Magnetostratigraphic study on post-Miocene transitions in the uplift-erosion processes, climate and biota in Nepal Himalaya

尼泊尔喜马拉雅地区后中新世隆升侵蚀过程、气候和生物区系的磁性地层学研究

• 批准号: 17540427
• 负责人: GAUTAM Pitambar
• 金额: $ 2.4万
• 依托单位: Hokkaido University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17540427/
• 关键词: Nepal; Siwalik group; Miocene; Magnetostratigraphy; Kathmandu Valley; Tectonics; Magnetic susceptiblity; Sedimentology; 堆積祖; 粒度分析

New magnetic and sedimentological data from Nepalese Subhimalayan and Kathmandu Valley sediments obtained in this project provide following valuable geoscientific/environmental information:1. Magnetic polarity data for 8 up to 5km thick Siwalik sediment sections, including Tinau Khola North studied anew, over 600 km length of the Sub Himalaya firmly bracket the sediment deposition age from >16 to 1 myr ago. Sediment accumulation rate ranged from 25 to 65 cm/kyr with two peaks during 10.9-9.7 and 5.2-3.6 myr ago; the former likey to be a combined response of multiple causal phenomena such as uplift of Higher Himalayan Crystallines, elevated mountain erosion/denudation, and effects marked by initiation of flood-flow dominated meandering system in the foreland basin, basin subsidence, etc. triggered by advent of summer monsoon. A consistent W-E to NW-SE magnetic lineation in fine-grained sediments records weak deformation induced by mild N-S or NNE-SSW directed compression and serves as a … More paleostress proxy.2. In Kathmandu Valley, reversal stratigraphy in Lukundol section reveals sediment deposition during 1.1-0.7 myr ago and gives evidence for massive deposition of gravel at ca. 0.96 myr ago coinciding with uplift of Mahabharat range that now forms the southern valley wall. New data from the basin's north bracket the age of Gokarna Formation at Dhapasi to ca. 45-34 kyr ago supported by Laschamp reversal event near the base of Dhapasi section. Laser granulometry of fine-grained prodelta deposits-indicators of calm subaqueous deposition suggests bi- to trimodal distribution for the silt to silty sand deposits indicative of a mixed sediment provenance or post-depositional sediment mixing.3. Magnetic susceptibility serves as a practical tool for mapping the Lesser Himalayan formations, rapid lithological correlation of the adjacent sections and deciphering the cyclic deposition in Kathmandu basin, and also quantification of paleo- and present- day environmental pollution (e.g. due to vehicular traffic). Less

本项目从尼泊尔亚喜马拉雅和加德满都河谷沉积物中获得的新的磁性和沉积学数据提供了以下有价值的地学/环境信息：1.重新研究了包括Tinau Khola North在内的8到5公里厚的Siwalik沉积物剖面的磁极性数据，确定了长达600多公里的亚喜马拉雅沉积年龄为&Gt；16-1 Myr。泥沙堆积速率在25~65 cm/KYR之间，在10.9-9.7和5.2-3.6 MYR之间出现两个高峰，前者可能是高喜马拉雅结晶抬升、山体侵蚀剥蚀抬升等多种原因的综合反应，以及夏季风到来引发的前陆盆地洪流主导型曲流系统的启动、盆地下沉等多种原因的综合作用。细粒沉积物中一致的W-E至NW-SE磁性线理记录了温和的N-S或NNE-SSW向挤压导致的微弱变形，并作为…更多的古应力代表2.在加德满都河谷，Lukundol剖面的反转地层学揭示了1.1-0.7 MYR前的沉积物沉积，并提供了约0.96MYR前的大量砾石沉积的证据，同时也与现在形成南部谷墙的Mahabharat山脉的抬升相吻合。来自盆地北缘达帕西戈卡纳组时代至约45-34KYR前的新资料支持了达帕西剖面底部附近的拉尚反转事件。细粒前三角洲沉积的激光粒度测量--平静水下沉积的指示物--表明粉砂到粉砂沉积的双-三态分布，指示混合沉积物物源或沉积后沉积物混合。磁化率是绘制小喜马拉雅建造图、快速进行相邻地段的岩性对比和破译加德满都盆地旋回沉积的实用工具，也是量化古代和现代环境污染(如车辆交通造成的)的工具。较少

项目成果

Assessment of traffic-induced environmental pollution : Magnetic properties and heavy metal chemistry of dusts on streets and leaves from Kathmandu, Nepal

交通引起的环境污染评估：尼泊尔加德满都街道和树叶灰尘的磁性和重金属化学

• 发表时间: 2009
• 期刊: Journal of Nepal Geological Society 39(印刷中)
• 作者: Tsugawa;T.;S. -R. Zhang;A. J. Coster;Y. Otsuka;J. Sato;A. Saito;and Y. Zhang;Gautam P.
• 通讯作者: Gautam P.

Integration of magnetism and heavy metal chemistry of soils to quantify the environmental pollution in Kathmandu, Nepal

• DOI: 10.1111/j.1440-1738.2005.00496.x
• 发表时间: 2005-12-01
• 期刊: ISLAND ARC
• 影响因子: 1.5
• 作者: Gautam, P;Blaha, U;Appel, E
• 通讯作者: Appel, E

A new Late Miocene great ape from Kenya and its implication for the or igins of African great apes and humans

肯尼亚一种新的中新世晚期巨猿及其对非洲巨猿和人类起源的启示

• 发表时间: 2007
• 期刊: Proceedings of the National Academy of Sciences of the United States of America 104
• 作者: Sato;J.;Tsugawa;T;Kunimatsu Y.
• 通讯作者: Kunimatsu Y.

Rockmagnetic characteristics of the Kathmandu valley sediments: potential for correlation and paleoenvironmental reconstruction

加德满都河谷沉积物的岩磁特征：关联和古环境重建的潜力

• 发表时间: 2007
• 作者: Gautam;P.;Gautam P.
• 通讯作者: Gautam P.

Discovery of sediments indicating rapid lake level fall in the Late Pleistocene Gokarna Formation, Kathmandu Valley, Nepal : implication for lake terrace formation

尼泊尔加德满都谷地晚更新世戈卡纳组中发现的沉积物表明湖泊水位快速下降：对湖泊阶地形成的影响

• 发表时间: 2006
• 期刊: 第四紀研究 45・2
• 作者: Sakai;T.
• 通讯作者: T.