Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Yamasaki, Seiko; Umeda, Koji
Ganseki Kobutsu Kagaku, 41(2), p.39 - 46, 2012/05
The thermal history of the Toki granite body exposed in the eastern Sanyo Belt, Central Japan, was evaluated from various chronological data by K-Ar, fission track methods and Rb-Sr. The K-Ar ages obtained from biotite ranged from 72 to 74 Ma, which were concordant with the K-Ar ages of hornblende and the reported Rb-Sr whole-rock isochron ages. Fission-track ages for zircon and apatite in the Toki granite were 64 to 73 Ma and 37 to 40 Ma, respectively. These thermochronological data revealed two distinctive cooling stages for the Cretaceous Toki granite; (1) a rapid cooling stage which the granitic magma was cooled to the temperature of host rock soon after intrusion at depths of 5 - 6 km in the upper crust, and (2) the subsequent slow cooling stage (7 - 10 
C/m.y.) associated with the exhumation of the granite body after ca. 60 Ma.
Yuguchi, Takashi; Tsuruta, Tadahiko; Nishiyama, Tadao*
Ganseki Kobutsu Kagaku, 39(2), p.50 - 70, 2010/03
Umeda, Koji; Danhara, Toru*
Ganseki Kobutsu Kagaku, 37(5), p.131 - 136, 2008/09
The fission-track ages of zircons for four volcaniclastics from the Mutsu-Hiuchidake volcano and it's basement, Northeast Japan, are determined as 0.81
0.14 Ma and 0.770.10 Ma (pyroclastic flow deposits), 2.60.2 Ma and 3.00.3 Ma (basement rocks). The activity period of the volcano is estimated to be from 1.2 to 0.5 Ma, based on FT ages, K-Ar ages, TL ages and stratigraphic relationships.
Hanamuro, Takahiro; Umeda, Koji; Takashima, Isao*; Negishi, Yoshimitsu*
Ganseki Kobutsu Kagaku, 37(2), p.27 - 38, 2008/03
The high temperature hot springs such as in Yunomine and Tosenji and the hydrothermal alteration zones of the Hongu area are distributed in the southern part of Kii peninsula, though no Quaternary volcanoes exist. In this research, it has aimed to understand the heat history that the rocks received by the measurement technique of several dating methods for distributed Hongu area and Totsukawa area in the high temperature hot springs and the alteration zones. As a result of the TL, FT and K-Ar dating, after the activity of the high temperature alteration until tens of millions of years ago, the activity of the relatively low temperature alteration from at least hundreds of thousands of to tens of thousands of years ago in Hongu area and Totsukawa area. These thermal histories can be understood by combining the measurement techniques of several dating methods.
Tomiyama, Shingo*; Umeda, Koji; Hanamuro, Takahiro; Takashima, Isao*; Hayashi, Shintaro*; Negishi, Yoshimitsu*; Masudome, Yukiko*
Ganseki Kobutsu Kagaku, 36(4), p.111 - 121, 2007/07
To clarify a progress history of the alteration accompanied by Mutsu-Hiuchidake volcanic activities, the study on distribution and characteristics of alteration zones and alteration dating at the Mutsu-Hiuchidake Volcano. The results of alteration zoning and alteration dating suggest that alteration zones generated by hydrothermal activities accompanied by Mutsu-Hiuchidake volcanic activities are distributed along the fracture zones and enlarged by fractures or highly permeable zones in the body of volcano and basement. The result of measurement of homogeneous temperatures of fluid inclusion suggests that the highest temperature of these hydrothermal alterations is about 200 to 250C.
Utsumi, Wataru; Funakoshi, Kenichi*; Yagi, Naoto*; Urakawa, Satoru*; Otaka, Osamu*; Katsura, Tomoo*; Irifune, Tetsuo*; Inoue, Toru*; Uchida, Takeyuki*
Ganseki Kobutsu Kagaku, 30(2), p.100 - 101, 2001/03
no abstracts in English
Funakoshi, Kenichi*; Utsumi, Wataru; Otaka, Osamu*; Irifune, Tetsuo*; Inoue, Toru*; Ito, Eiji*; Katsura, Tomoo*; Kubo, Atsushi*; Hirose, Kei*; Ando, Junichi*; et al.
Ganseki Kobutsu Kagaku, 30(2), p.102 - 103, 2001/03
no abstracts in English
