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i~J<br />

123<br />

The NADW overlying th~ AABW in the region of the Greater<br />

Antilles Outer Ridge was recognized to have a general<br />

northerly source (Worthington and Wright, 1970), although the<br />

details of NADW transfer to this region had not been worked<br />

out. The sloping isotherms in the IGY sections across the<br />

western North Atlantic at 24°N and 67°W (Fuglister, 1960,<br />

pls. 33 and 51) and the southerly persistence of low silicate<br />

NADW along the western margin of the North American basin<br />

(Fig. 2 of Metcalf, 1969) suggest a southerly extension of<br />

the Western Boundary Undercurrent (WBUC) into the region of<br />

the Greater Antilles Outer Ridge. The WBUC has generally<br />

been considered to consist of NADW. Hydrographic observa-<br />

tions where direct current measurements were made in the<br />

\<br />

) WBUC (Swallow and Worthington, 1961; Volkmann, 1962; Barrett,<br />

1965; Richardson and Knauss, 1971; Zimmerman, 1971;<br />

Worthington and Kawai, 1972) have shown potential temperatures<br />

warmer than 1.8°8 and salinities greater than 34.890/00.<br />

However, water as cold as 1.66°8 and of salinity 34.860/00<br />

was reported deep on the flanks of the Blake-Bahama Outer<br />

Ridge as part of the WBUC (Amos, Gordon, and Schneider, 1971).<br />

Few di rect current measurements have been made on the<br />

Greater Antilles Outer Ridge. Bruce (1964) examined the flow<br />

between 19° and 230N lat. at 660W long. with closely spaced<br />

hydrographic observations, drogues and Swallow floats. His<br />

dy n ami c c a 1 c u 1 at ion s, bas e don are fer en c e 1 eve 1 at 3800 m<br />

(the depth of the lower oxygen maximum) showed general

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