H/ H measurements of amphiboles and nominally anhydrous minerals (clinopyroxene, garnet and diamond) using high-temperature continuous flow elemental analyser/pyrolysis/isotope ratio mass spectrometry.

Rationale: We have used a high-precision, high-efficiency method for the measurement of the H/ H ratios of hydrous silicates (amphiboles) and nominally anhydrous minerals (NAM) such as clinopyroxene, garnet and diamond, which are usually extremely resistant to pyrolysis. This opens up new fields of investigation to better understand the conditions of formation for deep-Earth minerals.

Methods: The technique described here involves Isotope Ratio Mass Spectrometry (IRMS) on-line in continuous flow mode with an Elemental Analyser (EA) using "purge and trap" technology rather than separation by conventional packed column gas chromatography (GC).

The 2.1 Ga old Francevillian biota: biogenicity, taphonomy and biodiversity.

The Paleoproterozoic Era witnessed crucial steps in the evolution of Earth's surface environments following the first appreciable rise of free atmospheric oxygen concentrations ∼2.3 to 2.1 Ga ago, and concomitant shallow ocean oxygenation.

Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago.

The evidence for macroscopic life during the Palaeoproterozoic era (2.5-1.6 Gyr ago) is controversial.