These findings are significant because they suggest that Ba in the finest 
fraction of drilling mud may be transported over very wide areas of the bank, 
to the east as well as to the west. Butman and others (1982a) have stated 
that the mean westerly flow can reverse on the southern flank of Georges Bank 
in response to strong winds from the southwest. Transport of sediment to 
stations on transect I from the easternmost drilling locations (blocks 410 and 
145) approximately 35 km could have taken place during these eastward current 
flows. We plan to examine meteorological data and any available current 
records to determine if a strong easterly current flow occurred sometime prior 
to cruise 8. It is also possible that the Ba particles carried in the Georges 
Bank gyre could be transported from drilling locations in a clockwise circular 
motion to stations 2 and 3. 
Trace metals in different size fractions of sediment 
As a special study initiated during this program, we used nylon sieves to 
separate bulk sediment from Georges Bank into various grain-size classes and 
analyzed the material in each size class for trace metals. We used this 
approach to determine how those trace metals (notably Ba) whose concentrations 
are elevated by drilling are distributed within the sediment size fractions. 
This information may be useful in predicting the transport and dispersion of 
metals carried by various sediment-size classes. 
Based on the textural analyses of standard barite by the American 
Petroleum Institute, only about 4 percent of the barite used in well drilling 
is in the 60-150 um fraction and the remaining 96 percent is finer than 
60 wm. Drilling mud is known to adhere to drill cuttings, however, which are 
often greater than 1,000 um in size. 
Samples were collected on cruises 4 and 10 from the O-2-cm interval at 
stations 16 and 5-2 adjacent to drilling sites. To determine the natural 
37 
