T1[Topic] Tectonics

11:00 AM - 11:15 AM JST(2:00 AM - 2:15 AM UTC)HighlightECS: Early Career Scientist

[T1-O-6] Feasibility study for zircon and apatite thermochronology on the uplifting Noto Peninsula

*Ruby Connemara MARSDEN¹, Noriko HASEBE¹ (1. Kanazawa University)

【ハイライト講演】 本講演は,低温熱年代学を用いて能登半島の新生代テクトニクスを議論する．2024年能登半島沖地震とそれに伴う離水イベントにより，能登半島の隆起を伴うテクトニクスに注目が集まっている．しかし，日本海拡大を含む新生代に渡る能登半島のテクトニクスの理解は十分に進んでいない．本講演は熱年代学的手法を用いて，基盤岩の隆起・沈降に伴う複雑な熱履歴を復元し，能登半島の新生代テクトニクスの議論を行う意欲的な発表である． ※ハイライト講演とは．．．

Keywords:

Thermochronology,Noto Peninsula,Forward modelling

Thermochronometers, such as (U-Th)/He dating or fission track dating carried out on zircon and apatite crystals, can be used to determine the thermal history of a sample. These thermal histories can be used in geological studies in areas such as volcanism (Marsden et al., 2021), sedimentary basins (House et al., 2002) and regional exhumation studies (Reiners et al., 2003). In this work we aim to use modelling to understand how to best use thermochronology to determine the thermal history of samples from the Noto peninsula and what geological interpretations can be made from these histories.
Current earthquakes occurring on the Noto peninsula are predominantly reverse-thrust earthquakes, indicating the current tectonic regime is that of compression. However, in the Miocene, this area was under the opposite stress due to slab-roll back and the opening of the back arc basin. This led to the Noto peninsula separating from the continent and the formation of the Japan Sea (Sato, 1994; Okamura et al., 1995). Many of the igneous outcrops on the Noto peninsula are associated with this extensional regime.
The timing of uplift and fault activity on the Noto peninsula has been investigated over the Holocene using marine terraces showing fault activity occurring over the past 250 ka (Malatesta et al., 2025). However, pre-Holocene regional thermal histories are still unknown for the Noto peninsula. This presentation will report the forward modelling results for two selected samples from the Noto peninsula, a basement igneous intrusion and a sample of rift volcanics. Using these results we show the feasibility of using standard thermochronometers to constrain burial and exhumation over the past ca. 30 Ma. Additionally, the extent to which significantly older events can be constrained by multiple thermochronometers will be presented.

References
House, M.A., Kohn, B.P., Farley, K.A. and Raza, A., 2002. Evaluating thermal history models for the Otway Basin, southeastern Australia, using (U-Th)/He and fission-track data from borehole apatites. Tectonophysics, 349(1-4), pp.277-295.
Malatesta, L. C., Sueoka, S., Weiß, N.-M., Gailleton, B., Tsukamoto, S., Ishimura, D., et al., 2025. Landscape signature of seismogenic faults in the off and onshore domains of the Noto Peninsula in Japan's back-arc. Geophysical Research Letters, 52, e2025GL116602. https://doi.org/10.1029/2025GL116602
Marsden, R.C., Danišík, M., San Ahn, U., Friedrichs, B., Schmitt, A.K., Kirkland, C.L., McDonald, B.J. and Evans, N.J., 2021. Zircon double-dating of quaternary eruptions on Jeju Island, South Korea. Journal of Volcanology and Geothermal Research, 410, p.107171.
Okamura, Y., Watanabe, M., Morijiri, R. and Satoh, M., 1995. Rifting and basin inversion in the eastern margin of the Japan Sea. Island Arc, 4: 166-181. https://doi.org/10.1111/j.1440-1738.1995.tb00141.x
Reiners, P.W., Zhou, Z., Ehlers, T.A., Xu, C., Brandon, M.T., Donelick, R.A. and Nicolescu, S., 2003. Post-orogenic evolution of the Dabie Shan, eastern China, from (U-Th)/He and fission-track thermochronology. American Journal of Science, 303(6), pp.489-518.
Sato, H., 1994. The relationship between Late Cenozoic tectonic events and stress field and basin development in northeast Japan, J. Geophys. Res., 99(B11), 22261–22274, doi:10.1029/94JB00854.