Linking granulites, silicic magmatism, and crustal growth in arcs: ion microprobe (zircon) U-Pb pages from the Hidaka metamorphic belt, Japan
Kemp, A.I.S., Shimura, T., Hawkesworth, C.J., and Edinburgh Ion Microprobe Facility, (2007) Linking granulites, silicic magmatism, and crustal growth in arcs: ion microprobe (zircon) U-Pb pages from the Hidaka metamorphic belt, Japan. Geology, 35 (9). pp. 807-810.
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View at Publisher Website: http://dx.doi.org/10.1130/G23586A.1
There is no consensus as to how the extreme metamorphic conditions required to form granulites are attained, or how these rocks relate to crustal growth and differentiation processes. Studying young granulites offers two advantages: the tectonic setting is likely to be well constrained, and the ambiguities that result from overprinting by younger metamorphic events are potentially avoided. We report the first ion microprobe U-Pb (zircon) ages for orthopyroxene-bearing granulites, tonalites, and gabbros of the Cenozoic Hidaka metamorphic belt (Hokkaido, Japan) to clarify the magmatic-metamorphic connection in this area. The data support a two-stage evolution for this terrane, which is attributed to episodes of supra-subduction zone magmatism (late Eocene) and back-arc extension (early Miocene). We relate granulite facies metamorphism and garnet-orthopyroxene tonalite generation to mafic magma under-accretion and lithosphere thinning due to the opening of the Japan Sea at 19 Ma. The Hidaka granulites are thus among the youngest exposed granulites on Earth, and manifest the thermal response to continental growth.
|Item Type:||Article (Refereed Research - C1)|
|Keywords:||granulite; zircon; U-Pb dating; crustal growth; Hidaka metamorphic belt|
|FoR Codes:||04 EARTH SCIENCES > 0403 Geology > 040304 Igneous and Metamorphic Petrology @ 50%|
04 EARTH SCIENCES > 0403 Geology > 040303 Geochronology @ 25%
04 EARTH SCIENCES > 0403 Geology > 040313 Tectonics @ 25%
|SEO Codes:||97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 100%|
|Deposited On:||07 May 2009 08:19|
|Last Modified:||18 Oct 2013 00:27|
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