抄録
The distribution and carbon isotope composition of 17β(H), 21β(H)-bishomohopanoic acid (ββC32-HA) were investigated in Miocene to recent marine sediments from Site 1178 of ODP Leg 190, Nankai Trough, offshore Shikoku, Japan. The concentration of ββC32-HA tends to be higher in accreted sediments, which are characterized by a large contribution of terrestrial organic matter. The δ13C values of ββC32-HA are lighter in accreted sediments than in slope sediments, indicating different sources to some degree. The constant δ13C values within the slope sediments and within the accreted sediments indicate that the sources of ββC32-HA were unchanged during the deposition of each unit. In accreted sediments, the δ13C value of ββC32-HA is similar to that in soil components, suggesting that the hopanoic acids in accreted sediments may be mainly terrestrial organic compounds derived from the oxidation products of bacteriohopanepolyols on land.
