| PENG Jun,LI Ping,CHEN Hongquan. 2016. The magnetic properties of sediment and sedimentary environment in the Huanghe Delta area after the last glacial maximum. Acta Oceanologica Sinica, 35(5):113－123 |
| The magnetic properties of sediment and sedimentary environment in the Huanghe Delta area after the last glacial maximum |
| 末次冰盛期后黄河三角洲沉积物的磁性特征及其沉积环境 |
| Received:April 12, 2015 Revised:June 16, 2015 |
| DOI：10.1007/s13131-016-0863-4 |
| Key words:the Huanghe (Yellow River) Delta magnetic properties sedimentary environment grain size dating |
| 中文关键词: 黄河三角洲 磁性特征 沉积环境 粒度 测年 |
| 基金项目:The National Natural Science Foundation of China under contract Nos 41306077 and 41501567; the Major Program of University Natural Science Foundation of Jiangsu Province of China under contract No. 14KJA170006; the Natural Science Foundation of Shandong Province of China under contract No. ZR2013DQ025. |
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| Abstract: |
| On the basis of measuring the magnetic parameters of sediment in Core YDZ1, combined with a grain size analysis and Carbon-14 dating, the magnetic properties of sediment and sedimentary environment in the Huanghe (Yellow River) Delta area after the last glacial maximum have been studied. The results show that the ferrimagnetic minerals of a pseudo single domain and multi domain particles dominate the magnetic properties of sediment in Core YDZ1. The imperfect anti ferrimagnetic minerals have more contribution on sediment in a depth of 24.0-22.1 m, and more stable-single domain and pseudo single domain particles exist. The susceptibility of anhysteretic remanent magnetization and the ratio of the susceptibility of anhysteretic remanent magnetization to saturation isothermal remanent magnetization show a decrease trend below depth of 24 m, a marked increase trend in a depth of 24.0-13.5 m, and a rapid decrease at depth of 13.5 m, then a fluctuation trend upward. The above two magnetic parameters and the ratio of the susceptibility of anhysteretic remanent magnetization to the mass susceptibility can be regarded as the proxy indicators for the content of clay (<4 μm) and the fine-grained size (<32 μm). The sedimentary environment after the last glacial maximum in the Huanghe Delta area has experienced the fluvial facies, the tidal flat facies, the neritic facies, the pro delta facies, the delta front facies and the floodplain facies. Thickness of the Holocene transgression layer is 10.5 m and the depth of substrate is about 24 m according to the YDZ1 core. The sedimentary dynamic has a variation trend with strong-weak-strong, which has been proved by the Flemming triangular schema. |
| 中文摘要: |
| 通过测量黄河三角洲YDZ1柱样沉积物的磁学参数,结合沉积物粒度分析和AMS14C测年数据,对末次冰盛期后黄河三角洲沉积物的磁性特征和沉积环境进行分析。结果表明,以假单畴-多畴晶粒为主的亚铁磁性矿物主导了YDZ1柱样沉积物的磁性特征,但在22.1-24.0m深度不完整反铁磁性矿物贡献较大,且稳定单畴和假单畴晶粒较多。在垂向变化上,磁学参数中的χARM,和χARM/SIRM在24m深度以下呈减小趋势,从24.0m到13.5m呈显著增大趋势,在13.5m深度处迅速减小,13.5m深度以上呈波动变化趋势。磁学参数中的χARM, χARM/SIRM和χARM/χ可视为粘土(<4μm)或细粒组分(<32μm)含量的代用指标。末次冰盛期后黄河三角洲的沉积环境依次经历了河流相、潮坪相、浅海相、前三角洲相、三角洲前缘相和泛滥平原相,其中全新世海侵沉积层厚度约10.5m,基底深度约在24m;沉积动力表现为强-弱-强的变化过程,这点可以从Flemming三角图式分析中得以证明。 |
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