Magnetic properties have been measured as a function of temperature from 2 K to room temperature for twenty-one samples of subaerial basalts of different origin and age, using an MPMS instrument. In all samples but four, titanomagnetite with a titanium content of less than 5 per cent has been determined as a dominant magnetic mineral carrying NRM from c ( T ) measurements above room temperature and Verwey transition observations. However, the new low-temperature experiments yielded evidence of the presence of another magnetic mineral in all samples. This mineral accounts for up to 70 per cent of saturation magnetization at 2 K and acquires a relatively strong but thermally unstable SIRM at this temperature. Comparison of susceptibility vs. temperature curves measured in low and high DC biasing fields reveals evidence of superparamagnetic behavior, peaks marking the effective blocking temperatures being shifted from <2 K to about 16 K by a 4.8 T DC magnetic field. At the same time, the presence of peaks in the high-field susceptibility curves indicate that the corresponding magnetic phase does not reach saturation, even in the highest field available to us. A possible candidate to account for these properties is a hemoilmenite with 8-10 mole per cent of hematite, originating from high-temperature deuteric oxidation. This is in accordance with the prevailing occurrence of exsolution lamellae within titanomagnetite grains observed in scanning electron microscopy (SEM) images.
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机译：使用MPMS仪器，已经测量了21种不同起源和年龄的地下玄武岩样品的磁性能随温度从2 K到室温的变化。根据室温以上的c（T）测量和Verwey转变观测结果，除四个样品外，钛含量均低于5％的钛磁铁矿已被确定为携带NRM的主要磁性矿物。但是，新的低温实验提供了所有样品中都存在另一种磁性矿物的证据。这种矿物在2 K下占饱和磁化强度的70％，在此温度下获得相对较强但热不稳定的SIRM。在低直流偏置磁场和高直流偏置磁场中测得的磁化率与温度曲线的比较揭示了超顺磁行为的迹象，峰值表明有效阻断温度通过4.8 T DC磁场从<2 K变为约16K。同时，高磁化率曲线中出现峰值表明即使在我们可用的最高磁场中，相应的磁相也不会达到饱和。考虑到这些性质的一种可能的候选物是源自高温氘氧化的，具有8-10摩尔％的赤铁矿的堇青石。这与在扫描电子显微镜（SEM）图像中观察到的钛磁铁矿晶粒中析出层的普遍存在是一致的。
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