Abstract

We investigated the applicability of micro-Raman spectroscopy for determining carbon isotopic compositions (<sup>13</sup>C/<sup>12</sup>C) of minute CO<sub>2</sub> fluid inclusions in minerals. This method is nondestructive and has sufficiently high spatial resolution (1 μm) to measure each fluid inclusion independently. Raman spectra of CO<sub>2</sub> fluid have <sup>12</sup>CO<sub>2</sub>-origin peaks at about 1285 cm<sup>−1</sup> and 1389 cm<sup>−1</sup> (V<sub>−</sub><sup>[12]</sup> and V<sub>+</sub><sup>[12]</sup>) and a <sup>13</sup>CO<sub>2</sub>-origin peak at about 1370 cm<sup>−1</sup> (V<sub>+</sub><sup>[13]</sup>). The relationship between carbon isotopic compositions and peak intensity ratios of V<sub>+</sub><sup>[12]</sup> and V<sub>+</sub><sup>[13]</sup> was calibrated. Considering several factors affecting the peak intensity ratio, the error in obtained carbon isotopic composition was 2% (20%). The reproducibility of the intensity ratio under the same experimental environment was 0.5% (5%). Within these error values, we can distinguish biogenic CO<sub>2</sub> from abiogenic CO<sub>2</sub>.

PDF Article

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription