Rason Throssel combined ppm thorium grid geodetic

The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth�s surface as the result of the natural radioactive decay of potassium, uranium and thorium. The data are collected on airborne geophysical surveys conducted by Commonwealth, State & NT Governments and the private sector.放射测量法（Radiometric），又称伽马射线能谱法（Gamma-ray Spectrometric），可探测地球表面附近由钾、铀、钍天然放射性衰变产生的伽马射线自然变化。本数据集采集自澳大利亚联邦政府、各州政府及北领地（Northern Territory, NT）政府与私营部门开展的航空地球物理调查。