TY - JOUR
T1 - The Cretaceous Okhotsk-Chukotka Volcanic Belt (NE Russia)
T2 - Geology, geochronology, magma output rates, and implications on the genesis of silicic LIPs
AU - Tikhomirov, P. L.
AU - Kalinina, E. A.
AU - Moriguti, T.
AU - Makishima, A.
AU - Kobayashi, K.
AU - Cherepanova, Yu I.
AU - Nakamura, E.
N1 - Funding Information:
Authors are grateful to Mr. J.-P. Londero (Kinross Gold, Toronto, Canada) for his friendly help with the organization of fieldwork, and to V.O. Ispolatov (Barrick Gold of Australia Ltd.) who kindly improved English and gave valuable comments on the manuscript. P. Tikhomirov thanks R. Tanaka, T. Ota and C. Sakaguchi (Pheasant Memorial Laboratory, Misasa, Japan) for their assistance with the preparation of samples, and all members of the Pheasant Memorial Laboratory for the friendly and constructive environment. This study was funded by the Ministry of Education, Sports, Science and Technology of Japan , the program “Center of Excellence for the 21st Century in Japan” (E.N.) from the Japanese Society for the Promotion of Science , and in part by grants from the Ministry of Education, Science, Sports and Culture of Japan (T.M.). The work of P.T. was partially supported by Russian Foundation for Basic Research , grants 03-05-64623-a and 09-05-01197-a .
PY - 2012/4/1
Y1 - 2012/4/1
N2 - The Cretaceous Okhotsk-Chukotka volcanic belt (OCVB) is a prominent subduction-related magmatic province, having the remarkably high proportion of silicic rocks (ca. 53% of the present-day crop area, and presumably over 70% of the total volcanic volume). Its estimated total extrusive volume ranges between 5.5×10 5km 3 (the most conservative estimate) and over 10 6km 3. This article presents a brief outline of the geology of OCVB, yet poorly described in international scientific literature, and results of a geochronological study on the northern part of the volcanic belt. On the base of new and published U-Pb and 40Ar/ 39Ar age determinations, a new chronological model is proposed. Our study indicates that the activity of the volcanic belt was highly discontinuous and comprised at least five main episodes at 106-98Ma, 94-91Ma, 89-87Ma, 85.5-84Ma, and 82-79Ma. The new data allow a semi-quantitative estimate of the volcanic output rate for the observed part of the OCVB (area and volume approximately 10 5km 2 and 2.5×10 5km 3, respectively). The average extrusion rate for the entire lifetime of the volcanic belt ranges between 1.6 and 3.6×10 -5km 3yr -1km -1, depending on the assumed average thickness of the volcanic pile; the optimal value is 2.6×10 -5km 3yr -1km -1. Despite imprecise, such estimates infer the time-averaged volcanic productivity of the OCVB is similar to that of silicic LIPs and most active recent subduction-related volcanic areas of the Earth. However, the most extensive volcanic flare-ups at 89-87 and 85.5-84Ma had higher rates of over 9.0×10 -5km 3yr -1km -1.The main volumetric, temporal and compositional parameters of the OCVB are similar to those of silicic LIPs. This gives ground for discussion about the geodynamic setting of the latters, because the widely accepted definition of a LIP implies a strictly intraplate environment. Considering the genesis of the OCVB and other large provinces of silicic volcanism, we propose that residual thermal energy preserved in the continental crust after a previous major magmatic event may have been one of major reasons for high proportion of felsic rocks in a volcanic pile. In this scenario, underplating of mantle-derived basalts causes fast and extensive melting of still hot continental crust and generation of voluminous silicic magmas.
AB - The Cretaceous Okhotsk-Chukotka volcanic belt (OCVB) is a prominent subduction-related magmatic province, having the remarkably high proportion of silicic rocks (ca. 53% of the present-day crop area, and presumably over 70% of the total volcanic volume). Its estimated total extrusive volume ranges between 5.5×10 5km 3 (the most conservative estimate) and over 10 6km 3. This article presents a brief outline of the geology of OCVB, yet poorly described in international scientific literature, and results of a geochronological study on the northern part of the volcanic belt. On the base of new and published U-Pb and 40Ar/ 39Ar age determinations, a new chronological model is proposed. Our study indicates that the activity of the volcanic belt was highly discontinuous and comprised at least five main episodes at 106-98Ma, 94-91Ma, 89-87Ma, 85.5-84Ma, and 82-79Ma. The new data allow a semi-quantitative estimate of the volcanic output rate for the observed part of the OCVB (area and volume approximately 10 5km 2 and 2.5×10 5km 3, respectively). The average extrusion rate for the entire lifetime of the volcanic belt ranges between 1.6 and 3.6×10 -5km 3yr -1km -1, depending on the assumed average thickness of the volcanic pile; the optimal value is 2.6×10 -5km 3yr -1km -1. Despite imprecise, such estimates infer the time-averaged volcanic productivity of the OCVB is similar to that of silicic LIPs and most active recent subduction-related volcanic areas of the Earth. However, the most extensive volcanic flare-ups at 89-87 and 85.5-84Ma had higher rates of over 9.0×10 -5km 3yr -1km -1.The main volumetric, temporal and compositional parameters of the OCVB are similar to those of silicic LIPs. This gives ground for discussion about the geodynamic setting of the latters, because the widely accepted definition of a LIP implies a strictly intraplate environment. Considering the genesis of the OCVB and other large provinces of silicic volcanism, we propose that residual thermal energy preserved in the continental crust after a previous major magmatic event may have been one of major reasons for high proportion of felsic rocks in a volcanic pile. In this scenario, underplating of mantle-derived basalts causes fast and extensive melting of still hot continental crust and generation of voluminous silicic magmas.
KW - Geochronology
KW - Magma output rate
KW - Northeastern eurasia
KW - Okhotsk-chukotka belt
KW - Silicic LIP
KW - Volcanism
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U2 - 10.1016/j.jvolgeores.2011.12.011
DO - 10.1016/j.jvolgeores.2011.12.011
M3 - Review article
AN - SCOPUS:84857249113
VL - 221-222
SP - 14
EP - 32
JO - Journal of Volcanology and Geothermal Research
JF - Journal of Volcanology and Geothermal Research
SN - 0377-0273
ER -