered granulites showed significant differences in distribution of medium and HREE in garnets from mafic and felsic protoliths over the course of the metamorphic evolution.
Lu-Hf Dating: The Lu-Hf Isotope System | SpringerLink
The Lu-Hf isotope system, with applications to geo- and cosmochemistry, was first investigated in the early s Patchett b ; Patchett and Tatsumoto a, b , c , following the successful implementation of the Rb-Sr and Sm-Nd isotope systems several years earlier. There are some obvious similarities between the Lu-Hf and Sm-Nd isotope systems and, as a result, they have long been used in concert in a wide range of studies e. In these two systems all elements are lithophile and refractory with high condensation temperatures. Because of these characteristics it has long been assumed that their abundances in the Earth can be approximated by chondritic meteorites see discussion below. In addition, all elements in these systems behave incompatibly during melting and are concentrated in the melt over the residual solid. In both systems, the daughter element e. Both Lu and Hf are highly immobile and insoluble and, as is the case with the Sm-Nd system, are thought to be resistant to perturbations and retain their isotopic information through significant degrees of alteration and metamorphism.
The Wyoming province contains some of the oldest rocks in North America and preserves a long history of magmatism and metamorphism from the Mesoarchean to the Mesoproterozoic. The details of these geological events throughout the province, however, remain elusive. Determining when and how these rocks formed—and how they have been modified by later tectonic processes—is important not only for understanding the geologic history of this region, but also for understanding how North America was formed and assembled. In this study we use U-Pb zircon and Lu-Hf garnet geochronology to determine magmatic and metamorphic ages to constrain the geologic history in the Ruby Range in southwestern Montana, located in northwest Wyoming province. In detail, the focus of this study is on the Christensen Ranch Metasedimentary Sequence CRMS , a package of metasedimentary lithologies located along the western flank of the Ruby Range.
Lutetium—hafnium dating is a geochronological dating method utilizing the radioactive decay system of lutetium — to hafnium — The trace concentration of the Lu and Hf in earth materials posed some technological difficulties in using Lu—Hf dating extensively in the s. Lutetium is a rare-earth element , with one naturally-occurring stable isotope Lu and one naturally-occurring radioactive isotope Lu.