Geomagnetism and magnatic evolution from Iceladic Volcanics

冰岛火山的地磁和地磁演化

• 批准号: 05041059
• 负责人: KONO Masaru
• 金额: $ 6.08万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05041059/
• 关键词: Iceland; Palesmagnetism; k-Ar dating; Paleosecular variation; Paleointensity; 台地玄武岩; クラフラ火山; ヘクラ火山; 古地磁気層序; K-Ar年代; 古地磁気極

Field works were performed in Iceland during July 1993 and July 1994. Major effort was directed to the collection of paleomagnetic samples from successive lava flows with ages of Pliocene and Pleistocene. Samples were also collected from historic and prehistoric acidic lava flows for geochemical studies. Experiments using paleomagnetic as well as geochemical samples are under progress in Department of Geophysics and Planetary Physics (DEPP) and Earthquake Research Institute (ERI), University of Tokyo, Department of Earth and Planetary Sciences, Tokyo Institute of Technology, and Institute for Study of Earth's Interior (ISEI). Following is a brief description of various research activities.1.Paleomagnetism of successive lava flows.About 250 lava flows were sampled in each year. Five cores were drilled and orientation was measured in terms of directions of sun, reference, or magnetic directions. For a small number of samples, measurement of natural remanent magnetization was carried out in the field using spinner magnetometer and alternating field demagnetizer.2.K-Ar dating.About 50 samples from Storutjarnir section are now dated by K-Ar method. Potassuim is measurementry flame photometry at ERI,while Argon isotope ratios are measured by mass spectrometer at ISEI.3.Paleointensities.Paleointensity of the earth's magnetic field was studied using Icelandic samples by Thellier's method. Result from Western Iceland indicates that the intensity low at the time of polarity reversal continues sometime after the reversal of direction was completed.4.Secular variation data.With the use of Icelandic data as well as data from other areas worldwide, paleosecular variation (PSV) of the geomagnetic field was studied. A paleointensity database was set up through the compilation of published data, and models of PSV were developed in terms of the randomly varying Gauss coefficients.

1993年7月和1994年7月在冰岛进行了实地工作。主要的工作是从上新世和更新世的连续熔岩流中收集古地磁样品。还从历史和史前酸性熔岩流中采集了样品进行地球化学研究。东京大学地球物理学和行星物理学系（DEPP）和地震研究所（ERI）、东京工业大学地球和行星科学系以及地球内部研究所（ISEI）正在进行使用古地磁和地球化学样品的实验。以下是各种研究活动的简要描述：1.连续熔岩流的古地磁。每年约有250个熔岩流样品。钻取了五个岩心，并根据太阳方向、参考方向或磁方向测量了方位。2.K-Ar法测年，对Storutjarnir剖面的50多个样品进行了K-Ar法测年。3.古磁场强度用Thellier方法研究了冰岛样品的古磁场强度。冰岛西部的结果表明，极性反转时的强度低在方向反转完成后的某个时间持续存在。4.长期变化数据。利用冰岛数据以及世界其他地区的数据，研究了地磁场的古长期变化（PSV）。通过整理已发表的地震烈度资料，建立了古地震烈度数据库，并根据随机变化的高斯系数建立了地震烈度的PSV模型。

项目成果

Tanaka, H., M.Kono, and H.Uchimura: "Some global features of paleointensity in geological time" Geophys.J.Int.120. 97-120 (1995)

Tanaka, H.、M.Kono 和 H.Uchimura：“地质时期古强度的一些全球特征”Geophys.J.Int.120。

Tanaka,H.,A.Otsuka,T.Tachibana,and M.Kono: "Paleointensities for 10-22 ka from volkanic rocks in Japan and New Zealand" Earth Planet.Sci.Lett.,. 122. 29-42 (1994)

Tanaka,H.,A.Otsuka,T.Tachibana,and M.Kono：“来自日本和新西兰火山岩的 10-22 ka 的古强度”Earth Planet.Sci.Lett.，。

Kono,M.and P.H.Roberts: "Kinematic dynamos with anisotropic α-effect" Geophys.Astrophys.Fluid Dynam.,22GD05:(in press). (1995)

Kono, M. 和 P.H. Roberts：“具有各向异性 α 效应的运动发电机”Geophys.Astrophys.Fluid Dynam.，22GD05：（出版中）。

広井 修,田中 秀文,河野 修,小屋口 剛博,牧島 昭夫: "アイスランド北部における鮮新世連続溶岩の古地磁気層序" 地球惑星科学関連学会予稿集. (1994)

Osamu Hiroi、Hidefumi Tanaka、Osamu Kono、Takehiro Koyaguchi、Akio Makishima：“冰岛北部上新世连续熔岩的古地磁地层学”地球与行星科学协会论文集（1994 年）。

Tanaka, H., A.Otsuka, T.Tachibana, and M.Kono: "Paleointensities for 10-22 ka from volcanic rocks in Japan and New Zealand" Earth Planet.Sci.Lett.122. 29-42 (1994)

Tanaka, H.、A.Otsuka、T.Tachibana 和 M.Kono：“日本和新西兰火山岩的 10-22 ka 古强度”Earth Planet.Sci.Lett.122。