Wang 2015

Tremendous advances have been made in the analytical techniques used for study of mineral deposits. Examples include modern microbeam techniques, most usefully, e.g., electron microprobe (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), ion microprobe, infrared microthermometer, new dating techniques (Ar-Ar, FT) and new isotope systems (Ge, B, etc.), that are now widely applied to analyze a variety of minerals in many ore deposits and provide more information on the genesis of mineral deposits. The EPMA is a microbeam instrument used primarily for in-situ non-destructive chemical analysis of solid samples. After its appearance in 1951 (Castaing, 1951), the EPMA led to a revolution in solid material sciences (Newbury, 2001). Using this great new technique, mineralogy made a very important progress in understanding micron-scale textures, particularly in-situ chemical features of minerals. Recent advances in EPMA, include background fitting and lowering detection limits for trace element analysis (Donovan, 2011), use of low accelerating voltage for improvement of spatial resolution (Armstrong et al., 2013), and in-situ U-Th-Pb chemical dating and age mapping (Williams et al., 2007). Recent developments in the use of LA-ICP-MS allows in-situ measurement of U-Pb isotopes and a large number of trace elements with relatively low detection limit of ~1 ppb (Gao et al., 2013; Liu et al., 2008; Nadoll and Koenig, 2011). LA-MC-ICP-MS is also been widely used to determine isotopic compositions (e.g. B, Sr, Nd, etc.) of many minerals. As highlighted in this Special Issue, in-situ LA-ICP-MS trace elemental analyses can be applied tomagnetite from a variety of deposit types. Traditional dating for accessory minerals was established mainly based on TIMS instrumentation. Recent progress with SIMS and LA- (MC)-ICP-MS analyses allow direct U-Pb isotopic dating of suitable Urich and Pb-poor accessory minerals (e.g., titanite, uraninite, columbitetantalite, and monazite) in many types of mineral deposits. We believe that it is timely to highlight some of these advances in analytical techniques and thus, have assembled a number of high quality papers that document their application to the study of mineral deposits in order to provide a better understanding of ore genesis. In this Special Issue, we have assembled 27 papers that report on the use of thesemodern techniques in five broad areas related to the study of a variety of mineral deposits