{"title":"中新世-始新世南海俯冲带沉积物产状--从沉积物运移到堆积:对堆积棱镜地层的影响","authors":"P. H. Cornard, H. L. Dawson, K. T. Pickering","doi":"10.1029/2023GC011393","DOIUrl":null,"url":null,"abstract":"<p>Based on U-Pb dating of zircon crystals and petrographic analysis, this study provides new insights into the paleogeographic and accretion evolution along SW Japan. Our data are consistent with an older submarine fan identified from drilling in the Shikoku Basin (Kyushu Fan ∼14.7–12.2 Ma), having a mixed sand provenance from the paleo-Yangtze/Yellow rivers and the Shimanto Belt, and the younger Zenisu Fan (∼9.2–7.6 Ma), which is mainly sourced from the Shimanto Belt and the Izu-Bonin/Honshu arc collision. Our results are in agreement with the hypothesis of very oblique subduction or strike-slip motion between the northern Shikoku Basin and mainland Honshu from ∼12.2 to 9.2 Ma, after which essentially orthogonal subduction occurred after ∼8 Ma. The two main sandbodies drilled at IODP Site C0002 within the inner Nankai Accretionary Prism have similar petrographic signatures to those of the Zenisu and Kyushu submarine fans in the Shikoku Basin. The incorporation of the Shikoku Basin deposits most likely resulted from the seaward propagation of in-sequence thrusts forming an outer accretionary wedge. The incorporation of the Kyushu Fan into the inner accretionary prism implies that the décollement was located in the hemipelagic interval beneath the Kyushu Fan at least until ∼2 Ma, whereas it is now located in the hemipelagic intervals below the Zenisu Fan. Such shifts in décollement location are most likely related to changes in physical properties of the hemipelagic interval due to significant compaction and diagenesis during subduction.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"25 8","pages":""},"PeriodicalIF":2.9000,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GC011393","citationCount":"0","resultStr":"{\"title\":\"Sediment Provenance Along the Middle Miocene-Pleistocene Nankai Subduction Zone From Sediment Transport to Accretion: Implications for Stratigraphy in the Accretionary Prism\",\"authors\":\"P. H. Cornard, H. L. Dawson, K. T. Pickering\",\"doi\":\"10.1029/2023GC011393\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Based on U-Pb dating of zircon crystals and petrographic analysis, this study provides new insights into the paleogeographic and accretion evolution along SW Japan. Our data are consistent with an older submarine fan identified from drilling in the Shikoku Basin (Kyushu Fan ∼14.7–12.2 Ma), having a mixed sand provenance from the paleo-Yangtze/Yellow rivers and the Shimanto Belt, and the younger Zenisu Fan (∼9.2–7.6 Ma), which is mainly sourced from the Shimanto Belt and the Izu-Bonin/Honshu arc collision. Our results are in agreement with the hypothesis of very oblique subduction or strike-slip motion between the northern Shikoku Basin and mainland Honshu from ∼12.2 to 9.2 Ma, after which essentially orthogonal subduction occurred after ∼8 Ma. The two main sandbodies drilled at IODP Site C0002 within the inner Nankai Accretionary Prism have similar petrographic signatures to those of the Zenisu and Kyushu submarine fans in the Shikoku Basin. The incorporation of the Shikoku Basin deposits most likely resulted from the seaward propagation of in-sequence thrusts forming an outer accretionary wedge. The incorporation of the Kyushu Fan into the inner accretionary prism implies that the décollement was located in the hemipelagic interval beneath the Kyushu Fan at least until ∼2 Ma, whereas it is now located in the hemipelagic intervals below the Zenisu Fan. Such shifts in décollement location are most likely related to changes in physical properties of the hemipelagic interval due to significant compaction and diagenesis during subduction.</p>\",\"PeriodicalId\":50422,\"journal\":{\"name\":\"Geochemistry Geophysics Geosystems\",\"volume\":\"25 8\",\"pages\":\"\"},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2024-08-02\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GC011393\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Geochemistry Geophysics Geosystems\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1029/2023GC011393\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geochemistry Geophysics Geosystems","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1029/2023GC011393","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
