Vol. 24  Issue 2¡ÊJune¡Ë

Invited Article

1.  Evolution Processes of Ordovician-Devonian Arc System in the South-Kitakami Massif and its Relevance to the Ordovician Ophiolite Pulse
Kazuhito Ozawa, Hirokazu Maekawa, Ken Shibata, Yoshihiro Asahara, Masako Yoshikawa

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Key Words : Hayachine-Miyamori ophiolite, island arc evolution, ophiolite pulse, South Kitakami.

Rseach Article

£²¡¥Graphitization of carbonaceous material in sedimentary rocks on short geologic time-scales: An example from the Kinsho-zan area, central Japan
Natsumi Mori, Simon wallis and Hiroshi Mori

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¤¹¤ë¡¥10Ëüǯ°Ê¾å¤Î»þ´Ö¥¹¥±¡¼¥ë¤Ë¤ª¤¤¤ÆÇ®¤òÈï¤Ã¤¿Å·Á³»îÎÁ¤Î¥é¥Þ¥ó¥¹¥Ú¥¯¥È¥ë¤Ï¡¤·ë¾½²½ÅÙ¤¬Äê¾ï¾õÂÖ¤Ë㤹¤ë¤³¤È¤ò¼¨¤¹¡¥°ìÊý¡¤¼¼Æâ¼Â¸³¤Î¸¦µæ¤Ç¤Ï¡¤3.5½µ´Ö¡¤1000¡î¤Î²ÃÇ®¸å¤Ç¤âú¼Áʪ¤Î·ë¾½²½Å٤ϤۤȤó¤ÉÊѲ½¤·¤Ê¤¤¤³¤È¤¬¼¨¤µ¤ì¤Æ¤¤¤ë¡¥
·ë¾½²½ºîÍѤˤĤ¤¤Æ¤Î»þ´Ö¥¹¥±¡¼¥ë¤Î¤µ¤é¤Ê¤ëÀ©Ìó¤Ë¤Ï¡¤¿ôǯ¡Á¿ôËüǯ¥¹¥±¡¼¥ë¤Ç¤Î¸¡¾Ú¤¬É¬ÍפǤ¢¤ê¡¤¤³¤Î¤è¤¦¤ÊĹ»þ´Ö¤Î»þ´Ö¥¹¥±¡¼¥ë¤Ë´Ø¤·¤Æ¤Ï¡¤ÈïÇ®»þ´Ö¤ÎŤµ¤¬ÌÀ¤é¤«¤Ç¤¢¤ëú¼Áʪ¤ò´ÞÍ­¤¹¤ëÅ·Á³¤Î´äÀФòÎã¤È¤¹¤ë¤³¤È¤Ç¤Î¤ß¡¤Æ³¤¯¤³¤È¤¬²Äǽ¤Ç¤¢¤ë¡¥´ôÉ츩¡¦ÀÖºäÀг¥´äÃÏ°è¤ÎÉý13m¤Î´äÌ®¼þÊÕ¤Ëȯã
¤¹¤ëÀÜ¿¨ÊÑÀ®ºîÍѤˤĤ¤¤Æ¤ÎÇ®¥â¥Ç¥ê¥ó¥°·ë²Ì¤Ï¡¤ÈïÇ®»þ´Ö¥¹¥±¡¼¥ë¤¬£±¡Á100ǯ¤Ç¤¢¤ë¤³¤È¤ò¼¨¤¹¡¥¥é¥Þ¥ó¥¹¥Ú¥¯¥È¥ë¤Ï¡¤´äÌ®¤Î£³m°ÊÆâ¤Ë¤ª¤¤¤Æú¼Áʪ¤Î·ë¾½²½ÅÙ¤ÎÃø¤·¤¤Áý²Ã¤ò¼¨¤¹¡¥ÀÜ¿¨ÊÑÀ®°è¤Ë¤ª¤¤¤Æ¿äÄꤵ¤ì¤ë²¹ÅÙ¤Èú¼Áʪ¤Î·ë¾½²½ÅÙ¤ÎÈæ³Ó·ë²Ì¤Ï¡¤´äÌ®¶á˵¤Ç¤¢¤Ã¤Æ¤â¡¤Ãº¼Áʪ¤¬Äê¾ï¾õÂÖ¤Ë㤷¤Ê¤¤¤³¤È¤ò¼¨¤¹¡¥¤³¤ÎÊѲ½¤Ï¡¤¿ôǯ¤ÎÈïÇ®»þ´Ö¥¹¥±¡¼¥ë¤Ë¤ª¤¤¤Æ¡Ê¥â¥Ç¥ê¥ó¥°²¹ÅÙ¤¬¡Ë550¡î°Ê¾å¤Ç³«»Ï¤¹¤ë¡¥Å·Á³¤ÎÃϼÁ³ØŪ¤Ê¾ò·ï²¼¤Ç¤Ï¡¤Ãº¼Áʪ¤Î·ë¾½²½ºîÍѤˤª¤±¤ëÄê¾ï¾õÂ֤γÍÆÀ¤Ë¤Ï¡¤Ìó100ǯ°Ê¾å¤Î»þ´Ö¥¹¥±¡¼¥ë¤Î²ÃÇ®¤¬É¬ÍפǤ¢¤ë¡¥Ëܸ¦µæ¤Ï¡¤´äÀÐÃæ¤Îú¼Áʪ·ë¾½²½ºîÍѤΥ«¥¤¥Í¥Æ¥£¥¯¥¹¤ò·èÄꤹ¤ë¤¿¤á¤Ë¡¤Å·Á³¼Â¸³¸¦µæ¤òÍѤ¤¤ë¤³¤È¤¬Í­ÍѤǤ¢¤ë¤³¤È¤ò¼¨¤¹¡¥

