Investigating soil magnetic properties with pedogenic variation along a precipitation gradient in loess-derived soils of the Golestan province, northern Iran
Investigating soil magnetic properties with pedogenic variation along a precipitation gradient in loess-derived soils of the Golestan province, northern Iran
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DOI：
10.1016/j.quaint.2019.11.022
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发表时间：
2020-06
影响因子：
2.2
通讯作者：
J. Sharifigarmdareh;F. Khormali;S. Scheidt;C. Rolf;M. Kehl;M. Frechen
中科院分区：
文献类型：
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作者：
J. Sharifigarmdareh;F. Khormali;S. Scheidt;C. Rolf;M. Kehl;M. Frechen
在伊朗北方的戈莱斯坦省，有大量的黄土沉积物和广泛的黄土土壤。虽然从北到南的强降水梯度（每年200-700毫米）是其特征，但温度差异可以忽略不计（每年17-18 °C）。近年来，有关黄土性古土壤和现代土壤的研究成果较多，但对黄土性古土壤和现代土壤磁性的研究较少，也没有将其作为古气候重建指标的潜力。为了研究戈莱斯坦省沿着降水梯度的土壤磁性，选择了6个现代土壤的耕层。分析了土样的理化性质、粘土矿物学和磁性参数。磁化率测量（20.2-130.77 × 10− 8 m3 kg −1）、ARM磁化率值（0.00489-0.068 m3 kg − 1）、磁化率值（0.0027-0.0105 Am 2kg −1）和磁滞测量为细粒铁磁矿物含量随年平均降水量增加而增加提供了重要证据。同时，SP大小的颗粒的量增加。磁铁矿、磁赤铁矿和赤铁矿是所研究样品中的主要磁性矿物，因此磁铁矿似乎在伊朗北方黄土高原的土壤中占主导地位。通过首次提供伊朗北方这一地区的数据，为磁特性作为古气候重建代用指标的应用提供了另一个例子。中国黄土高原，俄罗斯草原和美国中西部的黄土性土壤的成土敏感性和MAP的类似关系的数据进行了比较。
In the Golestan province in northern Iran extensive loess deposits, and widespread loess-derived soils crop out. While a strong precipitation gradient (200–700 mm per year) from North to South is characteristic, temperature differences are negligible (17–18 °C per year). Recently, many studies on loess-derived palaeosols and modern soils from this region were published; However, in these publications only limited information on the magnetic properties of loess and loess-derived soils is given, nor the potential of these properties to be applied as proxies for palaeoclimate reconstruction. In order to study soil magnetic properties along the precipitation gradient in the Golestan province, six pedons of modern soils were selected. The physicochemical properties, the clay mineralogy and magnetic parameters of soil samples were analysed. Susceptibility measurements (20.2–130.77 × 10−8m3kg−1), ARM susceptibility values (0.00489–0.068 m3kg-1), IRM values (0.0027–0.0105 Am2kg−1), and hysteresis measurements provide significant evidences for an increase of the content of fine grained ferromagnetic minerals with increasing mean annual precipitation. Simultaneously, the amount of SP sized particles increase. Magnetite, maghemite, and hematite are the major magnetic minerals in the studied samples, whereby magnetite seems to be dominant in the soils of the loess plateau of northern Iran. By presenting data from this region of the northern Iran for the first time, another example is provided for the application of magnetic properties as proxies for the reconstruction of the paleoclimate. The results are compared to data of the Chinese loess plateau, the Russian steppe and loessic soils from the midwestern United State with similar relations of pedogenic susceptibility and MAP.