摘要
这项研究基于锆石晶体的 U-Pb 定年和岩石学分析,为了解日本西南部的古地理和增生演化提供了新的视角。我们的数据与四国盆地钻探发现的较古老的海底扇(九州扇∼14.7-12.2Ma)和较年轻的善洲扇(∼9.2-7.6Ma)相一致,前者的砂源来自古长江/黄河和岛山东带,后者的砂源主要来自岛山东带和伊豆-波宁/本州弧碰撞。我们的研究结果与四国盆地北部和本州大陆之间在 12.2 ∼ 9.2 Ma 期间发生非常倾斜的俯冲或撞击滑动运动的假说相一致,之后在 8 Ma ∼ 8 Ma 期间发生了基本上正交的俯冲运动。IODP C0002站点在南海内侧断积棱岩中钻探到的两个主要沙体与四国海盆中的天须和九州海底扇的岩相特征相似。四国海盆沉积物的形成很可能是由形成外增生楔的内序推力向海传播的结果。九州扇被纳入内增生棱柱意味着,至少在 ∼2 Ma 之前,地壳位于九州扇下方的半深海层间,而现在则位于 Zenisu 扇下方的半深海层间。这种沉积物位置的变化很可能与半沉积层的物理特性变化有关,因为在俯冲过程中,半沉积层发生了严重的压实和成岩作用。
Sediment Provenance Along the Middle Miocene-Pleistocene Nankai Subduction Zone From Sediment Transport to Accretion: Implications for Stratigraphy in the Accretionary Prism
Based on U-Pb dating of zircon crystals and petrographic analysis, this study provides new insights into the paleogeographic and accretion evolution along SW Japan. Our data are consistent with an older submarine fan identified from drilling in the Shikoku Basin (Kyushu Fan ∼14.7–12.2 Ma), having a mixed sand provenance from the paleo-Yangtze/Yellow rivers and the Shimanto Belt, and the younger Zenisu Fan (∼9.2–7.6 Ma), which is mainly sourced from the Shimanto Belt and the Izu-Bonin/Honshu arc collision. Our results are in agreement with the hypothesis of very oblique subduction or strike-slip motion between the northern Shikoku Basin and mainland Honshu from ∼12.2 to 9.2 Ma, after which essentially orthogonal subduction occurred after ∼8 Ma. The two main sandbodies drilled at IODP Site C0002 within the inner Nankai Accretionary Prism have similar petrographic signatures to those of the Zenisu and Kyushu submarine fans in the Shikoku Basin. The incorporation of the Shikoku Basin deposits most likely resulted from the seaward propagation of in-sequence thrusts forming an outer accretionary wedge. The incorporation of the Kyushu Fan into the inner accretionary prism implies that the décollement was located in the hemipelagic interval beneath the Kyushu Fan at least until ∼2 Ma, whereas it is now located in the hemipelagic intervals below the Zenisu Fan. Such shifts in décollement location are most likely related to changes in physical properties of the hemipelagic interval due to significant compaction and diagenesis during subduction.
期刊介绍:
Geochemistry, Geophysics, Geosystems (G3) publishes research papers on Earth and planetary processes with a focus on understanding the Earth as a system. Observational, experimental, and theoretical investigations of the solid Earth, hydrosphere, atmosphere, biosphere, and solar system at all spatial and temporal scales are welcome. Articles should be of broad interest, and interdisciplinary approaches are encouraged.
Areas of interest for this peer-reviewed journal include, but are not limited to:
The physics and chemistry of the Earth, including its structure, composition, physical properties, dynamics, and evolution
Principles and applications of geochemical proxies to studies of Earth history
The physical properties, composition, and temporal evolution of the Earth''s major reservoirs and the coupling between them
The dynamics of geochemical and biogeochemical cycles at all spatial and temporal scales
Physical and cosmochemical constraints on the composition, origin, and evolution of the Earth and other terrestrial planets
The chemistry and physics of solar system materials that are relevant to the formation, evolution, and current state of the Earth and the planets
Advances in modeling, observation, and experimentation that are of widespread interest in the geosciences.