Key Words : carbonaceous material, contact metamorphism, Raman spectroscopy, thermal modeling
 

£³¡¥Laboratory measurements of‘porosity-free’intrinsic Vp and Vs in an olivine gabbro of the Oman ophiolite: Implication for interpretation of the seismic structure of lower oceanic crust
Satoshi Saito, Masahiro Ishikawa, Makoto Arima, Yoshiyuki Tatsumi

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Key Words : elastic wave velocity, gabbro, oceanic crust, Oman ophiolite, piston-cylinder high-pressure apparatus, porosity.

£´¡¥Foldback reflectors near methane hydrate bottomsimulating reflectors: Indicators of gas distribution from 3D seismic images in the eastern Nankai Trough
Marc Humblet, Chuki Hongo and Kaoru Sugihara

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¥é¥Õ¤Ç¼Â»Ü¤µ¤ì¤¿»°¼¡¸µÈ¿¼ÍË¡ÃÏ¿Ìõºº¤Ëǧ¤á¤é¤ì¤¿¡¤¥¬¥¹¥Ï¥¤¥É¥ì¡¼¥È¤Î·ÁÀ®¤äήÂΰÜÆ°¤Ë´ØÏ¢¤¹¤ë¤È¤ß¤é¤ì¤ëÆÃħŪ¤ÊÈ¿¼ÍÌ̤ˤĤ¤¤ÆÊó¹ð¤¹¤ë¡¥¤½¤Î·ÁÂÖ¤«¤é¤³¤ÎÈ¿¼ÍÌ̤òËܸ¦µæ¤Ç¤Ï¡ÖÀÞ¤êÊÖ¤·È¿¼ÍÌÌ¡ÊFoldback reflector, FBR¡Ë¡×¤È¸Æ¤Ö¡¥FBR¤Ï¥¬¥¹¡Ê¥á¥¿¥ó¡Ë¥Ï¥¤¥É¥ì¡¼¥È³¤Äìµ¼»÷È¿¼ÍÌÌ¡ÊBottom simulating¡¡reflector, BSR¡Ë¤Î±ïÊÕ¤«¤é²¼Êý¤Ë¸þ¤±¤ÆÀÞ¤êÊÖ¤¹¤³¤È¤ò·«¤êÊÖ¡¡¤·¤¿·Á¾õ¤ò¤·¤Æ¤ª¤ê¡¤Á´ÂΤȤ·¤ÆÃÏÁؤËÊ¿¹Ô¤Ê¡ÖÀÞ¤êÌܡפò»ý¤Ä¼ØÊ¢¾õ¤Î¹½Â¤¤òÄ褹¤ë¡¥FBR¤ÏÀÞ¤êÊÖ¤¹Ëè¤Ë°ÌÁê¤òȿž¤µ¤»¤ë¡¥FBR¤ò¦Êý¤Ë¸Ù¤¤¤Ç°Û¤Ê¤ë¥µ¥¤¥¹¥ß¥Ã¥¯¥Õ¥¡¥·¥¹¤¬Ç§¤á¤é¤ì¡¤BSR¤è¤ê²¼°Ì¤ÎÃÏÁؤÏÁêÂÐŪ¤ËÄ㿶Éý¤Ç¹â¼þÇÈ¿ôÀ®Ê¬¤Ë˳¤·¤¯È¿¼ÍÌ̤¬ÉÔÌÀÎƤʷ¹¸þ¤ò¼¨¤¹¤Î¤ËÂФ·¡¤BSRʬÉۤγ°Â¦¤Ë¤¢¤ëÃÏÁؤÏÌÀÎƤÊÈ¿¼ÍÌ̤ò°Ý»ý¤·¤Æ¤¤¤ë¡¥¤Þ¤¿¡¤È¿¼ÍÌ̤¬ÉÔÌÀÎƤÊÎΰè¤Ï¼þ°Ï¤è¤êÃÆÀ­ÇÈ®ÅÙ¤¬Ä㤤Îΰè¤ËÂбþ¤·¤Æ¤¤¤ë¡¥¤³¤Î¤è¤¦¤ÊÄã®Åٰ۾浪¤è¤ÓÈ¿¼ÍÆÃÀ­¤ÏÂÏÀÑÁØÃæ¤Ë¥¬¥¹¤¬Â¸ºß¤¹¤ë¤³¤È¤ò¼¨º¶¤·¤Æ¤¤¤ë¡¥FBR¤Ïδµ¯ÂÓ¤ÎÎɤ¯À®Áؤ·¤¿ÂÏÀÑÁؤËȯ㤹¤ë·¹¸þ¤¬¤¢¤ë¡¥FBR¤Î·¹¼ÐÊý¸þ¤Ï¡¤FBR¤Îȯ㤹¤ëÃÏÁؤη¹¼Ð¤Ëµ¬À©¤µ¤ì¤Æ¤¤¤ë¤È¤ß¤é¤ì¤ë¡¥FBR¤Î±ïÊդϤ·¤Ð¤·¤ÐÈ¿¼Í¶¯ÅÙ¤ÎÂ礭¤¤È¿¼ÍÌ̤ËÂбþ¤·¤Æ¤¤¤ë¡¥¤³¤Î¤è¤¦¤ÊFBR¤Îȯ¸½¤Ï¡¤BSR¤ÈƱÍͤËÃÏ°èŪ¤Êδµ¯¤äÁØÍýÌ̱褤¤ÎήÂΰÜÆ°¤¬FBR¤Îȯã¤Ë´Ø¤ï¤Ã¤Æ¤¤¤ë¤³¤È¤ò¼¨º¶¤·¤Æ¤¤¤ë¡¥

