Chemical compositions of amphiboles and their references to formation conditions of granitoids from Nam Rom and Song Ma massifs, Northwest Vietnam

Pham Ngoc Can; Tran Tuan Anh; Tran Trong Hoa; Vu Hoang Ly; Pham Thi Phuong Lien; Ngo Thi Huong

doi:10.15625/0866-7187/42/1/14760

Author affiliations

Authors

Pham Ngoc Can Institute of Geological Sciences, VAST, Hanoi, Vietnam
Tran Tuan Anh Institute of Geological Sciences, VAST, Hanoi, Vietnam
Tran Trong Hoa Institute of Geological Sciences, VAST, Hanoi, Vietnam
Vu Hoang Ly 1) Institute of Geological Sciences, VAST, Hanoi, Vietnam 2) Novosibirsk State University
Pham Thi Phuong Lien Institute of Geological Sciences, VAST, Hanoi, Vietnam
Ngo Thi Huong 1) Institute of Geological Sciences, VAST, Hanoi, Vietnam 2) Novosibirsk State University

DOI:

https://doi.org/10.15625/0866-7187/42/1/14760

Keywords:

Nam Rom, Song Ma, amphibole, plagioclase, geobarometer

Abstract

In this paper, the mineralogical and geochemical characteristics of amphiboles and plagioclases of granitoids from the Nam Rom and Song Ma massifs have been investigated to understand their formation conditions. The Nam Rom amphibole and plagioclase are subhedral to euhedral fine- to medium-grained crystals. Whereas, the Song Ma amphibole and plagioclase are anhedral to subhedral fine-grained crystals. Geochemical compositions of amphiboles suggest that Nam Rom and Song Ma amphiboles are edenite and ferro-edenite, respectively. Nam Rom edenite has higher contents of basic constituents (Mg and Ca) and lower contents of felsic constituents (Na and K) compared with the Song Ma ferro-edenite. On the other hand, Si-(Na+K) and Si-Ca apfu ratios of the Nam Rom edenite and the Song Ma ferro-edenite and Al/(Na+K)-Al/(Ca+Na+K) atom per formula unit (apfu) ratios of the Nam Rom edenite and andesine and the Song Ma ferro-edenite, andesine and oligoclase are similar. Formation conditions of the Nam Rom and Song Ma granitoids were calculated using amphibole-plagioclase geobarometer. The Nam Rom granitoid was formed at 3.07-5.32 kbar (10.1-17.6 km under paleo-surface) and 750-785°C. The Song Ma granitoid was formed at 1.04-3.08 kbar (3.4-10.2 km under paleo-surface) and 715-745°C. Therefore, Nam Rom and Song Ma granitoids are thought to be crystallized from the same magma. The former was formed from the immature and more basic stage of magma; the latter was formed from the mature and more felsic stage of magma.

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References

Blundy J.D., Holland T.J.B., 1990. Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer: Contributions to Mineralogy and Petrology, 104, 208–224.

Bowen N.L., 1956. The Evolution of Igneous Rocks: Canada, Dover Publications.

Dao D.T., Huynh T., Tran Q.H., Ngo V.K., Phan V.K., Do V.L., Nguyen D.T., Tran T.T., Le T., Phan T., Tran T., Nguyen V.Q., Nguyen K.Q., 1995. Geology of Vietnam. Volume II: Magmatic formations: Ha Noi, General Department of Geology and Minerals of Vietnam, 360p.

Dovzhikov A.E., Bui P.M., Vasilevskaja E.D., Zhamoida A.I., Ivanov G.V., Izokh E.P., Le D.H., MaReitchev A.I., Nguyen V.C., Nguyen T.T., Tran D.L., Pham V.Q., Pham D.L., 1965. Geology of North Vietnam - Explanatory note to the Geological map of Northern Vietnam on 1:500.000 scale: Ha Noi, Science and Technics Publishing House.

Hammarstrom J.M., Zen E.A., 1986. Aluminum in hornblende: An empirical igneous geobarometer: American Mineralogist, 71, 1297–1313.

