Particle Size Specific Magnetic Properties Across the Norwegian‐Greenland Seas: Insights Into the Influence of Sediment Source and Texture on Bulk Magnetic Records
Particle Size Specific Magnetic Properties Across the Norwegian‐Greenland Seas: Insights Into the Influence of Sediment Source and Texture on Bulk Magnetic Records
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DOI：
10.1029/2018gc007894
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发表时间：
2019-02
期刊：
影响因子：
3.7
通讯作者：
R. Hatfield;B. Wheeler;B. Reilly;J. Stoner;B. Housen
中科院分区：
文献类型：
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作者：
R. Hatfield;B. Wheeler;B. Reilly;J. Stoner;B. Housen
我们从格陵兰岛南部和挪威海的71个地芯顶部对磁性质的粒度变化进行了基本观察。这些数据首次提供了详细的区域特征，说明了总体磁性能如何随沉积物质地、沉积物来源和沉积物运输而变化。测定了大块泥沙和5个组成泥沙粒度组分（粘土、细粉土、中粉土、粗粉土和砂土）的磁化率和磁滞参数。中等粉砂粒级的质谱中值比砂粒级和粘土粒级的质谱中值高~3 ~ 5倍，对沉积物结构具有较强的敏感性。粘土粒级的滞回特性相对均匀，与粉砂粒级的滞回特性形成鲜明对比，在研究区内表现出区域差异。这些较粗的组分更受输运限制，利用中淤泥滞回测量和低温质谱行为，我们建立了三个端元，有效地解释了整个地区观察到的变异性。我们模拟了整体磁性对沉积物结构变化的响应，并提出沉积物来源的变化需要解释在格陵兰岛南部和挪威海的岩心中观察到的整体磁性变化。这些发现表明，沉积物来源对驱动该地区整体磁性变率的影响比以前假设的要大。
We make fundamental observations of the particle size variability of magnetic properties from 71 core tops that span the southern Greenland and Norwegian Seas. These data provide the first detailed regional characterization of how bulk magnetic properties vary with sediment texture, sediment source, and sediment transport. Magnetic susceptibility (MS) and hysteresis parameters were measured on the bulk sediment and the five constituent sediment particle size fractions (clay, fine silt, medium silt, coarse silt, and sand). The median MS value of the medium silt size fraction is ~3–5 times higher than that of the sand and clay size fractions and results in a strong sensitivity of bulk MS to sediment texture. Hysteresis properties of the clay size fraction are relatively homogeneous and contrast that silt and sand size fractions which show regional differences across the study area. These coarser fractions are more transport limited and using medium silt hysteresis measurements and low temperature MS behavior we establish three endmembers that effectively explain the variability observed across the region. We model the response of bulk magnetic properties to changes in sediment texture and suggest that variations in sediment source are required to explain the bulk magnetic property variability observed in cores across the southern Greenland and Norwegian Seas. These findings imply that sediment source has a greater influence on driving bulk magnetic property variability across this region than has previously been assumed.