Key Words : 3D seismic survey, accretionary prism, fluid migration, methane hydrate, uplift.
 

£µ¡¥Cretaceous granitoids and their zircon U-Pb ages across the south-central part of the Abukuma Highland, Japan
Shunso Ishihara, and Yuji Orihashi

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Key Words : Abukuma Highland, Cretaceous granitoids, U-Pb age, zircon.
 

£¶¡¥Petrology and geochemistry of ultrahigh-temperature granulites from the South Altay orogenic belt, northwestern China: Implications for metamorphic evolution and protolith composition
Xiaoqiang Yang, Zilong Li, Huihui Wang, Hanlin Chen, Yinqi Li and Wenjiao Xiao

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Ãæ¹ñËÌÀ¾Éô¡¤Æ¥ë¥¿¥¤Â¤»³ÂÓ¤ÎĶ¹â²¹¡ÊUHT¡Ë¥°¥é¥Ë¥å¥é¥¤¥È¤Ï²¼ÉôÃϳ̤ι½À®Êª¤È¸ÅÀ¸Âå¤Ë¤ª¤±¤ëÃæ±û¥¢¥¸¥¢Â¤»³ÂӤΥƥ¯¥È¥Ë¥Ã¥¯¤Ê¿Ê²½¤Ë¤Ä¤¤¤Æ½ÅÍפʲòÅú¤òÄ󶡤¹¤ë.ËÜÏÀʸ¤Ï¥¢¥ë¥¿¥¤UHT¥°¥é¥Ë¥å¥é¥¤¥È¤Î¸»´ä¤ÈÊÑÀ®¾ò·ï¤Î¿Ê²½¤òÍý²ò¤¹¤ë¤¿¤á¤Ë¡¤Á´´äÃϵ岽³ØµÚ¤Ó¹Ûʪ¤ÎÆÃħ¤òÌÀ¤é¤«¤Ë¤·¤¿¡¥¥¢¥ë¥¿¥¤¥°¥é¥Ë¥å¥é¥¤¥È¤Ï¡Ý9.27¡Á¡Ý3.95¤ÈÉé¤ÎȽÊÌ´Ø¿ôÃÍ¡ÊDF¡Ë¤ò¼¨¤¹¤³¤È¤«¤é¡¤ÂÏÀѴ䡤¤ª¤½¤é¤¯¤ÏÅ¥¼Á´äµ¯¸»¤È»×¤ï¤ì¤ë¡¥920¡Ý1010¡î¤Ø¡¤£¹kbar°Ê¾å¤Î¥Ô¡¼¥¯ÊÑÀ®²¹ÅÙ°µÎϾò·ï¤È¥¹¥Ô¥Í¥ë¡ÊÄãZnO¡Ë¡ÜÀбѵڤӼÐÊýµ±ÀСÊAl2O3 9.2 wt%°Ê²¼¡Ë¡Ü·¾ÀþÀСÜÀбѤζ¦À¸¤Ï¡¤Ä¶¹â²¹ÊÑÀ®ºîÍѤò¼¨¤¹¡¥ÆóÃʳ¬¤Î¸åÂàÊÑÀ®ºîÍѤ¬Ç§¤á¤é¤ì¤ë¡¨¤Ï¤¸¤á¤Ë750¡î¡¤5.2-5.8 kbar¤ËÅù²¹¸º°µ¤·¡¤¼¡¤¤¤Ç4.8¡Ý5.2 kbar¡¤520¡Ý550¡î ¤Ø¤È²¹ÅÙ¤¬Äã²¼¤·¤¿¡¥Àè¹Ô¸¦µæ¤È¹ç¤ï¤»¤Æ¡¤¥¢¥ë¥¿¥¤UHTÅ¥¼Á¥°¥é¥Ë¥å¥é¥¤¥È¤¬¼¨¤¹»þ·×²ó¤ê¤Î²¹ÅÙ°µÎÏÊѲ½¤Ï¡¤¥·¥Ù¥ê¥¢¥×¥ì¡¼¥È¤È¥«¥¶¥Õ¥¹¥¿¥ó¡Ý¥¸¥ã¥ó¥¬¡¼¥×¥ì¡¼¥È´Ö¤Î¾×ÆÍ¡¦ÉղòáÄø¤ò¼¨º¶¤¹¤ë¤È¹Í¤¨¤é¤ì¤ë¡¥

Key Words : geochemistry, mineral characteristics, provenance reconstruction, P-T estimate, South Altay orogenic belt, ultrahigh-temperature granulite.
 

