U–Pb age determination of schorlomite garnet by laser ablation inductively coupled plasma mass spectrometry

Abstract

We report the first U–Pb geochronological investigation of schorlomite garnet from carbonatite and alkaline complexes and demonstrate its applicability for U–Pb age determination using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) due to its relatively high U and Th abundances and negligible common Pb content.

Garnet U-Pb and O isotopic determinations reveal a shear-zone induced hydrothermal system

“…9 and Yang et al . 52 . Laser working conditions were: 50 s ablation time, 6 Hz repetition rate, 7 mJ energy with 90% beam attenuation, resulting in a fluence of 10 J cm −2 .…”

U–Pb dating of andradite-rich garnet by SIMS

“…No inclusion and compositional zonation were found through BSE imaging. Yang et al 8 obtained a U-Pb age of 96.4 AE 1.8 Ma by LA-ICP-MS analysis.…”

“…3 In recent years, grossular-andradite (Ca 3 -Al 2 Si 3 O 12 -Ca 3 Fe 2 Si 3 O 12 ) has been found in high U/Pb ratios and is suitable for U-Pb dating. [4][5][6][7][8] The Grs-Adr solid-solution series usually occurs in alkaline and ultramac intrusions [9][10][11] or emerges with Fe, W, Zn, and Mo skarn deposits. 12 Unlike accessory minerals such as zircon and monazite, garnet usually is the main rock-forming mineral, which means that it can directly record the onset time of alkaline and ultramac rock intrusion or hydrothermal activity.…”

“…4,7,13,14 Currently, in situ garnet U-Pb dating methods have been developed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). [6][7][8]13,15 SIMS dating of garnet, with higher spatial resolution, has not yet been explored due to the lack of suitable reference materials. In fact, both methods have their advantages.…”

U–Pb geochronology of calcite carbonatites and jacupirangite from the Guli alkaline complex, Polar Siberia, Russia

“…In comparison with perovskite, Ca-Fe-Ti garnets [Ca 3 (Fe,Ti,Zr,Mg) 2 (Si,Fe,Al) 3 O 12 ] are a relatively new U–Pb geochronometer, whose full potential remains yet to be fully explored (Deng et al , 2017; Salnikova et al , 2018, 2019; Yang et al , 2018; Stifeeva et al , 2020). The principal advantage of calcic garnets over perovskite is their wider distribution across a spectrum of igneous and contact-metamorphic rocks.…”