Full Text:   <1374>

CLC number: P58; P59

On-line Access: 

Received: 2005-03-16

Revision Accepted: 2005-05-10

Crosschecked: 0000-00-00

Cited: 0

Clicked: 3872

Citations:  Bibtex RefMan EndNote GB/T7714

-   Go to

Article info.
1. Reference List
Open peer comments

Journal of Zhejiang University SCIENCE A 2005 Vol.6 No.7 P.649~655


Petrological study of the western Iratsu mass from the Sambagawa metamorphic belt, central Shikoku, Japan

Author(s):  LI Zi-long, TAKASU Akira

Affiliation(s):  Department of Earth Science, Zhejiang University, Hangzhou 310027, China; more

Corresponding email(s):   zilongli@zju.edu.cn

Key Words:  Petrology, P-T-t path, Western Iratsu mass, Sambagawa belt

LI Zi-long, TAKASU Akira. Petrological study of the western Iratsu mass from the Sambagawa metamorphic belt, central Shikoku, Japan[J]. Journal of Zhejiang University Science A, 2005, 6(7): 649~655.

@article{title="Petrological study of the western Iratsu mass from the Sambagawa metamorphic belt, central Shikoku, Japan",
author="LI Zi-long, TAKASU Akira",
journal="Journal of Zhejiang University Science A",
publisher="Zhejiang University Press & Springer",

%0 Journal Article
%T Petrological study of the western Iratsu mass from the Sambagawa metamorphic belt, central Shikoku, Japan
%A LI Zi-long
%J Journal of Zhejiang University SCIENCE A
%V 6
%N 7
%P 649~655
%@ 1673-565X
%D 2005
%I Zhejiang University Press & Springer
%DOI 10.1631/jzus.2005.A0649

T1 - Petrological study of the western Iratsu mass from the Sambagawa metamorphic belt, central Shikoku, Japan
A1 - LI Zi-long
A1 - TAKASU Akira
J0 - Journal of Zhejiang University Science A
VL - 6
IS - 7
SP - 649
EP - 655
%@ 1673-565X
Y1 - 2005
PB - Zhejiang University Press & Springer
ER -
DOI - 10.1631/jzus.2005.A0649

The western Iratsu mass, the largest tectonic body in the Sambagawa metamorphic belt, central Shikoku, is mainly composed of epidote amphibolite with minor amounts of eclogite. Systematically, a majority of garnets show bell-shaped chemical zoning of pyrope contents and Mg/(Mg+Fe2+) monotonously increasing outward. The grossular component in zonal garnet increases outwards, maximizes at an intermediate part, and then decreases towards the outermost rim, reflecting a process from increasing to decreasing pressure conditions during the prograde metamorphism. Jadeite contents of omphacite range from 25~20 mole% within the cores to 15~10 mole% at the rims, implying a pressure-decreasing process (from 11×105 Pa to 8×105 Pa). The peak pressure-temperature (P-T) condition of 630~680 °C and ca. 15×105 Pa in the western Iratsu mass is much higher than that of (610±25) °C and (10±1)×105 Pa of the Sambagawa oligoclase-biotite zone schists. The authors suggest a clockwise p-T-t path for the western Iratsu mass.

Darkslateblue:Affiliate; Royal Blue:Author; Turquoise:Article


[1] Aoya, M., 2001. P-T-D path of eclogite from the Sambagawa belt deduced from combination of petrological and microstructural analyses. J. Petrol., 42:1225-1248.

[2] Banno, S., Sakai, C., Higashino, T., 1986. Pressure-temperature trajectory of the Sambagawa metamorphism deduced from garnet zoning. Lithos, 19:51-63.

[3] Coleman, R.G., Lee, D.E., Beatty, L.B., 1965. Eclogites and eclogites: their differences and similarities. Geol. Soc. Am. Bull., 76:483-508.

