Bulk density (GRA)

Gamma ray attenuation (GRA) data were acquired using a Cs-137 collimated source and a sodium iodide (thallium), or NaI(Tl), scintillation detector. The signal was calibrated using water and aluminum standards to provide a proxy for bulk density. This measurement was performed by a sensor mounted on either the Whole-Round Multisensor Logger (WRMSL) or the Special Task Multisensor Logger (STMSL); which track was used for a given data set is indicated in the data.

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
	Offset (cm): position of the observation made, measured relative to the top of a section.
	Depth CSF-A (m): location of the observation expressed relative to the top of a hole.
	Depth CSF-B (m): location of the observation expressed relative to the top of a hole.
	Bulk density (GRA) (g/cm3): computed bulk density of sample.
	Configuration filename: filename of configuration file.
	Timestamp (UTC): date and time the observation was made.
	Instrument: abbreviation or mnemonic for the GRA sensing device used to make this observation (GRA1 or GRA2).
	Instrument group: abbreviation or mnemonic for the data collection device (logger) used to acquire this observation (WRMSL).
	Text ID: automatically generated unique database identifier for a sample, visible on printed labels.
	Comments: observer's notes about a measurement, the sample, or the measurement process.