Averages from logged Intervals

The fabric intensities logged in two spreadsheets were processed to present downhole distribution diagrams. Depth shifts to correct for overcored intervals were applied to remove overlapped data before transporting the data to other processing programs, following the shiftz.xls file.

All calculations were done and plotted in Matlab. Matlab programs and input data, extracted from tables of both Expeditions 304 and 305, are placed in a calculation spreadsheet. All calculations are performed by running do_averages.m. The downhole averaging is done with the routine downhole.m (text code of downhole.m is also available), which is called from within do_averages.m. do_averages.m and downhole.m have explanatory comments. do_averages.m also saves sets of files (interval arrays, average arrays, and 1 cm stratigraphic columns). Other routines used are dodepth.m (to convert core number, section number, and depth below top of section into depth below seafloor after shifts of curated core section depths). The program do_plots.m calls additional subprograms to generate report figures and associated calculations.

The function downhole.m is written as dataout = downhole(datain, zbigin, zend, dz). A brief summary of how to use the function is as follows:

Before running the function downhole.m, each intensity in the two logged spreadsheets should be arranged into a set of input data: the depth of top of interval (mbsf), the depth of bottom of interval (mbsf), and an intensity value in this interval. These data were input into datain in the function.

The function requires one data file and three constants: datain, zbegin, zend, and dz. The datain is the data file consisting of a set of input data as described above. The three constants are (1) zbegin, the depth of top of desired profile (mbsf); (2) zend, the depth of bottom of desired profile (mbsf); and (3) dz, an interval for average, which should be chosen for a desired profile to calculate downhole average for each intensity.

Calculation procedure: At first, the function creates a 1 cm stratal column of intensity values based on intervals given by datain. Second, a mean value and standard deviation is calculated for each desired interval based on the 1 cm stratal column.

Results are output in dataout, the depth of middle of each interval, a standard deviation of the mean intensity value, and a percentage of the “logged” length with respect to each interval for average (dz) that represents a “recovery rate” for each interval. In case of no logged data in an interval, NaN (not a number) is marked for a mean value and its standard deviation in such an interval.

This Directory

This directory contains cleaned up data and Matlab code. do_averages.m calculates averages with a 5-m running window. do_plots.m calls the different do_fig##.m files and does plots similar to those on Expedition 305 Report. downhole.m is a routine to calculate averages down the hols. holearray.m is a routine to calculate an array frominterval data. dodepths.m is a routine to calculated curated+shifted depths from core and section number + depth below top of Section.  The programs are documented.

I have attempted to document the programs, so that, while reading through them, you can see what files corresponds to what if it is not clear from the file names.

Javier Escartin
27 Feb 2005
escartin@ipgp.jussieu.fr