£·¡¥Geologic evidence for late Quaternary repetitive surface faulting on the Isurugi fault along the northwestern margin of the Tonami Plain, north-central Japan
Tadashi Maruyam, Masaru Saito

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Å×ÇÈÊ¿ÌîËÌÀ¾±ï¤ËʬÉÛ¤¹¤ëÀÐÆ°¡Ê¤¤¤¹¤ë¤®¡ËÃÇÁؤÎÂè»Íµª¸å´ü¤Î³èÆ°À­¤òÌÀ¤é¤«¤Ë¤¹¤ë¤¿¤á¡¤¹Ò¶õ¥ì¡¼¥¶¾ÜºÙÃÏ·Á¥Ç¡¼¥¿²òÀÏ¡¤¸½ÃÏƧºº¡¤¥È¥ì¥ó¥Á·¡ºïÄ´ºº¤ò¼Â»Ü¤·¤¿¡¥¤½¤Î·ë²Ì¡¤Æ±ÃÇÁؤ¬¹¹¿·À¤¸å´ü°Ê¹ß¤ËÃÏ¿ÌÃÇÁؤòȼ¤¦ÃϿ̱¿Æ°¤ò·«¤êÊÖ¤·¡¤¤½¤ÎºÇ¿·³èÆ°¤Ï´°¿·À¤¸åȾ¤Ç¤¢¤ë¤³¤È¤¬ÌÀ¤é¤«¤Ë¤Ê¤Ã¤¿¡¥ÊÑÆ°ÃÏ·Á³ØŪ¤ËǧÄꤵ¤ì¤ëÀÐÆ°ÃÇÁؤγèÃÇÁإȥ졼¥¹¤Ïû¤¤¶è´Ö¤Ë¸ÂÄꤵ¤ì¤ë¤¬¡¤¤³¤ì¤ÏƱÃÇÁؤËÊ¿¹Ô¤·¤Æή¤ì¤ë¾®ÌðÉôÀî¤Î¿¯¿©¤äËäÀѤαƶÁ¤ò¼õ¤±¤¿¤³¤È¤Ë¤è¤ë¤â¤Î¤Ç¤¢¤ê¡¤ÃÏ¿ÌÃÇÁؤòȼ¤¦ÂçÃϿ̤ò°ú¤­µ¯¤³¤¹µ¬ÌϤÎÃÇÁؤ¬Éúºß¤·¤Æ¤¤¤ë²ÄǽÀ­¤¬¤¢¤ë¡¥

Key Words : active fault, backthrust, Isurugi fault, LiDAR,thrust fault, trenching.
 

£¸¡¥Tectonic reconstruction of batholith formation based on the spatiotemporal distribution of Cretaceous-Paleogene granitic rocks in southwestern Japan
Kazuya Iida, Hikaru Iwamori, Yuji Orihashi, Taeho Park, Yong-Joo Jwa, Sung-Tack Kwon, Tohru Danhara, and Hideki Iwano

À¾ÆîÆüËܤËʬÉÛ¤¹¤ëÇò°¡µª¡Ý¸ÅÂè»°µª²ÖÖ¾´ä¤Î»þ´Ö¶õ´ÖʬÉۤ˴ð¤Å¤¯À®°ø¤È¥Æ¥¯¥È¥Ë¥¯¥¹¤ÎÉü¸µ
ÈÓÅÄÏÂÌ顦´ä¿¹ ¸÷¡¦ÀÞ¶¶ÍµÆó¡¦Taeho Park¡¦Yong-Joo Jwa¡¦Sung-Tack Kwon¡¦Ãɸ¶ Å°¡¦´äÌî±Ñ¼ù


