HR-SIMS lab

A rock consists of minimum units named mineral. After determination of major-element concentration of a rock, you want to describe major-element concentration of each mineral to describe spatial distribution of elements in a rock.

Size of a mineral varies in five order of magnitude from nano-meter to centi-meter. Our nominal electron-beam technique can describe elemental distribution down to sub micron scale. The first step is to identify what are the minerals and describe petrographic and symbiotic relationship among the minerals.

We identify phases in a rock via three approaches, that are Raman spectrometry, Fourier transform infrared spectrometry, and scanning-electron microscopy (SEM).

After identification of the minerals, you want to determine major-elemental concentration of each mineral. The most common approach is to analyze X-ray coming from surface of minerals, using SEM equipped with X-ray detector referred as EDS semi-quantitatively. As the next step, you may want to determine the major-element composition precisely using electron-probe micro-analyzer in the other room.

In the similar way, you want to describe trace-element distribution in a rock. Say you have determine distribution of trace elements in a rock.

Next, you want to determine isotope composition of minerals. Isotope composition will give you idea about source, kinetic process, and age. To determine isotope composition of trace element in a tiny minerals, you want to utilize high-sensitive and high-spatial-resolution mass spectrometry, that is secondary-ion mass-spectrometry. Focused ion beam (typically 15 micron) will sputter area of interest to ionizemineral-consisting elements. The ions of concern are mass filtered and the ion intensities are determined by ion counter. The direct ion detection makes this technique high sensitive and allows determination of isotope composition of trace-elements.

Methods and techniques:

in situ Li, B, and Pb isotope analyses
• Kobayashi el al. (2004). Lithium, boron and lead isotope systematics of glass inclusions in olivines from Hawaiian lavas: evidence for recycled components in the Hawaiian plume, Chemical Geology, 212(1-2), 143-161.

U–Pb dating of zircons
• Usui et al. (2002). U-Pb isotope systematics of micro-zircon inclusions, Proceedings of the Japan Academy, Series B, 78(3), 51-56.

1280 Lab Spherical Image - RICOH THETA

Related Work

• Nakamura et al. (2019). Hypervelocity collision and water-rock interaction in space preserved in the Chelyabinsk ordinary chondrite, Proceedings of the Japan Academy, Series B, 95(4), 165-177.
• Kunihiro et al. (2019). Lithium- and oxygen-isotope compositions of chondrule constituents in the Allende meteorite, Geochimica et Cosmochimica Acta, 252, 107-125.
• Ota et al. (2019). Tourmaline in a Mesoarchean pelagic hydrothermal system: Implications for the habitat of early life, Precambrian Research, 334, 105475.
• Steller et al. (2019). Boron Isotopes in the Puga Geothermal System, India, and Their Implications for the Habitat of Early Life, Astrobiology, 19, 1459-1473.
• Ranaweera et al. (2018). Circa 1 Ga sub-seafloor hydrothermal alteration imprinted on the Horoman peridotite massif, Scientific Reports, 8, 9887.
• Tikhomirov et al. (2017). Post-collisional Magmatism of Western Chukotka and Early Cretaceous Tectonic Rearrangement in Northeastern Asia, Geotectonics, 51, 131-151.
• Schiavi et al. (2015). Geochemical heterogeneities in magma beneath Mount Etna recorded by 2001-2006 melt inclusions, Geochemistry, Geophysics, Geosystems, 16(7), 2109-2126.
• Rehman et al. (2013). Ion microprobe U–Th–Pb geochronology and study of micro-inclusions in zircon from the Himalayan high- and ultrahigh-pressure eclogites, Kaghan Valley of Pakistan, Journal of Asian Earth Sciences, 63, 179-196.
• Nakamura et al. (2012). Space environment of an asteroid preserved on micrograins returned by the Hayabusa spacecraft, Proceedings of the National Academy of Sciences of the United States of America, 109(11), E624-E629.
• Sakyi et al. (2012). Inherited Pb isotopic records in olivine antecryst-hosted melt inclusions from Hawaiian lavas, Geochimica et Cosmochimica Acta, 95, 169-195.
• Schiavi et al. (2012). Trace element and Pb–B–Li isotope systematics of olivine-hosted melt inclusions: insights into source metasomatism beneath Stromboli (southern Italy), Contributions to Mineralogy and Petrology, 163, 1011-1031.
• Tikhomirov et al. (2012). The Cretaceous Okhotsk– Chukotka Volcanic Belt (NE Russia): Geology, geochronology, magma output rates, and implications on the genesis of silicic LIPs, Journal of Volcanology and Geothermal Research, 221-222, 14-32.
• Fourie et al. (2011). Provenance and reconnaissance study of detrital zircons of the Palaeozoic Cape Supergroup in South Africa: revealing the interaction of the Kalahari and Río de la Plata cratons, International Journal of Earth Sciences (GR Geologische Rundschau), 100, 527-541.
• Maruyama et al. (2009). Elemental and isotopic abundances of lithium in chondrule constituents in the Allende meteorite, Geochimica et Cosmochimica Acta, 73(3), 778-793.
• Schiavi et al. (2009). Degassing, crystallization and eruption dynamics at Stromboli: trace element and lithium isotopic evidence from 2003 ashes, Contributions to Mineralogy and Petrology, 159, 541-561.
• Ota et al. (2008). Boron cycling by subducted lithosphere; insights from diamondiferous tourmaline from the Kokchetav ultrahigh-pressure metamorphic belt, Geochimica et Cosmochimica Acta, 72(14), 3531–3541.
• Tang et al. (2007). Lithium isotopic systematics of peridotite xenoliths from Hannuoba, North China Craton: Implications for melt-rock interaction in the considerably thinned lithosphereic mantle, Geochimica et Cosmochimica Acta, 71(17), 4327-4341.
• Usui et al. (2003). Fate of the subduted Farallon plate inferred from eclogite xenoliths in the Colorado Plateau, Geology, 31, 589–592.