Development and Application of Oxygen and Carbon Isotopic Measurements of Biogenic Carbonates by Ion Microprobe

Abstract

The analytical capabilities of the ims 1270 ion microprobe (SIMS) in determining O and C isotope compositions in biogenic carbonate samples have been tested. Results indicated that, with a spot size of ≊ 30 μm, the average reproducibility at the 1s level was 0.3‰ for oxygen isotopes and 0.6‰ for carbon isotopes. Nevertheless, this reproducibility can reach 0.2‰ for oxygen isotope determinations during some sessions. These reproducibilities allowed us to perform analyses on biogenic carbonate samples for environmental studies. In this paper, examples of oxygen and carbon isotope measurements are presented for a modern coral and the Holocene scleractinian coral, Porites lutea.

In situ measurements of oxygen isotopic composition in deep-sea coral, Lophelia pertusa: Re-examination of the current geochemical models of biomineralization

“…Ion probe oxygen isotope analyses were performed at CRPG-CNRS (Nancy, France) using the Caméca ims 1270. The vacuum and instrumental conditions are similar to those described in Rollion-Bard et al (2007). A primary beam of Cs + ions with an impact energy of 10 kV and an intensity of 7 nA was focused to a spot of approximately 10 lm wide and 30 lm long using Kohler illumination, resulting in an homogeneous beam density and a flat-bottomed sputter crater.…”

Intra-shell oxygen isotope ratios in the benthic foraminifera genus Amphistegina and the influence of seawater carbonate chemistry and temperature on this ratio

“…The stability of the instrument was monitored by multiple measurements of two calcite internal standards (i.e. Carb and MEX, Rollion-Bard et al, 2007). The external reproducibility obtained on this standard during an entire one-day analytical session can reach ±0.12& (1r).…”

Optical Observations and Geochemical Data in Deep-Sea Hexa- and Octo-Coralla Specimens

“…In multicollection, the L'2 and H1 Faraday cup gains were systematically inter-calibrated at the beginning of each analytical session. During the analytical session, the internal reproducibility was better than ±0.1‰ and the external reproducibility, based on repeated measurements of two in-house calcite reference materials (MEX and CARB, [50]), was between ±0.1‰ and ±0.3‰ (1σ), depending on the analytical session. As gorgonian corals are composed of high-Mg calcite, the effect of Mg content on the instrumental mass fractionation was corrected using the method described in [51].…”

“…The instrumental conditions are similar to those described in [50]. Briefly, a primary beam of Cs + ions with an impact energy of 10 kV and an intensity of 5 nA was focused to a spot of approximately 5 µm wide and 15 µm long.…”