ËÜÏÀʸ¤Ç¤Ï¡¤ÄÀ¤ß¹þ¤ßÂӤˤª¤±¤ë²ÖÖ¾´ä¤ÎÀ®°ø¤È¥Æ¥¯¥È¥Ë¥Ã¥¯¥»¥Ã¥Æ¥£¥ó¥°¤òÌÀ¤é¤«¤Ë¤¹¤ë¤¿¤á¤Ë¡¤À¾ÆîÆüËÜÇò°¡µª?¸ÅÂè»°µª¤Î²ÖÖ¾´ä¤Î¾ÜºÙ¤ÊǯÂå¬Äê¤ò¹Ô¤Ã¤¿¡¥Ä»¼è¡¤²¬»³¡¤¹áÀ¤ËʬÉÛ¤¹¤ë92¥µ¥ó¥×¥ë¤ÎU-Pb¥¸¥ë¥³¥óǯÂå¬Äê¤ò¹Ô¤¤¡¤Æ¤éË̤ˤ«¤±¤ÆÃʳ¬Åª¤ËǯÂ夬¼ã¤¯¤Ê¤ë¤³¤È¤ò¼¨¤·¤¿¡¥¤³¤Î¤è¤¦
¤Ê°ÜÆ°¤òÀâÌÀ¤¹¤ë¥â¥Ç¥ë¤È¤·¤Æ¡¤³¤ÎæÄÀ¤ß¹þ¤ß¤ÈÄÀ¤ß¹þ¤ß³ÑÅÙ¤ÎÊѲ½¤¬¹Í¤¨¤é¤ì¤ë¡¥¿ôÃÍ·×»»¤Ë¤è¤êξ¥â¥Ç¥ë¤ÎÍÏÍ»Îΰè¤ò·×»»¤·¡¤´Ñ¬¤È¤ÎÈæ³Ó¤ò¹Ô¤Ã¤¿¡¥³¤ÎæÄÀ¤ß¹þ¤ß¥â¥Ç¥ë¤Ç¤Ï¡¤¥»¥°¥á¥ó¥È¤òȼ¤Ã¤¿45 kmÉý¤Î¥ê¥Ã¥¸¤¬1.6 cm/yr¤ÇÄÀ¤ß¹þ¤à¤³¤È¤Ë¤è¤êÍÏÍ»Îΰ褬¤ª¤è¤½ºÆ¸½¤Ç¤­¤ë¤³¤È¤¬Ê¬¤«¤Ã¤¿¡¥°ìÊý¤Ç¡¤ÄÀ¤ß¹þ¤ß³ÑÅÙ¤ÎÊѲ½¤ÇÀâÌÀ¤¹¤ë¾ì¹ç¡¤ÄÀ¤ß¹þ¤ß³ÑÅÙ¤¬37°¤«¤é20°¤ËÊѲ½¤¹¤ë¤³¤È¤Ë¤è¤ê¡¤Ãʳ¬Åª¤Ê»þ¶õ´ÖÊѲ½¤òºÆ¸½¤Ç¤­¤ë¤³¤È¤¬Ê¬¤«¤Ã¤¿¡¥³¤ÎæÄÀ¤ß¹þ¤ß¥â¥Ç¥ë¤ÎÊý¤¬¡¤²ÐÀ®³èÆ°¤¬Á´ÂΤȤ·¤Æ¸Â¤é¤ì¤¿´ü´Ö¤Ëµ¯¤³¤ëÅÀ¤ò¤è¤êÎɤ¯ÀâÌÀ¤¹¤ë¡¥

Key Words : age, granite, heat source, ridge subduction, SW Japan, zircon.
 

£¹¡¥Dating of altered mafic intrusions by applying a zircon fission track thermochronometer to baked country rock, and implications for the timing of volcanic activity during the opening of the Japan Sea
Hiroyuki Hoshi, Hideki Iwano, Tohru Danhara, and Naoyoshi Iwata

ÊѼÁ¶ìÅ´¼Á´ä¤ÎǯÂå¤òÈïÇ®Êì´ä¤Î¥¸¥ë¥³¥óFTǮǯÂå¬Äê¤Ë¤è¤Ã¤Æ·è¤á¤ë¡§ÆüËܳ¤³ÈÂç´ü¤Î²Ð»³³èÆ°¥¿¥¤¥ß¥ó¥°
À± Ç¡¦´äÌî±Ñ¼ù¡¦Ãɸ¶ Å°¡¦´äÅľ°Ç½


