ROCK-MAGNETIC CHARACTERISTICS OF THE TIANSHAN LOESS AND THE MECHANISM FOR ENHANCING MAGNETIC SUSCEPTIBILITY
-
摘要: 天山北坡海拔2 400~2 700 m不同高度的地貌面上分布有大片风成黄土,是详细研究我国西北内陆极端干旱区形成演化过程和中亚内陆黄土岩石磁学性质与物源物质、气候条件相互关系的理想材料。通过对天山北坡沙湾县东湾镇清水河第6级阶地黄土剖面进行采样、高精度的磁化率及其他岩石磁学参数的测量分析,发现天山黄土的磁学性质主要为低矫顽力的亚铁磁性矿物(如磁铁矿和磁赤铁矿)所主导,与黄土高原地区黄土沉积序列明显不同。成壤作用形成的细颗粒磁性矿物对天山黄土磁化率的影响微弱,而来自源区的粗颗粒磁铁矿含量的增加是天山地区磁化率增强的主要影响机制。磁化率和粒度自0.8 Ma以来逐渐增加和变粗的趋势,可能是对亚洲内陆中更新世以来干旱化过程的响应。Abstract: The large area of eolian loess distributed over the northern slope of the middle Tianshan between the altitude of 2 400~2 700 m has provided a good opportunity to study the loss rock magnetic properties of Central Asia and the evolutionary process of the extreme arid areas of NW China. Our research profile is located on the sixth terrace of Qingshui river on the northern slope of Tianshan. We collected 580 of bulk samples for analysis of the rock magnetic susceptibility at a 10~20 cm interval and selected several samples for analyses of other magnetic parameters. Results show that the magnetic properties of the Tianshan Loess are mainly controlled by low-coercivity ferrimagnetic minerals (such as magnetite and maghemite), significantly different from the loess sequence of the Loess Plateau, and the contribution of ultrafine pedogenically-produced magnetic grains to loess magnetic susceptibility is very limited, while the increased coarse ferrimagnetic minerals from the source region play a decisive role in increasing magnetic susceptibility in the Tianshan region. The gradual increasing trend in magnetic susceptibility and the coarsening upwards trend of grain size since 0.8Ma may be the response to the aridification process in the inland Asia since the mid-Pleistocene.
-
Keywords:
- loess /
- magnetic susceptibility /
- rock magnetism /
- Tianshan
-
-
[1] Heller F, Evans M E. Loess magnetism[J].Reviews of Geophysics,1995,33:211-240.
[2] Heller F, Liu Tungsheng. Magnetism of Chinese loess deposits[J].Geophysical Journal of the Royal Astronomical Society, 1984,77:125-141.
[3] 刘秀铭,刘东生,John Shaw.中国黄土磁性矿物特征及其古气候意义[J].第四纪研究,1993,13(3):281-287. [LIU Xiuming, LIU Tungsheng, John Shaw. Magnetic mineral characteristics of Chinese loess and its palaeoclimatic significance[J]. Quaternary Sciences,1993,13(3):281-287.]
[4] 刘秀铭,刘东生,Heller F,等.黄土频率磁化率与古气候冷暖变换[J].第四纪研究,1990,10(1):42-50. [LIU Xiuming, LIU Tungsheng, Heller F, et al. Frequency-dependent susceptibility of loess and Quaternary paleoclimate[J].Quaternary Sciences,1990,10(1):42-50.]
[5] An Z S,Kukla G,Porter S C,et al.Magnetic susceptibility evidence of monsoon variation on the Loess Plateau of Central China during the last 130000 years[J]. Quaternary Research, 1991,36(1):29-36.]
[6] An Z S, Kutzbach J E, Prell W L, et al. Evolution of Asian monsoons and phased uplift of the Himalaya-Tibetan Plateau since Late Miocene times[J].Nature,2001,411:62-66.
[7] 方小敏,徐先海,宋春晖,等.临夏盆地新生代沉积物高分辨率岩石磁学记录与亚洲内陆干旱化过程及原因[J].第四纪研究,2007,27(6):989-1000. [FANG Xiaomin, XU Xianhai, SONG Chunhui,et al. High resolution rock magnetic records of Cenozoic sediments in the Linxia Basin and their implications on drying of Asian inland[J].Quaternary Sciences,2007,27(6):989-1000.]
