<At the time of Leg 170, ODP data were not written to the new Janus database yet. The files saved from the new MST data acquisition program are therefore made available on this CD-ROM. This readme file provides some additional information for the NGR spectral raw data files.>
<There are two types of NGR files included on this CD: NGR####.dat (raw data) and NGR_Hole_CoreSection-CoreSection (report files).>
NGR####.dat
<Raw data files, as acquired for each core section. Each file also contains the calibration data (slope and intercept) needed to convert channel numbers to energy, and background counts (to be subtracted from core measurements) measured the last time before the core section was measured. The file structure is:>
<Core Section Header>
run_number run_date_time
system_id
run_type core_status
liner_status requested_sampling_interval requested _sampling _period
calibration_date_time cal_m0 cal_m1 cal_mse
bkg_run_date_time std_name std_date_time bkg_total_counts <NOT normalized> bkg_sampling_period
number_of_windows <256 by default>
"Start Window Data"
<Background data; 256 rows for 256 channels; 3 columns as follows:>
1 channel number
2 window lenght <1 channel default>
3 counts
"End Window Data"
section_id
number_of_data_points
"Start of Data"
<core data; 1 row per measurement point; 267 columns as follows:>
1-9 ODP sample identifier
10 total counts per second <corrected for background>
11 sampling period (s)
12 core diameter (cm)
13-268 256 channel data <NOT corrected for background>
NGR_Hole_CoreSection-CoreSection
<Report files for a batch of core sections as indicated in the file name. The calibration and background data have been stripped, and depth (mbsf) has been added. The file structure is:1 row per measurement point; 269 columns as follows:>
1-9 ODP sample identifier
10 depth (mbsf)
11 total counts (sum of all channels, normalized to one second, corrected for bkg)
12 sampling period (s)
13 core diameter
14-269 256 channel data
NOTE: Excel and Kaleidagraph do not provide a sufficient number of columns to open the data. You need to use a more powerful program or write your own routines.
To use the spectral data, the user needs to:
- subtract the background spectrume from the core measurement spectrum;
- convert channel numbers into energy using the 2-point calibration coefficients m0 and m1 in the raw data, section file header.
LEG - Number identifying the cruise.
SITE - Number identifying the site. A site is the position of a beacon around which holes are drilled.
HOLE - Letter identifying the hole.
CORE - Number identifying the core. Cores are numbered serially from the top of the hole downward.
CORETYPE - A letter code identifying the drill bit/coring method used to retrieve the core. The coretype codes are:
B - Drill Bit
C - Center Bit
D - Positive Displacement
H - Hydraulic Piston Core
M - Miscellaneous
N - Downhole Mud Motor (Navidrill)
P - Pressure Core Barrel
R - Rotary
S - Side Wall Core
W - Wash Core
X - Extended Core Barrel
SECTION - A core is cut into 1.5 meter long sections that are numbered serially from the top of the core. A core with full recovery will have 7 sections and a core catcher and be approximately 9.8 meters long.
TOP_INTERVAL - Distance in centimeters from the top of the section to the top of the sample interval.
SUB_BOTTOM_DEPTH - Distance in meters from the seafloor to the top of the sample interval.