[4] Droop, G.T.R., 1987. A general equation for estimating Fe3+ concentration in ferromagnesium silicates and oxides from microprobe analysis using stoichiometric criteria. Mineralogical Magazine, 51:431-435.

[5] Enami, M., 1983. Petrology of pelitic schists in the oligoclase-biotite zone of the Sambagawa metamorphic terrain, Japan: phase equilibria in the highest-grade zone of a high-pressure intermediate type of metamorphic belt, Japan. J. Metamor. Geol., 1:141-161.

[6] Graham, C.M., Powell, R., 1984. A garnet-hornblende geothermometer: calibration, testing, and application to the Pelona schist, Southern California. J. Metamor. Geol., 2:13-31.

[7] Krogh, E.J., 1988. The garnet-clinopyroxene Fe-Mg geothermomter—a reinterpretation of existing experimental data. Contrib. Mineral. Petrol., 99:44-48.

[8] Kunugiza, K., Takasu, A., Banno, S., 1986. The origin and metamorphic history of the ultramafic and metagabbro bodies in the Sambagawa metamorphic belt. Geological Society of America, Memoir, 164:375-385.

[9] Massonne, H.J., Schreyer, W., 1987. Phengite geobarometry based on the limited assemblage with K-feldspar, phlogopite, and quartz. Contributions to Mineralogy and Petrology, 96:212-224.

[10] McCarthy, T.C., Patinon, D.A.E., 1998. Empirical calibration of the silica-Ca-tschermarks-anorthite (SCAn) geobarometer. J. Metamor. Geol., 16:675-686.

[11] Miyashiro, A., 1973. Metamorphism and Metamorphic Belts. George Allen and Unwin, London.

[12] Pattison, D.R.M., Newton, R.C., 1989. Reversed experimental calibration of the garnet-clinopyroxene Fe-Mg exchange geothermometer. Contrib. Mineral. Petrol., 101:87-103.

[13] Ravna, E.K., 2000. Distribution of Fe2+ and Mg between coexisting garnet and hornblende in synthetic and natural systems: an empirical calibration of the garnet-hornblende Fe-Mg geothermometer. Lithos, 53(3-4):265-277.

[14] Takasu, A., 1989. P-T Histories of Peridotite and Amphibolite Tectonic Blocks in the Sambagawa Metamorphic Belt, Japan. In: Daly, J.S., Cliff, R.A., Yardley, B.W.D. (Eds.), Evolution of Metamorphic Belt. Geological Society, London, p.533-538.

[15] Takasu, A., Dallmeyer, R.D., 1990. 40Ar/39Ar mineral age constraints for the tectonothermal evolution of the Sambagawa metamorphic belt, Central Shikoku, Japan: A cretaceous accretionary prism. Tectonophysics, 185:111-139.

[16] Takasu, A., Kohsaka, Y., 1987. Eclogites from the Iratsu epidote amphibolite mass in the Sambagawa metamorphic belt, Besshi district, Japan. Journal of Geological Society of Japan, 93:517-520 (in Japanese).

[17] Takasu A., Wallis, S.R., Banno, S., Dallmeyer, R.D., 1994. Evolution of the Sambagawa metamorphic belt, Japan. Lithos, 33:119-133.

[18] Velde, B., 1967. Si4+ content of natural phengites. Contrib. Mineral. Petrol., 14:250-258.

[19] Wallis, S.R., Aoya, M., 2000. A reevaluation of eclogite facies metamorphism in SW Japan: proposal for an eclogite nappe. Journal of Metamorphic Geology, 18:653-664.

Open peer comments: Debate/Discuss/Question/Opinion


Please provide your name, email address and a comment

Journal of Zhejiang University-SCIENCE, 38 Zheda Road, Hangzhou 310027, China
Tel: +86-571-87952783; E-mail: cjzhang@zju.edu.cn
Copyright © 2000 - Journal of Zhejiang University-SCIENCE