[8] 朱艳明,周力平,张世红.中国北方上新世晚期-更新世早期风成沉积物磁化率各向异性初探[J].第四纪研究,2007,27(6):1009-1015. [ZHU Yanming, ZHOU Liping, ZHANG Shihong. A preliminary study on anisotropy of magnetic susceptibility of the Late Pliocene-Early Pleistocene aeolian deposits in Northern China[J].Quaternary Sciences,2007,27(6):1009-1015.]
[9] 吕厚远,韩家懋,吴乃琴,等.中国现代土壤磁化率分析及其古气候意义[J].中国科学B辑,1994,24(12):1290-1297. [LV Houyuan, HAN Jiamao, WU Naiqin, et al. Analysis of soil magnetic susceptibility and its paleoclimate significance in modern China[J].Science in China(Series B),1994,21:1290-1297.]
[10] 王建力,方小敏,张宇田,等.青藏高原东北边缘黄土磁化率各向异性揭示古风向的初步研究[J].兰州大学学报:自然科学版,1995,31(4):155-159. [WANG Jianli, FANG Xiaomin, ZHANG Yutian, et al. The anisotropy of loess magnetic susceptibility in the northeastern fringe of Qinghai-Xizang (Tibetan) plateau as an indicator of palalowind direction[J]. Journal of Lanzhou University (Natural Sciences),1995,31(4):155-159.]
[11] Sun J M, Liu T S. Multiple origins and interpretations of the magnetic susceptibility signal in Chinese wind-blown sediments[J]. Earth and Planetary Science Letters,2000,180(3-4):287-296.
[12] 王勇,潘保田,管清玉,等.西北干旱区黄土-古土壤磁化率变化特征[J].海洋地质与第四纪地质,2008,28(1):111-114. [WANG Yong, PAN Baotian, GUAN Qingyu, et al. Magnetic susceptibility variation in semi-arid region of Northwestern China[J].Marine Geology and Quaternary Geology,2008,28(1):111-114.]
[13] 方小敏,史正涛,杨胜利,等.天山黄土和古尔班通古特沙漠发育及北疆干旱化[J].科学通报,2002,47(7):1381-1387. [FANG Xiaomin, SHI Zhengtao, YANG shengli, et al. Loess in Tianshan and its implications for the development of the Gurbantunggut Desert and drying of northern Xinjiang[J].Chinese Science Bulletin,2002,47(7):1381-1387.]
[14] 张家宝,邓子风.新疆降水概论.北京:气象出版社,1987.[ZHANG Jiabao, DENG Zifeng. An Introduction to the Precipitation in Xinjiang[M]. Beijing:China Meteorological Press,1987.] [15] 方小敏,吕连清,杨胜利,等.昆仑山黄土与中国西部沙漠发育和高原隆升[J].中国科学D辑,2001,31(3):177-184. [FANG Xiaomin, Lü Lianqing, YANG Shengli,et al. Loess in Kunlun Mountains and its implications on desert development and Tibetan plateau uplift in west China[J]. Science in China (Series D), 2001,31(3):177-184.]
[16] Dearing J. Magnetic susceptibility[M]//In:Walden J, Oldfield F, Smith J,eds.Environmental Magnetism:a practical guide no.6.London:Quaternary Research Association, 1999:35-62.
[17] 邓成龙,刘青松,潘永信,等.中国黄土环境磁学[J].第四纪研究,2007,27(2):193-209. [DENG Chenglong, LIU Qingsong, PAN Yongxin, et al. Environmental magnetism of Chinese loess-paleosol sequences[J].Quaternary Sciences,2007,27(2):193-209.]
[18] Thompson R, Oldfield F. Environmental Magnetism[M]. London:Allen Unwin,1986.
[19] Liu X M,Hesse P,Rolph T,et al.Properties of magnetic mineralogy of Alaskan loess:Evidence for pedogenesis[J]. Quaternary International,1999,62:93-102.
[20] Evans M E, Heller F. Environmental Magnetism[M]. London:Academic Press, 2003.
