Multi-step chemical abrasion thermal ionization mass spectrometry (CA-TIMS) methods were developed for monazite using six samples that vary in composition and age—Amelia, Jefferson County, Burke, Elk Mountain, 554 and Madagascar. To evaluate whether the multi-step CA-TIMS approach reveals complexities in either age or composition that might be masked by single-step analysis, this study presents...

Department of Earth and Environmental Sciences, The Open University, Milton Keynes, MK7 6AA, U.K. 2 Department of Mineralogy, The Natural History Museum, London, SW7 5BD, U.K. 3 Department of Earth & Planetary Systems Science, Hiroshima University, 1-3-1 Kagamiyama, HigashiHiroshima 739-8526, Japan Department of Geology, Banaras Hindu University, Varanasi, 221005, India 5 Post Graduate Departme...

The past 15 years have produced numerous innovations in geochronology, including experimental methods, instrumentation, and software that are revolutionizing the acquisition and application of geochronological data. For example, exciting advances are being driven by Laser-Ablation ICP Mass Spectrometry (LA-ICPMS), which allows for rapid determination of U-Th-Pb ages with 10s of micrometer-scale...

During the COUIX of I :50 000 scale regional mapping in the Northern Selkirk Mountains (NTS 082M) various granitic rocks were sampled for U-Pb geochronology. This report presents new U-Pb data, interpreted ages, and the implications of these results for hvo such samples from the Selkirk Allochthon: the Downie Creek otihogneiss, and the Goldstream Pluto”. The Downie Creek orthogneiss consists of...

The Tafassasset meteorite which was found the Tenere dessert, Niger, in 2000 and 2001 consists of 26 pieces with a total weight of ~110 kg. The well-preserved meteorite has been studied by several groups [1-4], but until today no consensus on the meteorite's classification was obtained. Reasons for this difficulty are:-texture and mineral abundances vary considerably,-different individual stone...

Introduction: Beta decay of Re is characterized by the lowest known decay energy, which makes direct counting determination of the decay constant very difficult. The best direct estimate for λRe (1.64·10 y ±3.1%) was obtained by the radiochemical in-growth method [1]. This result was generally accepted for geochronology, although its uncertainty precludes precise comparison of Re-Os ages with o...

In situ laser ablation inductively coupled mass spectrometry (LA ICP-MS) is used to determine the U-Th-Pb age of phosphates ferromerrillite and apatite in Los Angeles shergottitic meteorite. The initial 207Pb/206Pb was refined by analyzing K-rich diaplectic glass. LA ICP-MS mapping document zones elevated U Th content establish textural controls on isotope ages. By critically assessing dispersi...

The B and Pb isotope systems are widely applied tracers of recycling processes occurring during subduction. Studies examining these complementary systems as a pair enjoy considerable success, where B primarily records the thermal and fluid evolution of the subducting slab, whereas the tripartite Pb system constrains the source of subducted material returned to volcanic arcs. However, interpreta...