Magnetic characterization of oil sands at Osmington Mills and Mupe Bay, Wessex Basin, UK
Magnetic characterization of oil sands at Osmington Mills and Mupe Bay, Wessex Basin, UK
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DOI：
10.1144/sp371.6
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发表时间：
2012-06
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影响因子：
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通讯作者：
S. Emmerton;A. Muxworthy;M. Sephton
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文献类型：
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作者：
S. Emmerton;A. Muxworthy;M. Sephton
摘要本研究结合磁性实验和地球化学分析，探讨了英国威塞克斯盆地奥斯明顿米尔斯和马塞洛湾油砂中烃类与磁性矿物学之间关系的可能性。进行通过化学提取去除烃以允许比较（1）油砂和（2）清洁的砂。详细的磁性分析，包括低温和高温实验表明，除了一个样品是由菱铁矿为主，确定在37-38 K的内尔过渡，以及包含多畴磁铁矿（Verwey过渡110 K）和赤铁矿（Morin过渡250 K）的大颗粒。扫描电子显微镜和能量色散X射线分析证实了氧化铁的存在，特别是直径为500 nm-45 µm的framboids，可能是磁铁矿。滞后参数显示出不同的分组油砂相比，他们的清洁同行和负线性回归的日志空间中观察到（R2=0.7）之间的百分比可提取的有机物和磁化率。这些结果表明，磁性矿物与生物降解引起的石油蚀变之间存在关系，但目前尚未完全了解。可能的机制被认为是由于厌氧细菌或石油的运输，因为它通过寄主岩石迁移。
Abstract This study combines magnetic experimentation and geochemical analysis on oil sands from Osmington Mills and Mupe Bay, Wessex Basin, UK to investigate the possibility of a relationship between hydrocarbons and magnetic mineralogy. Removal of hydrocarbons by chemical extraction was conducted to allow comparison of (1) oil sands and (2) cleaned sands. Detailed magnetic analysis including low-temperature and high-temperature experimentation revealed that all but one sample was dominated by siderite, identified by the Néel transition at 37–38 K as well as containing large grains of multidomain magnetite (Verwey transition 110 K) and hematite (Morin transition 250 K). Scanning electron microscopy and energy dispersive x-ray analysis confirmed the presence of iron oxides, in particular framboids 500 nm–45 µm in diameter, probably magnetite. Hysteresis parameters showed distinct grouping of oil sands compared to their clean counterparts and a negative linear regression in log space was observed (R2=0.7) between the percentage of extractable organic matter and magnetic susceptibility. These results suggest a relationship exists between magnetic minerals and the alteration of oil due to biodegradation, which is not yet fully understood. Possible mechanisms are suggested to be due to anaerobic bacteria or the transportation of the oil as it migrates through the host rock.