Corrected IODP Gamma Ray Attenuation (GRA) densities and calculated porosities derived from the LILY Database

The dataset GRA_Densities_Corrected_and_Porosities_2023-12-26.csv is derived from an analysis of data from the LILY Database (https://doi.org/10.5281/zenodo.8408296) as described in Childress et al. (2024, https://doi.org/10.1029/2023GC011287). The file contains over 3.7 million corrected gamma ray attenuation (GRA) bulk density data derived from the LILY database file GRA_DataLITH.csv. It also contains over 3.7 million porosity estimates that are computed from the corrected GRA bulk density using grain densities computed for each lithology from Moisture and Density (MAD) grain densities (derived from LILY file MAD_DataLITH.csv).

Citation: Please cite Childress et al. (2024) when using these data:

Childress, L.B., Acton, G.D., Percuoco, V.P., Hastedt, M., 2024. The LILY Database: Linking Lithology to IODP Physical, Chemical, and Magnetic Properties Data, Geochemistry, Geophysics, Geosystems, 25, https://doi.org/10.1029/2023GC011287.

GRA_Densities_Corrected_and_Porosities_2023-12-26.csv file size uncompressed is 950 Mb.

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; see Table S3 in Childress et al., 2024, https://doi.org/10.1029/2023GC011287).

Sect: section number

Offset (cm): position of the observation, measured relative to the top of a section.

Depth CSF-A (m): location of the observation expressed relative to the top of a hole.

Bulk density (GRA): bulk GRA density measured on whole core sections in g/cm^3.

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.

Prefix: Prefix of the lithology

Principal: Principal lithology

Suffix: Suffix of the lithology

Full Lithology: full lithologic name = Prefix + Principal + Suffix

Simplified Lithology: categorization of lithologies (see Supporting Information in Childress et al., 2024, https://doi.org/10.1029/2023GC011287)

Lithology Type: Sedimentary, Igneous, or Metamorphic

Degree of Consolidation: consolidation state of the lithology.

Lithology Subtype: categorization of lithologies (see Supporting Information in Childress et al., 2024, https://doi.org/10.1029/2023GC011287).

Expanded Core Type: the actual coring type used, because some coring types were incorrectly grouped in the "Type" column (see Childress et al., 2024 for an explanation)

Latitude (DD): Latitude in decimal degrees

Longitude (DD): Longitude in decimal degrees

Water Depth (mbsl): water depth in meters below sea level

Grain Density: grain density associated with the Principal lithology, computed from MAD data

Mean MAD Bulk Density: mean MAD bulk density associated with the Principal lithology.

Std MAD Bulk Density: standard deviation in the MAD bulk densities for each Principal lithology.

Correction Basis: the GRA bulk densities are corrected based on coring tool used. If the RCB was used, then the lithology cored by the RCB is used in determining the size of the correction.

Median Difference: The correction that will be applied based on the median difference between the raw GRA bulk density and the colocated MAD bulk density for a specific Correction Basis.

GRA Bulk Density Corrected: The corrected GRA bulk density in g/cm^3.

Porosity: porosity computed from the corrected GRA bulk densities and grain density.

Deviation: difference between "GRA Bulk Density Corrected" and "Mean MAD Bulk Density", which is the deviation the corrected density has from that expected for its Principal lithology.

N Deviations: The number of standard deviations by which the observation differs from the expected value (= Deviation/(Std MAD Bulk Density)), which is useful for identifying outliers.

GitHub Repository:

Contains a few notebooks to demonstrate how to work with the LILY database

IODP LILY GitHub Repository