Natural Titanite Reference Materials for In SituIn Situ U‐Pb and Sm‐Nd Isotopic Measurements by LALA ‐( MCMC )‐ ICPICP ‐ MSMS

摘要

> Titanite is a common accessory mineral that preferentially incorporates considerable amounts of U and light rare earth elements in its structure, making it a versatile mineral for in?situ U‐Pb dating and Sm‐Nd isotopic measurement. Here, we present in?situ U‐Pb ages and Sm‐Nd isotope measurement results for four well‐known titanite reference materials (Khan, BLR ‐1, OLT 1 and MKED 1) and eight titanite crystals that could be considered potential reference material candidates (Ontario, YQ ‐82, T3, T4, TLS ‐36, NW ‐ IOA , Pakistan and C253), with ages ranging from ~?20?Ma to ~?1840?Ma. Results indicate that BLR ‐1, OLT 1, Ontario, MKED 1 and T3 titanite have relatively homogeneous Sm‐Nd isotopes and low common Pb and thus can serve as primary reference materials for U‐Pb and Sm‐Nd microanalysis. YQ ‐82 and T4 titanite can be used as secondary reference materials for in?situ U‐Pb analysis because of their low common Pb. However, internal structures and mineral inclusions in YQ ‐82 will require careful selection of suitable target domains. Pakistan titanite is almost concordant with an age of 21?Ma and can be used as a reference material when dating Cenozoic titanite samples.