Elemental analysis (CHNS)

Fundamental elemental component (total carbon, hydrogen, nitrogen, and sulfur) fluctuations help define the origin, depositional environment, and diagenetic alteration of source materials. To determine C, H, N, and S, solid samples are reacted with a catalyst, separated by chromatography, and detected by thermal conductivity on a FlashEA 1112 CHNS elemental analyzer. Organic carbon can be directly measured on the elemental analyzer by acidification of the sample to drive off carbonate as carbon dioxide before analyzing. Total organic carbon on this report is measured rather than calculated.

Data File format

    Exp: expedition number
    Site: site number
    Hole: hole number
    Core: core number
    Type: type indicates the coring tool used to recover the core (typical types are F, H, R, X).
    Sect: section number
    A/W: archive (A) or working (W) section half.
    Top offset (cm): position of the upper edge of the sample, measured relative to the top of the section.
    Bottom offset (cm): position of the lower edge of the sample, measured relative to the top of the section.
    Top depth CSF-A (m): location of the upper edge of the sample expressed relative to the top of the hole.
    Bottom depth CSF-A (m): location of the lower edge of the sample expressed relative to the top of the hole.
    Top depth [other] (m): location of the upper edge of the sample expressed relative to the top of the hole. The location is presented in a scale selected by the science party or the report user.
    Bottom depth [other] (m): location of the lower edge of the sample expressed relative to the top of the hole. The location is presented in a scale selected by the science party or the report user.
    Organic carbon (wt%): Organic carbon concentration calculated by difference (total C by CHNS - inorganic C by coulometer).
    Carbon (wt%): carbon concentration in sample.
    Hydrogen (wt%): hydrogen concentration in sample.
    Nitrogen (wt%): nitrogen concentration in sample.
    Sulfur (wt%): sulfur concentration in sample.
    Container number: number assigned to weighed sample.
    Sample mass (mg): mass of sample.
    CHNS datafile: excel file of CHNS data.
    Timestamp (UTC): time file was uploaded, which is typically a few minutes to hours after data were acquired.
    Text ID: automatically generated unique database identifier for a sample, visible on printed labels.
    Test No: unique number associated with the instrument measurement steps that produced these data. 
    Sample comments: observations recorded about the sample itself.
    Test comments: observations about a measurement or the measurement process; some measurement observations may be under Result comments.
    Result comments: observations about a measurement or the measurement process; some measurement observations may be under Test comments.