Challenge to field mapping of sedimentary environment by field measurements of environmental radiation spectrum

为了量化碎屑岩的物源分析，我使用Th和K的伽马射线强度作为连接碎屑岩和源岩的数据。在测量条件上，我发现在水深40厘米以上，测量时间为1000秒的沉积物中是实用的。为了阐明沉积物成分与物源地质的关系，将从物源地质计算的预期伽马射线强度与三条河流的河流沉积物进行了比较。因此，在所有三条河流中，K的伽马射线强度的测量值不太均匀。来自变质岩的样品中Th的测定值较低。钍主要存在于独居石和锆石中。由于花岗岩及其变质矿物的粒度分布不同，其沉积行为也不同。

In order to quantify the provenance analysis of clastics , I used the gamma-ray intensity on Th and K as data linking detritus and source rocks. On the measurement condition, I found that more than 40 cm depth, measurement time of 1000 seconds is practical in the sediment. In order to elucidate the relationship of sediment composition and geology of the provenance, the expected gamma-ray intensity calculated from the geology of the provenance was compared those of the river sediment in three rivers. As a result, the measured value was less uniformly in all three rivers on gamma-ray intensity on K. The measured value on Th was lower in samples originating from metamorphic rocks for Th. Th is included in the monazite and zircon. Because the grain size distribution of granite and metamorphic mineral of them are different, the behavior is different to sedimentology.