Environmental magnetic-study of irrigation ponds sediment

1. 建立了在不扰动湖面的情况下，从湖底至4 m左右深度为1 m的沉积物取样方法。磁致战术细菌的存在与否已被池塘澄清，它不依赖于沉积物。此外，磁致战术细菌分布在以深度约1 cm为中心的表层沉积物中，在3 cm的情况下，即使它们很深，也没有被5 cm或更小的地方观察到。提出了通过冷冻样品分离目前未固定的磁性矿物颗粒的贡献（可移动成分）和已固定的磁性矿物颗粒的贡献（固定成分）的方法。虽然在除霜和冻结过程中，当固定成分变为活动成分时，固定成分可能会大大减少，但由该过程推断出的固定成分可能增加的幅度一般为两者总和的10%或更少。即使在地表，可移动分量也只有30 - 600/0左右。在相对较多的岩心中，该值随着深度的增加而减小，直到深度达到10-20厘米。有两个岩心在20厘米或更深的深度中活动分量增加了2000或更多。通过这些岩心，可能产生碎屑剩磁采集时间的部分反演现象。在这些岩心中，初始磁化率的频率依赖性与可动分量之间存在一定的相关性。认为这是由于稳定的单畴小磁铁矿颗粒的速率发生了变化，沉积环境的改变导致了可动组分的变化。

1. The method of sampling sediment up to I m in depth from bottom of a lake to about 4 m, without disturbing the surface was established.2. The existence or nonexistence of magneto tactic bacteria has clarified by the pond, and it does not depend on sediment. Moreover, magneto tactic bacteria were distributed in the surface sediment centering on the depth of about I cm, and in many cases, 3 cm, even if they were deep, they were not observed by 5 cm or less.3. The method for separating contribution of the magnetic mineral particle currently not fixed (movable component) and contribution of the magnetic particle already fixed (fixed component) by freezing samples was developed. Although a fixed component may decrease greatly when a fixed component transformed into a movable component in 'the process of defrosting and a freeze, the possible increase in the fixed component deduced by the process is ten or less percent of both sum total in general.4. The movable component was only about 30 - 600/0 even at the surface. In comparatively many cores, the value was seen decrease as it became deep until it became in depth of 10-20 cm.5. There was two cores in which the movable component increases 2000 or more in the depth of 20 cm or deeper. By these cores, the partial inversion phenomenon of the acquisition time of detrital remanent magnetism may arise. A certain amount of correlation between a frequency dependence of initial susceptibility and the movable component was seen in these cores. It is thought that this is because the rate of small magnetite particle of stable single domain is changed and it has contributed to the change of a movable component by change of deposition environment.