Gas Chemistry of Pore Fluids from Oomine Ridge on the Nankai Accretionary Prism - Accretionary Prisms and Convergent Margin Tectonics in the Northwest Pacific Basin - page 250

JAPAN

34N 34N

Kumano

33N 33N

km

0 50 100

32N 32N

135E 136E 137E 138E

b 136°28'30"E 136°29'00"E

D754C1

D744C3

33°07'30"N 33°07'30"N

D685C4

PC08

D752C2

D756C1

D674C4
D674C5

D744C1
D674C1

D674C3

33°07'00"N 33°07'00"N

D685C1

km

0 0.5

136°28'30"E 136°29'00"E

Fig. 1 ( a ) Map showing Oomine Ridge in the Nankai Trough. Oomine Ridge ( star ) is located at
33°7.32¢N, 136°28.75¢E. ( b ) Map showing the sites of cores from Oomine Ridge used in this study,
together with the sampling sites of Toki et al. ( 2004 ). Contour interval is 50 m. Shaded area repre-
sents the area where we observed many bacterial mats scattered at intervals of several hundred
meters at water depths ranging from 2,500 to 2,550 m. Star show the position where the core sample
was taken in the present study (PC08). Circles denote the positions where core samples include low-
Cl fluids in the sediments, but not triangles, as described in detail in Toki et al. ( 2004 )