Abstract
The Sanbagawa Metamorphic Belt in Japan is one of the best studied high-pressure, low temperature metamorphic belts. Recent work applying new dating techniques has challenged the previously accepted temporal framework for the evolution of the belt, as it was shown that large parts of the belt contain detrital zircons of Late Cretaceous age (younger than 100. Ma), i.e. they have protolith ages younger than the previously accepted age of metamorphism at ca. 110. Ma. A 2000. m bore hole from north-western Shikoku provided an excellent opportunity to further evaluate the areal extent of Late Cretaceous protoliths as the drill hole was drilled in an area considered to be part of the Jurassic to Early Cretaceous part of the Sanbagawa Belt. Dating of single zircon grains using the LA-ICP-MS U-Pb dating method shows that all but one sample contain zircons younger than 100. Ma and thus the protoliths are younger than the previously accepted age of metamorphism of the Sanbagawa Belt. The single sample that contains only zircons dated at 136. ±. 3. Ma, apparently is of volcanic origin and could be a clast representing the source of 130-140. Ma zircons of the sample taken about 120 above this sample. In addition, three surface samples were analysed. Two of these also contain zircons younger than 100. Ma, whereas the third sample contains only zircons older than 159. Ma. The zircons from this sample also exhibit an age spectrum different from that exhibited by the other samples. The exact significance of this sample is not clear as yet.
| Original language | English |
|---|---|
| Pages (from-to) | 148-161 |
| Number of pages | 14 |
| Journal | Journal of Asian Earth Sciences |
| Volume | 96 |
| DOIs | |
| Publication status | Published - Sep 16 2014 |
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Keywords
- Age of Sanbagawa protoliths
- Sanbagawa high-P Metamorphic Belt
- Shimanto Belt
- U-Pb zircon dating
ASJC Scopus subject areas
- Earth-Surface Processes
- Geology
Cite this
U-Pb ages of detrital zircons from the Sanbagawa Belt in western Shikoku : Additional evidence for the prevalence of Late Cretaceous protoliths of the Sanbagawa Metamorphics. / Knittel, U.; Suzuki, Shigeyuki; Nishizaka, N.; Kimura, K.; Tsai, W. L.; Lu, H. Y.; Ishikawa, Y.; Ohno, Y.; Yanagida, M.; Lee, Y. H.
In: Journal of Asian Earth Sciences, Vol. 96, 16.09.2014, p. 148-161.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - U-Pb ages of detrital zircons from the Sanbagawa Belt in western Shikoku
T2 - Additional evidence for the prevalence of Late Cretaceous protoliths of the Sanbagawa Metamorphics
AU - Knittel, U.
AU - Suzuki, Shigeyuki
AU - Nishizaka, N.
AU - Kimura, K.
AU - Tsai, W. L.
AU - Lu, H. Y.
AU - Ishikawa, Y.
AU - Ohno, Y.
AU - Yanagida, M.
AU - Lee, Y. H.
PY - 2014/9/16
Y1 - 2014/9/16
N2 - The Sanbagawa Metamorphic Belt in Japan is one of the best studied high-pressure, low temperature metamorphic belts. Recent work applying new dating techniques has challenged the previously accepted temporal framework for the evolution of the belt, as it was shown that large parts of the belt contain detrital zircons of Late Cretaceous age (younger than 100. Ma), i.e. they have protolith ages younger than the previously accepted age of metamorphism at ca. 110. Ma. A 2000. m bore hole from north-western Shikoku provided an excellent opportunity to further evaluate the areal extent of Late Cretaceous protoliths as the drill hole was drilled in an area considered to be part of the Jurassic to Early Cretaceous part of the Sanbagawa Belt. Dating of single zircon grains using the LA-ICP-MS U-Pb dating method shows that all but one sample contain zircons younger than 100. Ma and thus the protoliths are younger than the previously accepted age of metamorphism of the Sanbagawa Belt. The single sample that contains only zircons dated at 136. ±. 3. Ma, apparently is of volcanic origin and could be a clast representing the source of 130-140. Ma zircons of the sample taken about 120 above this sample. In addition, three surface samples were analysed. Two of these also contain zircons younger than 100. Ma, whereas the third sample contains only zircons older than 159. Ma. The zircons from this sample also exhibit an age spectrum different from that exhibited by the other samples. The exact significance of this sample is not clear as yet.
AB - The Sanbagawa Metamorphic Belt in Japan is one of the best studied high-pressure, low temperature metamorphic belts. Recent work applying new dating techniques has challenged the previously accepted temporal framework for the evolution of the belt, as it was shown that large parts of the belt contain detrital zircons of Late Cretaceous age (younger than 100. Ma), i.e. they have protolith ages younger than the previously accepted age of metamorphism at ca. 110. Ma. A 2000. m bore hole from north-western Shikoku provided an excellent opportunity to further evaluate the areal extent of Late Cretaceous protoliths as the drill hole was drilled in an area considered to be part of the Jurassic to Early Cretaceous part of the Sanbagawa Belt. Dating of single zircon grains using the LA-ICP-MS U-Pb dating method shows that all but one sample contain zircons younger than 100. Ma and thus the protoliths are younger than the previously accepted age of metamorphism of the Sanbagawa Belt. The single sample that contains only zircons dated at 136. ±. 3. Ma, apparently is of volcanic origin and could be a clast representing the source of 130-140. Ma zircons of the sample taken about 120 above this sample. In addition, three surface samples were analysed. Two of these also contain zircons younger than 100. Ma, whereas the third sample contains only zircons older than 159. Ma. The zircons from this sample also exhibit an age spectrum different from that exhibited by the other samples. The exact significance of this sample is not clear as yet.
KW - Age of Sanbagawa protoliths
KW - Sanbagawa high-P Metamorphic Belt
KW - Shimanto Belt
KW - U-Pb zircon dating
UR - http://www.scopus.com/inward/record.url?scp=84907667921&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84907667921&partnerID=8YFLogxK
U2 - 10.1016/j.jseaes.2014.09.001
DO - 10.1016/j.jseaes.2014.09.001
M3 - Article
VL - 96
SP - 148
EP - 161
JO - Journal of Asian Earth Sciences
JF - Journal of Asian Earth Sciences
SN - 1367-9120
ER -