ÊѼÁ¶ìÅ´¼Á´ä¤Î´ÓÆþǯÂå¤ò°ìÈÌŪ¤ÊÊü¼ÍǯÂå¬Äê¤Ç·è¤á¤ë¤Î¤ÏÆñ¤·¤¤¡¥²æ¡¹¤Ïº£²ó¡¤´ÓÆþ¤Ë¤è¤Ã¤Æ¾Æ¤«¤ì¤¿Êì´ä¤ËFTǮǯÂå³Ø¤Î¼êË¡¤òŬÍѤ¹¤ë¤³¤È¤ÇÊѼÁ¶ìÅ´¼Á´ä¤Î´ÓÆþǯÂå·èÄê¤ò»î¤ß¤¿¡¥Ä¹Ì¹â±óÃÏ°è¤ËʬÉÛ¤¹¤ëÊѼÁ¥É¥ì¥é¥¤¥È´äÌ®¤ÎǯÂå¤ò·èÄꤹ¤ë¤¿¤á¤Ë¡¤Êì´ä¤ÎÇò°¡µª²ÖÖ¾´ä¤«¤é»îÎÁ¤òºÎ¼è¤·¤¿¡¥´ÓÆþÌ̤«¤é£¸mm°ÊÆâ¤Î¥¸¥ë¥³¥ó¤Ï°ìÍͤË17¡Á16 Ma¤ÎFTǯÂå¤ò¼¨¤·¤¿¡¥FTĹ²òÀϤˤè¤ê¡¤Çò°¡µª°Ê¹ß¤ËÃßÀѤµ¤ì¤¿FT¤Ï¥É¥ì¥é¥¤¥È´ÓÆþ»þ¤Ë¥ê¥»¥Ã¥È¤µ¤ì¡¤¸½ºß¸«¤é¤ì¤ëFT¤Ï¤½¤Î¸å¤ËÀ¸¤¸¤¿¤â¤Î¤Ç¤¢¤ë¤³¤È¤¬³Îǧ¤µ¤ì¤¿¡¥´ÓÆþÌ̤«¤é20 mm¤Þ¤ÇÈϰϤò¹­¤²¤ë¤È¡¤FT¤¬¥ê¥»¥Ã¥È¤µ¤ì¤¿¥¸¥ë¥³¥ó¤È¤½¤¦¤Ç¤Ê¤¤¥¸¥ë¥³¥ó¤Îº®¹ç¤Ë¤è¤ëǯÂ夬ÆÀ¤é¤ì¤¿¡¥°Ê¾å¤Î·ë²Ì¤Ï¥É¥ì¥é¥¤¥È¤ÎǯÂ夬17¡Á16 Ma¤Ç¤¢¤ë¤³¤È¡¤¤ª¤è¤ÓÈïÇ®Êì´ä¤ËÂФ¹¤ëFTǮǯÂå¬Ä꤬ÊѼÁ¶ìÅ´¼Á´ÓÆþ´ä¤ÎǯÂå·èÄê¤ËÍ­¸ú¤Ç¤¢¤ë¤³¤È¤ò¼¨¤¹¡¥À¾ÆîÆüËÜÅìÉô¤Ç¤Ï18¡Á15 Ma¤Ë²Ð»³¥Õ¥í¥ó¥È¤¬Á°¸Ì¦¤ËÄ¥¤ê½Ð¤·¡¤²Ð»³³èÆ°¤¬»¶ºßŪ¤Ëµ¯¤³¤Ã¤¿¡¥¤³¤ì¤ÏÆüËܳ¤³ÈÂç´ü¤ËÁ°¸Ì¦¥Þ¥ó¥È¥ë¥¦¥§¥Ã¥¸¤Þ¤ÇÇ®¤¤¥¢¥»¥Î¥¹¥Õ¥§¥¢Êª¼Á¤¬¿¯Æþ¤·¤¿¤¿¤á¤«¤â¤·¤ì¤Ê¤¤¡¥¤Ê¤ª¥¢¥Ñ¥¿¥¤¥È¤Ï¤è¤ê¼ã¤¤FTǯÂå¤ò¼¨¤·¡¤Ãæ´üÃæ¿·À¤°Ê¹ß¤Î¶É½êŪ¤Ê¥Þ¥°¥Þ³èÆ°¤Î±Æ¶Á¤ò¼õ¤±¤¿²ÄǽÀ­¤¬¤¢¤ë¡¥

Key Words : apatite, dolerite, fission track dating, fission track thermochronometry, geochronology, Japan Sea opening, mafic intrusion, Miocene, Southwest Japan, zircon.
 

10¡¥Petrogenesis of diabase from accretionary prism in the southern Qiangtang terrane, central Tibet : Evidence from U-Pb geochronology, petrochemistry and Sr-Nd-Hf-O isotope characteristics
Jin-Xiang Li, Ke-Zhang Qin, Guang-Ming Li, Jun-Xing Zhao, and Ming-Jian Cao

