log10Hf

Log10Hf is a terminology used in geochemistry and analytical chemistry to denote the base-10 logarithm of hafnium abundance or concentration in a sample. In practice, log10Hf is usually defined as the logarithm of a hafnium quantity that has been normalized to a reference, such as a standard concentration or a well-established natural reference like chondritic or mantle-normalized values. As a result, log10Hf is a dimensionless quantity, even though it originates from a measured concentration that carries units.

Calculation and interpretation of log10Hf typically follow one of two forms. The common form is log10Hf = log10(C_Hf / C_ref), where C_Hf is the measured hafnium concentration and C_ref is a reference concentration. An alternative form is log10Hf = log10(C_Hf) when the data have already been normalized to a reference value that renders the ratio dimensionless. When reporting log10Hf, it is important to specify the unit system, the normalization standard, and the measurement method.

Measurement methods for hafnium, and thus log10Hf, usually involve techniques such as inductively coupled plasma mass spectrometry (ICP-MS) or ICP-optical emission spectroscopy (ICP-OES) after appropriate sample digestion and matrix correction. log10Hf is useful for handling wide concentration ranges, enabling linear relationships in log space and facilitating statistical analyses, comparisons across samples, and data visualization.

Caveats include handling nondetects, zero values, and the choice of reference standard, all of which can significantly affect the resulting log10Hf. See also hafnium, Hf isotopes, and geochemical normalization.