COLOR REFLECTANCE by the Oregon State University SCAT


INTRODUCTION

Quantitative estimates of sediment diffuse spectral reflectance were generated 
by the shipboard sedimentologists using the OSU-SCAT.  The OSU-SCAT 
spectrophotometer system (Mix et al., 1992) consists of a computer-controlled 
motorized-track assembly that advances a core section into sampling position 
under a commercially available light integration sphere.  The integration sphere 
is brought into contact with the sediment via a computer-controlled vertical 
stepping motor.  During operation, light with known spectral characteristics 
passes through fiber optics and is steered using a directional mirror toward two 
reference ports and a measurement port.  The light that is diffusely reflected 
off the sediments is integrated within the sphere, split into constituent 
wavelengths by a diffraction grating, and collected with a multichannel 
detector.

Reflected light was measured in 1024 0.682-nm-wide bands ranging from 250 to 950 
nm at Site 1088, but in the visible and nIR range only (~400-950 nm) at Sites 
1089-1094 because of a failure of the UV light source.  For shipboard analysis, 
the raw data was converted to percent reflectance and averaged into four 100-nm-
wide bands defined as UV (250-350 nm), blue (450-550 nm), red (650-750 nm), and 
nIR (850-950 nm).


EXPLANATION OF DATA ITEMS 

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.

TYPE - 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.

BOTTOM_INTERVAL - Distance in centimeters from the top of the section to the 
bottom of the sample interval.

DEPTH (mcd)- Distance in meters composite depth from the seafloor to the sample 
interval.

DEPTH (mbsf)- Distance in meters from the seafloor to the sample interval.

MARK - A data quality field.  Mark is set to zero (0) if both conductivity 
channels of the SCAT made contact with the sediments, indicating a very good 
landing.  Mark is set to one (1) if only one of the two channels made contact 
with the sediments, indicating an adequate landing.

250-350nm - Average of color reflectance values between 250 and 350 nm.

450-550nm - Average of color reflectance values between 450 and 550 nm.

650-750nm - Average of color reflectance values between 650 and 750 nm.

850-950nm - Average of color reflectance values between 850 and 950 nm.