DOI: 10.5281/zenodo.17155518
title: Experimental Mohole X-ray Fluorescence (XRF), Magnetic Susceptibility (MS), and Line Scan Images

description: Data Collection

Line scan imaging, X-ray fluorescence (XRF), and magnetic susceptibility (MS) data were acquired on cores from the Experimental Mohole Guadalupe Site with the Avaatech 6th generation core scanner at the Scripps Institution of Oceanography in January-February 2025. Line scan images were collected on both the archive and working core halves at 0.025 mm downcore resolution. The line scan camera (JAI LT-400 CL) recorded color data in three channels: red (630 nm), green (535 nm), and blue (450 nm). A linear collimated light source (Metaphase UL-CLL209) coupled with the camera provided uniform light conditions for each core scan. A white calibration was performed prior to each image acquisition, and camera aperture was adjusted manually by an analyst to optimize color saturation. XRF and MS measurements were made on the archive core halves at approximately 1 cm intervals along the center of the core's long axis, with some measurement locations shifted or omitted due to irregular surfaces or cracks in the sediment. The XRF system includes the X-ray tube (Oxford Instruments Neptune 5200 series), detector (Rayspec SiriusSD XRF200i), and multi-channel analyzer (Brightspec Topaz-X Digital MCA). Each XRF data point was acquired within a window measuring 10 mm down-core and 12 mm cross-core. XRF data were measured at 10, 30, and 50 keV with no-filter, Pd-thick, and Cu filters respectively, allowing measurement of relative elemental abundances from sodium to barium. The MS system is a Bartington Instruments MS3 and MS2E, which had a 2 cm-diameter circular sensor window. All MS values presented here were internally corrected for sensor drift and background field by the Avaatech software using background measurements made in the air above the core after each core MS measurement.

Data

Core section naming convention: EM-{hole}-{run}_{top depth in run}-{bottom depth in run}cm_{Archive/Working}. Example: EM-8-10_0-159cm_A means Experimental Mohole (EM), Hole 8, Run 10, Top of section in run (0 cm), Bottom of section in run (159 cm), Archive half (A - working half is denoted W).



Line Scan Images: Mohole_LineScan.zip



subfolders: named by core section (EM-{hole}-{run}_{top depth in run}-{bottom depth in run}cm_{Archive/Working})



.txt file: Contains image metadata as well as machine-output average R, G, B, L*, a*, and b* values across the width of the core at specified positions down the core.



Position[mm]: Position in mm in the down core direction corresponding to the RGBL*a*b* averages

DownCore[ppcm], CrossCore[ppcm]: Down Core pixels per cm, Cross Core pixels per cm, 

ExposureTime[ms]: Exposure time in ms

FirstPixel_DC: First Pixel Down Core, 

PixelCount_DC: Number of pixels imaged down the length of the core

FirstPixel_CC, LastPixel_CC: First and last pixels in the Cross Core direction that are included in the RGBL*a*b* averages

WhiteCalLevel: White Calibration Level = 255 indicates proper calibration.

Aperture: Camera aperture was manually adjusted on the camera and input into the system manually



.jpg and .tif: image of core section





Magnetic Susceptibility: Mohole_MS.zip



subfolders: named by core section (EM-{hole}-{run}_{top depth in run}-{bottom depth in run}cm_{Archive/Working})



.csv and .dat: Magnetic susceptibility data and metadata



Position[mm]: Position in mm in the down core direction of the center of the magnetic susceptibility sensor

Raw: Magnetic Susceptibility measured with no correction

DriftMeasured: Drift measurements were made in the air above the sample

DriftCalculated: n/a, should always be 0

Corrected: Magnetic Susceptibility measurement with correction applied

Temperature: Ambient temperature in C

Unit: Measurement units (SI)







X-Ray Fluorescence: Mohole_XRF.zip



subfolders: named by core section (EM-{hole}-{run}_{top depth in run}-{bottom depth in run}cm_{Archive/Working})



.csv: XRF data and metadata made at the energy specified in the file name (10kV, 30kV, 50kV)



Spectrum: Core section name

CoreID, SectionID: n/a, should always be 0

CoreDepth: same as X Position-mm

DateID: date

TubeVoltage-kV, TubeCurrent-uA: XRF tube voltage (kV) and current (μA)

X Position-mm: Position in mm in the down core direction of the center of the XRF sensor

Y Position-mm: Position in mm in the cross core direction of the center of the XRF sensor

Filter: Type of filter between sample and detector

SlitSize DC-mm, SlitSize CC-mm: XRF measurement window slit dimensions in down core and cross core directions

RunCount: n/a, should always say Run1

Replicate Nr Count: The primary measurements are denoted Rep0. Higher numbers mean the same point was measured again.

Acquisition time: Time of day that acquisition occurred

Live time: Duration of X-ray excitation (seconds)

Real time: How long the measurement took (s)

Elemental abundance data: Data labeled 'Area' contains the number of counts within the energy peak associated with the named element. Ka and La denote the peak excited for the named element.







Data_All_Mohole_GuadalupeSite.csv



Summary table of all of the co-located measurements from the Guadalupe Site (Holes 6-10)



Includes



Corename: Core identification

Aperture: camera aperture during imaging

Exp: Expedition = EM = Experimental Mohole

Hole, Run: Core identification

position_mbsf: Position of the center of the measurement location in meters below sea floor

DCmid_mm_MS, CCmid_mm_MS: center of MS sensor in mm in down core and cross core directions

radius_mm_MS: radius of magnetic susceptibility sensor

Npix_MS: number of pixels in the image corresponding to the MS sensor window

Nblackpix_MS, Nwhitepix_MS, Nredpix_MS: number of designated black, white, or red pixels in Npix_MS

Rmean_MS, Gmean_MS, Bmean_MS: mean value of Red, Green, and Blue components of pixels within MS sensor window

DCtop_mm_XRF, DCbot_mm_XRF, CCleft_mm_XRF, CCright_mm_XRF: top, bottom, left, and right edge position of XRF measurement window in mm in down core and cross core directions

Npix_XRF: number of pixels in the image corresponding to the XRF sensor window

Nblackpix_XRF, Nwhitepix_XRF, Nredpix_XRF: number of designated black, white, or red pixels in Npix_XRF

Rmean_XRF, Gmean_XRF, Bmean_XRF: mean value of Red, Green, and Blue components of pixels within XRF sensor window

Position_mm_MS: same as DCmid_mm_MS

Raw_MS: Magnetic Susceptibility measured with no correction

DriftMeasured_MS: Drift measurements were made in the air above the sample

DriftCalculated_MS: n/a, should always be 0

Corrected_MS: Magnetic Susceptibility measurement with correction applied

Temperature_MS: Ambient temperature in C

Units_MS: Measurement units (SI)

Elemental abundance data: Named as {Element symbol}_{Ka or La peak}Area_{energy level}kV







RGBmean_All_20mmCC_2mmDC_Mohole_GuadalupeSite



Color data averaged across the middle 2 cm cross core of the image in 2 mm intervals down core







DCtop_mm, DCbot_mm, DCleft_mm, DCright_mm: edges of the window within which colors were averaged in mm

Npix: number of pixels in the image corresponding to the averaging window

Nblackpix, Nwhitepix, Nredpix: number of designated black, white, or red pixels in Npix

Rmean, Gmean, Bmean: mean value of Red, Green, and Blue components of pixels within averaging window

Position_mbsf: Position of the center of the measurement location in meters below sea floor

Hole, Run: Core identification

Aperture: camera aperture during imaging

Corename: Core identification