Geological and petrological study of the middle Miocene regional basalts from the Japan Sea side in the NE Japan arc

日本东北弧日本海一侧中新世区域玄武岩的地质和岩石学研究

• 批准号: 62540617
• 负责人: SHUTO Kenji
• 金额: $ 1.09万
• 依托单位: Niigata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62540617/
• 关键词: The Northeast Japan Arc; Lateral Variation of LIL Elements; Non Island Arc-Type Volcanic Rock; Late Miocene (8-6 Ma) Volcanic Rock; Pliocene (4-2 Ma) Volcanic Rock; Middle Miocene (16-14 Ma) Volcanic Rock; Plate Subduction; Mantle Diapir; 後期中新世(8〜

Abundances of major elements and seven trace elements, Rb, Sr, Nb, Y, Zr, Ni and Cr were determined by X-ray fluorescence analysis for 111 samples from twelve Pliocene volcanic centers in the NE Japan are. The petrographical and analytical results in this study and the published ones on other Pliocene volcanic rocks indicate that systematic zonal variation of petrological features, i.e., mafic phenocryst assemblages and rock series, as well as gradual increase in K_2O, Rb and Sr contents are recognized in the Pliocene volcanic rocks from the Pacific Ocean side to the Japan Sea side across the NE Japan arc. Furthermore, systematic across-arc variation of chemical compositions and petrological features, similar to those in the Pliocene to Quaternary volcanic rocks, are also observed in the late Miocene (8-6 Ma) volcanic rocks throughout the NE Japan arc.Similarity of across-arc variation. with regard to both the petrological and geochemical features among the volcanic rocks from the late … More Miocene to Quaternary through Pliocene time suggests that igneous activity which is related to a mechanism for magma generation determined by plate subduction bas been continuous in the NE Japan arc at least during 8 Ma ago to the present.On the other hand, the NE Japan arc of the middle Miocene (16-14 Ma) are characterized by occurrence of rocks of non island arc-type volcanic rocks such as E-type MORB like basalt which is enriched in Ti and other HFS elements, basaltic rocks hailing intermediate nature between the island arc tholeiite and the back arc basin basalt in bulk rock chemistry and icelandite like andesite and dacite, in association with volcanics of the island arc tholeiite series and calc-alkaline series. These volcanic rocks increase gradually in K_2O from the Japan Sea side toward the Pacific Ocean side across the NE Japan arc, indicating the lateral variations dissimilar to the case of volcanic rocks produced during 8 Ma ago to the present.It is possible that such non island arc-type volcanics were derived from a upper mantle material which is different from the present one in the NE Japan arc. These volcanics could have been generated from a mantle diapir ascending from asthenosphere during the spreading of the Japan Sea. The middle Miocene volcanics of island arc tholeiite series and calc-alkaline series in the NE Japan arc may have been originated from partial melting of upper mantle and lower crust heated by the ascending mantle diapir. Less

主要元素和七个微量元素的丰度，RB，SR，NB，Y，ZR，NI和CR，通过X射线荧光分析确定了日本NE日本十二个上新世火山中心的111个样品。 The petrographical and analytical results in this study and the published ones on other Pliocene volcanic rocks indicate that systematic zonal variation of petrological features, i.e., mafic phenocryst assemblages and rock series, as well as Gradual increase in K_2O, Rb and Sr contents are recognized in the Pliocene volcanic rocks from the Pacific Ocean side to the Japan Sea side across the NE Japan arc.此外，在整个日本的中新世（8-6 Ma）火山岩晚期，在整个日本的中新世晚期（8-6 Ma）火山岩中也观察到了化学成分和岩石学特征的系统跨性别变化，类似于上新世至第四纪火山岩的变化。关于从晚期的火山岩石之间的岩石学和地球化学特征……中新世到四循环至季化时间，这表明，与岩浆生成机制相关的火成活性至少在8 ma中是在8 ma中持续到现在。在非岛弧形火山岩（例如诸如玄武岩之类的非岛型火山岩石）中，它丰富了Ti和其他HFS元素，在岛上tholeite和Back arc Basin Basalt之间在散装岩石化学和冰岛的底座盆地之间，在岛上的山弧形盆地之间，与岛上的冰岛和冰岛群体相连，以火山的速度和冰岛系列carcellasic cast and Island and carcers carcers and carcers carcers and Island arc and arc arc arc arc arc arc arc arc arc arc arc arc arc arc arc arc arc arc arc arc，这些火山岩在K_2O中从日本海面逐渐增加，到达日本NE弧的太平洋一侧，表明与8 MA前至今的火山岩相关的横向变化可能与现在的Ne and Ne Ne Ne Ne Ne Ene One Arc不同。这些火山可能是由日本海传播期间从软圈升起的地幔钻石产生的。日本NE弧的岛弧线菌群和钙碱性系列中的中新世火山均可能是由上地幔的部分熔化和下层地壳被升高的地幔钻石加热而来的。较少的

项目成果

土屋信高: "A newly discovered Quaternary volcano from northeast Japan Sea:K-Arage of andesite dredged from the Shiribeshi Seamount." 日本岩石鉱物鉱床学会誌(岩鉱). 84. 391-397 (1989)

Nobutaka Tsuchiya：“日本东北部新发现的第四纪火山：从 Shiribeshi 海山挖出的安山岩 K-Arage。”日本岩石和矿物沉积学会杂志（岩石矿山）84. 391-397（1989）。

Shim-ich Tamura: "Lateral variation of major and trace elements in the late Miocene volcanicrocks from central part of Northeast Japan" Jour,Min.Pet.Econ.Geol. 84. 444-459 (1989)

Shim-ich Tamura：“日本东北部中部中新世晚期火山岩中主量元素和微量元素的横向变化”Jour，Min.Pet.Econ.Geol。