Gawler Craton Airborne Survey Merge Radiometrics - Th equivalent concentration grid (AWAGS)

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 (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.This radiometric thorium grid has a cell size of 0.0004 degrees (approximately 41m) and shows thorium element concentration of the Gawler Craton Airborne Survey Magnetic Radiometric and DEM Merge, SA, 2017-2019 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2019 by the SA Government, and consisted of 1660000 line-kilometres of data at 200m line spacing and 60m terrain clearance. To constrain long wavelengths in the grid, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey grid.放射性测量法（radiometric method，又称伽马能谱法（gamma-ray spectrometric method）），可探测地表附近的伽马射线自然变化，此类变化源自钾（K）、铀（U）与钍（Th）的天然放射性衰变。采集所得数据将通过标准流程进行处理，以确保记录的响应信号仅源自地下岩石。经处理得到的数据集可通过解译揭示地下地质构造。经处理的数据将由GA地球物理学家开展质量核查，以确保GA发布的最终数据符合使用要求。本放射性钍网格的单元格尺寸为0.0004度（约合41米），展示的是2017-2019年南澳大利亚（South Australia, SA）高勒克拉通（Gawler Craton）航空磁测-放射性测量与数字高程模型（Digital Elevation Model, DEM）融合调查的钍元素浓度，单位为百万分之一（parts per million, ppm）。本网格的制作数据由南澳政府（SA Government）于2019年采集，涵盖166万测线公里的测量数据，测线间距为200米，飞行离地高度为60米。为约束网格中的长波长分量，本次调查使用了独立数据集——全澳航空地球物理调查（Australia-wide Airborne Geophysical Survey, AWAGS）的航空磁测数据，以校准测网的基准值。