Diagenesis and distribution of sterenes in Late Miocene to Pliocene marine siliceous rocks from Horonobe (Hokkaido, Japan)

Change in hydrogen isotope composition of n-alkanes, pristane, phytane, and aromatic hydrocarbons in Miocene siliceous mudstones with increasing maturity

“…The rocks can still be a potential parameter for evaluating paleo-hydrology/humidity on land. 20S/20S+20R; 5a-C29 sterane isomer ratio, 22S/22S+22R; C32 hopane isomer ratio, Sterane/Sterene; 5a-sterane/(5a-sterane+ster-5-ene) ratio (Amo et al , 2007) Table2 -113 -140 -108 -172 -127 -169 -153 -169 -112 -105 -147 -166 -205 -209 -156 -188 -288 -281 n.d. n.d. n.d. n.d. 8111061 -140 -170 -169 -182 -175 -185 -184 -174 -172 -173 -172 -181 -167 -186 -176 -184 -310 -329 -141 -107 -137 -137 83002 -156 -182 -184 -176 -177 -181 -181 -180 -180 -181 -182 -178 -175 -165 -179 -172 -289 -296 n.d. n.d. n.d. n.d. 83001 -166 -182 -186 -174 -180 -180 -184 -179 -146 -161 -165 -164 -162 -150 -178 -157 -284 -287 n.d. -94 -99 -107 90101 -197 -191 -196 -183 -187 -183 -189 -184 -178 -177 -173 -174 -175 -183 -187 -178 -307 -307 n.d. n.d. -96 -82 8111055 -131 -131 -131 -135 -134 -136 -138 -131 -131 -128 -123 -124 -112 -112 -133 -118 -235 -232 n.d. -135 -126 -112 90103 -189 -187 -182 -177 -176 -173 -172 -169 -167 -167 -166 -172 -183 -165 -182 -168 -263 -251 n.d. n.d. -136 -142 90104 -185 -188 -180 -189 -185 -186 -180 -175 -175 -170 -165 -166 -165 -169 -188 -167 -267 -264 n.d. n.d. n.d. -77 8111056 -164 -172 -175 -174 -171 -171 -169 -165 -151 -158 -152 -146 -154 -151 -173 -149 -197 -220 reflectance is from Taguchi et al (1986) and Suzuki et al (1987). Tetraaromatic lupine, J.…”

“…1). These siliceous mudstones are a known hydrocarbon source rock in northeast Japan, and a set of samples from Yakumo region (42˚23'N, 140˚10'E) and Shinjo region (38˚51'N, 140˚08'E) provided sediment in the opal-A, opal-CT, and quartz zones (Taguchi et al, 1986;Amo et al, 2007Amo et al, , 2008. We used these samples to investigate the effects of diagenetic changes on biomarker D/H ratios.…”

“…Vitrinite reflectance (R o ) of siliceous mudstones from Shinjo region is in the range from 0.4 to 0.7% (Taguchi et al, 1986). Aoyagi and Kazama (1980), Suzuki (1984Suzuki ( , 1990, and Amo et al (2007) reported that paleo-maximum temperatures range from 40 to 140ºC in these samples. A set of the siliceous mudstone samples characterized by similar lithology and organic composition, but with different maturity levels, is essential in a study of diagenetic change of the D/H ratios of saturated and aromatic hydrocarbons.…”

“…Immature to mature Middle Miocene diatomaceous siliceous mudstones are well distributed in northeastern Japan along the Japan Sea. Previously studies of these rocks have focused on the thermal transformation of organic matter with increasing maturation (Taguchi et al, 1986;Amo et al, 2007Amo et al, , 2008. In this paper, we examine the diagenetic changes in the D/H ratios of aliphatic and aromatic hydrocarbons.…”

Expedition 337 summary

“…In addition, the degree of thermal alteration of sediment can be gauged from the conversion of sterenes to steranes and using biomarker data previously calibrated against temperature in the Hokkaido region (Amo et al, 2007). A critical temperature threshold for this process in the subsurface is the range of 40°-60°C (Amo et al, 2007).…”