Ãæ±û¥Á¥Ù¥Ã¥È¡¤ÆîÉôQiangtang¥Æ¥ì¡¼¥ó¤ÎÉÕ²ÃÂÎÃæ¤Î¥À¥¤¥¢¥Ù¡¼¥¹¤ÎÀ®°øÏÀ

LhasaµÚ¤ÓQiangtang¥Æ¥ì¡¼¥ó´Ö¤ÎBangong-Nujiang¡ÊBNS¡ËË¥¹çÂӤϡ¤½ÅÍפʶ­³¦¤òÀê¤á¡¤¤½¤Î´äÀгØŪÀ®°ø¤Ë¤Ä¤¤¤Æ¤Ï¤è¤¯¤ï¤«¤Ã¤Æ¤¤¤Ê¤¤¡¥ÆîÉôQiangtang¥Æ¥ì¡¼¥ó¤ÎÉÕ²ÃÂΤΥÀ¥¤¥¢¥Ù¡¼¥¹Ãæ¤Î¥¸¥ë¥³¥ó¤Ï181.3 ± 1.4 Ma¤ÎU-PbǯÂå¤ò¼¨¤¹¡¥¥À¥¤¥¢¥Ù¡¼¥¹¤Ï¥½¥ì¥¢¥¤¥È¼Á¸¼Éð´äÁÈÀ®¤Ç¤¢¤ê¡¤¤ä¤ä·Ú´õÅÚÎีÁǤËÉÙ¤à¥Ñ¥¿¡¼¥ó¡¤¤µ¤Þ¤¶¤Þ¤ÊÄøÅÙ¤ËÉÙ¤àÉÔŬ¹ç¸µÁÇ¡ÊTh, Rb¤Ê¤É¡Ë¡¤HFS¸µÁÇ¡ÊNb, Ta¤Ê¤É¡Ë°Û¾ï¤ò·ç¤¯ÅÀ¤Ç¡¤¥¨¥ó¥ê¥Ã¥Á¤·¤¿Ãæ±û³¤Î渼Éð´ä¡ÊE-MROB¡Ë¤ËÎà»÷¤¹¤ë¡¥ÁêÂÐŪ¤Ë¶Ñ¼Á¤ÊÁ´´äNdƱ°ÌÂÎÁÈÀ®¡ÊεNd¡Êt¡Ë=7.3-9.1¡Ë¤È¥¸¥ë¥³¥ó¤ÎHf-OƱ°ÌÂÎÁÈÀ®¡ÊεHf¡Êt¡Ë=14.8-16.1,δ18O=4.57-6.12 ‰¡Ë¤Ï¡¤Ãϳ̤κ®À÷¤¬¤Û¤È¤ó¤É¤Ê¤¯¸Ï³é¤·¤¿¥Þ¥ó¥È¥ë¤¬Í»²ò¤·¤¿¤³¤È¤ò¼¨¤¹¡¥Á´´ä²½³ØÁÈÀ®ÊѲ½¤«¤é¥À¥¤¥¢¥Ù¡¼¥¹¤ÏBangong-Nujiang³¤¤ÎÃæ±û³¤Îæ¤È¥×¥ë¡¼¥à¤ÎÁê¸ßºîÍѤˤè¤Ã¤ÆÀ¸¤¸¤¿¤È¹Í¤¨¤é¤ì¤ë¡¥

Key Words : diabase, petrogenesis, Qiangtang terrane, Tibet, zircon Hf-O isotope.

¡ÎThematic Article¡ÏPetrogenesis and chemogenesis of oceanic and continental orogens in Asia: Recent progress, Part II

11¡¥Extensive normal faulting during exhumation revealed by the spatial variation of phengite K-Ar ages in the Sambagawa metamorphic rocks, central Shikoku, SW Japan
Toru Takeshita, Koshi Yagi, Chitaro Gouzu, Hironobu Hyodo,and Tetsumaru Itaya

À¾ÆîÆüËÜ¡¤»Í¹ñÃæ±ûÉô»°ÇÈÀîÊÑÀ®´äÃæ¤Î¥Õ¥§¥ó¥¸¥ã¥¤¥ÈK-ArǯÂå¤Î¶õ´ÖÊѲ½¤Ë´ð¤Å¤­ÌÀ¤é¤«¤Ë¤µ¤ì¤¿¾å¾ººïñ³»þ¤Î¹­ÈϰϤÊÀµÃÇÁسèÆ°
Ãݲ¼ Å°¡¦È¬ÌÚ¸ø»Ë¡¦¶¿ÄÅÃÎÂÀϺ¡¦Ê¼Æ£Çî¿®¡¦ÈÄëŰ´Ý