[21] 朱日祥,李春景,吴汉宁,等.中国黄土磁学性质与古气候意义[J].中国科学B辑,1994,24(9):992-997. [ZHU Rixiang, LI Chunjing, WU Hanning,et al. Loess magnetic properties and its paleoclimate significance, China[J].Science in China(Series B),1994,24(9):992-997.]
[22] Nagata T,Kobayashi K,Fuller M D. Identification of magnetite and hematite in rocks by magnetic observation at low temperature[J].Geophysical Research,1964:69(10):2111-2120.
[23] 刘秀铭,刘东生,Heller F.中国黄土磁化率与第四纪古气候研究[J].地质科学,1992:279-285.[LIU Xiumin, LIU Tungsheng, Heller F. Study on magnetic susceptibility of loess and Quaternary climate in China[J]. Scientia Geologica Sinica, 1992:279 -285.]
[24] 刘青松,Banerjee S K,Jackson M J,等. 低温氧化作用对中国黄土记录剩磁的影响[J]. 科学通报,2003,48(2):193-198. [LIU Qingsong, Banerjee S K,Jackson M J, et al. Influences of low-temperature oxidation to remanence of the Chinese loess[J]. Chinese Science Bulletin, 2003,48(2):193-198.]
[25] 吕镔,刘秀铭,赵国永,等.新疆博乐黄土岩石磁学特征及环境意义[J].兰州大学学报:自然科学版,2012,48(5):1-8. [LV Bin, LIU Xiuming, ZHAO Guoyong, et al. Rock magnetic properties of Bole loess in Xinjiang and its environmental significance[J]. Journal of Lanzhou University (Natural Sciences),2012,48(5):1-8.]
[26] 昝金波,杨胜利,方小敏,等.西昆仑山黄土的岩石磁学特征及其磁化率增强机制[J].第四纪研究,2010, 30(1):46-53. [ZAN Jinbo,YANG Shengli,FANG Xiaomin,et al.Rock-magnetic characteristics and the enhancing mechanism of magnetic susceptibility for west Kunlun mountains loss[J].Quanternary Sciences,2010,30(1):46-53.]
[27] Hovan S A, Rea D K, Pisias N G. Late Pleistocene continental climate and oceanic variability recorded in Northwest Pacific sediments[J]. Paleoceanography,1991,6(3):349-370.
-
期刊类型引用(7)
1. 刘帆，廖慧鸿，梅安鑫，梁茹，彭宇. 应用自然伽马能谱法恢复碳酸盐岩沉积时的古水深——以山西兴县关家崖马五_5亚段为例. 中国地质调查. 2024(01): 57-64 . 
百度学术
2. 梁金同，周刚，曾云贤，和源，朱华，罗冰，谢忱，刘四兵，李笑天，张浩，文华国. 基于自然伽马能谱测井资料的碳酸盐岩层序地层划分及其对古环境恢复的指示意义——以川东北LT1井下寒武统龙王庙组为例. 地质论评. 2023(02): 448-460 . 百度学术
3. 曹子颜，徐国盛，颜瑞晶. 黔北坳陷北缘寒武系娄山关群地球化学特征及古海洋环境恢复. 天然气地球科学. 2023(09): 1652-1665 . 百度学术
4. 李斌，董振国，罗群. 自然伽马能谱测井在海相页岩储层评价中的应用研究. 核电子学与探测技术. 2023(03): 604-614 . 百度学术
5. 叶涛，王清斌，代黎明，陈容涛，崔普媛. 台地相碳酸盐岩层序划分新方法——以渤中凹陷奥陶系为例. 岩性油气藏. 2021(03): 95-103 . 百度学术
6. 曹庆超，白壮壮，李浩武，张宁宁. 测井数据小波变换在川中寒武系洗象池群层序地层划分中的应用. 地质科技通报. 2021(04): 242-251 . 百度学术
7. 李峰峰，郭睿，余义常. 层序地层划分方法进展及展望. 地质科技情报. 2019(04): 215-224 . 百度学术
其他类型引用(8)
计量
- 文章访问数: 2055
- HTML全文浏览量: 190
- PDF下载量: 52
- 被引次数: 15
下载:
