translucent yellow to a tan iron-oxide stain; it has an angular to subrounded 
grain shape. The minerals making up the sand fraction are primarily quartz 
with minor amounts of feldspar and trace amounts of heavy minerals. 
Authigenic minerals such as framboidal pyrite and ferromanganese micronodules 
have been found at various locations on the bank in very low concentrations 
(Poppe and others, 1984). 
The concentrations of silts and clays in the regional samples are 
generally less than 4 percent (fig. 3), and the mean station values for year 3 
are similar to those of years 1 and 2. The relative paucity of silts and 
clays reflects the strong winnowing processes associated with tidal and storm- 
generated currents on Georges Bank (Butman and Folger, 1979; Butman and Moody, 
1983; Butman and others, 1982a; Parmenter and others, 1984). On sampling 
transects I, II, and III (fig. 1A), the content of sediment finer than 63 ym 
(silt plus clay) increases slightly toward the shelf edge, perhaps in response 
to increasing water depth. 
Areas that showed a significant concentration of fine sediments (finer 
than 63 wm) during each sampling cruise were located at regional station 14A 
(80-90 percent fines) in the Gulf of Maine, regional station 7A (22-30 percent 
fines) at the head of Lydonia Canyon, and regional stations 13 and 13A (34-50 
and 92-97 percent fines, respectively) located south of Nantucket Island. 
This last area, known as the Mud Patch, is thought to be one of the 
depositional sites for sediments from upstream areas on Georges Bank (Bothner 
and others, 1981; Twichell and others, 1981). The close correlation between 
the concentration of fine sediment, organic carbon, and trace metals was 
discussed in the report for year 1 (Bothner and others, 1982). 
Determination of the major minerals in the clay fraction of the sediments 
by X-ray diffraction indicates that illite is predominant, with moderate 
23 
