Information about the contents of this folder (DEMAGPCA)

Data are separated in U1256A_BASALT and U1256B_SED folders, containing the results for basalt and sediment samples, respectively.

RAW_DATA
The data output from the cryogenic magnetometer using 2G Enterprise LongCore software are give in the *.DAT file.

These samples were measured at the University of Otago.
375-U1526B-4H-4W-07.DAT
375-U1526B-4H-4W-24.DAT
375-U1526B-4H-4W-31.DAT
375-U1526B-4H-4W-40.DAT
375-U1526B-4H-4W-61.DAT
375-U1526B-4H-4W-67.DAT
375-U1526B-4H-4W-79.DAT
375-U1526B-4H-4W-87.DAT

All other discrete sediment samples were measured at the University of Hawaii.
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PROCESSED_DATA: These are formatted to be used with program ZPLOTIT, which creates modified Zijderveld plots and computes PCA results.

375-U1526A-discretes-Hawaii-zpt: Paleomagnetism data from discrete basalt samples (8cc cubes) from Hole U1526A measured in the University of Hawaii Paleomagnetism Lab. 

375-U1526A-discrete-samples-shipboard-zpt.xlsx: Paleomagnetism data from discrete basalt samples (8 cc cubes) from Hole U1526A measured on the ship with a JR6 magnetometer.

375-U1526B-04H-shipboard-section-half-data-zpt.xlsx: Paleomagnetism data from shipboard section-half measurements for Core U1526B-04H.

375-U1526B-discrete-samples-Hawaii-zpt.xlsx: Paleomagnetism data from discrete samples (~7 cc Japanese cubes) from Hole U1526B measured in the University of Hawaii Paleomagnetism Lab. All of these are sediment samples. 

375-U1526B-discrete-samples-Otago-zpt.xlsx: Paleomagnetism data from discrete samples (~7 cc Japanese cubes) from Core U1526B-04H measured in the University of Otago Paleomagnetism Lab. All of these are sediment (nannofossil ooze) samples. 


Key to ZPLOTIT files:
Sample: sample ID
Labcode: A code for where the measurements were made
Demag: The demagnetization step in mT or degrees C
Intensity (A/m): Magnetization intensity in A/m
Depth (mbsf): Depth in meter below seafloor
Sample Type: Descriptive lithology (optionally provided)
Treatment Type: Alternating field demagnetization (AFD) or thermal demagnetization (TD)
Alternate Sample ID: Optionally provided alternate sample ID.
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PCA_RESULTS
The mean paleomagnetic direction is estimated from the demagnetization data using the principal component analysis (PCA) method of Kirschvink (1980).

The PCA FREE option: The best-fit line that passes through the vector demagnetization data is not forced to be anchored to the origin of vector demagnetization space, but is allowed to freely fit the data. 

The PCA ANCHORED option: The best-fit line that passes through the vector demagnetization data and is forced to be anchored to the origin of vector demagnetization space. 

SEP: Stable End Point, which is a Fisherian mean of the 2 or 3 highest demagnetization steps used in the free option line fit.

PCA parameters, in addition to the direction (inclination and declination), are:
    Sample ID: Sample identification
    Depth (mbsf): Depth in meter below seafloor. For discrete samples, this may be the Top Depth, which is the depth to the top of the sample.
    Inclination: Paleomagnetic inclination
    Declination: Paleomagnetic declination
    MAD =  Maximum angular deviation.
    Length = Distance from origin of the vector demagnetization space to the centroid of the data (in A/m) used to find the best-fit line.
    Deviation Angle = The angle between the best-fit line and a line that passes through the origin and centroid. 
    Steps: Number of demagnetization steps used in finding the best-fit line.
    Low = The lowest demagnetization step used in finding the best-fit line.
    High = The highest demagnetization step used in finding the best-fit line.

For comparison, we also compute a Fisherian mean of the highest two or three demagnetization steps for each sample. This is referred to as the stable end point direction. Typically the highest three demagnetization steps are used in the average, unless the mean of these three directions have a dispersion parameter <200, in which case the largest outlier is removed and an average direction is computed from the remain two directions.

Stable end point parameters, in addition to the mean direction (inclination and declination), are:
    k = the Fisherian dispersion parameter
    N = the number of directions from the three highest demagnetization steps that were averaged. 

Angular Distance = the angular distance between the Free PCA direction and the stable end point direction.