ÊÑÀ®´ä¤ÎÃÏɽ¤Ë¸þ¤±¤Æ¤Î¾å¾º¤Ë¤ª¤¤¤Æ¡¤ÊÑ·Á¥â¡¼¥É¤Ï¾å¾º¤È¤È¤â¤Ë±äÀ­ÊÑ·Á¤«¤éÀÈÀ­ÊÑ·Á¤ËÊѲ½¤¹¤ë¡¥²æ¡¹¤Ï±îÅÄÀîÃÏ°è¤Î»°ÇÈÀîÊÑÀ®´ä¡Ê¹­µÁ¡Ë¤ò¹½À®¤¹¤ëÅ¥¼ÁÊÒ´äÃæ¤Î¥Õ¥§¥ó¥¸¥ã¥¤¥ÈK-ArǯÂ夬ÃÇÁسèÆ°¤Ë¤è¤Ã¤ÆÍ𤵤ì¤Æ¤¤¤Ê¤¤¤«¤ò¸¡Æ¤¤¹¤ë¤¿¤á¡¤¤½¤Î¶õ´ÖÊѲ½¤òÄ´ºº¤·¤¿¡¥¤½¤Î·ë²Ì¡¤²æ¡¹¤Ï²¼°Ì¥¬¡¼¥Í¥Ã¥ÈÂӤȥ¢¥ë¥Ð¥¤¥È¡Ý¹õ±ÀÊìÂÓ¤ª¤è¤Ó¥¢¥ë¥Ð¥¤¥È¡Ý¹õ±ÀÊìÂӤȾå°Ì¥¬¡¼¥Í¥Ã¥ÈÂӤΣ²¤Ä¤Î¶­³¦¤ò²£Àڤäơ¤Ç¯Â夬Ìó£µÉ´ËüǯÊѲ½¤·¤Æ¤¤¤ë¤³¤È¤òÌÀ¤é¤«¤Ë¤·¤¿¡¥¤³¤ì¤é¤Î¥Õ¥§¥ó¥¸¥ã¥¤¥ÈKArǯÂå¤Î¶õ´ÖÊѲ½¤Ï¡¤¤ª¤½¤é¤¯ÀÈÀ­-±äÀ­Å¾°Ü¤Î¾ò·ï¡ÊÌó300¡î¡Ë¤ÇÀ¸¤¸¤¿D£²»þÁê¤ÎÂ絬ÌϤÊÀµÃÇÁسèÆ°¤Ë¤è¤Ã¤ÆÊÑÀ®´äÁؤ¬ÀÚÃǤµ¤ì¤¿¤³¤È¤Ë¤è¤ë¡¥Íýͳ¤Ï¥¢¥¯¥Á¥Î¥é¥¤¥È´ä¤¬Á°¼Ô¤Î¶­³¦¤Ë·ÁÀ®¤µ¤ì¤Æ¤¤¤ë¤«¤é¤Ç¤¢¤ë¡¥¤³¤³¤Ç¡¤D£²»þÁêľÁ°¤Ë¤ÏÊÑÀ®´äÁؤ¬¿åÊ¿¤Ç¤¢¤ê¡¤ÊÑÀ®´ä¤Î¾å¾ºÂ®ÅÙ¤¬°ÊÁ°¿äÄꤵ¤ì¤Æ¤¤¤¿ÃÍ¡¤£±km/É´Ëüǯ¤Ç¤¢¤Ã¤¿²¾Äꤹ¤ë¤È¡¤£µÉ´Ëüǯ¤Î¥Õ¥§¥ó¥¸¥ã¥¤¥ÈK-ArǯÂå¤ÎÊѲ½¤Ï¡¤°ÊÁ°¤Î¸¦µæ¤ÇÊó¹ð¤µ¤ì¤Æ¤¤¤¿ËÌ·¹¼Ð¤ÎÄã³ÑÀµÃÇÁؤ˱è¤Ã¤ÆÌó10 km¤ÎÊѰ̤¬À¸¤¸¤¿¤³¤È¤ò¼¨¤¹¡¥¥¢¥¯¥Á¥Î¥é¥¤¥È´ä¤«¤é¤Î¥Õ¥§¥ó¥¸¥ã¥¤¥È40Ar/39ArǯÂå¡ÊÌó85 to 78 Ma¡Ë¤Ï¼þ°Ï¤ÎÃÇÁسèÆ°¤ò¼õ¤±¤Æ¤¤¤Ê¤¤Å¥¼ÁÊÒ´ä¤ÎK-ArǯÂå¤È¹çÍýŪ¤ËÈæ³Ó½ÐÍè¤ë¡¥¤½¤ÎÍýͳ¤È¤·¤Æ¼þ°Ï¤ÎÅ¥¼ÁÊÒ´ä¤ÎK-ArǯÂå¤â¡¤¥Õ¥§¥ó¥¸¥ã¥¤¥ÈÃæ¤Î¥¢¥ë¥´¥ó¤Î³È»¶ÊĻ߲¹ÅÙ¡ÊÌó500¡Ý600¡î¡Ë¤è¤ê¤â¤Ï¤ë¤«¤ËÄ㤤ÀÈÀ­-±äÀ­Å¾°Ü¤Î²¹ÅÙ¾ò·ï°Ê²¼¤ËÎä¤ä¤µ¤ì¤Æ¤«¤é¤Î·Ð²á»þ´Ö¤ò¼¨¤·¤Æ¤¤¤ë¤³¤È¤¬¹Í¤¨¤é¤ì¤ë¡¥

Key Words : exhumation, normal faulting, phengite K-Ar ages, Sambagawa metamorphic rocks.

¡ÎThematic Article¡ÏCarbonate sedimentation on Pacificcoral reefs, Part II

12¡¥Carbonate sedimentation in seagrass beds on Ishigakijima, Ryukyu Islands, southwestern Japan
Keita Fujita, Ryuji Asami, Hideko Takayanagi, and Yasufumi Iryu

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m2¡¿Ç¯¤Ç¡¤¼þ°Ï¤ÈÈæ¤Ù¤ÆÃø¤·¤¯Â¿¤¯¡¤¤³¤ì¤Ï³¤ÁðÁô¾ì¤¬ÂÏÀÑʪ¤ò¥È¥é¥Ã¥×¤¹¤ëµ¡Ç½¤òÍ­¤·¤Æ¤¤¤ë¤³¤È¤ò¼¨¤¹¡¥¤³¤Î¤è¤¦¤Ë¡¤Î°µåÎóÅç¤Î³¤ÁðÁô¾ì¤Ç¤Ï¡¤Â¿Î̤ÎÂÏÀÑʪ¤¬Î®Æþ¤·¤Æ¤¤¤ë¤Ë¤â´Ø¤ï¤é¤º¡¤ÂÏÀÑ®ÅÙ¤¬¶Ëü¤ËÃÙ¤¯¡¤Î®Æþ¤·¤¿ÂÏÀÑʪ¤Î¤Û¤ÜÁ´¤Æ¤Ï³¤ÁðÁô¾ì¤Î³°¤Ø°ÜÆ°¤·¤Æ¤¤¤ë¤È»×¤ï¤ì¤ë¡¥

Key Words : carbonate, Ryukyu Islands, seagrass, seagrass bed.