ENVIRONMENTAL MAGNETISM OF QUATERNARY MARINE SEDIMENTS FROM THE ANTARCTIC REGION AND ITS PALEOCLIMATE IMPLICATIONS.

南极地区第四纪海洋沉积物的环境磁性及其古气候影响。

• 批准号: 15540442
• 负责人: NAKAI Mutsumi
• 金额: $ 2.11万
• 依托单位: DAITO BUNKA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15540442/
• 关键词: marine sediment; Antarctica; rock magnetism; paleomagnetism; grain distribution; Quaternary; environmental magnetism; 氷床; 南極海域; 環境磁気; 氷床変動; 古気候; モレーン; 海洋

Paleomagnetic and rock magnetic studies were performed on 22 sediment core samples taken by the Antarctic Geological and Geophysical Research Project of the Japan National Oil Corporation (JNOC). These cores were transferred to the Geological Survey of Japan. These cores did not suffer serious magnetic damage, though they have been kept in a room temperature since 2002 after being kept refrigerated for more than 10 years. Our results of measurements of natural remanent magnetization (NRM) and magnetic susceptibility agree with the results of the JNOC reports. We measured some rock magnetic parameters, anhysteretic remanent magnetization (ARM), saturation isothermal remanent magnetization (SIRM), anisotropy of magnetic susceptibility (AMS) and high and low temperature thermo-magnetic curves. In addition, we measured grain size distributions of some samples. The grain size distribution shows these sediments came from Antarctica transported with ice sheets. Rock magnetic results show magnetic minerals of these sediments are magnetite and maghemite. We could not find iron sulfide. Therefore, we concluded Quaternary marine environment around Antarctica were oxygen rich.We correlated grain size distributions and rock-magnetic parameters in marine sediments from off Wilkesland, East Antarctica (60-75deg.S, 110-180deg.E), because the rock magnetic parameters show several clear changes. These parameters are S-ratio (back magnetic field : 0.1T), Hrc/Hc, Mr/Ms, and SIRM/k. As a result, clear correlation was found between grain size distribution and both S-ratio and SIRM/k. The age at bottom of these core are about 0.7Ma. We concluded these rock magnetic parameter changes caused by decrease and increase of ice sheets.

对日本国家石油公司 (JNOC) 南极地质和地球物理研究项目采集的 22 个沉积物岩心样本进行了古地磁和岩石磁学研究。这些岩心被转移到日本地质调查局。这些磁芯在冷藏了 10 多年后，自 2002 年起一直保存在室温下，但并未遭受严重的磁损坏。我们的自然剩磁 (NRM) 和磁化率测量结果与 JNOC 报告的结果一致。我们测量了一些岩石磁性参数，非滞回剩磁（ARM）、饱和等温剩磁（SIRM）、磁化率各向异性（AMS）以及高低温热磁曲线。此外，我们还测量了一些样品的晶粒尺寸分布。粒度分布表明这些沉积物来自南极洲，随冰盖运输。岩石磁学结果显示这些沉积物的磁性矿物为磁铁矿和磁赤铁矿。我们找不到硫化铁。因此，我们得出结论，南极洲周围的第四纪海洋环境富含氧气。我们将南极洲东部威尔克斯兰（60-75°S，110-180°E）海洋沉积物中的粒度分布和岩石磁性参数相关联，因为岩石磁性参数显示出几个明显的变化。这些参数是 S 比（反向磁场：0.1T）、Hrc/Hc、Mr/Ms 和 SIRM/k。结果发现，晶粒尺寸分布与 S 比和 SIRM/k 之间存在明显的相关性。这些岩心底部的年龄约为0.7Ma。我们得出结论，这些岩石磁参数的变化是由冰盖的减少和增加引起的。

项目成果

NAKAI, M.: "Paleomagnetisc study of rhyolitic lavas in Kozu-shima Island, Japan."大東文化大学紀要 <自然科学>. 42. 17-31 (2004)

NAKAI, M.：“日本神津岛流纹岩熔岩的古磁学研究。”大东文化大学通报 <自然科学> 42. 17-31 (2004)。

UENO, N., Z.ZHENG, H.UENO: "Self-reversal pTRM evidence found in Sakurajima volcanic rocks."J.Toyo Univ., Gen.Edu.. 48. 99-132 (2004)

UENO, N., Z.ZHENG, H.UENO：“在樱岛火山岩中发现的自我反转 pTRM 证据。”J.Toyo Univ., Gen.Edu.. 48. 99-132 (2004)

NAKAI, M, T.OGISHIMA, H.SHIMAZAKI: "Magnetic susceptibility mapping of ground pollution in parking area of Daito-Bunka Univ., and of Mejiro Gauen Girls' High School."IUGG abstracts. (2003)

NAKAI, M, T.OGISHIMA, H.SHIMAZAKI：“大东文化大学和目白高园女子高中停车场地面污染的磁化率测绘。”IUGG 摘要。

MORIJIRI, Rie, M.NAKAGAWA: "Magnetic properties and opaque mineralogy of serpentinized peridotites from Iwanai-dake and Mitsuishi ultramafic rock bodies Hokkaido, Japan."IUGG abstracts. (2003)

MORIJIRI、Rie、M.NAKAGAWA：“来自日本北海道岩内岳和三石超镁铁岩体的蛇纹石化橄榄岩的磁性和不透明矿物学。”IUGG 摘要。

中井睦美: "地球科学入門講座 もっと使ってほしい「古地磁気学・岩石磁気学」"地球科学. 58・2. 121-126 (2004)

中井睦美：“地球科学入门课程：应该更多地使用的‘古地磁学和岩石磁学’”地球科学58・2（2004）。