Hawthorne F.C., Oberti R., Harlow G.E., Maresch W.V., Martin R.F., Schumacher J.C., Welch M.D., 2012. Nomenclature of the amphibole supergroup: American Mineralogist, 97, 2031–2048.

Hollister L.S., Grissom G.C., Peters E.K., Stowell H.H., Sisson V.B., 1987. Confirmation of the empirical correlation of Al in hornblende with pressure of solidification of calc-alkaline plutons: American Mineralogist, 72, 231–239.

Izokh E.P., Dovzikov A.E., 1981. General scheme of magmatism of Vietnam: Geological map, 50, 13–32.

Johnson M.C., Rutherford M.J., 1989. Experimental calibration of the aluminum-in-hornblende geobarometer with application to Long Valley caldera (California) volcanic rocks: Geology, 17, 837–841.

Le Bas M.J., Streckeisen A., 1991. The IUGS systematics of igneous rocks: Journal of the Geological Society, London, 148, 825–833.

Leake B.E., Woolley A.R., S. A.C.E. Birch, W.D. Gilbert, M.C. Grice, J.D. Hawthorne F.C., Kato A., Kisch H.J., Krivovichev V.G., Linthout K., Laird J., Mandarino J.A., Maresch W.V., Nickel E.H., Rock N.M.S., Schumacher J.C., Smith D.C., Stephenson N.C.N., Ungaretti L., Whittaker E.J.W., Youzhi G., 1997. Nomenclature of amphiboles: report of the subcommittee on amphiboles of the international mineralogical association, commission on the minerals and mineral names: The Canadian Mineralogist, 35, 219–246.

Nguyen X.T., Tran V.T., Nguyen B., Dang V.C., Nguyen T.C., Phan T.D., Gatinsky Y.G., Nguyen T.G., Nguyen X.K., Nguyen N.L., Pham D.L., Rodnikova R.D., Bui M.T., Pham H.T., Phan T.T., Tran X.V., 1992. Geological formations and geodynamics of Vietnam: Ha Noi, Science and Technics Publishing House, 274p.

Phan S., Dao D.T., Nguyen D.T., Tran V.T., 2005. Geological and mineral resources map of Vietnam on 1:200.000 scale. Muong Kha - Son La sheet, with Explanatory note: Ha Noi, General Department of Geology and Minerals of Vietnam.

Schmidt M.W., 1992. Amphibole composition in tonalite as a function of pressure: an experimental calibration of the Al-in-hornblende barometer: Contributions to Mineralogy and Petrology, 110, 304–110.

Schumacher J.C., 1991. Empirical ferric iron corrections: necessity, assumptions, and effects on selected geothermo-barometers: Mineralogical Magazine, 55, 3–18.

Streckeisen A., 1973. Plutonic Rocks. Classification and nomenclature recommended by the IUGS Subcommission on the Systematics of Igneous Rocks: Geotimes, 18, 26–30.

Tran D.T., Nguyen V.H., Pham V.D., An V.T., Nguyen B.H., 2005. Geological and mineral resources map of Vietnam on 1:200.000 scale. Phong Sa Ly-Dien Bien Phu sheet, with Explanatory note: Ha Noi, General Department of Geology and Minerals of Vietnam.

Tran T.H., Izokh A.E., Polyakov G.V., Borisenko A. S., Ngo, T. P., Balykin, P. A., Tran T.A., Rudnev S.N., Vu V.V., Bui A.N., 2008. Permo-Triassic magmatism and metallogeny of North Vietnam in relation to Emeishan’s Plume: Russian Geology and Geophysics, 49, 480–491.

Tran T.H., Nguyen V.N., 2006. Tectonic setting of the intrusive rocks in the Muong Lay area, Dien Bien Province: Journal of Mining and Geological Science and Technics, 14, 43–50 (in Vietnamese).

Tran V.T., Nguyen V.C., Le V.C., Duong X.H., Le H., Vu K., Pham D.L., Pham K.N., Tran D.N., Hoang H.Q., Tong D.T., Phan T.T., Trinh T., Nguyen T., Nguyen X.T., Nguyen D.U., 1977. Geology of Vietnam - the North part. Explanatory note to the geological map on 1:1.000.000 scale: Ha Noi, Science and Technics Publishing House.