Vitrinite reflectance and consolidation characteristics of the post‐middle Miocene Forearc Basin in central and eastern Boso Peninsula, central Japan: Implications for basin subsidence
Vitrinite reflectance and consolidation characteristics of the post‐middle Miocene Forearc Basin in central and eastern Boso Peninsula, central Japan: Implications for basin subsidence
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日本中部房总半岛中部和东部中中新世后弧前盆地镜质体反射率和固结特征：对盆地沉降的影响
DOI：
10.1111/iar.12344
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发表时间：
2020
期刊：
影响因子：
1.5
通讯作者：
Lin Weiren
中科院分区：
文献类型：
--
作者：
Kamiya Nana;Yamamoto Yuzuru;Zhang Feng;Lin Weiren
为了了解房总弧前盆地的沉积发展，日本中部，自~ 3 Ma以来，我们调查了古构造和固结趋势，在弧前盆地的中部和东部地区，通过镜质体反射率测量和固结试验。镜质组反射率（Rm）的范围为0.33%至0.61%的三浦群在弧前盆地的中部和0.34%至0.41%的三浦和Kazusa群在东部。这些值表明，从中部到东部的三浦群的镜质体反射率大致均匀。在盆地东部的~ 3 Ma黑泷不整合面上没有观察到明显的镜质体反射率差异。固结屈服应力（pc）计算为27.5 MPa和32.2 MPa的清隅组和Amatsu组的三浦群在东部，分别。两个pc值在数量上一致，代表了由上覆沉积物厚度和密度估计的最大上覆压力的趋势，而pc的差异是由采样地点地层的最大埋深所预期的。盆地东部的pcin值随上覆沉积物厚度的增加而增加，表明黑泷不整合面上没有间断。考虑到三浦群的侵蚀厚度，东部三浦群和Kazusa群之间的镜质体反射率和固结的连续趋势反映了房总弧前盆地东部自~ 2.3 Ma以来的较大沉积。
To understand the sedimentary development of the Boso Forearc Basin, central Japan, since ~ 3 Ma, we investigated paleothermal structure and consolidation trends in the central and eastern parts of the forearc basin through vitrinite reflectance measurements and consolidation tests. Vitrinite reflectance (Rm) was in the range 0.33 % to 0.61 % for the Miura Group in the central part of the forearc basin and 0.34 % to 0.41 % for the Miura and Kazusa Groups in the eastern. These values suggest a roughly uniform vitrinite reflectance for the Miura Group from the central to eastern parts. No significant vitrinite reflectance difference is observed across the ~ 3 Ma Kurotaki Unconformity in the eastern part of the basin. The consolidation yield stress (pc) was calculated as 27.5 MPa and 32.2 MPa for the Kiyosumi and Amatsu Formations of the Miura Group in the eastern part, respectively. Both thepcvalues are consistent quantitatively with represent the trend of the maximum overburden pressure estimated from the thickness and density of overlying sediments, and the difference inpcis expected by the maximum burial depths of the strata at the sampling localities. Values ofpcin the eastern part of the basin increase with thickness of overlying sediment, showing no break across the Kurotaki Unconformity. Considering the eroded thickness of the Miura Group, the continuous trends in vitrinite reflectance and consolidation between the Miura and Kazusa Groups in the eastern part reflect the greater deposition of the eastern part of the Boso Forearc Basin since ~ 2.3 Ma.